Rozprawy doktorskie na temat „VFOA”

Ett av världens största miljöproblem är plastnedskräpning. På många platser kan spår av mänsklig närvaro ses i form av skräp av plast. År 2011 tillverkades det 280 miljoner ton plast, det motsvarar ungefär 28 000 Eiffeltorn. I Sverige förbrukades år 2010 ungefär 880 000 ton plast. I Asien produceras ungefär 50 % av all världens plast och Kina står för cirka hälften av detta. Nordamerika och Europa står för cirka 40 % av världens plastproduktion. Resterande produktion av plast är fördelat på Afrika och Sydamerika. Kommersiell plast är uppbyggd av små enheter kallade polymerer. Polymerer är i sin tur uppbyggda av ännu mindre enheter som kallas monomerer. Dessa monomerer är i dagsläget framställda av petroleum (råolja/mineralolja). Ungefär 4 % av världens oljekonsumtion går åt som råvara till att producera plast och lika mycket olja används som bränsle i tillverkningsprocessen. Begreppet bioplast är en hel familj av material som är biologiskt nedbrytbar, biobaserade eller bådadera. Det är dock inte en självklarhet att bioplaster besitter båda egenskaperna. PHA-plast är biobaserad och biologisk nedbrytbar, vilket är anledningen till att den står i fokus under detta examensarbete. För produktion av PHA-plast används en trestegsprocess, vilket innefattar ett fermenteringssteg, ett selektionssteg och ett ackumuleringssteg. Sist sker en extraktion för att frigöra PHA- plasten från det övriga organiska materialet. Syftet med det här examensarbetet är att med hjälp av framställning av bioplast främja miljön, vilket en anläggning som producerar bioplast skulle göra eftersom en del av den fossiloljebaserade plasten skulle kunna bytas ut mot bioplasten PHA. Större framställningsmöjligheter av bioplast i Värmland skulle medföra ett ökat intresse av en produktionsanläggning. Målet är att inventera olika industrier runt om i Värmland, i första hand matindustrier och skogsindustrier, och utreda deras processavloppsvattens potential att producera VFA. I detta examensarbete har fermenteringsförsök genomförts satsvis på processavloppsvatten från OLW, Barilla (Wasa), Skoghall, Gruvön och Rottneros. Försöken visar deras potential att producera VFA. Experimenten utfördes med ett konstant pH på 6 och varierande uppehållstid. Resultaten visade att OLW och Barilla har bäst potential till VFA-produktion med 4500 mg/l respektive 1610 mg/l. Spädning av OLWs och Barillas processavloppsvatten visade sig vara en gynnsam åtgärd, då VFA-produktionen ökade snabbare i jämförelse med de tester som utfördes vid icke-spädning. Dock erhölls inte lika stor totalmängd av VFA. Det är dock bättre att producera en större mängd VFA och på så vis låta processen ta längre tid. Vid fortsatta experiment rekommenderas att göra ytterligare försök på OLW och Barillas processavloppsvatten då de visade bäst potential till VFA-produktion.
One of the biggest environmental problems is the plastic littering. In many places traces of human presence is seen in the form of plastic littering. In the year 2011, 280 million tons of plastic was produced, which represents about 28 000 Eiffel Towers. In Sweden, about 880 000 tons of plastic a year is consumed, according to figures from 2010. Approximately 50 % of all the world's plastics are produced In Asia and China accounts for about half of it. North America and Europe account for about 40% of the world's plastic production. The remaining production is distributed between Africa and South America. Commercial plastic is made from small units called polymers. A polymer consists of smaller units called monomers. In present, these monomers are produced out of petroleum (crude oil/ mineral oil). Approximately 4% of the world’s oil consumption is spent as raw material to produce plastic and the same amount of oil is used as fuel in the plastic production process. The term bio-plastic is used for a family of materials which are biodegradable, bio- based or both. However, it is not given that bioplastics do possess both properties. PHA plastics are both bio based and biodegradable, which is why it is the focus for this thesis. Production of PHA plastic is a three-step process comprising a fermentation step, a selection step, and an accumulation stage. Finally, there is an extraction to release the PHA plastic from the organic material. The aim of this thesis is to aid the production of bioplastics in order to lessen the environmental load of plastics. The more bioplastic that can be produced, the greater the interest of a bioplastic-producing plant in Värmland. The goal is to make an inventory of industries around Värmland, primarily food industries and forest industries, and to quantify the potential of their process wastewaters to produce VFA. In this thesis, fermentation experiments conducted batch-wise was performed with process wastewater from OLW, Barilla (Wasa), Skoghall, Gruvön and Rottneros. The experiments showed the wastewaters potential to produce VFA. The experiments were performed with a constant pH of 6 and with varying residence time. The results showed that OLW and Barilla has the highest potential for VFA production with 4500 mg/l and 1610 mg/l, respectively. Dilution of OLWs and Barillas process water turned out to be favorable, as the VFA production increased rapidly in comparison with those tests that were conducted under non-dilution. The total production of VFA, however, was not as high. In further experiments, it is recommended to make another attempt at the OLWs and Barillas process wastewater since they showed the best potential for VFA production.

Syfte: Att undersöka förekomst av hyperopi i förhållande till läskunnighet hos hjälpsökande hos VFA i Bolivia, samt jämföra med studier från andra delar av världen.

Metod: Studien utfördes i april 2010 på tre olika orter i centrala Bolivia. Patienterna sökte själva upp platsen för att få en undersökning. Subjektiv refraktion utfördes binokulärt, utan dimning, med hjälp av provbåge, provlåda och syntavla med Snellen E, uppsatt på 5 meters avstånd. Hyperopi räknades som sfärisk ekvivalent ≥ +1,00 D, myopi som ≤ –0,25 DS.

Resultat: 1 313 personer undersöktes, varav 1 271, mellan 6 och 92 år gamla, ingick i studien. Förekomsten av hyperopi var totalt 23,8% (som mest 39,8% hos kvinnor 66-92 år gamla, och som minst 10,7% hos kvinnor 6-19 år gamla), läskunnighet totalt var 81,7% (kvinnor 74,7%, män 90,7%). Det var något lägre läskunnighet bland hyperoper (78,1%) än bland myoper (83,2%) och emmetroper (82,7%).

Slutsats: Bolivia verkar ha större förekomst av hyperopi än Asien och Europa. Hyperopi ökar med åldern, främst efter 50-årsåldern. Miljöfaktorn ser ut att ha viss betydelse.

Optimization of the dark fermentation process for the recovery of volatile fatty acids (VFA). The work is divided into pilot-scale fermentation tests on mixtures of sewage sludge and food residues, investigating different process parameters that influence fermentation yields. A machine learning approach will be used for data management and the development of a model that will be able to correlate the process performance (s) on the basis of different inputs (operational parameters).

The purpose of this research was to investigate the relationship between the oxidation-reduction potential (ORP) measurement and volatile fatty acid (VFA) production in the acid-phase anaerobic digestion process under different conditions of temperature and residence time. Two identical anaerobic digesters were operated while VFAs, SCOD, VSS, alkalinity, ORP and pH were measured. In digester 1, VFA production of 5,556 mg/L was generated with an ORP of -315 mv at a 10 day SRT; while 5,400 mg/L of VFA with an ORP of -389 mv was recorded in digester 2. The SRT was adjusted at 5, 8, 10, 12 and 15 days and the optimum SRT was 10 days in both digesters. The results of this study indicate there were no tight relationship between VFA production and ORP values, thus ORP by itself is not a good predictor of the amount of VFAs generated. However, ORP combined with temperature had good linear relationship with VFA production. An ORP range of -315 to -390 mv was desirable for maximizing VFA production in both anaerobic digesters. Different temperatures (14, 29 and 37 ℃) were trialed and the results indicate that the conditions at 29 ℃ and 37 ℃ were not significantly different in terms of VFA production, however, less VFAs were generated at the lowest temperature of 14 ℃.

Bakgrund: Små-medelstora-företag (SME) har en viktig roll i dagens samhälle. SMEs står idag för en stor del av arbetsgivarsegmentet samt för en stor del av den ekonomiska utveckling som sker i Europa. Inom tillverkningsindustrin är en av utmaningarna att säkerställa robusta processer med hög kvalitet. För SMEs innebär det kontinuerlig uppföljning av de interna samt externa processerna för att hela tiden försäkra sig om att verksamheten följer uppsatta ramar, vilket generellt kan vara svårt eftersom tillgängliga resurser är begränsade. Andra utmaningar som tillverkande företag står inför är långa ledtider, högt antal produkter i arbete (PIA), lagerbildningar mellan processer och kassationer. En av de viktigaste egenskaperna för tillverkande SMEs konkurranskraftighet är företagets förmåga att leverera i tid.   Syfte: Syftet är att undersöka leveranssäkerheten i ett SME inom tillverkningsindustrin, med tillhörande frågeställning: Hur kan Lean-verktyg appliceras för att minimera PIA och ledtider samt bibehålla hög leveranssäkerhet?   Ansats: För att undersöka leveranssäkerheten i ett SME inom tillverkningsindustrin valdes ett företag med flera produktionsanläggningar och globala kunder med höga krav att leverera i tid till kunden. Värdeflödesanalys (VFA) tillämpades för att utforska hur produktionssystemet i företaget presterade, ge insikt till hur företaget arbetar med leveranssäkerhet och om leveranssäkerheten kan ökas genom implementering av identifierade förbättringsmöjligheter. Semistrukturerade intervjuer utfördes för att samla data om hur fallföretaget och dess personal arbetar och säkerhetsställer att produkter levereras i tid. För produktions- och leveransrelaterad data utfördes observationer på en av fallföretagets produktionsanläggningar för en högvolymprodukt. Insamlad data från observationer, dokumentation och intervjuer bearbetades med Lean-verktyg och metoder och jämfördes sedan mot den teoretiska referensramen genom mönsterpassning som analysmetod för att uppnå studiens syfte och ge svar på studiens frågeställning.   Resultat: Genom att analysera fallföretagets produktionssystem har faktorer som kan påverka leveranssäkerheten undersökts med hjälp av VFA och förbättringsområden identifierats. Ett teoretiskt förslag har tagits fram där en balansering av befintligt produktionssystem utförts. I förslaget har både ledtider och PIA reducerats. Genom implementering av det teoretiska förslaget kan fallföretaget uppnå en reducering av PIA och ledtider samt bibehålla sin höga leveranssäkerhet. Vidare skapar det teoretiska förslaget möjligheter för fallföretaget att ha en flexiblare produktion eftersom överskottskapacitet finns i produktionssystemet för produktion av andra produkter.   Originalitet/värde: Studien ger insikt i hur ett SME företag i tillverkningsindustrin arbetar med leveranssäkerhet och hur högre leveranssäkerhet kan erhållas genom applicering av Lean-verktyg.

pH control is a tool to improve some aspects of Enhanced Biological Phosphorus Removal (EBPR) process. Filipe et al (2001a, 2001b, and 2001c) found strong evidence that the stability of EBPR systems can be improved by increasing the pH of the anaerobic zone, thereby creating conditions where phosphorus-accumulating organisms (PAOs) are able to take up acetate faster than glycogen-accumulating organisms (GAOs). They explained this observation by comparing the growth rate of phosphorus-accumulating organisms (PAOs) and glycogen-accumulating organisms (GAOs) and found that pH has little effect on PAOs growth rate but adversely affects GAOs growth rate when it increases (at pH values greater than 7.25, PAOs would take acetate faster than GAOs would). They used synthetic wastewater rich in acetic acid. In this study, we used real wastewater and the dominant volatile fatty acid available to microorganisms was propionic acid in continuous EBPR system. It was found that lower anaerobic zone pH (6.5 vs. 7.2) reduced the anaerobic P release both on an MLVSS specific basis and also on a non-specific (absolute value for the process) basis. In addition, the observed yield was significantly decreased. Aerobic P uptake was lower in the low-pH system (on a non-specific basis) due to the lower observed yield, and thus lower MLVSS concentration. Net P uptake was hard to interpret because of the effect of P release in the secondary clarifier of Train 2 (high pH). However, on a specific basis it was clear that net P uptake was either equal or better in the low-pH system regardless of how the secondary clarifier data was interpreted. Carbon transformations were not impacted in as consistent a fashion as anaerobic P release was. On a specific basis, PHA content remained unchanged although the PHV/PHB ratio was impacted with much lower PHV content in the low-pH system. Glycogen content and the amount of labile glycogen (delta glycogen) were higher in the low-pH system, in spite of the fact that MLVSS P content did not decrease. However, due to the impact of the low observed yield at low pH, absolute values resulted in higher PHA content for the process reactors as a whole, higher glycogen content, and unchanged labile glycogen. Low pH resulted in increased biomass P content, however the lower observed yield offset this on a process basis so that effluent P levels were nearly equal. So low pH improved P removal on a specific basis, but not on a process basis. Since it is unknown if the low observed yield is repeatable, and due to the impact of the secondary clarifier in the high pH system, it cannot be concluded that the effect of low pH on net P removal would be similar in other EBPR systems.
M.S.Env.E.
Department of Civil and Environmental Engineering
Engineering and Computer Science
Environmental Engineering

EMBA Project Report
EXECUTIVE SUMMARY: Strike Fighter Squadron ONE ZERO SIX (VFA-106), the only East Coast F/A-18 Fleet Replacement Squadron (FRS), has identified problems in Cubic Instructor (CI) capacity during periods of high demand as a result of combining series of aircraft, C/D and E/F, into larger “Super” classes. Subsequently, the squadron is forced to augment CIs with Instructor Pilots (IPs) or Instructor Weapons System Officers (IWSOs) to increase capacity or forego utilization of some of their 70 simulator hours allotted to them daily. A simulator process improvement study was undertaken to help VFA-106 address these issues, ultimately improving production and time-to-train. FINDINGS • The current CI contract is inefficient due to its inflexibility • Simply increasing CI manning is not a long-term solution • The current VFA-106 simulator scheduling construct is insufficient and lacks long-term vision RECOMMENDATIONS • Draft and utilize a more flexible CI contract • Institute simulator scheduling process improvements to provide more continuity and a long-term vision

