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1
Chanouri, Hamza. "Valorisation des terres rares à partir du phosphogypse et boues phosphoriques : cas d'utilisation de la lixiviation basique." Electronic Thesis or Diss., Université Côte d'Azur, 2024. http://www.theses.fr/2024COAZ5029.
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Les approches hydrométallurgiques dévouées à l'extraction et la séparation des éléments de terres rares (TRs) ont devenus des thématiques de recherche d'actualité à l'échelle internationale en raison des propriétés physico-chimiques cruciales des TRs dans la technologie de pointe. Par conséquent, la dernière décennie a connu une forte préoccupation focalisée sur le développement des méthodes durables pour valoriser les TRs à partir des ressources de faible concentration, afin de remédier au problème de la dynamique croissante du marché de TRs issue du déséquilibre entre l'approvisionnement et la demande. En outre, les inquiétudes concernant l'épuisement des réserves naturelles primaires ont rendu nécessaire d'exploiter les ressources secondaires. Ainsi, plusieurs pays ont commencé à investir massivement dans la recherche, afin de développer des techniques rentables d'extraction des TRs à partir des ressources secondaires, des minerais à faible teneur et des déchets et sous-produits industriels, e.g., les argiles à adsorption d'ions, les boues rouges, les roches phosphatées, les phosphogypses (PG) et les boues phosphoriques (PS). À la lumière de toutes ces considérations, l'objectif de la présente thèse est de développer des nouveaux procédés pour la récupération des TRs à partir des sous-produits de l'industrie de phosphate, i.e., PG et PS, générés lors de la production et de la concentration d'acide phosphorique. Bien que la concentration des TRs dans ces sous-produits soit faible, leurs grandes quantités les positionnent comme des alternatives pertinentes. Cependant, la limitation de la faible concentration ainsi que la focalisation exclusive sur les TRs ont restreint la conception d'une méthode de lixiviation acide directe appropriée pour extraire ces éléments à partir du PG et des PS, ce qui souligne l'impératif d'explorer et de développer d'autres procédés basiques efficaces. Nos études se sont concentrées sur le déchiffrement de la spéciation probable des TRs dans les différentes matrices, leurs récupérations, ainsi que leurs enrichissements en utilisant différentes approches dépendantes du pH. En plus de susmentionné, la stratégie adoptée envisage le développement d'un procédé intégré pour exploiter tout le potentiel du PG et du PS, par co-extraction et valorisation d'autres composants de haute valeur ajoutée, i.e., le pentoxyde de phosphore, les sulfates, le calcium, le fluor, etc., pour une économie circulaire efficace qui se base sur la transformation des sous-produits en produits de hautes valeurs ajoutéesThe hydrometallurgical approaches for extracting and separating rare earth elements (REEs) have emerged as international research hotspots due to the indispensable physicochemical properties of REEs in advanced technology. Hence, the last decade has witnessed a dramatic increase in the necessity of developing processing techniques to valorize REEs from low-grade resources to overcome the serious problem of balancing supply and demand. In addition, the concerns regarding the depletion of principal natural resource reserves have made it necessary to look for the cusp of a significant breakthrough that may pave the way for the mining of secondary resources. In light of all these considerations, several countries have started investing heavily in research and development of technologies directed towards cost-effective extraction of REEs from secondary resources, low-grade ores, and industrial wastes and by-products, such as ions adsorption clays, red muds, phosphate rocks, phosphogypsum (PG), and phosphoric sludges (PS). Consequently, the aim of this thesis is to contribute to the development of new technologies for REEs recovery from phosphate-derived minerals, i.e., PG and PS generated during phosphoric acid production and concentration in fertilizer industries. Despite the low concentration of REEs in these by-products but given their large amount they were considered as relevant alternatives. However, the tenuous concentration and sole targeting of REEs have constrained the development of an appropriate direct acidic leaching approach for REEs extraction from PG and PS, which enhanced the necessity of investigating the development of effective alkaline based processes. To address the challenging question regarding the beneficiation of REEs from diluted phosphate-derived by-products our research studies focused on deciphering the probable speciation of REEs in the parent matrices, their recovery, as well as their enrichment using different pH-dependent approaches. In addition, the investigated-developed processes embraced the strategy of by-products to high added value products by considering the development of an integrated process to make of use of all untapped potential of PG and PS, by co-extraction and valorization of other high value components, i.e., phosphorus pentoxide, sulfates, calcium, fluorine, etc., for an effective circular economy
2
Burke, Russell Armstrong. "Biological excess phosphorus removal in short sludge age activated sludge systems." Master's thesis, University of Cape Town, 1986. http://hdl.handle.net/11427/7582.
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Includes bibliography.The objective of this investigation was to test, at laboratory-scale, the behaviour of short sludge age biological excess P removal systems, to assess the response of the systems under non-nitrifying and nitrifying conditions, to determine the optimal system configuration(s) and operational parameters, and to check the settling characteristics of the mixed liquor produced in the systems. A secondary objective was to use the observed response data to test the predictive qualities of both the general activated sludge model of Dold, Ekama. and Marais (1985) and the semi-empirical biological excess P removal model of Wentzel, Dold, Ekama and Marais (1984). The objectives were fulfilled by operating a number of laboratory scale anaerobic/aerobic and anaerobic/anoxic/aerobic systems with varying sludge ages, anaerobic, anoxic and aerobic mass fractions, mixed liquor recycle ratios and COD loading rates.