Att rena vatten är kostsamt, från både en ekonomisk och miljömässig synpunkt, då behovet av fällningskemikalier, kolkällor och energi är stort. Det är därför önskvärt att titta på alternativa lösningar som möjliggör reningsverk att bli mer självförsörjande och kretsloppsanpassande. Hammarby Sjöstadverket är en pilotanläggning för avloppsvattenrening belägen i Stockholms sydöstra stadsdel i Henriksdal och ägs av IVL, Svenska Miljöinstitutet samt KTH. Sedan pilotanläggning byggdes år 2002, har flera olika reningstekniker utvärderats där fokus ligger på att sträva efter miljövänliga och kretsloppsanpassade system. Bland annat har en förfällningsteknik, så kallad trepunktsfällning utvärderats. Trepunktsfällningen innebär att ett metallsalt följt av två olika polymer tillsätts i flockningskammaren i inbördes ordning för att på så sätt kunna reducera en högre halt av det organiska materialet. Tidigare fällningsförsök på Hammarby Sjöstadsverket, har visat på att trepunktsfällningen kan avskilja det organiska materialet med upp till 90 %, vilket kan jämföras med en avskiljning på endast 75 % med vanlig förfällning. Detta examensarbete syftar till att validera redan framtagna resultat inom trepunktsfällning samt att genom biologisk hydrolys av primärslam, utvinna en kolkälla till efterdenitrifikationen innehållande så höga halter flyktiga fettsyror, Volatile Fatty Acids, (VFA) som möjligt samt undersöka kostnaderna för ett avloppsreningsverk med trepunktsfällning, biogasutvinning och uttag av intern kolkälla från primärslammet vid en uppskalning motsvarande 100 000 personekvivalenter. Fällningsförsöken utfördes i pilotskala med fällningskemikalien PAX XL-36 kombinerat med en lågmolekylär organisk polymer, Purfix-120, följt av en högmolekylär oorganisk polymer Superflock C-494. Syftet med trepunktsfällningen var att validera redan framtagna resultat inom trepunktsfällning och på så sätt avskilja så stora mänger organiskt material som möjligt i förfällningen så att ett primärslam innehållande en hög halt Chemical Oxygen Demand (COD) erhålls. Två olika doseringar med PAX XL-36 testades, 145 respektive 193,5 g/m3. Bäst reduktion av COD och fosfor erhölls då 193 g/m3 PAX XL-36 kombinerades med 60 g/m3 Purfix-120 samt 0,025 g/m3 Superflock C-494. Då erhölls en COD-reduktion på 75 % samt en totalfosforreduktion på 83 %. Genom hydrolys av primärslam i laboratorieskala undersöktes torrsubstanshalter (TS-halter) på 1, 2 respektive 3 % och uppehållstider på upptill åtta dagar. Syftet med hydrolysen var i detta fall att undersöka vilken torrsubstanshalt samt vilken uppehållstid som gav högst produktion av VFA. Försöken visade att en TS-halt på 3 % producerade högst andel VFA och att produktionen av VFA för samtliga TS-halter var som störst under dygn två. VFA- och COD-produktionen ökade linjärt för samtliga TS-halter fram till och med dygn fem. Efter dygn fem började produktionen av VFA och COD för TS-halterna 1 och 2 % avta något. TS 3 % visade dock inte samma avtagande trend för VFA.  Även den dagliga ammoniumhalten och pH undersöktes. Ammoniumhalten ökade i takt med att VFA-halten ökade. pH hade generellt sett en avtagande trend. Fyra olika denitrifikationsförsök genomfördes i laboratorieskala med det uttagna hydrolysatet där den tillsatta COD-halten antingen var 3,3 eller 4 gånger den initiala nitratkvävekoncentrationen. Syftet med denitrifikationsförsöken var att utvärdera det framtagna hydrolysatets funktion som en kolkälla. Denitrifikationsförsöken uppvisade denitrifikationshastigheter mellan 4,3 och 7 mg NO3-N/g volatile suspended solids*h med kol-kvävekvoter (C/N-kvoter) mellan 3,9 och 12,3 mg COD/mg NO3-N. Lägst C/N-kvot erhöll lägst denitrifikationshastighet. Dock kunde inte slutsatsen dras att högst C/N-kvot gav högst denitrifikatioshastighet. Även de ekonomiska aspekterna undersöktes i syfte att utreda kostnaderna för ett avloppsreningsverk med trepunktsfällning, biogasutvinning och uttag av intern kolkälla från primärslammet vid en uppskalning motsvarande 100 000 personekvivalenter. Uttaget av en intern kolkälla skulle trots förlust i biogasutvinning vara ekonomiskt gynnsamt. Vinsten, i form av att ej behöva inhandla en extern kolkälla, i detta fall etanol, motsvarar biogasförlustens belopp. Trepunktsfällningens fällningskemikaliekostnader var den största posten och uppgick till 8 060 000 kr. Denna kostnad kontra mindre energiförbrukning i biosteget undersöktes också. Här uppgick besparingarna i biosteget till ca 1/8 av fällningskemikaliekostnaderna. Då trepunktsfällningen endast kunde ge en 75-procentig COD-reduktion, vilket motsvarar en vanlig förfällning, anses trepunktsfällningen vara ekonomisk ogynnsam då den medför extra kostnader av polymerer.  Istället borde trepunktsfällningen ersättas med en förfällning. Sammanfattningsvis kan det konstateras att en intern kolkälla i form av hydrolyserat primärslam skulle kunna ersätta en extern kolkälla rent funktionsmässigt. Dock måste åtgärder göras för att minimera produktionen av ammonium under slamhydrolysen. Ur ett ekonomiskt perspektiv skulle utvinningen av en intern kolkälla endast vara ekonomisk gynnsam då trepunktsfällningen ersätts med förfällning.
Water treatment is costly, from both an economic and environmental point of view, since the need for precipitation chemicals, carbon sources and energy is high. It is therefore desirable to look for alternative solutions that enable plants to be more self-sustaining. Hammarby Sjöstadsverket is a pilot plant for wastewater treatment located in Henriksdal, a southeastern neighborhood of Stockholm. The plant is owned by IVL, Svenska Miljöinstitutet and Kungliga Tekniska Högskolan (KTH). Since the pilot plant was built in 2002, several different cleaning techniques have been evaluated with focus on striving for eco-friendly and eco-adapted systems. For instance, a pre-precipitation technique, so-called three step precipitation have been evaluated. The three step precipitation implicates that a metal salt followed by two different polymers are added in the flocculation chamber in the particular order to thereby enable to reduce a higher content of the organic material. In previous precipitation tests at Hammarby Sjöstadsverket, one managed to remove up to 90 % of the organic material using the three step precipitation (IVL, Hammarby Sjöstadsverket, 2011). This can be compared to a removal of only 75 % with ordinary pre-precipitation. This thesis aims to validate already obtained results within three step precipitation and with biological hydrolysis of primary sludge, extract a carbon source for post-denitrification containing as high concentrations of Volatile Fatty Acids (VFA) as possible and to investigate the cost of a wastewater treatment plant with three step precipitation, biogas generation and collection of internal carbon source from primary sludge at an upscaling corresponding to 100,000 person equivalents. Precipitation experiments were carried out in pilot scale with the precipitation chemicals, PAX-XL 36, combined with a low molecular weight organic polymer, Purfix-120, followed by a high molecular weight inorganic polymer, Super Flock C-494. The purpose of the three step precipitation was to validate the already produced results within three step precipitation and thus separate as large amounts of organic material as possible in the precipitation so that a primary sludge containing a high chemical oxygen demand (COD) can be obtained.Two different dosages of Purfix-120 were tested: 45 and 60 g/m3. The best reduction of COD and phosphorus were obtained when 193 g/m3 PAX XL-36 was combined with 60 g/m3 Purfix-120 and 0.025 g/m3 Super Flock C-494. Hereby a COD reduction of 75 % and a total phosphorus removal of 83 % were obtained. By hydrolysis of primary sludge in batch experiments Total Solid (TS) concentrations of 1, 2 and 3 % and residence times of up to eight days were examined. The purpose of the hydrolysis in this case was to investigate which TS concentration and residence time that gave the highest production of VFA. The experiments showed that a TS concentration of 3 % produced the highest amount of VFA and that the VFA production of the three different TS concentrations peaked at the second day. The VFA and COD production increased linearly for the three TS concentrations up until day five. After day five the COD and VFA production, for the TS concentrations of 1 and 2 %, started to decrease slightly. However TS 3 % did not show the same declining trend for VFA. Furthermore the daily ammonium and pH were investigated.  As the VFA and COD concentration increased the ammonium concentration increased as well. pH had overall a  decreasing trend. Four different denitrification tests were performed in batch experiments with the extracted hydrolyzate. The added COD content from the hydolyzate was either 3.3 or 4 times the initial nitrate concentration. The denitrification tests showed denitrification rates between 4.3 and 7 mg NO3-N / g volatile suspended solids * h with carbon-nitrogen ratios (C/N ratio) between 3.9 and 12.3 mg COD/mg NO3-N. The lowest C/N ratio received the lowest denitrification rate. However, it could not be concluded that the maximum C/N ratio had the highest denitrification rate. Futhermore the financial aspects were examined in order to investigate the cost of a wastewater treatment plant with three step precipitation, biogas generation and collection of internal carbon source from primary sludge at an upscaling corresponding to 100,000 person equivalents. The extraction of an internal carbon source would, despite loss of biogas production, be economically beneficial. Gain, in terms of not having to purchase an external carbon source, in this case ethanol, amounts to the amount of the biogas loss. The three step precipitation chemical costs were the largest item, amounting to 8,060,000 SEK. This cost versus less energy utilization in the biological step was also examined. In this case the savings in the biological step amounted to about 1/8 of precipitation chemical cost. Since the three step precipitation only managed to remove 75 % of the COD, a removal which corresponds to an ordinary pre-precipitation, the three step precipitation is considered to be economically unfavorable as it involves additional costs of polymers. Instead the three step precipitation should be replaced with a pre-precipitation. In summary it can be stated that an internal carbon source in the form of hydrolyzed primary sludge could replace an external carbon source in a functional way. However, steps must be taken to minimize the production of ammonium during sludge hydrolysis. From an economic perspective, the extraction of an internal carbon source would only be economical favorable if the three step precipitation is replaced with pre-precipitation.

I Sverige förekommer strikta krav på fosforrening av avloppsvatten och detta har bidragit till att kemisk fällning har kommit att dominera som reningsmetod för fosfor vid svenska avloppsreningsverk. Fällningskemikalier är dyrt för reningsverken att köpa in och ger negativ påverkan på miljön vid tillverkning och transport. Strängare reningskrav har ökat behovet av nya reningsmetoder som på ett effektivt och miljövänligt sätt kan rena avloppsvatten från näringsämnen utan att kostnaderna för reningen blir för stora. Biologisk fosforavskiljning (bio-P) utnyttjar mikroorganismer som naturligt kan ackumulera fosfor i sina celler. En kritisk faktor för en väl fungerande biologisk fosforavskiljning är tillgången till kolkälla i form av flyktiga fettsyror (VFA). Kommunalt avloppsvatten innehåller vanligen för lite VFA för att tillgodose bio-P-processens behov. Den totala tillgången på organiskt material i avloppsvattnet är dock ofta stor och möjligheten finns därmed att genom biologisk slamhydrolys internt producera VFA. Vid biologisk hydrolys av slam utnyttjas mikroorganismers naturliga förmåga att under anaeroba förhållanden bryta ned organiskt material till mer lättomsättliga föreningar. Duvbackens avloppsreningsverk i Gävle tillämpar biologisk fosforavskiljning och producerar VFA till bio-P-processen genom primärslamshydrolys och sidoströmshydrolys av returslam. I detta examensarbete har hydrolysprocesserna vid reningsverket utvärderats med avseende på processernas förmåga att producera VFA till det biologiska reningssteget. Utvärderingen gjordes genom att mäta förändringen i halten organiskt material över hydrolysbassängerna samt genom att bedöma effektiviteten i bio-P-processen i fullskala och vid labskaleförsök. Möjligheten att stänga av primärslamshydrolysen vid verket undersöktes. Ett försök till att optimera driften av sidoströmshydrolysen gjordes genom att utföra hydrolysförsök i laboratorieskala. Resultaten indikerade att produktionen av VFA i primärslamshydrolysen var begränsad och att processen därmed bör kunna stängas av. Innan detta görs bör dock kompletterande mätningar av halten löst COD över primärslamshydrolysen utföras. Vid samtliga mättillfällen uppmättes en betydande ökning i halten organiskt material över sidoströmshydrolysen. Baserat på detta och den i examensarbetet konstaterade effektiviteten i bio-P-processen drogs slutsatsen att sidoströmshydrolysprocessen vid Duvbackens reningsverk var välfungerande. Hydrolysförsöken pekade på att ett större utbyte av VFA skulle erhållas om en kortare uppehållstid än den nuvarande användes i sidoströmshydrolysen. Detta bör vidare undersökas genom fullskaleförsök vid verket.
The strong regulations concerning phosphorus removal from wastewater in Sweden has resulted in chemical precipitation being the most common treatment method for phosphorus at Swedish wastewater treatment plants (WWTP). Precipitation chemicals are expensive and have a negative environmental impact when produced and transported. More stringent wastewater treatment requirements have increased the need of new, eco-friendly treatment methods that effectively can remove nutrients from wastewater without being too expensive. Enhanced biological phosphorus removal (EBPR) utilizes microorganisms that have the natural capability of accumulating phosphorus in their cells. A critical factor for a well-functioning EBPR-process is the availability of carbon source in form of volatile fatty acids (VFA). Municipal wastewater normally contains too small amounts of VFA to satisfy the need of the EBPR-process. The total amount of organic matter in the wastewater is on the other hand large and the possibility consequently exists to internally produce VFA through sludge hydrolysis. Biological sludge hydrolysis takes advantage of the natural capability of microorganisms to degrade complex organic compounds into easily degradable organics. Duvbacken WWTP in Gävle uses EBRP for phosphorus removal and produces carbon source through hydrolysis of primary sludge and sidestream hydrolysis of return sludge. In this master thesis the hydrolysis processes at the WWTP was evaluated with regard to the capacity of the processes to produce VFA to the biological treatment step. The evaluation was performed by measuring the change in organic material content over the hydrolysis basins and by estimating the effectiveness of the EBPR-process in full scale and by laboratory experiments. The possibility to turn off the primary sludge hydrolysis process was examined. An attempt to optimize the operation of the sidestream hydrolysis process was made by conducting hydrolysis experiments in laboratory scale. The results indicated that the production of VFA by primary sludge hydrolysis was limited and that it thus would be possible to turn off the process. Before this is done complementary measurements of COD levels over the primary hydrolysis basin should be performed. At all times considerable increments in COD content was measured over the sidestream hydrolysis basin. Based on this and the in the thesis confirmed effectiveness of the EBRP-process the conclusion was drawn that the sidestream hydrolysis of return sludge at Duvbacken WWTP was well functioning. The hydrolysis experiments indicated that a larger VFA yield would be obtained if a shorter retention time than the present was used in the sidestream hydrolysis process. This should further be investigated by experiments in full scale at the WWTP.

Since the beginning of the 20th century plastic has been a widely used material, which has resulted in large quantities of plastic being produced in the last century. The plastics of today are mainly produced from fossil raw materials, which gives it a high climate impact. Plastic also has a long service life, which creates problems with handling after the new period when new plastic is produced at a faster rate than plastic debris can be recycled or incinerated. One possible approach is to switch from plastic from fossil sources to bioplastics, which is produced by renewable sources. This means a reduction in the environmental impact as the amount of fossil CO2 emissions from combustion of plastics would decrease. Polyhydroxyalkanoates (PHAs) are created by short volatile fatty acids (VFAs) added to bio sludge from a wastewater treatment plant at a pulp and paper mill where there is a lot of bacteria and microorganisms. Some of the bacteria in the sludge have the ability to accumulate PHA when VFA is added in excess and then be able to use it as an energy and carbon source in cases of starvation. This means that PHA produced in this way can be degraded by bacteria making it biodegradable while having similar properties as oil-based plastics. Production of PHA is currently expensive as it is often necessary to purchase VFA for production. To make it economically sustainable to replace oil-based plastics with PHA, the cost of PHA production must therefore be reduced. This can be done by using mixed bacterial cultures from, for example, industrial wastewater treatment plants and by creating their own composition of VFA through fermentation. At the paper mill at BillerudKorsnäs Gruvön there are several process streams that today are led to the water treatment plant, one of which is from PM6 (Paper Machine 6). By fermenting that stream, VFA can be formed with a composition of acetic acid, propionic acid, and butyric acid. The current may thus be suitable to use as a substrate in PHA production. Another way to produce VFA is to ferment the residual flow from hydrothermal carbonation (HTC) of bio sludge. According to (Samorì et al., 2019), acetic acid, butyric acid and valeric acid are formed, which means that even this stream may be suitable as a substrate for PHA production. The purpose of this thesis is to investigate the effects of the composition of VFA on the production of PHA from forest industrial bio sludge. The study covers two different cases, Case PM6 and Case HTC, where two different types of composition of VFA are added to paper sludge from the paper mill. The experiments were performed in cylindrical tanks on three occasions where the first two experiments had a volume of 30 liters and the last experiment a volume of 10 liters. On the first occasion, the maximum accumulation rate in the growth phase was studied. In the second instance, a high accumulation rate was sought, but also survival after the growth phase. The first two trials were batch trials where the sludge was dosed until saturation was achieved. On the third occasion, the possibility of carrying out PHA production with a continuous sludge exchange was studied. The experiments were analyzed by FTIR which provided information on the absorbance of the sludge which shows how the PHA concentration increased during the course of the experiments. Extractions were then performed to obtain the concentration of PHA that eventually accumulated in the sludge. The results show that biomass from BillerudKorsnäs Gruvön's mills accumulated PHA faster with VFA composition from fermented PM6 effluent compared to VFA composition from fermented HTC condensate. Calculations made with input from the experiments indicate that it is possible to produce a larger amount of PHA per year with Case PM6. The conclusion is therefore that Case PM6 is preferable if as large a PHA production as possible wants to be achieved. Case HTC is instead preferred if reduced PHA production can be tolerated in favor of biocarbon production.

Företaget Boliden är världens främsta producent av zink och ledande i Europa medproduktion av koppar och nickel.För att nå malmen under jord drivs ramper och orter genom borrning, sprängningoch bergförstärkning. Dessa arbetsmoment kräver att stora mängder vatten tillförs,bland annat för att binda dammet som uppstår vid arbetsmomenten och även för attkyla maskinerna. Vattnet som är i omlopp i gruvan hanteras av länspumpar, sompumpar vattnet runt i gruvan eller upp till reningsverk.Bolidens gruva i Renström har länge haft problem med pumparna under jord, bådegällande den låga tillgängligheten och höga reparationskostnader. Syftet med dennarapport är att analysera och utvärdera möjligheterna att minska de kostnader somfinns kopplat till trasiga pumpar. Det slutgiltiga målet är att utvärdera och gekonkreta rekommendationer på hur Boliden Renström kan hantera de trasigapumparna i framtiden. De avgränsningar som fastställts är att enbart ganskaprocessflödet från när trasiga pumpar anländer till nivå 1125 tills de är tillbakareparerade på nivå 1125. Vissa ekonomiska faktorer som är svårbedömda kommeratt baseras på grova beräkningar och antaganden.Med hjälp av observationer och intervjuer ritades ett värdeflöde över nuläget.Värdeflödesanalysen och Lean’s teorier om slöseri jämfördes för att hitta onödigamoment i nuläget. Förbättringsåtgärder togs fram för att eliminera det slöseri somfanns. Dessa förbättringsåtgärder är; Minska antalet pumpar i flödet Ställa högre reparationsvillkor på den interna reparatören Hantera pumpar styckevis istället för stora partistorlekar Ändra beställningsrutinerna i Maximo Vidare analyserades tre olika framtida tillstånd för pumpreparationerna; reparerabåde internt och externt, endast reparera internt eller endast reparera externt. Dessatre framtida tillstånd analyserades med SWOT-analyser för att se dess fördelar och nackdelar.Rekommendationen som lämnas är att reparera alla pumpar internt, då det är detbilligaste alternativet samt har kortare ledtid än nuläget. Enligt SWOT-analysenframkom några svagheter och hot, dessa bör Boliden Renström se över innan någrabeslut tas. En avslutande rekommendation är att se över om det finns möjlighet attendast jobba med en serie av pumparna och dess modeller, anpassat efterverksamhetens behov.De framtida studier som lämnas till företaget är att se över om det är möjligt attordna en gemensam verkstad för Bolidenområdets pumpar. Vidare skulle det ävenvara intressant att se vad resultatet blir om pumpstyrning och fasföljdstyrninginstalleras i pumparna.

The use of environmentally friendly products increased the interest in renewable resources as alternatives to petrochemical products. Polyhydroxyalkanoates (PHAs) are examples of such promising products, as they are biodegradable polymers with numerous potential applications. PHA production approach consists of using an open mixed microbial culture (MMC) and inexpensive feedstocks (waste or industry byproducts feedstock). The PHA process generally comprises three stages: (1) acidogenic fermentation (AF) stage (conversion of organic carbon into fermentation products); (2) culture selection stage (enrichment in PHA-storing organisms by applying Feast and Famine regime); and (3) PHA production stage (PHA accumulation up to the culture’s maximum capacity). AF of protein-rich residues results in ammonia-rich fermented streams, which can be presented as a challenge for the PHA production stage. The presence of ammonia during this stage may induce organisms to grow instead of producing PHAs. For this reason, the assessment of the effect of a high content of ammonia on PHA production it is the utmost importance. The main goal of the current project is to select a MMC enriched in PHA-accumulating organisms in conditions of high ammonia content and to evaluate the effects of ammonia presence during PHA accumulation. The culture was selected applying the Feast & Famine strategy, and fed, firstly, using a synthetic mixture of VFAs and later using a fermented stream obtained from the fermentation of protein-rich raw materials. The selected culture could accumulate up to 24% PHA per VSS with the synthetic mixture of VFAs and up to 29% for the real fermented stream. The PHA accumulation resulted in different production in the presence and absence of ammonia. Regarding to the synthetic feed, 59%wt. PHA (VSS basis) in the absence of ammonia, and 55%wt. (VSS basis) in the presence, were obtained. For the real feed, the PHA content was about 40%wt. (VSS basis) in both reactors.

Small ruminant species are utilized for their diverse products including meat, dairy products, and wool. Effective and humane management are essential to maintain high production rates and comfortable animals. To attain this objective, managers needs to have an extensive knowledge of husbandry techniques, understanding of physiological processes, and familiarity with nutritional requirements. We examined the effects of varying feed components on two different ruminal species. In Chapter 1, we conducted a study to evaluate"¯the effects"¯of a low metabolizable energy (LME) and high metabolizable energy (HME) diet on twenty-two Friesian/Lacuane"¯cross ewes and lamb nutritional status."¯Effects on milk production during early lactation stages"¯and the growth of the neonatal lambs were also investigated. We anticipate energy levels will have an effect on milk production and lamb growth. Our results indicate that ewes on the LME diet produced more milk with higher concentrations of fat though this group maintained lower body condition. We concluded that neither the HME nor the LME diet met the needs of the sheep due to the shift in nutrient partitioning towards milk production rather than allocating nutrients to maintaining both body condition and milk production. Limited energy requirements are further evidenced by the decline in back fat (BF) for both the HME and LME groups for the duration of the study. We determined the degradation parameters of grass hay supplemented with soybean meal (SBM) and the effects of SBM on compartment 1 (C1) ammonia and volatile fatty acid (VFA) concentrations in alpacas. Our findings show that the degradation rate was not different for dry matter (DM), but it was for crude protein (CP) (P<0.05). With this data it can be concluded that SBM can be a CP supplement when the diet is insufficient to improve microbial yield. It should be noted that care should be taken to avoid causing a protein-energy imbalance. The results of these two studies indicate shifts in nutrients availability and changes in feeding strategies can affect both the health of the animal and their subsequent offspring.

Ergot alkaloids present in endophyte-infected (E+) tall fescue are thought to be the causative agent of fescue toxicosis, a syndrome affecting cattle in the eastern United States. Many of the observed signs of fescue toxicosis are thought to be attributed to peripheral vasoconstriction; however, there are data indicating that ergot alkaloids can alter blood flow to the gut. An experiment was conducted using right ruminal artery and vein collected from heifers shortly after slaughter. Vessels were mounted in a multi-myograph to determine the vasoconstrictive potentials of ergot alkaloids present in E+ tall fescue. Results indicated ergot alkaloids have the potential to induce vasoconstriction of foregut vasculature. A second experiment was conducted to determine if the additional ergot alkaloids present in E+ tall fescue increase the vasoconstrictive response above that of ergovaline. Results indicated that ergovaline is the main alkaloid responsible for vasoconstriction in bovine vessels. A third study was performed to determine the effect of ergot alkaloids on ruminal epithelial blood flow in the washed rumen of steers exposed to E+ or endophyte-free (E-) tall fescue seed. Steers were dosed with seed followed by a washed rumen experiment with differing levels of ergovaline incubated in the rumen. Results indicated that E+ tall fescue seed treatment reduced ruminal epithelial blood flow. Additionally, incubating ergovaline in the rumen during the washed rumen further decreased epithelial blood flow and volatile fatty acid (VFA) absorption. A final study was conducted to determine the acute effects of ergot alkaloids on isolated rumen epithelial absorptive and barrier functions and the potential for ruminal ergovaline absorption. Results indicate that acute exposure to ergot alkaloids does not alter the absorptive or barrier function of rumen epithelium and ergovaline is absorbed from the rumen. Data from this series of experiments have shown that ergot alkaloids from E+ tall fescue can induce vasoconstriction of blood vessels in the foregut of cattle, reduce blood flow to the rumen epithelium, and decrease VFA absorption. The decrease in nutrient absorption could contribute to the observed symptoms of fescue toxicosis, including depressed growth rates and general unthriftiness.

Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2017-06-09T18:09:43Z No. of bitstreams: 1 2008 - Stela Gomes Pelegrino.pdf: 247744 bytes, checksum: edcaaef4e983d4522513a9fcb967acdc (MD5)
Made available in DSpace on 2017-06-09T18:09:43Z (GMT). No. of bitstreams: 1 2008 - Stela Gomes Pelegrino.pdf: 247744 bytes, checksum: edcaaef4e983d4522513a9fcb967acdc (MD5) Previous issue date: 2008-04-29
The search of better quality of the milk induces that changes and advances should be reached trought manipulation of de diet of the animals. The evaluation of the food absorption processes have been a very important in the investigation of the animal nutrition. The objective was to evaluate the on ruminal fermentation parameters in high yielding dairy cows fed total mixed ration (TMR). Eighteen Holstein cows in initial third of lactation were distributed to three groups. Cows were fed ad libitum thirty a day. The diet containing corn silage, barley, cottonseed and commercial ration, with forage:concentrate ratio of 45:55. Ruminal fluid was used for sampling at 0, 2, 4 and 6 hours after first meal for determination of ammonia, pH and VFA. The daily average intakes of nutrients, coefficients digestibility and milk production was evaluated how index of the production. There was no effect for averages of molar ruminal concentration ammonia. Was different, 4 hour after fed for the parameters: pH, VFA, acetic, butyric acids evidencing intense ruminal fermentative activity. Total VFA and pH was different in 4 hour after fed. The values of the propionic acid had followed the same trend of the AGV but they had not presented significant difference, the relation acetate: propionato was remained above of 3, keeping adjusted the text of fat of milk. This study demonstrates that the use of total diet provided a ruminal environment with adequate conditions of fermentation without large oscillations, what it diminishes the incidence of metabolic riots in cows of high production.
As melhores mudan?as na produ??o do leite podem ser atingidas atrav?s da manipula??o da dieta dos animais. Avaliar os processos de absor??o de alimentos direcionados para a s?ntese do leite tem sido de grande import?ncia nas pesquisas de nutri??o animal O objetivo deste trabalho foi avaliar os par?metros ruminais de vacas de alta produ??o alimentadas com dieta total. Dezoito animais da ra?a Holandesa, no primeiro ter?o de lacta??o, foram divididos em tr?s grupos, por ordem de pari??o. Os animais receberam dieta total ? vontade (ad libitum) tr?s vezes ao dia composta por silagem de milho, cevada ?mida, caro?o de algod?o e ra??o comercial, com a rela??o volumoso:concentrado de 45:55. Amostras de l?quido ruminal foram coletadas nos hor?rios de 0, 2, 4 e 6 horas, ap?s a alimenta??o, no per?odo da manh?, sendo utilizadas para determina??es das concentra??es de am?nia, pH e AGV do l?quido ruminal. Os valores de consumo m?dio di?rio, coeficiente de digestibilidade, produ??o de leite foram avaliados como indicadores da produ??o. N?o foi observado efeito significante nas concentra??es m?dias ruminais de am?nia. Na quarta hora ap?s a alimenta??o foi observada diferen?a significativa dos par?metros: pH, AGV total, ?cidos ac?tico e but?rico, evidenciando a intensa atividade fermentativa ruminal. Os valores m?dios de ?cido propi?nico seguiram a mesma tend?ncia dos AGV mas n?o apresentaram diferen?a significativa, a rela??o acetato:propionato manteve-se acima de 3, mantendo adequado o teor de gordura do leite. Este trabalho demonstra que o uso de dieta total proporcionou um ambiente ruminal com condi??es adequadas de fermenta??o sem grandes oscila??es, o que diminui a incid?ncia de dist?rbios metab?licos em vacas de alta produ??o.

Metodologia di lavoro. Il lavoro si articola su diverse runs di processo, in condizioni di fermentazione anaerobica termofila, su substrati organici di origine urbana. In particolare, verrà valutata la produzione di VFA in reattori di laboratorio (800 ml) a partire da miscele di “fanghi di depurazione-food waste”. I processi verranno monitorati su 3 differenti tempi di residenza idraulici (HRT). Parte sperimentale prevista. Test di fermenazione acidogenica in condizioni termofile tramite colture microbiche miste in reattori CSTR di laboratorio. La parte sperimentale prevede una fase iniziale di caratterizzazione delle diverse matrici (prima e dopo eventuale idrolisi termica) e il successivo avvio dei test fermentativi in parallelo. Questi ultimi verranno effettuati su una matrice composita (“fanghi-food waste”), in corrispondenza di tre differenti HRT (4-5-6 giorni). Area di ricerca. Impianti chimici (09/D3) – Processi biochimici industriali Risultati attesi. La fermentazione acidogenica di matrici organiche di scarto permette l’ottenimento di prodotti con un loro valore economico nel rispettivo mercato di interesse. I VFA rappresentano una tipologia di tali prodotti, e la loro produzione verrà investigata su diverse matrici di origine urbana, in bioreattori termofili a diversi tempi di residenza. Eventuali pre-trattamenti (termico o alcalino) incentivano l’idrolisi della sostanza organica con successiva solubilizzazione, utile all’incremento del COD solubile e alla sua successiva conversione in VFA nello step successivo di fermentazione. I diversi HRT investigati, indicheranno la migliore condizione attuabile su una maggiore scala, in termini di concentrazione finale di VFA ottenibile (10-20 gCOD/L) e rapporto VFA/COD solubile (0.6-0.8 COD/COD). Attenzione particolare verrà data alla tipologia di VFA prodotti, soprattutto C5-C6 (a maggior valore di mercato) e al rapporto tra i VFA a catena pari (numero pari di atomi di carbonio) e VFA a catena dispari, caratteristica particolarmente importante nell’ottica di utilizzo di tali VFA per la sintesi microbica di biopolimeri.

Il seguente lavoro di tesi mira a sviluppare tecnologie e processi sostenibili per la produzione di biopolimeri, quali poliidrossialcanoati (PHA). I PHA sono poliesteri di base biologica prodotti dai batteri, in sistemi di fermentazione a colture microbiche miste (MMC). Come substrato carbonioso è stata utilizzata la frazione organica dei rifiuti solidi urbani (FORSU). Il processo consiste in un sistema accoppiato di fermentazione acidogenica e strippaggio in ipertermofilia (70°C), per la produzione e recupero di acidi grassi volatili (VFA), utilizzati come fonte carboniosa in MMC per la produzione di PHA. Lo strippaggio è stato utilizzato come tecnica di recupero dei VFA dalla fermentazione, i primi test sono stati effettuati mediante l’utilizzo di soluzioni standard raggiungendo una resa massima del 99 % di VFA in 23h. L’esperimento reale, (fermentazione acidogenica accoppiata a strippaggio) ha auto una conversione massima del 65 % di FORSU in VFA, il recupero tramite lo strippaggio è stato del 90 % mentre la resa globale del processo accoppiato è stata pari al 18%. Per la produzione di PHA è stato utilizzato il ProBiotipo, impianto pilota di B-PLAS DEMO, progetto finanziato dalla EIT Climate-KIC. Le percentuali di produzione di PHA da MMC raggiunte sono dell’83 % su peso secco. Successivamente sono state effettuate estrazioni di PHA dalle biomasse batteriche con l’utilizzo di sodio dodecil solfato (SDS) per lisare la parete cellulare e dimetilcarbonato (DMC) solvente green per l’estrazione. Le rese di estrazione sono state del 94 %.

Master of Science
Department of Animal Sciences and Industry
James S. Drouillard
Two experiments were conducted to evaluate the efficacy of [italic]Megasphaera elsdenii[italic] strain NCIMB 41125 and its potential use in the mitigation of ruminal acidosis. In experiment 1, a metabolism study was conducted to evaluate ruminal parameters, quantify changes in ruminal bacterial populations, and determine in vitro capacity for lactate utilization following intraruminal dosing of a placebo or [italic]M. [italic]elsdenii strain NCIMB 41125 and an abrupt diet change. Angus crossbred steers (n=20; average BW=253 ± 24 kg) fitted with ruminal cannulas were blocked by BW and assigned randomly to treatments. Treatments consisted of intraruminal dosing with a placebo (100 mL of autoclaved culture), or 10, 100, or 1,000 mL of a live culture containing 1.62×108 CFU/mL of [italic]M. elsdenii[italic] strain NCIMB 41125. Prior to inoculation, cattle were placed into individual pens in an enclosed facility and allowed free access to alfalfa hay, salt, and water. Feed and water were removed for 24 h prior to administering treatments, after which, cattle were allowed free access to a diet consisting of 34% alfalfa hay and 66% steam-flaked corn-based concentrate. On d 7, cattle were fed an 80% concentrate diet. On d 12, steers were started on the final finishing diet of 94% concentrate. Ruminal pH and concentrations of lactate and VFAs were monitored following introduction of each concentrate diet. Ruminal samples were collected at 0, 2, 4, 6, 8, and 24 h after feeding for quantitative rt-PCR detection of native and introduced strains of [italic]M. elsdenii[italic], as well as total bacterial genomes. Capacity for metabolism of lactic acid was evaluated by inoculating 0.2 mL of strained ruminal fluid into anaerobic culture tubes containing 15 mL of semi-defined lactate medium. Tubes were incubated at 39˚C, and turbidity changes were determined by measuring absorbance at 2 h intervals up to 12 h. Experiment 2 was conducted in a commercial feedlot to evaluate the efficacy of [italic]M. elsdenii[italic] strain NCIMB 41125 for improving feedlot performance. A second objective of the study was to determine if oral dosing of [italic]M. elsdenii[italic] has the potential for reducing the number of cattle treated for bovine respiratory disease. Angus steers and heifers (n = 3179; average BW = 356 ± 58.4kg) were used in a randomized complete block design with two treatments. Cattle were assigned to treatment on an every-other-head basis such that every-other-animal was orally drenched with 100 mL of a culture medium containing 1.5×108 cfu/mL [italic]M. elsdenii[italic] strain NCIMB 41125 at processing. Cattle were blocked by gender and date of arrival. To maximize profitability, cattle were sorted via visual appraisal to identify cattle that were market ready. Cattle were shipped to a commercial abattoir in Lexington, NE for harvest. Data obtained for each pen of cattle included feedlot performance, morbidity, mortality, carcass characteristics, and grid-based program carcass qualifications. In trial 1, compared to the placebo group, cattle administered [italic]Megasphaera[italic] maintained higher ruminal pH 24 h after the carbohydrate challenge (P < 0.05). Ruminal lactate concentrations increased in response to the diet change (P < 0.05), but concentrations were lower for cattle that received [italic]Megasphaera[italic] compared to the placebo group (P < 0.05). Total number of bacterial genomes 24 h after inoculation was unaffected by intraruminal dosing of [italic]M. elsdenii[italic] strain NCIMB 41125 (P > 0.05), but populations of undifferentiated [italic]M. elsdenii[italic] and strain NCIMB 41125 increased by 24 h after inoculation (P < 0.05). Turbidity of cultures inoculated with ruminal fluid increased in response to [italic]M. elsdenii[italic] administration (P < 0.05), suggesting a greater capacity for lactate utilization in inoculated cattle compared to the placebo group. In trial 2, no differences in feed efficiency were observed (P > 0.05). Compared to cattle dosed with [italic]Megasphaera[italic], the control group had more USDA yield grade 2 carcasses (P < 0.05), and cattle dosed with [italic]M. elsdenii[italic] had more USDA yield grade 5 carcasses (P < 0.05). [italic]Megasphaera[italic] cattle also tended to have more USDA Prime carcasses (P = 0.14). No effects on incidence of liver abscesses were observed. Dosing cattle with [italic]M. elsdenii[italic] prior to introduction of typical concentrate diets may be useful in preventing ruminal lactate accumulation and associated depressions in ruminal pH. Inoculating cattle with [italic]M. elsdenii[italic] is effective in bolstering populations of ruminal lactate utilizers, and may be useful in preventing ruminal lactate accumulation in grain-fed cattle. No effects on reducing episodes of BRD were noted.

Dissertação para obtenção do Grau de Mestre em Engenharia Química e Bioquímica
Os polihidroxialcanoatos (PHA) são plásticos biodegradáveis produzidos por uma grande variedade de microorganismos a partir de fontes renováveis. Actualmente, os PHA são produzidos de forma eficiente através de matérias-primas quimicamente definidas, fermentadas por culturas puras. No entanto, a implementação da produção tem sido limitada devido aos elevados custos desta, em comparação com plásticos convencionais. As culturas microbianas mistas surgem como uma alternativa, usando subprodutos industriais e sem necessidade de condições de esterilização. Contudo, a produção de PHA através de culturas mistas necessita de optimização. O estudo descrito nesta dissertação teve como objectivo estudar o impacto da redução do teor proteico na primeira etapa da produção de PHA por culturas mistas, a fermentação acidogénica. A matéria-prima utilizada foi o soro de leite, uma matéria-prima de elevado teor proteico. Ao longo do trabalho foram produzidos diferentes fracções de soro de leite em composição e topologia. A recuperação de uma fracção do soro de leite tem como objectivo produzir um produto adicional de valor acrescentado ao processo de produção de PHA. A redução do teor proteico tem como objectivo a recuperação de um teor proteico de modo a produzir um produto de valor acrescentado na produção de PHA. Inicialmente foi abordada a aplicação de processos de separação com membranas. A utilização de processo de ultrafiltração com diferentes limites de exclusão molecular, de modo a produzir fracções com teor e tipologia de proteínas diferentes. A concentração de lactose e sais não foi alterada pela aplicação do processo. O primeiro permeado continha péptidos e aminoácidos, o segundo além desta por α-LA e β-LG (as proteínas em maior quantidade no soro de leite), e um terceiro com toda a tipologia do soro de leite. O fluxo de permeado foi tanto mais prejudicado quanto maior foi o limite de exclusão molecular da membrana utilizada. A utilização dos processos dia-ultrafiltração com uma membrana de 30kDa e osmose inversa possibilitou a concentração de 3,5 vezes em relação ao processo de ultrafiltração com a mesma membrana. O permeado obtido era maioritariamente composto por aminoácidos, péptidos e as proteínas de menor tamanho do soro de leite (α-LA e β- LG). A utilização do permeado obtido no processo de dia-ultrafiltração e osmose, com 60% do teor proteico do soro de leite, foi suficiente para igualar a produção de ácidos gordos voláteis (VFA) e crescimento celular do reactor de referência efectuado com soro de leite não fraccionado. Além disso, o rendimento de crescimento, o rendimento de produção de VFA e os perfis de VFA não foram alterados. Pode-se concluir que o processo de dia-ultrafiltração permitiu recuperar 40% das proteínas presentes no soro de leite sem comprometer a produção de VFA (percursores de PHAs) pelo processo de fermentação acidogénica. Deste modo, será possível aumentar a rentabilidade económica do processo, sem prejudicar a produção biológica de PHA.

Il presente lavoro di tesi riguarda lo sviluppo di un innovativo processo di produzione di poliidrossialcanoati (PHA), volto a diminuire i costi ed incrementare la sostenibilità ambientale dei processi attualmente utilizzati per produrre PHA. A tal fine sono state utilizzate colture microbiche miste (MMC) presenti nei fanghi attivi derivanti dai processi di depurazione delle acque reflue e substrati di scarto dell’industria vitivinicola. I substrati sono stati inizialmente fermentati anaerobicamente per ottenere acidi grassi volatili (VFA), fonte di carbonio ideale per produrre PHA tramite MMC. Il processo di produzione sviluppato nel presente lavoro di tesi è suddiviso in tre stadi, mediante l'accoppiamento di processi termochimici e biologici: 1. Fermentazione anaerobica di varie matrici di scarto provenienti dall'industria vitivinicola per produrre VFA. Tutti i substrati sono stati testati sia con inoculo tal quale e sia con inoculo autoclavato per inibire l’attività degli Archea metanogeni. Nel primo caso sono stati ottenuti elevati quantitativi di biogas (~70% di resa), mentre il pre-trattamento dell’inoculo ha portato un’elevata produzione di VFA, soprattutto nel caso della vinaccia (45% di resa). 2. Pre-trattamento termochimico dei fanghi di depurazione e scarti tramite pirolisi al fine di rendere il carbonio contenuto negli scarti più disponibile per i batteri anaerobi. In questo caso le rese di VFA sono sensibilmente aumentate rispetto alla digestione della biomassa tal quale, con valori prossimi al 99% nel caso della vinaccia. 3. Valutazione delle capacità delle popolazioni batteriche che compongono il fango aerobico di accumulare naturalmente PHA, testando fanghi provenienti da impianti di depurazione sia industriali che urbani. Solo le comunità batteriche presenti nei fanghi di tipo urbano hanno mostrato buona potenzialità di accumulare PHA, senza che questi siano stati inizialmente sottoposti a regimi ciclici alimentari.

Made available in DSpace on 2016-04-28T14:59:47Z (GMT). No. of bitstreams: 1 2009 - Stela Gomes Pelegrino.pdf: 247744 bytes, checksum: edcaaef4e983d4522513a9fcb967acdc (MD5) Previous issue date: 2008-04-29
Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico
The search of better quality of the milk induces that changes and advances should be reached trought manipulation of de diet of the animals. The evaluation of the food absorption processes have been a very important in the investigation of the animal nutrition. The objective was to evaluate the on ruminal fermentation parameters in high yielding dairy cows fed total mixed ration (TMR). Eighteen Holstein cows in initial third of lactation were distributed to three groups. Cows were fed ad libitum thirty a day. The diet containing corn silage, barley, cottonseed and commercial ration, with forage:concentrate ratio of 45:55. Ruminal fluid was used for sampling at 0, 2, 4 and 6 hours after first meal for determination of ammonia, pH and VFA. The daily average intakes of nutrients, coefficients digestibility and milk production was evaluated how index of the production. There was no effect for averages of molar ruminal concentration ammonia. Was different, 4 hour after fed for the parameters: pH, VFA, acetic, butyric acids evidencing intense ruminal fermentative activity. Total VFA and pH was different in 4 hour after fed. The values of the propionic acid had followed the same trend of the AGV but they had not presented significant difference, the relation acetate: propionato was remained above of 3, keeping adjusted the text of fat of milk. This study demonstrates that the use of total diet provided a ruminal environment with adequate conditions of fermentation without large oscillations, what it diminishes the incidence of metabolic riots in cows of high production.
As melhores mudan?as na produ??o do leite podem ser atingidas atrav?s da manipula??o da dieta dos animais. Avaliar os processos de absor??o de alimentos direcionados para a s?ntese do leite tem sido de grande import?ncia nas pesquisas de nutri??o animal O objetivo deste trabalho foi avaliar os par?metros ruminais de vacas de alta produ??o alimentadas com dieta total. Dezoito animais da ra?a Holandesa, no primeiro ter?o de lacta??o, foram divididos em tr?s grupos, por ordem de pari??o. Os animais receberam dieta total ? vontade (ad libitum) tr?s vezes ao dia composta por silagem de milho, cevada ?mida, caro?o de algod?o e ra??o comercial, com a rela??o volumoso:concentrado de 45:55. Amostras de l?quido ruminal foram coletadas nos hor?rios de 0, 2, 4 e 6 horas, ap?s a alimenta??o, no per?odo da manh?, sendo utilizadas para determina??es das concentra??es de am?nia, pH e AGV do l?quido ruminal. Os valores de consumo m?dio di?rio, coeficiente de digestibilidade, produ??o de leite foram avaliados como indicadores da produ??o. N?o foi observado efeito significante nas concentra??es m?dias ruminais de am?nia. Na quarta hora ap?s a alimenta??o foi observada diferen?a significativa dos par?metros: pH, AGV total, ?cidos ac?tico e but?rico, evidenciando a intensa atividade fermentativa ruminal. Os valores m?dios de ?cido propi?nico seguiram a mesma tend?ncia dos AGV mas n?o apresentaram diferen?a significativa, a rela??o acetato:propionato manteve-se acima de 3, mantendo adequado o teor de gordura do leite. Este trabalho demonstra que o uso de dieta total proporcionou um ambiente ruminal com condi??es adequadas de fermenta??o sem grandes oscila??es, o que diminui a incid?ncia de dist?rbios metab?licos em vacas de alta produ??o.

Biodiversity is a key component for life on Earth since it contributes to clean water, fresh air and food security. Today, fatty fish farmed in aquaculture is the main Omega 3 source consumed by humans, including the essential fatty acid docosahexaenoic acid (DHA). DHA origin from plants and accumulate in fish via the marine food web. Therefore, DHA in the form of fish oil is often added to fish feed used in aquaculture. This process is dependent on fossil energy and marine raw materials, which infer increased global warming, damage to ecosystem and ultimately loss of biodiversity. In order to reduce the environmental impact, the essential fatty acid could instead be derived from the marine primary producer of DHA: microalgae. In this thesis, a life cycle approach was used to assess global warming, use of fossil fuels and Ecosystem damage when DHA is produced by the microalgae Crypthecodinium Cohnii. The environmental impact was modelled using SimaPro 9 and assessed with CML-IA and ReCiPe Endpoint. In this model, volatile fatty acids derived from dark fermentation of food waste was used as feedstock to the algae. The studied systems consisted of two parallel scenarios, one conventional food waste-to-biogas with DHA from fish oil and one conceptual food waste-to-DHA with DHA from algae oil. The aim was to evaluate the future potential of DHA produced from algae, by assessing and comparing environmental impact to DHA produced from Peruvian anchovy. For every ton DHA produced by microalgae the assessed impact was -1.9E+02 tonCO2e, -1.9 TJ and 9.7E-04 species.yr. DHA produced by microalgae using VFA from food waste was shown to mitigate global warming and reduce use of fossil fuels. The most important conclusion show that DHA from algae infer 37% lower biodiversity loss in comparison to DHA from Peruvian anchovy. Thus, DHA from microalgae could reduce dependency on marine raw material and decrease biodiversity loss.
Biodiversitet är en nyckelkomponent för liv på jorden eftersom det bidrar till rent vatten, frisk luft och säker livsmedelsproduktion. Idag är fet fisk odlad i vattenbruk den viktigaste källan till Omega 3 som konsumeras av människor, inklusive den essentiella fettsyran dokosahexaensyra (DHA). Då DHA härstammar från växter och ackumuleras i fisk via den marina näringskedjan, tillsätts DHA ofta till fiskfoder i form av fiskolja. Denna process är beroende av fossil energi och marina råmaterial, som leder till ökad global uppvärmning, skadar naturliga ekosystem och orsakar förlust av biologisk mångfald. För att minska miljöpåverkan skulle den essentiella fettsyran istället kunna produceras från den marina primärproducenten av DHA: mikroalger. I detta examensarbete användes livscykelanalys för att utvärdera miljöpåverkan med avseende på global uppvärmning, användning av fossila bränslen och påverkan på biodiversitet, då DHA produceras av mikroalgen Crypthecodinium Cohnii. Flyktiga fettsyror, VFA, som bildas vid mörk fermentering av matavfall användes som råmaterial till algerna. De studerade systemen bestod av två parallella scenarier, en konventionell matavfall-till-biogas med DHA från fiskolja och en konceptuell matavfall-till-DHA med DHA från algolja. Systemet modellerades i SimaPro 9 och miljöpåverkan beräknades med CML-IA och ReCiPe Endpoint. Syftet var att utvärdera DHA som produceras från alger genom att beräkna miljöpåverkan och jämföra med DHA producerad från peruansk ansjovis. För varje ton DHA producerat av mikroalger var påverkan -1.9E+02 tonCO2e, -1.9 TJ och 9.7E-04 arter per år. DHA producerad av mikroalger där VFA från matavfall använts som näring, visade sig minska den globala uppvärmningen, reducera användningen av fossila bränslen och innebar 37% lägre förlust av biologisk mångfald jämfört med DHA producerad från peruansk ansjovis. Denna studie visade därmed att DHA från mikroalger kunde minska beroendet av marina råmaterial och minska förlusten av biologisk mångfald.

Dopo una premessa preliminare sulla bioraffineria, si passa alla descrizione in dettaglio della carboxylate platform e dei suoi possibili sviluppi, fra cui vi è quello dello studio di sistemi bioelettrochimici, nello specifico elettrosintetici catodici. A questo punto si passa per una breve descrizione del metabolismo di un fango da digestione anaerobica, prima di arrivare all'obiettivo della tesi. L'obiettivo è udi fare una valutazione dell'influenza di nanoparticelle di magnetite sull'attività di alcuni sistemi bioelettrosintetici microbici (inoculati con fango da digestione anaerobica): un sistema batch a celle e uno con configurazione reattoristica in continuo, passando per un sistema di controllo di verifica abiotico. L'attenzione è focalizzata sulla cinetica e sulla produttività di questi sistemi in termini di prodotti di sintesi utili (VFA e metano), a partire da anidride carbonica come unica fonte di carbonio e un potenziale esterno, fra i comparti catodico e anodico, imposto e fisso come fonte di potere riducente per l'inoculo biotico catodico

La tesi della ha come obiettivo la valorizzazione delle acque di scarto derivanti dalla produzione del bioetanolo da colture cerealicole dedicate. Nella prima parte si studia la produzione di VFA mediante digestione anaerobica. In seguito, sono eseguiti batch tests per valutare la conversione dei VFA in MCFA. Infine, si focalizza sul processo di dowstream per il recupero degli acidi carbossilici dal brodo di fermentazione attraverso reactive extraction e back extraction.

La vinaccia è uno scarto proveniente dall’industria vinicola generato stagionalmente in abbondanti quantità. Questa possiede caratteristiche antimicrobiche che la rendono non prontamente biodegradabile. Una corretta gestione di questo scarto è tassativa per evitare danni all’ambiente. Attualmente, gran parte della vinaccia è trattata per recuperare etanolo mediante distillazione; una possibile alternativa per valorizzare questo scarto consiste nella produzione di acidi grassi volatili (VFAs), acidi carbossilici a corta catena, tra cui acido acetico (C2H4O2), propionico (C3H6O2), isobutirrico e butirrico (C4H8O2), isovalerico e valerico (C5H10O2), isocaproico e caproico (C6H12O2). L’obiettivo di questo lavoro è stato produrre miscele di VFAs con un alto contenuto di acido caproico, il quale può essere recuperato ed utilizzato nella produzione di poliidrossialcanoati, poliesteri accumulati da batteri aerobici, completamente biodegradabili, che possono sostituire le plastiche tradizionali in determinate applicazioni. A questo scopo, sono stati applicati processi biotecnologici di fermentazione acidogenica a scala di laboratorio, in condizioni batch e in continuo, che hanno consentito di ottenere fino a 17 g/L di acido caproico. Il raggiungimento di queste concentrazioni è stato possibile grazie ad uno screening iniziale che ha permesso di determinare le condizioni di pH e temperatura ottimali. Infine, è stato condotto uno studio della cinetica del processo, attraverso il quale è stato individuato anche il contenuto di solidi totali ottimale per la produzione di acido caproico.

Följande examensarbete är den avslutande delen av högskoleingenjörsprogrammet innovationsteknik och design på Karlstads Universitet. Arbetet har en omfattning på 22,5hp och genomfördes ifrån januari- till juni 2020. Uppdragsgivaren är Granqvist Sportartiklar AB (fortsättningsvis i rapporten benämnt som Granqvists) som har sitt säte i Karlstad, medan uppdraget utfördes på deras fabrik i Zlotow, Polen. Granqvist har tillverkat handskar för sport- och skydd sedan 1984 och har alltid ägt hela produktionen, råmaterial till färdig slutprodukt. Då företaget har växt både i omsättning och personalstyrka har den svenska ledningen funnit ett behov av förbättringsarbete inom produktionen, vilket följande examensarbete behandlar. Arbetets upplägg följer den strategi som presenteras boken ”LEAN, gör avvikelser till framgång” rörande värdeflödesanalyser och hur man bäst utnyttjar dem. Genom den utförda värdeflödesanalysen var det möjligt att dokumentera hela processen för en vald produktfamilj sett ur ett helikopterperspektiv, vilket var brandhandsken texgrip. Nuläget visar på att ett stort antal mellanlager växer fram inom produktionen som en följd av ett osynkroniserat produktionsflöde där varje process har egna körscheman. Efter analysering av nuläget samt intervjuer med medarbetare inom produktionen och tjänstemän kunde ett antal förbättringsförslag genereras. Övergripande har 19 förbättringsförslag fördelade över tre kategorier presenterats, samt 9 huvudpunkter med åtgärder som går att genomföra för att nå ett jämnare flöde i produktionen. Huvudpunkterna för flödet presenteras i form av en simulering i programvaran Flexsim 2020. Detta på grund av de rådande omständigheterna avseende Covid-19 vilket påverkade genomförandefasen av förbättringsförslagen. Simuleringen visar att de två planerade lagringsplatserna med kontrollerat lager räcker för de nyskapade flödesgrupperna, och därmed bör modellen ej förkastas. Simuleringen skall även kunna fungera som ett verktyg för uppdragsgivaren med syfte att visa vad man kan göra och hur man tar sig dit i produktionen. Samt att den skall stödja dem i deras fortsatta utvecklingsarbete med möjligheter till att bygga på modellen utifrån hela produktionsanläggningen.
The following bachelors thesis is the final part of the engineering program innovation technology and design at Karlstad University. The work has a scope of 22.5hp and was carried out between January and June 2020. The client is Granqvist Sportartiklar AB, which has its headquarters in Karlstad, while the assignment was carried out at their factory in Zlotow, Poland. Granqvist has been manufacturing gloves for sports and protection since 1984 and has always owned the entire production from raw material to finished product. As the company has grown both in sales and staff strength, the Swedish management has found a need for improvements in the production, which the following work deals with. The work follows the strategy presented in the book ”LEAN, gör avvikelser till framgång” regarding value flow analyzes and how to best utilize them. By performing a current-situation analysis, it was possible to document with a helicopter perspective the entire process for a selected product family. The current situation shows that a large number of intermediate stocks are growing within production as a result of an unsynchronized production flow where each process has its own schedules. After analyzing the current situation, interviews with production employees and officials, a number of improvement suggestions was generated. Overall, 19 improvement proposals across three categories have been presented, as well as 9 main points with measures that can be implemented to achieve a more even flow in the production. These points for the flow are presented in the form of a simulation in the software Flexsim 2020, when Covid-19 ravaged globally at the time the thesis was written, which led to difficulties in implementing some of the improvement proposals. The simulation shows that the two planned controlled storage locations are sufficient for the newly created flow groups, and thus the model is considered approved. The simulation should also serve as a tool for the client, a tool with the purpose of showing what you can do and how to get there in the production, aswell as being a foundation for future work in simulating the whole production and all it´s products.

Volatile fatty acids (VFAs) have become attractive and gained high research interest due to its significance for the chemical industry and economical advantage. These acids can be produced by utilizing organic waste such as food waste as substrate through anaerobic digestion. Anaerobic digestion is an environmental process that occurs naturally and produces biogas as the main product. VFAs are intermediate products formed during anaerobic digestion where acetic acid, a type of VFA, is the primary product. The main objective of this study was to utilize acetic acid as carbon and energy source for production of edible fungi, Rhizopus ologisporus, Mucor indicus and Volvariella volvacea. The first step was to evaluate if acetic acid could be used as carbon and energy source for edible fungi production. The results showed, that acetic acid is suitable as carbon and energy source for fungal biomass production. The second step was to optimize growth in liquid media. The cultivations were carried out by using five different conditions, where the liquid media contained different combinations of acetic acid, yeast extract and minerals as well as comparing orbital and linear oscillations. Fungal cultivation was possible regardless of the medium composition and type of water shaking baths. However, a linear water shaking bath with a combination of acetic acid yeast extract and/or minerals seems to be the best. Finally, as step three, acetic acid concentrations, 0.2 g/l and 2.0 g/l were used under similar conditions as in step two to see whether a higher concentration of acetic acid would be beneficial. Although the cultivation containing 2.0 g/l gave a higher value of dry weight, the value of yield is questionable. Further studies are needed to confirm if a higher concentration is beneficial or if it might act as an inhibitor for fungal cultivation.
Flyktiga fettsyror (VFAs) har ekonomiska fördelar och kan användas inom kemiska industrier i olika sammanhang, detta har lett till ett stort forskningsintresse för att kunna nyttja VFAs. Organiskt avfall, såsom matavfall, kan användas som substrat för att producera fettsyror genom anaerob rötning. Anaerob rötning är en miljövänlig process och VFAs bildas som intermediära produkter under den anaeroba nedbrytningen där annars bildas biogas som slutprodukt. Syftet med denna studie var att använda ättiksyra, (den vanligaste typen av VFAs), som kol- och energikälla vid odling av tre olika ätbara svampar, som Rhizopus oligosporus, Mucor indicus, och Volvariella volvacea. Först odlades dessa ätbara svampar i odlingsmedium innehållande ättiksyra. Resultatet visade att ättiksyra kan användas som kol- och energikälla vid produktion av svampbiomassa. Målet i de nästkommande stegen var att optimera tillväxtförhållande för svampodlingen. Fem olika odlingsmedier som innehöll olika kombinationer av ättiksyra, jästextrakt och mineraler användes. Det undersöktes dessutom hur två olika skakmetoder, orbitalt, eller linjärt, skakbad påverkar odlingen. Svamptillväxt var möjligt vid alla olika förhållanden oavsett sammansättningen av medium och typ av skakbad, däremot verkar odlingsmedium som innehåller ättiksyra, jästextrakt och/eller mineraler i kombination med linjär skakning vara de bästa förutsättningar för tillväxt av biomassa. I det sista steget kultiverades svamp med olika koncentrationer av ättiksyra, 0,2 g/l och 2,0 g/l, under liknande optimerade förhållanden som ovan, för att undersöka om en högre koncentration av ättiksyra skulle vara fördelaktig. Det producerades mer svampbiomassa (som torrvikt) vid koncentration av 2,0 g/l ättiksyra jämfört med när 0,2 g/l ättiksyra användes, dock var det svårt att säkerställa utbytet. Det behövs därför ytterligare fortsatta studier för att kunna bevisa om en högre koncentration av ättiksyra är fördelaktig för odlingen, eller om en högre koncentration skulle verka inhiberande för tillväxten.

The recovery of Carboxylic acids were based on two particular objective: the study of the efficiency of a cation exchange resin, used in order to reduce the pH of the actual effluent, considering it is necessary to have a low pH for the anion exchange resin to be able to adsorb the acids from the effluent, and the preliminary studies perfomerd on the anion exchange resin, at various flow rates and both mode of operation, expanded and packed bed mode, using a simulated effluent, were the carboxylic acids were represented by just acetic acid, as the target molecule.

Obiettivo della presente ricerca è stato la valutazione dell’utilizzo degli scarti derivanti dal processo di vinificazione come substrato per la digestione anerobica finalizzata alla produzione di VFA (“Volatile Fatty Acids”). I VFA sono acidi grassi a corta catena, convenzionalmente fino a 6 atomi di carbonio, che possono essere utilizzati industrialmente nell’ambito della “Carboxilation Platfrorm” per produrre energia, prodotti chimici, o biomateriali. La sperimentazione si è articolata in due fasi principali: 1) Produzione di VFA in processi batch alimentati con vinacce e fecce come substrato; 2) Recupero dei VFA prodotti dall’effluente anaerobico (digestato) mediante processi di adsorbimento con resine a scambio anionico. Nella prima fase sono stati studiati i profili di concentrazione dei principali VFA nel brodo di fermentazione al variare della tipologia di substrato (vinacce e fecce, bianche e rosse) e della temperatura di incubazione (35 °C e 55 °C). La condizione ottimale rilevata per la produzione di VFA è stata la digestione anaerobica di vinacce rosse disidratate e defenolizzate alla temperatura di 35 °C (mesofilia), che ha permesso di raggiungere una concentrazione di VFA totali nel digestato di circa 30 g/L in 16 giorni di monitoraggio. Nella seconda fase è stato analizzato il processo di estrazione in fase solida (Solid Phase Extraction, SPE) con resine a scambio anionico per il recupero dei VFA dal digestato di vinacce rosse. Sono state messe a confronto le prestazioni di quattro diverse resine a scambio anionico: Sepra SAX, Sepra SAX-ZT, Sepra NH2, Amberlyst A21. I parametri operativi ottimali per l’adsorbimento sono risultati essere condizioni di pH acido pari al valore naturale delle soluzioni indicate sopra (~2.5) e tempo di contatto di 2 ore. Tra le quattro resine quella che ha fornito i migliori risultati è stata la Amberlyst A21, una resina polimerica a scambio anionico debolmente basica il cui gruppo funzionale caratteristico è un’ammina terziaria. Infine è stato valutato il processo di desorbimento dei VFA adsorbiti dalla resina con tre diverse soluzioni desorbenti: acqua demineralizzata, etanolo (EtOH) ed acqua basificata con NaOH (1 mol/L). I risultati migliori sono stati conseguiti nel caso dell’EtOH, ottenendo un recupero finale del 9,1% dei VFA inizialmente presenti nel digestato di vinacce rosse incubate in termofilia.

Biomass and biomass-derived waste are important renewable energy sources which plays a vital role in greenhouse gas reduction from fossil fuel.  Biomass can be degraded in a process known as anaerobic digestion (AD) to produce biogas. Biogas is a mixture of methane and carbon dioxide which is utilized as a renewable source of energy. This project was based on the investigation of AD process in Nordvästra Skånes Renhållnings AB (NSR) a biogas facility in Helsingborg Sweden. A lab simulation of NSR digesters was conducted to evaluate the effects of swine manure on AD using two continuously stirred tank reactors (CSTR) R1 (control) and R2 with a working volume of 4L for 21 weeks. The study was divided into 4 periods and the investigation was carried out by increasing the organic loading rate (OLR) step wise from 2.5 to 3.6 gVSL-1day-1. To assess the effects of swine manure, the performance and stability of the reactors were monitored by collecting data from process parameters. These process parameters included biogas production, pH, volatile fatty acids, methane yield, methane content and organic solids (total and volatile solids). Increase in OLR resulted in increase biogas production in both reactors, however R2 with additional swine manure (15%) produced more biogas than R1. Methane yield was fairly stable during the experiment and had a similar trend in both reactors, but however R2 had a slightly higher average yield (730±60 mLCH4 gVS-1) than R1 (690±60 mLCH4 gVS-1) during the entire experiment. Increase OLR resulted in increase VFA in period 2; R2 with additional swine manure had a lower peak VFA concentration of 25 mM as compared to 33mM in R1.  The characteristics of NSR substrate mix and swine manure provided a good buffering system (stable pH), and reactors were still running stably at 3.6 gVSL-1day-1. Furthermore swine manure was investigated to contain macro-nutrients and trace metals which might have enhanced the AD process in R2 containing more Co, Zn, Ni and Mo than R1. Since this investigation was a simulation, the waste mix used at NSR contained 7% swine manure, this made it difficult to give clearer conclusions about the effects of co-digestion of swine manure on the biogas process since the control (R1) had 7% swine manure. Keywords: Anaerobic digestion, co-digestion, swine manure, substrate mix, organic loading rate, biogas production, methane yield, VFA, process parameters, CSTR.

Doutoramento em Ciências e Engenharia do Ambiente
Biodegradation is an eco-friendly option for the disposal and recovery of organic waste, including food waste (FW). These residues can be treated and recovered through anaerobic digestion processes, thereby reducing their pollutant content and, at the same time, producing high value-products such as volatile fatty acids (VFA). These compounds resulting from acidogenic fermentation are the preferred carbon sources for the production of added-value products, namely polyhydroxyalkanoates (PHA) or bioenergy, in the form of methane or hydrogen. In this work, it was studied the acidogenic fermentation of several organic residues, such as the organic fraction of municipal solid waste (OFMSW), waste from the tomato processing industry (TW), coffee grounds waste (CG) and waste activated sludge (WAS) from a wastewater treatment plant. The assays were performed in batch and semi-continuous reactors, either in mono- or co-digestion assays, in order to assess and optimize its potential for VFA production. In these tests, the effects of various parameters, such as 1) total solids (TS) content in the reactor, 2) alkalinity addition, 3) organic loading rate (OLR) applied and 4) carbon-nitrogen ratio (C:N) were studied. In the mono-digestion assays, a very distinct behavior was observed in the four substrates studied, with a substantially higher acidification rate for TW (49 %) and OFMSW (41 %) than for CG (10 %) and WAS (6 %). It was also observed that in the co-digestion assays, the assay with the highest percentage of TW (75 %) and GC (25 %) showed the highest acidification degree (57 %), confirming the synergy that occurred with this mixture. Out of the three kinetic models used to study the co-digestion performance between the two major residues in Cape Verde (OFMSW and WAS), the model that presented the best correlation to obtain the methanogenic potential was exponential Curve factor model. The values for the methanogenic rate constant increased with the increase of OFMSW in the mixture, with the maximum experimental value of kM (0.27 d-1) obtained in the 75 % OFMSW assay. It was also found that, despite the low biodegradability of WAS, this substrate promoted the stability of the OFMSW digestion process in this assay, thus avoiding the inhibition of methane production due to low pH values and high concentrations of VFA, as verified experimentally in the OFMSW mono-digestion test. Thus, the kinetic study provided a simple and useful tool to predict reactor performance with respect to methane production, taking into account the proportions of each of the co-substrates, and under the conditions applied. Analyzing the results of the response surfaces obtained for the OFMSW digestion assays, it has been demonstrated that the increase in the TS reactor content led to a decrease in the acidification degree whereas the increase in the alkalinity addition led to the increase of the degree of acidification. Therefore, the highest degree of acidification (78 %) was obtained at the lowest TS reactor content (5 %) and the highest alkalinity addition (50 gCaCO3.L-1). However, depending on the ultimate use of the produced VFA mixture, the conditions presenting the highest VFA content (99 %) with high propionic acid concentration (VFA mixture more suitable for the production of high quality PHA), were the intermediate TS reactor content (8 %). From the response surfaces obtained, it was also observed that all response variables under study (VFA production, degree of acidification and effluent quality) presented a higher dependency on TS reactor content than on initial alkalinity addition. The FORSU acidogenic fermentation process was further developed in a semi-continuous CSTR reactor, which was operated under long-term and several operational conditions (organic load between 3.0 - 6.5 g COD L-1 and alkalinity between 2.0 - 5.0 g CaCO3L-1).The operational condition correspondent to of 6.0 g COD L-1d-1 and the alkalinity of 2.5 g CaCO3 L-1, was the condition where the highest degree of acidification (59 %), the best effluent quality In terms of VFA (66 %), and a good odd-to-even ratio in VFA (0.44) were achieved. In general, the increase on the organic load applied led to the increase of VFA, with acetic, propionic and butyric acids being always the predominant species in all experimental stages. The acidified effluent in the anaerobic process was then used as substrate in SBR reactors operated for the selection of mixed microbial cultures with high capacity for PHA accumulation, where it was applied a regime of dynamic feeding (feast/famine) under aerobic conditions. Three organic loads and two C:N ratios were studied, in order to evaluate the enrichment potential of the microbial mixed culture. During the process, all tested conditions showed a COD removal efficiency higher than 80 % with a PHA accumulation capacity between 17 % and 53 %. In PHA accumulation studies carried out in fed-batch reactors, three different pH values, between 7 and 8.5 were studied, where PHA accumulation was more favorable at neutral pH, , resulting in a PHA content of 25 % (w/w). The HB monomer was the main compound of the polymer synthesized from acidified OFMSW. Based on these results, it can be concluded that organic waste from food sources can be treated by biological processes, as a conventional waste treatment, and at the same time can be converted into value-added materials.
A biodegradação constitui uma opção ecológica e sustentável para a eliminação e valorização de resíduos orgânicos, nomeadamente de origem alimentar. Estes resíduos podem ser tratados e valorizados através de processos de digestão anaeróbia, reduzindo assim o seu teor poluente e ao mesmo tempo produzir compostos intermediários valorizáveis, como os ácidos orgânicos voláteis (AOV). Estes compostos resultantes da fermentação acidogénica são fontes de carbono preferenciais para a obtenção de produtos de valor acrescentado, nomeadamente polihidroxialcanoatos (PHA) ou bioenergia, sob a forma de metano ou hidrogénio. Neste trabalho estudou-se a fermentação acidogénica de vários resíduos orgânicos, em mono ou co-digestão, nomeadamente a fração orgânica de resíduos sólidos urbanos (FORSU), resíduos da indústria de processamento de tomate (RT), borras de café (BC) e lamas ativadas prevenientes de uma estação de tratamento de águas residuais domésticas (LA), em reatores descontínuos e semi-contínuos, a fim de avaliar o seu potencial de produção de AOV. Nestes ensaios foram estudados os efeitos de vários parâmetros, nomeadamente a 1) concentração de sólidos totais (ST) no interior do reator, 2) a alcalinidade, 3) a carga orgânica (CO) e 4) a relação carbono-azoto (C:N). Nos ensaios de mono-digestão, verificou-se um comportamento muito distinto nos quatro substratos estudados, com um grau de acidificação substancialmente superior para o RT (49 %) e FORSU (41 %) do que para as borras de café (10 %) e lamas ativadas (6 %). Observou-se também que nos ensaios de co-digestão, o ensaio com a percentagem mais elevada de RT (75 %) e BC (25 %) apresentaram o mais elevado grau de acidificação (57 %), confirmando a sinergia que ocorreu com esta mistura. Dos três modelos cinéticos utilizados para estudar o desempenho da co-digestão entre os dois resíduos maioritários em Cabo Verde (FORSU e LA), o modelo que apresentou a melhor correlação para obtenção do potencial metanogénico foi o modelo de exponencial (com Curve factor). Os valores para a constante de velocidade metanogénica aumentaram com o aumento de FORSU na mistura, com o valor experimental máximo de kM (0.27 d-1) obtido no ensaio com 75% de FORSU. Verificou-se também que apesar da baixa biodegradabilidade das LA, este substrato promoveu a estabilidade do processo de digestão da FORSU neste ensaio, evitando assim a inibição da produção de metano devido a valores baixos de pH e a concentrações elevadas de AOV, conforme verificado experimentalmente no ensaio de mono-digestão da FORSU. Assim, o estudo cinético forneceu uma ferramenta simples e útil para prever o desempenho do reator no que diz respeito à produção de metano, tendo em conta as proporções de cada um dos co-substratos nas condições aplicadas. Recorrendo à modelação dos resultados obtidos na digestão da FORSU, através de superfícies de resposta, demonstrou-se que o aumento do teor de ST no digestor induziu uma diminuição do grau de acidificação, enquanto que o aumento da concentração de alcalinidade adicionada conduziu ao aumento do grau de acidificação. Por conseguinte, o maior grau de acidificação obtido foi de 78% com a combinação de ST mais baixo estudado (5 %) e a alcalinidade adicionada mais elevada (50 gCaCO3.L-1). No entanto, e dependendo da utilização final dos AOV que são produzidos, as condições que apresentaram elevado teor de AOV (99 %), com uma concentração elevada de ácido propiónico na sua composição (mais adequado para a produção de PHA de elevada qualidade), foram os teores de ST intermédios (8 %). A partir das superfícies de resposta obtidas observou-se também que todas as variáveis de resposta estudadas (produção de AOV, grau de acidificação e qualidade do efluente) apresentaram uma dependência maior do teor em ST do que da adição de alcalinidade. O processo de fermentação acidogénica da FORSU foi posteriormente desenvolvido em modo semi-contínuo num reator CSTR, que operou a longo prazo. De todas as condições testadas (carga orgânica entre 3.0–6.5 g COD L-1 e alcalinidade entre 2.0-5.0 g CaCO3 L-1), a condição onde se obteve o maior grau de acidificação (59 %), a melhor qualidade de efluente em termos de AOV (66 %), e uma boa razão impar-par em AOV (0.44), foi o ensaio com carga orgânica de 6,0 g CQO L-1d-1 e alcalinidade de 2,5 g CaCO3 L-1. O aumento da carga orgânica levou ao aumento de AOV, sendo os ácidos acético, propiónico e butírico as espécies predominantes em todas as fases do processo. O efluente acidificado no processo anaeróbio foi então usado como substrato em reatores SBR operados para seleção de culturas microbianas mistas com capacidade para acumular PHA, nos quais foi aplicado um regime de alimentação dinâmica (fartura/fome) em condições aeróbias. Foram estudadas três cargas orgânicas e duas razões C:N para avaliar o potencial de enriquecimento da cultura. Durante o processo, todas as condições testadas apresentaram uma eficiência de remoção de CQO superior a 80 %, com uma acumulação de PHA entre 17 % e 53 %. Em estudos de acumulação de PHA efetuados em reatores semi-contínuos foram estudados três valores de pH, entre 7 e 8.5, em que a acumulação de PHA foi mais favorável a pH neutro, resultando num teor de PHA de 25% (w/w). O monómero HB foi o principal composto do polímero sintetizado a partir de FORSU acidificada. Com base nestes resultados, pode concluir-se que os resíduos orgânicos de origem alimentar podem ser tratados por processos biológicos, com tratamento convencional de resíduos, e ao mesmo tempo podem ser convertidos em materiais de valor acrescentado.

Le veau nouveau-né possède un rumen peu développé et non fonctionnel. Au cours des premiers mois, les fonctions digestives s’établissent, avec l’implantation du microbiote composé majoritairement de bactéries, archées et protozoaires. Les objectifs de ce travail étaient doubles : i) caractériser et comprendre la séquence d’implantation taxonomique des microorganismes du rumen chez le veau par des techniques de biologie moléculaire et de dénombrement, ainsi que la séquence de mise en place des paramètres fermentaires (AGV et ammoniac) et des activités principales enzymatiques chez le veau en périodes pré- et post-sevrage, ii) étudier l’effet de l’addition de levures vivantes sur la mise en place de cet écosystème ruminal en périodes pré- et post-sevrage. D’une part, nos travaux ont permis de confirmer qu’à la naissance, le rumen chez le veau, est dépourvu de micro-organismes, d’AGV, d’activité xylanasique et amylasique, avec un pH proche de la neutralité et un Eh fortement positif. La colonisation du rumen se fait dès la naissance, pendant les 15 premiers jours de la vie de l’animal par un microbiote complexe prédominé par les bactéries (phyla Proteobacteria et Bacteroidetes) et comprenant aussi des archées (majoritairement Methanobrevibacter). En même temps, le Eh devient fortement négatif. Ces communautés entraînent la production de produits fermentaires grâce à leurs activités enzymatiques. Entre 15 jours et le sevrage, avec l’ingestion d’aliments solides, la composition du microbiote du rumen évolue pour se rapprocher de celle de ruminants adultes, sans atteindre pour autant la maturité en termes de densités et abondances relatives. A cette période, le phylum Bacteroidetes est majoritaire, avec le genre Prevotella. Après le sevrage de légers changements apparaissent sur certains paramètres fermentaires comme les AGV sans doute en raison d’une évolution du microbiote qui devient moins diversifié et plus adapté à la dégradation d’aliments solides. L’apparition, à partir de 90 jours, des protozoaires ciliés dans le rumen semble conditionnée par la présence d’animaux adultes à proximité. A 4 mois d’âge, l’écosystème ruminal tend à devenir proche de celui observé chez les animaux adultes en matière de paramètres fermentaires, activités enzymatiques et composition taxonomique du microbiote. D’autre part, nos travaux ont permis de conclure que, avant sevrage, une supplémentation en levures vivantes (Saccharomyces cerevisiae) diminue l’ingestion de concentrés, conduit à une apparition plus précoce de la communauté des protozoaires et une plus grande densité d’archées, mais a peu d'effets sur la densité et la diversité de la communauté bactérienne, à l'exception de variations d’abondances de quelques taxa mineurs. L’apport de levures entraîne une diminution de la protéolyse, une augmentation de la proportion d'acétate ruminal et une diminution de la proportion de propionate. Au cours de la période post-sevrage, les veaux supplémentés en levures consomment plus de foin et la densité en archées est plus importante alors qu’une réduction de la diversité et de la densité de la communauté bactérienne est observée, mais accompagnée d’une augmentation de l’abondance relative des bactéries dégradant l’amidon, les pectines, les protéines et majoritairement les parois cellulaires en fonction des substrats présents dans le rumen. Ces changements sont probablement à relier aux augmentations de l'activité xylanasique et de la proportion d'acétate. L’ensemble des résultats acquis dans ce travail de thèse a permis d’apporter un certain nombre de connaissances et une meilleure compréhension de la mise en place de l’écosystème ruminal chez le veau de race laitière en périodes pré- et post-sevrage, ainsi que quelques pistes pour orienter ou améliorer cette implantation pour une meilleure maîtrise de l’élevage des veaux d’élevage
The newborn calf has a little and non-fonctional rumen. During the first months of life, digestive functions establish, in relationship with the colonization by a microbiota mainly composed of bacteria, archaea and protozoa. This study had two objectves: i) characterize and understand the sequence of establishment of ruminal microbiota in calves by molecular biology and counting techniques abd describe the appearance of fermentation parameters (VFA and ammonia) and enzyme activities during the pre- and post-weaning periods, ii) define the effect of yeast supplementation on the establishment of the ruminal ecosystem in pre-and post-weaning periods. On the one hand, our work confirmed that at birth, calf rumen is devoid of micro-organisms, AGV, xylanase and amylase activities, with a pH close to neutrality and a strongly positive Eh. From 2 to 15 days of age, the rumen is colonized by a complex microbiota dominated by bacteria (Proteobacteria and Bacteroidetes phyla) and also containing archaea (with mainly the Methanobrevibacter genus), and Eh becomes strongly negative. These communities result in the production of fermentation products due to their enzymatic activities. Between 15 days and weaning, with the ingestion of solid food, the composition of rumen microbiota changes to become closer to that of adult ruminants without reaching maturity in term of densities and relative abundances. At this time, the phylum Bacteroidetes is predominant with the Prevotella genus. After weaning, slight differences occurs on some fermentative parameters such as VFA, probably related to a change in the microbiota that becomes less diversified and more adapted to the degradation of solid food. From 90 days, the establishment of ciliated protozoa in the calf rumen seems conditioned by the proximity with adult animals. From 4 months of age, considering fermentation, enzymatic and taxonomic composition of the microbiota, the ruminal ecosystem tends to be similar to that observed in adult animals. On the other hand, our work showed that during the pre-weaning period, the supplementation with live yeast (Saccharomyces cerevisiae) results in a lower concentrate intake, an earlier establishment of ciliated protozoa and a higher archaeal community density, but poorly affects the density and diversity of the bacterial community, with the exception of changes in abundances of some minors taxa. Yeast supplementation reduces proteolysis, increases the proportion of acetate and decreases that of propionate. During the post-weaning period, yeast supplemented calves consumed more hay, had a higher archaeal density, but a lower diversity and density of the bacterial community with an increased relative abundance of fiber, protein, starch, pectine degrading bacteria compared to control according to the substrates present in the rumen. These changes are probably related to increases of the xylanolytic activity and the proportion of acetate. Taken together, results obtained in his thesis have improved knowledge and understanding of the establishment of the ruminal ecosystem in the dairy calf in pre- and post-weaning periods, and carried some possibilities to orientate or improve the ruminal establishment for better control of calves rearing

Polyhydroxyalkanoates (PHA) are a family of biodegradable polyesters naturally synthesised by some bacteria and archaea. PHA have high industrial value as bioplastics for packaging and biomedical applications. However, their broader use is hindered by high production costs and uncontrolled variation of polymer properties. The extreme halophile Haloferax mediterranei shows bioprocess advantages that can be exploited for the low cost production of the PHA copolymer Poly(3-hydroxbutyrate-co-3-hydroxyvalterate) (PHBV). The focus of this thesis is to identify process variables responsible for the uncontrolled variation of PHA properties in order to progress towards the robust production of PHBV using H. mediterranei. The outcome of the investigation is a novel cultivation strategy for the reliable synthesis of PHBV copolymers with controlled composition and microstructure showing minor differences in material characteristics. Initially, growth kinetics and PHBV synthesis were characterised under nitrogen-excess and nitrogen-limiting conditions in ammonium and for the first time, nitrate. The nitrogen source and concentration influenced PHBV accumulation and variations in polymer composition were observed with ammonium, highlighting the importance of the control of cultivation conditions. Volatile fatty acids (VFA) were found to be a more direct approach to determine PHBV composition and for the first time were used as substrates in H. mediterranei cultures. When the cells were grown in C4:0/C5:0 mixtures, the 3HV fraction in the PHBV was proportional to the percentage of C5:0 in the feed mixture, allowing the synthesis of copolymers with a predefined composition ranging from pure PHB to pure PHV. The cultivation strategy proved effective for the synthesis of HV rich PHBV, which is not easily obtained due to the 3HV precursor toxicity. The polymer microstructure was controlled using different feeding strategies: co-feeding generated random copolymers, while sequential feeding created block and blend copolymers. The synthesis of block copolymers is of interest because the materials show enhanced yield strength and mechanical strength, making such materials more suitable for commodity uses. Bespoke random, block, and blend copolymers with 0−100 mol% 3HV were synthesized and their thermal and mechanical properties studied. Lastly, high temperature cultivation and several surfactants were tested to enhance the production of bespoke PHBV from VFA. PHBV productivity and accumulation was greatly improved in a fed-batch bioreactor fermentation at 37°C with Tween-80 and the maximum PHBV content 58.9% was obtained. The polymers from shake-flasks and from bioreactors showed minor variations in their material properties, demonstrating the scalability and the robustness of the process developed. Further understanding of the different process variables affecting polymer synthesis and composition was gained in this thesis. It is now possible to produce PHBV with controllable composition, microstructure and minor differences in material characteristics. The novel and robust production strategy developed address the bioprocess challenge of minimising the uncontrolled variation of polymer characteristics that is currently hindering the wider use of PHA hence allowing the production of high quality polymers for commodity goods, packaging and biomedical applications.

Mestrado em Biotecnologia - Biotecnologia Industrial e Ambiental
Polyhydroxybutyrate is a type of biodegradable plastic, fully synthesized by bacteria, with similar properties to the ones of conventional plastics. This biopolymer can be produced by mixed cultures (activated sludge form waste water treatment plants) using the volatile fatty acids present in waste streams. Although the huge potential of this process, its application for the industrial production of PHB still lacks development. Throughout this work, three different strategies to obtain PHB-producing bacteria by using waste streams were tested. In the first one PHB-producing bacteria were first selected by aerobic dynamic feeding conditions, while simultaneously providing hydrogen gas, followed by an accumulation stage. In the second strategy the conventional aerobic dynamic feeding conditions were imposed, followed by an accumulation stage. And a third one, where a mixed culture was straightly submitted to the accumulation stage, without previous selection. Aerobic dynamic feeding was operated in cycles og 8 hours (3 cycles per day). In the first two strategies, feast phase was intended to last 2h30 and the famine 5h30 for a feast/famine ratio of 0.45. While the accumulation stage lasted 22 hours. High biomass concentration were achieved using strategy 1, in a stable reactor, and it was possible to accumulate PHB up to 59 % of the VSS with a PHB production yield of 0.30 g SLB/g COD fed. The second strategy resulted in less stable rectors, and a PHB content of 40 % of the VSS was achieved, but with PHB production yields as low as 0.09 g PHB/ g COD. Furthermore, it was no always possible to produce PHB as carbon source seemed to be directed to other metabolic pathways. A PHB production yields of 0.31 g PHB/g COD consumed was achieved with the third strategy, although only with a PHB content of 21 % of VSS. The production of PHB was verified firstly by a thermogravimetric method developed at Avecom previously to this work. This method was replaced by other that comprises the extraction of PHB using 1,2 propylene carbonate as solvent. The development of this method is also addressed in this project.
Polihidroxibutirato é um tipo de plástico biodegradável, completamente sintetizado por bactérias, com propriedades semelhantes aos plásticos convencionais. Este biopolímero pode ser produzito por culturas mistas (lamas ativadas de estações de tratamento de águas) usando os ácidos orgânicos voláteis presentes no efluente. Embora este processo apresente um enorme potencial, ainda é necessário o seu desenvolvimento para a sua aplicação na produção de PHB a escala industrial. Durante este trabalho, foram testadas três estratégias diferentes para a seleção de bactérias produtoras de PHB forma testadas. A primeira, em que as bactérias produtoras de PHB foram primeiro selecionadas por condições de alimentação dinâmica aeróbia, com a alimentação simultânea de hidrogénio, seguida de uma fase de acumulação. Uma segunda estratégia, onde a alimentação dinâmica aeróbia foi utilizada, seguida de uma etapa de acumulação. E uma terceira, em que uma cultura mista foi imediatamente submetida a uma fase de acumulação, sem seleção prévia. Nas duas primeiras estratégias a alimentação dinâmica aeróbia consistiu em ciclos de 8 horas (3 ciclos por dia), em que se pretendeu-se que a fase de fartura durasse 2h30 A fase de fome por seu lado durou 5h30 para um rácio fome/fartura de 0.45. A fase de acumulação durou 22 horas. Foram atingidas altas concentrações de biomassa usando a estratégia 1, num reactor estável, em que foi possível atingir um conteúdo em PHB de 59 % dos SSV, com um rendimento de produção de PHB de 0.30 g SLB/g CQO alimentado. A segunda estratégia resultou num reactor menos estável. Um conteúdo em PHB de 40 % dos SSV foi obtido, embora o rendimento de produção de PHB tenho sido só 0.09 g PHB/g CQO. Para além isso, nem sempre foi possível produzir PHB, visto que a fonte de carbono parecia ser direcionada para outras vias metabólicas. Foi atingido um rendimento de produção de PHB de 0.31 PHB/g CQO na terceira estratégia, no entanto o conteúdo em PHB foi só 21 % dos SSV. A produção de PHB foi inicialmente verificada por um método termogavimétrico desenvolvido na Avecom previamente a este trabalho. Este método foi posteriormente substituído por outro que envolve a extração de PHB usando carbonato de propileno como solvente. O desenvolvimento deste método é abordado no presente trabalho.

The objective of this study is to illustrate that phase separation improves the efficiency of an anaerobic system which digests semi-solid organic wastes. Organic fraction of municipal solid waste (OFMSW) was the semi-solid organic waste investigated. In the first part of the study, the optimum operational conditions for acidified reactor were determined by considering the volatile solid (VS) reductions and average acidification percentages at the end of two experimental sets conducted. Organic loading rate (OLR) of 15 g VS/L.day, pH value of 5.5 and hydraulic retention time (HRT) of 2 days were determined to be the optimum operational conditions for the acidification step. Maximum total volatile fatty acid and average acidification percentage were determined as 12405 mg as HAc/L and 28%, respectively in the reactor operated at optimum conditions. In the second part, an acidification reactor was operated at the optimum conditions determined in the first part. The effluents taken from this reactor as well as the waste stock used to feed this reactor were used as substrate in the biochemical methane potential (BMP) test. The results of BMP test revealed that the reactors fed by acidified samples indicated higher total chemical oxygen demand (tCOD) removals (39%), VS reductions (67%) and cumulative gas productions (265 mL). The result of this study indicated that the separation of the reactors could lead efficiency enhancement in the systems providing that effective control was achieved on acidified reactors.

Submitted by JOSIANE SANTOS DE OLIVEIRA (josianeso) on 2018-01-31T12:54:08Z No. of bitstreams: 1 Nara Paula Schmeier_.pdf: 877010 bytes, checksum: f002cde3446d9c5552d9a747ff097801 (MD5)
Made available in DSpace on 2018-01-31T12:54:08Z (GMT). No. of bitstreams: 1 Nara Paula Schmeier_.pdf: 877010 bytes, checksum: f002cde3446d9c5552d9a747ff097801 (MD5) Previous issue date: 2017-11-20
CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Petrobras - Petróleo Brasileiro S. A.
PROSUP - Programa de Suporte à Pós-Gradução de Instituições de Ensino Particulares
O processo de digestão anaeróbia tem sido empregado com destaque no tratamento de resíduos sólidos orgânicos, por tratar-se de uma alternativa para amenizar problemas ambientais e também por uma questão energética, visto que possibilita a produção de energia para auxiliar a suprir a alta demanda, em consequência do elevado crescimento populacional e industrial. No entanto, questões relativas a escalas de trabalho, formas de operação, carga orgânica e influência de parâmetros como AGV, alcalinidade e nitrogênio amoniacal (NA) perduram. Desta forma o presente trabalho objetivou avaliar a operação de biodigestor, ao longo de 340 dias, mediante variação de frequências de adição de RSO e cargas orgânicas volumétricas (COV) de 7,98, 7,80, 9,64, 3,28, 4,10 e 5,00 kg STV/m3.d., com média de ST: 339,6 mg/g e umidade: 64%, frente a produção de biogás e CH4. Ademais, também buscou avaliar a influência de parâmetros como AGV, alcalinidade e nitrogênio amoniacal sobre o processo de DA. O sistema experimental foi composto por um biodigestor de câmara única, com volume de 0,28 m³, alimentado com RSO do restaurante universitário e inoculo ambientado a digestão de RSO. O monitoramento do processo experimental foi realizado por meio de caracterização físico-química (pH, DQO, DBO, alcalinidade, AGV, ST, STF, STV, NT, NA, PT e COT) das frações sólidas e líquidas, além da quantificação do biogás (volume e percentual de CH4). O processo de digestão revelou que aplicações de COVs de 3,28, 4,10 e 5,00 kg STV/m3.d. possibilitaram maiores rendimentos de biogás e CH4, em relação a COVs de 7,98, 7,80 e 9,64 kg STV/m3.d. A aplicação continua da COV de 4,10 kg STV/m3.d. apresentou o maior rendimento de biogás e CH4 em função dos STV aplicados, sendo 94,63 NL/kg STV e 45,42 NL/kg STV, respectivamente. No decorrer do processo de digestão, elevadas razões de AGV/Alcalinidade, baixas razões de C/NT e elevadas concentrações de AGV e NA levaram a uma condição de digestão que representou rendimentos reduzidos de biogás e metano.
The anaerobic digestion (AD) process has been used in the treatment of organic solid waste, for being an alternative to ease environmental problems and also an energy issue, since it allows the production of energy to help supplying the high demand, as a result of high population and industrial growth. However, issues concerning work scales, operation forms, organic loads and influence of parameters such as VFA, alkalinity and ammonia nitrogen (AN) to linger. In this way, the objective of this work was to evaluate the biodigester operation, during 340 days, by varying the frequencies of organic solid waste (OSW) and organic loading rate (OLR), of 7,98, 7,80, 9,64, 3,28, 4,10 e 5,00 kg STV/m3.d., with mean de TS: 339,6 mg/g and humidity: 64%, against production of biogas and CH4. In addition, it also sought to evaluate the influence of parameters such as VFA, alkalinity and AN on the DA process. The experimental system consisted of a single chamber biodigester with a volume of 0.28 m³, fed with OSW from a university restaurant and inoculum set to the digestion of OSW. The monitoring of the experimental process was carried out through physicochemical characterization (pH, COD, BOD, alkalinity, VFA, TS, TFS, TVS, TN, AN, PT and TOC) solid and liquid fractions, in addition to the quantification of biogas (volume and percentage of CH4). The digestion process revealed that OLRs applications of 3,28, 4,10 e 5,00 kg TVS/m3.d. allowed higher yields of biogas and CH4, in relation to OLRs of 7,98, 7,80 e 9,64 kg TVS/m3.d. The continuous application of OLR of 4,10 kg TVS/m3.d. showed the highest biogas yield and CH4 as a function of the VTS applied, being 94,63 NL/kg TVS and 45,42 NL/kg TVS, respectively. During the digestion process, high AGV/Alkalinity ratios, low C/N ratios and high concentrations of VFA and AN led to an digestion condition which represented reduced yields of biogas and methane.

In questo elaborato è descritto il progetto di un nodo sensore attivo piezoelettrico adatto per applicazioni nell'ambito del monitoraggio strutturale, in particolare per l'analisi ad ultrasuoni. Tale tecnica si avvale di almeno una coppia di sensori: un pulsatore attivo e un ricevitore passivo. A tal proposito, i più utilizzati sono i trasduttori piezoelettrici, i quali trovano un largo impiego anche nell'ambito biomedico. Le attrezzature commerciali utilizzate in questo campo allo stato dell'arte hanno grande ingombro, costi elevati e un alto voltaggio. Tuttavia, tramite un'analisi preliminare sulla struttura da monitorare è possibile individuare le zone di maggiore stress e quindi inserire i sensori in modo mirato, riducendo l'ingombro e il peso dell'elettronica utilizzata. In questo contesto si inserisce il lavoro di tesi, il cui obiettivo è il progetto di un nodo sensore attivo piccolo, leggero, a basso costo e a basso consumo di potenza, idoneo per essere installato permanentemente sulle strutture. Si è passati dalla definizione del problema alle possibili implementazioni circuitali utilizzando il software LTspice, fino alla scelta finale dei componenti fisici che sintetizzassero il blocco di driver/demodulatore, rispettivamente pilotando l'elemento piezoelettrico e demodulando il segnale PWM generato dal microcontrollore. Dopo aver utilizzato un induttore (flottante) per svolgere l'adattamento di impedenza, sono stati testati due componenti di natura induttiva: doppio circuito di Antoniou e doppio giratore. Nella fase successiva sono state disaccoppiate la funzione di driver e demodulatore, realizzate prima da un VFA e un filtro passa-basso e poi, nello step finale, da un CFOA e un filtro passa-basso. Come risultato finale è stato ottenuto un nodo sensore attivo, la cui tensione di uscita è caratterizzata da una dinamica pari a 6 V circa e una frequenza di risonanza di 20 KHz.

O presente trabalho teve como objetivo principal avaliar a performance e a estabilidade operacional de uma nova configuração de um reator anaeróbio híbrido (RAH) que combina um filtro anaeróbio de fluxo descendente seguido de uma câmara de manta de lodo de fluxo ascendente comparativamente ao reator UASB nas mesmas condições operacionais aplicados ao tratamento de esgoto sanitário. A avaliação da eficiência de remoção de remoção da matéria orgânica e dos sólidos suspensos nos reatores piloto foi por meio de testes da DQO, DBO, sólidos em suspensão totais (SST) e dos sólidos em suspensão voláteis (SSV).Os reatores UASB e RAH foram operados por um período de 240 dias na fase 1 e 150 dias na fase 2 com vazão afluente de 1,6 m3/h e TDH de 11,8 h. O TDH médio na câmara de entrada do RAH foi de 2,7h e de 9,1h na câmara ascendente de manto de lodo. Os reatores piloto apresentaram capacidade de tratamento para suportar os choques de carga orgânica devido à variabilidade do esgoto bruto. A eficiência de remoção de matéria orgânica em termos de DQO foi de 66% e 59% para o UASB e RAH, a eficiência de remoção de SST atingiu valores de 65% e 63% respectivamente, aliás, o reator UASB apresentando valores superiores de desempenho operacional em quase todos os parâmetros de monitoramento dos processos de digestão anaeróbia os valores médios dos parâmetros DQO, DBO5, SST e SSV não tiveram diferenças estatisticamente significativas. O pH para os sistemas piloto esteve na faixa ideal para o desenvolvimento dos microorganismos anaeróbios (6,5 a 7,5) e a alcalinidade e os AGVs demonstraram estabilidade dos reatores, corroborados pela estabilidade do pH no interior de cada sistema. A velocidade ascensional na câmara de manta de lodo (0,45 m/h) não causou efeito adverso na qualidade do efluente em termos de SST, com valor médio de 39,8 mg/L, na mesma faixa observada no reator UASB (41,6 mg/L). Foi observada menor concentração de biomassa no reator RAH (distribuição vertical) comparativamente ao reator UASB segundo os perfis verticais de lodo, entretanto, este fato não comprometeu a sua eficiência de remoção de matéria orgânica e dos sólidos suspensos. A retirada do lodo de excesso dos sistemas piloto foi baseada na relação STV/ST para estimar a fração de biomassa, a freqüência do descarte foi de 1 vez por mês retirando o equivalente aos 10% do volume de lodo das tomadas que apresentaram uma fração de STV menor que 50%. É viável a implementação da turbidez como parâmetro de detenção de perdida de lodo no efluente dos reatores anaeróbios devido a que a turbidez e os SST apresentaram uma relação direta o que ajudaria a simplificar mecanismos de controle operacional para a toma de decisões nas estações de tratamento, sendo que a turbidez é um parâmetro de leitura rápida “in situ” e poderia advertir do excesso de lodo ao interior do reator. Foram empregados diferentes métodos titrimétricos para a determinação dos AGVs no efluente do RAH e UASB. Após análise dos resultados, recomenda-se o uso do método de KAPP e RIPLEY para a determinação dos AGVs pela simplicidade metodológica e pela rapidez na obtenção do resultado.
This study aimed to evaluate the performance and operational stability of a new configuration of a hybrid anaerobic reactor (RAH) combining an anaerobic filter downflow followed by a sludge blanket chamber upflow compared to UASB in same operating conditions applied to sewage treatment. The evaluation of organic matter removal and removal efficiency of suspended solids in the pilot reactor was by testing COD, BOD, total suspended solids (TSS) and volatile suspended solids (VSS). The RAH and UASB reactors were operated for a period of 240 days in the first phase and 150 days in phase 2 with the inlet flow of 1,6 m3/h and 11,8h TDH. The average TDH RAH in the inlet chamber was 2.7h and 9,1h in ascending chamber sludge blanket. Pilot reactors showed treatment capacity to support organic shock loads due to the variability of raw sewage. The organic matter removal efficiency in terms of COD was 66% and 59% for the UASB and RAH, the TSS removal efficiency reached values of 65% and 63% respectively, by the way, the UASB presenting performance values higher operational in almost all parameters of the monitoring anaerobic digestion processes mean values of the parameters COD, BOD5, TSS and VSS were not statistically significant differences. The pH for the pilot systems was in the ideal range for the development of anaerobic microorganisms (6,5 to 7,5) and alkalinity and Volatile Fatty Acids (VFA) demonstrated stability of reactors corroborated by the pH stability within each system. The upflow velocity in the sludge blanket chamber (0,45 m/h) caused no adverse effect on effluent quality in terms of TSS, with an average of 39,8 mg/L, in the same range observed in UASB (41,6 mg/L). It was observed lower concentration of biomass in the reactor RAH (vertical distribution) compared to UASB second vertical sludge profiles, however, this fact did not compromise its removal efficiency of organic matter and suspended solids. The withdrawal of the pilot systems excess sludge was based on TSV/TS ratio to estimate the biomass fraction, the frequency of disposal was 1 once a month by removing the equivalent of 10% of the outlets sludge volume that had a fraction of TSV less than 50%. The implementation of turbidity as sludge lost detention parameter is viable in the effluent of the anaerobic reactors due to turbidity and TSS showed a direct relationship which would help simplify operational control mechanisms for decision making in treatment plants, wherein the turbidity is a quick read parameter "in situ" and could warn of excess sludge inside the reactor. Different titrimetric methods were employed for the determination of VFA and the effluent from the UASB and RAH. After analyzing the results, we recommend the use of KAPP and RIPLEY method for the determination of VFA by methodological simplicity and speed in obtaining results.

Vaccination constitutes one of the most efficient and cost-effective methods of promoting global health. Nevertheless, few vaccines are fully effective, for manifold reasons ranging from intrinsic limitations to more contingent shortcomings related, e.g., to cold chain transport, handling and storage. In this context, peptide-based vaccines that consist of a fully synthetic approach mimicking B-and T-cell epitopes have emerged as an attractive alternative to overcome many such issues. Unfortunately, short peptides have generally been related to low immunogenicity and weak protection. In this thesis, we continue the progress towards the development of efficient peptide vaccines against foot-and-mouth disease (FMD) –a highly contagious viral disease of livestock that has a major economic impact. Particularly, the protective immune response under different conditions (dose, duration, different T-cell epitopes and novel candidates) is assessed in animal models. Moreover, we report the chemical synthesis of higher polyvalent peptide dendrimers using “click” chemistry methods of chemoselective ligation.
La vacunació constitueix un dels mètodes més eficients i rendibles per promoure la salut mundial. No obstant això, poques vacunes són plenament efectives, per diverses raons que van des de limitacions intrínseques a deficiències més contingents relacionades, per exemple, amb el transport, manipulació i/o emmagatzematge en cadena de fred. En aquest context, les vacunes basades en pèptids, que plantegen un enfocament totalment sintètic en la reproducció d’epítops de cèl·lules B i T, han sorgit com una alternativa atractiva per superar molts d’aquests problemes. Malauradament, els pèptids lineals i curts s’han relacionat generalment amb baixa immunogenicitat i baixa protecció. En aquesta tesi continuem avançant cap al desenvolupament de vacunes peptídiques eficaces contra la febre aftosa, una malaltia vírica del bestiar altament contagiosa i amb important impacte econòmic. En particular, hem avaluat la resposta immune sota diverses condicions (dosi, durada, diferents epítops de cèl·lules T i nous candidats) en models animals. A més, també hem desenvolupat la síntesi de pèptids multivalents utilitzant reaccions de lligament quimioselectiu amb la coneguda química “click”.

Ce travail de thèse a eu pour objectif principal l'étude thermodynamique des changements métaboliques dans l'acidogénèse. L'acidogénèse est un procédé anaérobie à double intérêt qui en traitant des résidus organiques, permet de produire des composés chimiques comme l'hydrogène, l'éthanol et les acides organiques. Par conséquent, l'acidogénèse se place comme un procédé biotechnologique dans le concept de bioraffinerie. En outre, ce processus n'a pas besoin de conditions stériles d'opération et fonctionne sur une large gamme de pH. Ces changements métaboliques sont dépendants des modifications dans les conditions opératoires. Afin d'étudier ces changements métaboliques, des expériences basées sur des modifications du ciel gazeux du réacteur par introduction d'azote et sur des changements du pH, ont été menées. Un des résultats les plus intéressants a été l'augmentation du rendement de production d'hydrogène de 1 à 3,2 molH2/molglucose à pH 4,5 et débit de N2 de 58,4 L/d. Ce rendement est proche de la valeur théorique (4 molH2/molglucose). L'étude thermodynamique a permis d'expliquer les mécanismes métaboliques concernant l'hydrogène, dont la production importante, représentée par le rendement de 3,2 molH2/molglucose, est due à la réaction inverse H2/NAD+, qui est thermodynamiquement faisable à faibles pressions partielles d'hydrogène (par exemple 0,02 bar). En outre, les bas rendements en hydrogène ont été expliqués par l'action consommatrice d'hydrogène par la réaction d'homoacetogénèse. Cependant, le modèle n'a pas été capable d'expliquer les changements métaboliques de l'acétate, du butyrate et de l'éthanol lors de la fermentation acidogénique du glucose
This thesis deals with thermodynamic based modelling of metabolic shifts during acidogenic fermentation. Acidogenic fermentation is an anaerobic process of double purpose: while treating organic residues, it produces chemical compounds, such as hydrogen, ethanol and organic acids. Therefore, acidogenic fermentation arises as an attractive biotechnology process towards the biorefinery concept. Moreover, this process does not need sterile operating conditions and works under a wide range of pH.Changes of operating conditions produce metabolic shifts, inducing variability on acidogenic product yields. In order to study these metabolic shifts, an experiment design was based on reactor headspace N2-flushing (gas phase) and pH step changes (liquid phase). A major result was the hydrogen yield increase from 1 to 3.2 (molH2/molglucose) at pH 4.5 and N2-flushing of 58.4 L/d. This yield is close to the theoretical acidogenic value (4 molH2/molglucose).The thermodynamic model, based on the assumption that acidogenic fermentation is characterised by limited energy available for biological process, allowed to explain the mechanisms that govern hydrogen metabolic shifts, showing that the synthesis of extra hydrogen, i.e. yield of 3.2 (molH2/molglucose), was due to reverse H2/NAD+ redox reaction, which is thermodynamically feasible at low hydrogen partial pressures (e.g. 0.02 bar). Moreover, low hydrogen yields were explained by the action of homoacetogenesis hydrogen consuming reaction. However, the model was not capable to explain the metabolic shifts of acetate, butyrate and ethanol on acidogenic glucose fermentation

[EN] Phosphorus is very important in life because it plays an essential role in biological processes. The main use of phosphorus is in the fertilizer industry in the form of phosphates. These phosphates come mainly from phosphate rocks which might be exhausted in 50-100 years. The overexploitation of phosphate rocks has resulted in decreased quality of reserves, and it has raised the cost of extraction, processing and shipping. Moreover, phosphorus coming from wastewater, phosphate rock dissolution, and soil with an excessive supply of fertilizer, is deposited on the surface water bodies causing a serious pollution problem called eutrophication. One of the systems most used to reduced phosphorus levels in the wastewater is the enhanced biological phosphorus removal (EBPR). This process involves capturing biologically, alternating between anaerobic oxic/anoxic conditions, the wastewater phosphorus through the phosphorus accumulating organisms (PAOs). However, one of the main problems of this process is that the glycogen accumulating organisms (GAOs) compete with PAOs for volatile fatty acids (VFA). Even though there have been many studies on the factors affecting competition between PAOs and GAOs, there are still many unanswered questions regarding the metabolism of PAOs when they lack energy reserves in the form of intracellular polyphosphates (poly-P) and its effect on the population dynamics of PAOs and GAOs in an activated sludge system. Therefore, the main goal of this dissertation is to study short- and long-term the metabolic behavior of the PAOs to different levels of poly-P; to analyze the population dynamics of microorganisms involved in the process EBPR; to model mathematically that metabolic behavior; and finally, to evaluate the possible recovery of phosphorus by extracting poly-P present in the PAOs. In the short- and long-term study was observed a metabolic shift correlates with the content in poly-P so that under low contents of poly-P the PAOs are able to behave as GAOs but without a significant development of the GAO population. Although, in both studies was observed the same metabolic behavior, from the microbiological point of view were observed some differences. In the short-term, the PAO Type II clearly showed the metabolic shift, while long-term were the PAO Type I. From the experiments performed, necessary expressions (stoichiometric and kinetic) were developed to include new behaviors observed (metabolic rate) in metabolic models existing today. Monod type expressions were developed and implemented on the model of the PAOs to represent the change between the typical stoichiometric parameters of PAO and GAO metabolism. The model was calibrated and validated showing the ability to correctly represent the metabolic change of PAOs under low concentrations of poly-P. When was observed that with low concentrations of poly-P the PAOs have the ability to change its metabolism, without the process was deteriorated by the development of the GAO population, two operating strategies were evaluated to obtain a stream rich in phosphorus to allow later retrieval. The strategies studied differed in the level of extraction of the poly-P from PAOs. In the first strategy, it was extracted less than 40 % of poly-P, while the second strategy, it came to extract more than 90 % of poly-P. The second strategy showed a higher extraction efficiency, achieving recover up to 81 % of the phosphorus present in the wastewater. As a result, of work performed four articles were generated, three of them published in journals of particular importance (2 in the journal Water Research and 1 in the journal Chemical Engineering Journal) constituting the main body of this thesis.
[ES] El fósforo es de gran importancia para la vida debido a que desempeña un papel esencial en los procesos biológicos. El principal uso del fósforo está en la industria de los fertilizantes en forma de fosfatos. Estos fosfatos provienen principalmente de las rocas fosfáticas, las cuales podrían llegar a agotarse entre los próximos 50 y 100 años. La sobreexplotación de la roca fosfática, ha generado una disminución en la calidad de las reservas, y ha elevado el coste de su extracción, procesamiento y transporte marítimo. Por otra parte, el fósforo proveniente de las aguas residuales, de la disolución de las rocas fosfáticas y de los suelos con excesivo aporte de fertilizantes, se deposita en los cuerpos de aguas superficiales produciendo un grave problema de contaminación llamado eutrofización. Uno de los sistemas más empleados para reducir los niveles de fósforo en el agua residual es el proceso de eliminación biológica de fósforo (EBPR). Este proceso implica capturar biológicamente, alternando entre condiciones anaerobias óxicas/anóxicas, el fósforo del agua residual mediante organismos acumuladores de fósforo (PAOs). Sin embargo, uno de los principales problemas de este proceso, es la competencia de las PAOs con los organismos acumuladores de glucógeno (GAOs) por los ácidos grasos volátiles (AGV). Aunque si bien se han realizado muchos estudios sobre los factores que afectan la competencia entre PAOs y GAOs, existen aún muchas preguntas sin respuesta en relación al metabolismo de las PAOs cuando estas carecen de reservas energéticas en forma de polifosfatos intracelulares (poli-P) y a su efecto sobre la dinámica de las poblaciones de PAOs y GAOs en un sistema de fangos activados. Es por ello que el objetivo principal de esta tesis doctoral consiste en: estudiar a corto y largo plazo el comportamiento metabólico de las PAOs al cambiar el contenido en poli-P; analizar la dinámica poblacional de los microorganismos implicados en el proceso de EBPR; modelizar matemáticamente dicho comportamiento metabólico y por último evaluar la posible recuperación de fósforo mediante la extracción del poli-P presente en las PAOs. En el estudio a corto y largo plazo se observó un cambio metabólico correlacionado con el contenido en poli-P, de forma que a bajos contenidos de poli-P las PAOs se comportaban metabólicamente como las GAOs, pero sin que estas últimas se llegaran a desarrollar de forma significativa. A pesar de observar el mismo comportamiento metabólico en ambos estudios, desde el punto de vista microbiológico se observaron diferencias. A corto plazo, las PAO Tipo II mostraron claramente el cambio metabólico, mientras que a largo plazo fueron las PAO Tipo I. A partir de los experimentos realizados, se desarrollaron las expresiones necesarias (estequiométricas y cinéticas) para incluir los nuevos comportamientos observados (cambio metabólico) en los modelos metabólicos existentes en la actualidad. Expresiones tipo Monod fueron desarrolladas e implementadas en el modelo de las PAOs para representar el cambio entre los parámetros estequiométricos típicos del metabolismo PAO y GAO. El modelo fue calibrado y validado mostrando la capacidad de representar correctamente el cambio metabólico de las PAOs a concentraciones bajas de poli-P. Al observar que las PAOs tienen la habilidad de cambiar su metabolismo a bajas concentraciones de poli-P, sin que se deteriorara el proceso por el desarrollo de las GAOs, se evaluaron dos estrategias de operación para la obtención de una corriente rica en fósforo que permita su posterior recuperación. Las estrategias estudiadas se diferenciaban en el nivel de extracción de poli-P de las PAOs. En la primera estrategia se extraía menos del 40 % de poli-P, mientras que en la segunda estrategia se llegaba a extraer más del 90 % de poli-P. La segunda estrategia mostró una eficacia de extracción superior, consiguiendo recuperar hasta el 81
[CAT] El fòsfor és de gran importància per a la vida a causa que exerceix un paper essencial en els processos biològics. El principal ús del fòsfor està en la indústria dels fertilitzants en forma de fosfats. Aquests fosfats provenen principalment de les roques fosfatades, les quals podrien arribar a esgotar-se entre els pròxims 50 i 100 anys. La sobreexplotació de la roca fosfatada, ha generat una disminució en la qualitat de les reserves, i ha elevat el cost de la seua extracció, processament i transport marítim. D'altra banda, el fòsfor provinent de les aigües residuals, de la dissolució de les roques fosfatades i dels sòls amb excessiva aportació de fertilitzants, es diposita en els cossos d'aigües superficials produint un greu problema de contaminació anomenat eutrofització. Un dels sistemes més utilizats per a reduir els nivells de fòsfor en l'aigua residual és el procés d'eliminació biològica de fòsfor (EBPR). Aquest procés implica capturar biològicament, alternant entre condicions anaeròbies aeròbies/anòxies, el fòsfor de l'aigua residual mitjançant organismes acumuladors de fòsfor (PAOs). No obstant açò, un dels principals problemes d'aquest procés, és la competència de les PAOs amb els organismes acumuladors de glucogen (GAOs) pels àcids grassos volàtils (AGV). Encara que si bé s'han realitzat molts estudis sobre els factors que afecten la competència entre PAOs i GAOs, existixen encara moltes preguntes sense resposta en relació al metabolisme de les PAOs quan aquestes careixen de reserves energètiques en forma de polifosfat intracel·lulars (poli-P) i al seu efecte sobre la dinàmica de les poblacions de PAOs i GAOs en un sistema de fangs activats. És per això que l'objectiu principal d'aquesta tesi doctoral consisteix en: estudiar a curt i llarg termini el comportament metabòlic de les PAOs en canviar el contingut en poli-P; analitzar la dinàmica poblacional dels microorganismes implicats en el procés de EBPR; modelatge matemàticament d'aquest comportament metabòlic i finalment avaluar la possible recuperació de fòsfor mitjançant l'extracció del poli-P present en les PAOs. En l'estudi a curt i llarg termini es va observar un canvi metabòlic correlacionat amb el contingut en poli-P, de manera que a baixos continguts de poli-P les PAOs es comportaven metabolicament com les GAOs, però sense que aquestes últimes s'arribaren a desenvolupar de forma significativa. Malgrat observar el mateix comportament metabòlic en tots dos estudis, des del punt de vista microbiològic es van observar diferències. A curt termini, les PAO Tipus II van mostrar clarament el canvi metabòlic, mentre que a llarg termini van ser les PAO Tipus I. A partir dels experiments realitzats, es van desenvolupar les expressions necessàries (estequiomètriques i cinètiques) per a incloure els nous comportaments observats (canvi metabòlic) en els models metabòlics existents en l'actualitat. Expressions tipus Monod van ser desenvolupades e implementades en el model de les PAOs per a representar el canvi entre els paràmetres estequiomètrics típics del metabolisme PAO i GAO. El model va ser calibrat i validat mostrant la capacitat de representar correctament el canvi metabòlic de les PAOs a concentracions baixes de poli-P. En observar que les PAOs tenen l'habilitat de canviar el seu metabolisme a baixes concentracions de poli-P, sense que es deteriorara el procés pel desenvolupament de les GAOs, es varen avaluar dues estratègies d'operació per a l'obtenció d'un corrent ric en fòsfor que permeta la seua posterior recuperació. Les estratègies estudiades es diferenciaven en el nivell d'extracció de poli-P de les PAOs. En la primera estratègia es va extraure menys del 40 % de poli-P, mentre que en la segona estratègia s'arribava a extraure més del 90 % de poli-P. La segona estratègia va mostrar una eficàcia d'extracció superior, aconseguint recuperar fins al 81 % del fòsfor p
Acevedo Juárez, B. (2016). Estudio y modelación matemática del cambio metabólico de las bacterias responsables de la eliminación biológica de fósforo en el tratamiento de aguas residuales [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/62585
TESIS

La consommation de ressources pétrolières, épuisables et non renouvelables, conduit à rechercher de nouvelles voies de production pour l’industrie chimique. De plus, la production d’Ordures Ménagères Résiduelles (OMR) continue d’augmenter à l’échelle mondiale. La fermentation acidogène des OMR permet de répondre au double objectif de traiter ces déchets et réduire leur quantité tout en produisant des molécules plateformes biosourcées (acides organiques) d’intérêt pour la chimie.La teneur en solides élevée des OMR et le souci de limiter les coûts de procédé justifient le choix du réacteur à lit percolant ou LBR: il s’agit d’un procédé de fermentation discontinue en voie solide dans lequel une phase liquide est recirculée au sein d’un lit statique de déchets solides. De plus, la mise en œuvre de la fermentation en culture mixte vise à apporter de la diversité microbienne, donc de la robustesse face aux variations de conditions environnementales, et permet de s’affranchir de la nécessité de stériliser le milieu. Par souci de reproductibilité, le principal substrat d’étude a été une reconstitution d’OMR.La première partie de ce travail concerne la compréhension des processus biologiques et chimiques et de leur interaction, au cours de la fermentation acidogène en réacteur batchs séquentiels. L’impact de différents facteurs sur l’hydrolyse et la production de métabolites ont été étudiés: l’ajout d’un inoculum exogène au départ, l’acclimatation de la population microbienne initialement présente vis-à-vis des conditions environnementales, le pH. Il a ainsi été confirmé que le pH joue un rôle clé dans la solubilisation du substrat, la production de métabolites et le spectre de produits. L’analyse de l’évolution des communautés microbiennes a permis de corréler la sélection de certaines familles de bactéries aux performances observées. La fermentation a pu être effectuée avec l’utilisation unique du consortium microbien indigène et l’ajout d’un inoculum extérieur n’a pas contribué à améliorer les performances atteintes. En revanche, la réutilisation de communautés microbiennes, acclimatées aux conditions opératoires par les batchs séquentiels, a été déterminante pour augmenter les productions de métabolites. Ces conclusions ont été comparées à des résultats obtenus à forte teneur en solides.La teneur en solides a une influence considérable sur la réaction de fermentation. Toutefois, sa seule considération n’est pas suffisante car le lit de déchets solides constitue un milieu poreux multiphasique complexe au sein duquel la répartition de l’eau et les phénomènes de transfert sont aussi essentiels. La seconde partie de ce travail visait donc à caractériser le lit de déchets en LBR sur le plan physique et hydrodynamique, en conditions abiotiques. Pour cela, des OMR reconstituées, mais aussi réelles, ont été utilisées. En réalisant des cycles de percolation et drainage avant et après compaction des lits de déchets, la structure des massifs et la distribution de l’eau dans les compartiments ont été déterminées. L’application d’un modèle à double porosité classique pour représenter ces cycles a mis en évidence l’existence d’une fraction d’eau immobile dans la macroporosité. Aussi, un modèle amélioré a été proposé pour reproduire de manière plus adéquate ces dynamiques d’écoulement d’eau dans le massif. Des coefficients de transfert d’eau entre les compartiments ont alors pu être estimés via ce nouveau modèle.Les travaux pluridisciplinaires menés au sein de cette thèse se sont intéressés à deux aspects complémentaires de la fermentation acidogène en LBR et apportent aussi de nouvelles perspectives. Par exemple, la stratégie de recirculation, le contrôle de pH au sein de ce milieu complexe, mais aussi la validation sur des déchets réels sont autant de sujets à explorer afin de pouvoir mettre en œuvre la production optimale et reproductible des molécules plateformes par le procédé étudié, en accord avec les utilisations postérieures visées
The consumption of exhaustible and non-renewable petroleum resources leads to the search for new production routes for the chemical industry. In addition, the global production of Household Solid Waste (HSW) is expected to keep growing. Among a variety of recovery methods, acidogenic fermentation of HSW makes it possible to meet two objectives: treating this waste and reducing its quantity while producing biobased platform molecules of interest for chemical industry such as organic acids.The leach-bed reactor or LBR was chosen due to the high total solids content of HSW and the process cost efficiency. The technology consists of a discontinuous solid-state fermentation process in which a liquid phase is recirculated within a static solid waste bed. Moreover, the use of a mixed culture in fermentation aims to provide microbial diversity, and thus the robustness to face changes in environmental conditions. This strategy also eliminates the need to sterilise the environment. Finally, in this work, the main substrate studied was a reconstitution of HSW.The first part of this work concerns the understanding of the biological and chemical processes and their interaction, during the acidogenic fermentation in sequential batch reactors. The impact of different factors on the hydrolysis of the complex solid substrate and the production of metabolites was studied: the pH, the addition of an exogenous inoculum at start-up and the acclimation of the initial microbial population to the environmental conditions. It was confirmed that pH plays a key role in substrate solubilisation, metabolites production and product spectrum. The analysis of the evolution of microbial communities was assessed, which allowed to correlate the selection of certain families of bacteria with the performances observed. Furthermore, it was feasible to carry out acidogenic fermentation with the unique use of the indigenous microbial consortium and the addition of an external inoculum did not contribute to improve the performances. On the other hand, reusing the microbial communities, acclimated to the operating conditions through the sequential batches, was decisive for increasing the production of metabolites. These conclusions were also compared to results of supplementary experiments obtained at high total solids content.The total solids content has a considerable influence on the fermentation reactions. However, its sole consideration is insufficient because the solid waste bed constitutes a complex multiphase porous medium in which the distribution of water and transfer processes are also essential. Thus, the second part of this work aimed at characterising the physical and hydrodynamic features of the waste bed in a LBR under abiotic conditions. For this, reconstituted HSW as well as real HSW were used. By performing several percolation and drainage cycles, before and after compaction of the waste beds, their physical structure and the distribution of water in their compartments were determined. The application of a classical dual porosity model to represent these cycles helped to demonstrate the existence of a static water fraction in the macroporosity. An improved dual porosity model was proposed to reproduce more adequately the water flow dynamics in the waste bed. Water transfer coefficients between the compartments were then estimated using this new model.The multidisciplinary work carried out in this thesis, focused on two complementary aspects of acidogenic fermentation in a LBR and also brought new perspectives. For instance, the recirculation strategy, the pH control within this complex medium as well as the validation on real waste are all topics to further study in order to implement the optimal and reproducible production of platform molecules by this process, in accordance with the subsequent targeted uses

This thesis deals with the theoretical description of the qualitative characteristics and parameters of some modern active elements, also discusses the theory of signal flow graphs at the level applicable for the following frequency filter design methods. The thesis is also generally discussed the issue with the circuit simulator PSpice modeling theory and voltage amplifiers on the basic 6-levels. The practical part of the work is divided into two parts. The first practical part is dedicated to design four levels of simulation model of components LNVGA element. The second practical part contains detailed theoretical proposals for three circuit structures implementing the frequency filters 2nd order (based on the basic structure of the OTA-C) using signal flow graphs with configuration options of Q and fm based on the parameters of active elements in the peripheral structure and their verification with prepared LNVGA model layers.

Ce travail de recherche s'intéresse à la commande sans capteur mécanique du moteur synchrone à aimants permanents (MSAP) à pôles saillants, particulièrement en basse vitesse, avec détection de la position initiale du rotor. Après une présentation des techniques et approches qui ont initié nos travaux, en terme d'estimation de la vitesse et/ou de la position, nous avons choisi celles qui présentent plus d'intérêt de point de vue stabilité, robustesse, précision et simplicité d'implémentation. La première approche est basée sur le Système Adaptatif avec Modèle de Référence (MRAS). Quant à la deuxième, elle est réalisée autour d'un observateur non-linéaire pour l'estimation de la position et de la vitesse du MSAP à pôles saillants. Les deux techniques d'observation de la vitesse sont associées à une commande par orientation du flux rotorique avec la technique MLI vectorielle. Pour détecter la position initiale du rotor, nous avons utilisé une nouvelle approche qui permet d'estimer cette position avec une incertitude de 5° mécanique. Cette nouvelle approche est basée sur l'application de signaux tests aux bornes des phases statoriques du MSAP. Des résultats de simulation et expérimentaux sont présentés tout au long de ces travaux pour valider les études théoriques de la commande vectorielle sans capteur mécanique du MSAP. Enfin, nous avons étudié et analysé les performances de la commande tolérante aux défauts sans capteur mécanique du MSAP en présence de défaillances de types transistors à l'état-off. Les résultats expérimentaux obtenus avec les deux approches d'estimation de la vitesse en utilisant l'observateur MRAS et un observateur non linéaire ont permis d'améliorer la fiabilité du système de manière à rendre possible la commande vectorielle sans capteur mécanique en mode dégradé (alimentation avec deux bras de l'onduleur). En effet, les résultats de la commande sans capteur mécanique de la MSAP en mode dégradé montrent que l'observateur non linéaire est le mieux adapté pour ce type de fonctionnement car il présente de faible ondulation du couple et de vitesse. A l'aide d'un banc d'essais que nous avons développé au laboratoire LSIS-pôle Ecole Centrale de Marseille (ECM), nous avons pu valider expérimentalement les différentes approches proposées dans ce travail de recherche. Les résultats obtenus montrent l'efficacité des techniques mises en œuvre pour la commande vectorielle sans capteur mécanique du MSAP à pôle saillant en termes de robustesse, stabilité, précision et rapidité.

Accélérer la dégradation anaérobie des déchets enfouis, optimiser la production de biogaz et diminuer le temps et le coût de surveillance sont les enjeux principaux d'installation de stockage des déchets non dangereux (ISDND)-bioactives, ainsi que, plus classiquement, minimiser leurs impacts sanitaires et environnementaux. L'une des méthodes les plus efficaces pour atteindre ces objectifs est la recirculation de lixiviat et l'augmentation de l'humidité des déchets. Les objectifs du bioréacteur ne seront pas atteints sans une connaissance rationnelle des phénomènes hydrauliques, biologiques et thermiques qui s'y développent et de l'influence de l'un de ces phénomènes sur les autres. Les observations in situ, les expérimentations en laboratoire ainsi que les modèles numériques permettent ensemble une approche rationnelle de ces phénomènes. C'est ce qui constitue le corps de ce travail de thèse, où nous avons étudié le comportement hydro-thermo-biologique des déchets dans la phase anaérobie en laboratoire, sur site à partir de données hydro-thermiques de deux bioréacteurs situés en France et en développant un modèle numérique pour simuler ce comportement couplé des bioréacteurs. Les travaux en laboratoire nous ont permis d'étudier l'effet de la saturation et de la densité (compactage des déchets) sur la dégradation anaérobie des déchets ménagers et l'influence de ces paramètres sur la production de biogaz. Les données hydrauliques et thermiques in-situ des bioréacteurs nous ont permis de connaître les variations des paramètres essentiels comme la température et la saturation dans les déchets, à différentes profondeurs, et estimer d'autres paramètres qui sont difficile à déterminer expérimentalement. Le modèle numérique nous a permis d'étudier le comportement couplé, hydro-thermo-biologique, des bioréacteurs à long terme (pendant une dizaine d'années) aussi bien qu'à court terme pendant la recirculation de lixiviat. L'interdépendance des différents paramètres qui influent la dégradation des déchets est la principale raison nous ayant conduits à développer un modèle de couplage qui nous permette d'étudier chaque paramètre en fonction des autres. Les travaux en laboratoire et les données thermiques de site nous ont conduits à développer un modèle d'écoulement diphasique du liquide et du gaz dans les déchets, considérant les phénomènes biologiques, en fonction des paramètres clés de la dégradation comme la température et la saturation, pour aboutir à la production de biogaz et de chaleur. Les trois parties de ce travail, les expérimentations en laboratoire, le développement d'un modèle numérique et l'analyse des données de site ont été effectuées en parallèle de façon complémentaire. Les expérimentation de laboratoire tout comme l'analyse des données de site, nous ont montré l'importance des paramètres qu'il faut considérer dans le modèle et en retour le modèle numérique nous a aidé à diriger les expérimentations en laboratoire et montré la nécessité de conduire certaines analyses sur les pilotes expérimentaux, comme l'analyse de la biomasse, de la DCO et des AGV. L'analyse des données hydrauliques et thermiques de sites de bioréacteur nous a permis de caler les paramètres hydrauliques, biologiques et thermiques des déchets qui sont difficile à définir sur le site sans le perturber (comme la conductivité hydraulique, la saturation, la conductivité thermique, la capacité calorifique, la concentration en biomasse et en AGV). Le travail réalisé dans la thèse a permis de développer un modèle couplé hydro-thermo-biologique et de tester sa capacité à prévoir le comportement thermique d'un bioréacteur, la production totale et le taux de production de méthane. Nous avons montré qu'il était adopté à l'étude du comportement à long terme d'un bioréacteur, aussi bien qu'à court terme pendant la réinjection de lixiviat, là où les techniques de mesure et le temps sont limitants en laboratoire ou sur site

Despite significant efforts have been directed toward reducing waste generation and encouraging alternative waste management strategies, landfills still remain the main option for Municipal Solid Waste (MSW) disposal in many countries. Hence, landfills and related impacts on the surroundings are still current issues throughout the world. Actually, the major concerns are related to the potential emissions of leachate and landfill gas into the environment, that pose a threat to public health, surface and groundwater pollution, soil contamination and global warming effects. To ensure environmental protection and enhance landfill sustainability, modern sanitary landfills are equipped with several engineered systems with different functions. For instance, the installation of containment systems, such as bottom liner and multi-layers capping systems, is aimed at reducing leachate seepage and water infiltration into the landfill body as well as gas migration, while eventually mitigating methane emissions through the placement of active oxidation layers (biocovers). Leachate collection and removal systems are designed to minimize water head forming on the bottom section of the landfill and consequent seepages through the liner system. Finally, gas extraction and utilization systems, allow to recover energy from landfill gas while reducing explosion and fire risks associated with methane accumulation, even though much depends on gas collection efficiency achieved in the field (range: 60-90% Spokas et al., 2006; Huitric and Kong, 2006). Hence, impacts on the surrounding environment caused by the polluting substances released from the deposited waste through liquid and gas emissions can be potentially mitigated by a proper design of technical barriers and collection/extraction systems at the landfill site. Nevertheless, the long-term performance of containment systems to limit the landfill emissions is highly uncertain and is strongly dependent on site-specific conditions such as climate, vegetative covers, containment systems, leachate quality and applied stress. Furthermore, the design and operation of leachate collection and treatment systems, of landfill gas extraction and utilization projects, as well as the assessment of appropriate methane reduction strategies (biocovers), require reliable emission forecasts for the assessment of system feasibility and to ensure environmental compliance. To this end, landfill simulation models can represent an useful supporting tool for a better design of leachate/gas collection and treatment systems and can provide valuable information for the evaluation of best options for containment systems depending on their performances under the site-specific conditions. The capability in predicting future emissions levels at a landfill site can also be improved by combining simulation models with field observations at full-scale landfills and/or with experimental studies resembling landfill conditions. Indeed, this kind of data may allow to identify the main parameters and processes governing leachate and gas generation and can provide useful information for model refinement. In view of such need, the present research study was initially addressed to develop a new landfill screening model that, based on simplified mathematical and empirical equations, provides quantitative estimation of leachate and gas production over time, taking into account for site-specific conditions, waste properties and main landfill characteristics and processes. In order to evaluate the applicability of the developed model and the accuracy of emissions forecast, several simulations on four full-scale landfills, currently in operative management stage, were carried out. The results of these case studies showed a good correspondence of leachate estimations with monthly trend observed in the field and revealed that the reliability of model predictions is strongly influenced by the quality of input data. In particular, the initial waste moisture content and the waste compression index, which are usually data not available from a standard characterisation, were identified as the key unknown parameters affecting leachate production. Furthermore, the applicability of the model to closed landfills was evaluated by simulating different alternative capping systems and by comparing the results with those returned by the Hydrological Evaluation of Landfill Performance (HELP), which is the most worldwide used model for comparative analysis of composite liner systems. Despite the simplified approach of the developed model, simulated values of infiltration and leakage rates through the analysed cover systems were in line with those of HELP. However, it should be highlighted that the developed model provides an assessment of leachate and biogas production only from a quantitative point of view. The leachate and biogas composition was indeed not included in the forecast model, as strongly linked to the type of waste that makes the prediction in a screening phase poorly representative of what could be expected in the field. Hence, for a qualitative analysis of leachate and gas emissions over time, a laboratory methodology including different type of lab-scale tests was applied to a particular waste material. Specifically, the research was focused on mechanically biologically treated (MBT) wastes which, after the introduction of the European Landfill Directive 1999/31/EC (European Commission, 1999) that imposes member states to dispose of in landfills only wastes that have been preliminary subjected to treatment, are becoming the main flow waste landfilled in new Italian facilities. However, due to the relatively recent introduction of the MBT plants within the waste management system, very few data on leachate and gas emissions from MBT waste in landfills are available and, hence, the current knowledge mainly results from laboratory studies. Nevertheless, the assessment of the leaching characteristics of MBT materials and the evaluation of how the environmental conditions may affect the heavy metals mobility are still poorly investigated in literature. To gain deeper insight on the fundamental mechanisms governing the constituents release from MBT wastes, several leaching experiments were performed on MBT samples collected from an Italian MBT plant and the experimental results were modelled to obtain information on the long-term leachate emissions. Namely, a combination of experimental leaching tests were performed on fully-characterized MBT waste samples and the effect of different parameters, mainly pH and liquid to solid ratio (L/S,) on the compounds release was investigated by combining pH static-batch test, pH dependent tests and dynamic up-flow column percolation experiments. The obtained results showed that, even though MBT wastes were characterized by relatively high heavy metals content, only a limited amount was actually soluble and thus bioavailable. Furthermore, the information provided by the different tests highlighted the existence of a strong linear correlation between the release pattern of dissolved organic carbon (DOC) and several metals (Co, Cr, Cu, Ni, V, Zn), suggesting that complexation to DOC is the leaching controlling mechanism of these elements. Thus, combining the results of batch and up-flow column percolation tests, partition coefficients between DOC and metals concentration were derived. These data, coupled with a simplified screening model for DOC release, allowed to get a very good prediction of metal release during the experiments and may provide useful indications for the evaluation of long-term emissions from this type of waste in a landfill disposal scenario. In order to complete the study on the MBT waste environmental behaviour, gas emissions from MBT waste were examined by performing different anaerobic tests. The main purpose of this study was to evaluate the potential gas generation capacity of wastes and to assess possible implications on gas generation resulting from the different environmental conditions expected in the field. To this end, anaerobic batch tests were performed at a wide range of water contents (26-43 %w/w up to 75 %w/w on wet weight) and temperatures (from 20-25 °C up to 55 °C) in order to simulate different landfill management options (dry tomb or bioreactor landfills). In nearly all test conditions, a quite long lag-phase was observed (several months) due to the inhibition effects resulting from high concentrations of volatile fatty acids (VFAs) and ammonia that highlighted a poor stability degree of the analysed material. Furthermore, experimental results showed that the initial waste water content is the key factor limiting the anaerobic biological process. Indeed, when the waste moisture was lower than 32 %w/w the methanogenic microbial activity was completely inhibited. Overall, the obtained results indicated that the operative conditions drastically affect the gas generation from MBT waste, in terms of both gas yield and generation rate. This suggests that particular caution should be paid when using the results of lab-scale tests for the evaluation of long-term behaviour expected in the field, where the boundary conditions change continuously and vary significantly depending on the climate, the landfill operative management strategies in place (e.g. leachate recirculation, waste disposal methods), the hydraulic characteristics of buried waste, the presence and type of temporary and final cover systems.

Instrumentation is very important part in signal processing, most system there is a voltage feedback oscillator which provides oscillation to the instrument but nowadays there is a concept of current feedback oscillator which provides high oscillation which is a demand of fast world. Here using current feedback operational amplifier we are building modified current feedback operational amplifier (MCFOA). Use of high speed MCFOAs in analog signal processing offers several advantages over voltage feedback operational amplifier. These advantages are wide bandwidth, high slew rate, and ease of realizing various functions with the least possible number of external passive components. They do not require any component-matching requirements. There is also a growing demand/interest in realization of active filter, sinusoidal oscillators using MCFOA. The maximum frequency of operation of any circuit depends on the bandwidth of the amplifier. Signal generator build with a MCFOA will operate at higher frequencies than that of a VFOA. Today’s electronic systems require many signal waveform shapes in addition to the sinusoidal waveform. Common waveforms are the square wave, triangular wave, and single pulse wave with fixed duration. Fixed duration pulses are used in communication and control systems. Square waves are used as a clock for digital systems. Triangular waves are used for scanning an electron beam on a CRT screen, in precise time measurements, and in time modulation.