3
Bhasin, Aditi. "Recovery of Phosphorus from Incineration of Sewage Sludge." Thesis, KTH, Skolan för kemivetenskap (CHE), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-214991.
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The primary source of phosphorus, phosphate rock, is a non-renewable resource which is expected to get exhausted in the next 50 – 100 years. Sewage sludge in Sweden constitutes 25% of the annual phosphorus in the country, making it a potentially significant source for phosphorus recovery. The aim of this project was to identify the potential for phosphorus recovery from incineration of dewatered and digested sewage sludge in Fortum Värme’s power plants in Stockholm. The study was limited to two boilers located at Bristaverket, Stockholm - boiler B1, a bio-fired fluidized bed boiler and boiler B2, a waste-fired grate incinerator. A theoretical analysis for boiler B1 showed that it is possible to reach a concentration of 4.6% phosphorus in fly ash if sludge and recycled wood fuel are mixed in the ratio 48:52. A test program was executed in boiler B2 to burn up to 12.5% sludge with a mixture of household waste and industrial waste. A total of 755 tons of sludge was used over a period of three weeks during the test in boiler B2. The test was successful in terms of combustion and emissions. There was no increase in the emissions of nitrogen oxides, sulphur dioxide and hydrochloric acid in the flue gas. Mercury emissions in the chimney increased with an increase in the share of sludge, nevertheless, the emission level was below the limit set by the Swedish Environmental Protection Agency. Decrease in the amount of unburnt materials in bottom ash and in the emission of carbon monoxide showed that the burning of fuel was more efficient with input of sludge. The maximum phosphorus concentration was 0.7% in both bottom ash and fly ash from boiler B2 and occurred at an input of 12.5% sludge. This concentration is close to the expected theoretical value, however it is not expected to be feasible to recover phosphorus at such a low concentration. The ashes were sent to Fortum Waste Solutions and Ragn-Sells for recovery of phosphorus, however the results are not included in this report due to time constraints for thesis study. In order to increase the concentration of phosphorus in the ashes, a system approach is recommended, for instance, recirculation of bottom ash into the incinerator.Den primära källan till fosfor, fosforit, är en icke-förnybar resurs som är begränsad och förväntas bli förbrukad under de kommande 50-100 åren. Avloppsslam i Sverige innehåller 25% av det årliga fosforflödet, därmed är det en potentiellt viktig källa för fosforåtervinning. Syftet med detta projekt var att identifiera potentialen för fosforåtervinning från förbränning av rötat och avvattnat avloppsslam i Fortum Värmes kraftvärmeverk i Stockholm. Projektet avgränsades till fokus på två pannor i Bristaverket: panna B1, en bioeldad fluidiserad bäddpanna och panna B2, en avfallseldad rosterpanna. En teoretisk analys av panna B1 visade att det är möjligt att uppnå en koncentration på 4,6% fosfor i flygaska om slam och RT-flis blandas med förhållandet 48:52. Ett test program genomfördes på panna B2 för att förbränna uppe till 12,5% slam med en blandning av hushållsavfall och grovkross. Totalt användes 755 ton slam under en period av tre veckor då testet genomfördes i panna B2. Det var ett lyckat test med avseende på förbränning och utsläpp. Ingen ökning av kväveoxider, svaveldioxid och saltsyra i rökgasen observerades vid utsläppen. Kvicksilverutsläppet i skorstenen ökade med en ökad andel slam, dock var utsläppsnivån under den gränsen som är fastställd av Naturvårdsverket. Minskning av oförbrända material i bottenaska och i utsläpp av kolmonoxid visade att förbränningen av bränsle är effektivare med inmatning av slam. Den maximala fosforkoncentrationen var 0,7% i både bottenaska och flygaska från panna B2 vid ett intag av 12,5% slam. Denna koncentration ligger nära det förväntade teoretiska värdet, men det anses inte vara rimligt att återvinna fosfor vid en sådan låg koncentration ut ett ekonomist perspektiv. Askan skickades till Fortum Waste Solutions och Ragn-Sells för återvinning av fosfor, men resultatet redovisas inte i denna rapport på grund av tidsbegränsningen av detta examensarbete. För att öka koncentrationen av fosfor i askan rekommenderas en systeminriktning, till exempel recirkulation av bottenaska i pannan.
4
Stark, Kristina. "Phosphorus release and recovery from treated sewage sludge." Doctoral thesis, Stockholm : KTH Architecture and the Built Environment, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-402.
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Wentzel, Mark Charles. "Biological excess phosphorus removal in activated sludge systems." Doctoral thesis, University of Cape Town, 1988. http://hdl.handle.net/11427/8309.
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Includes bibliographies.When this investigation was commenced in 1983 two activated sludge systems had been developed in South Africa that accomplish biological excess phosphorus (P) removal, the UCT and modified Bardenpho systems. To predict the P removal in these systems, an empirical model had been developed. In the empirical model, P removal was formulated in terms of some of the system parameters, such as anaerobic mass fraction, available readily biodegradable COD and active mass concentration. Organisms directly implicated in biological excess P removal (poly P organisms) did not feature in the model and the P removal was not linked to any basic biological or biochemical behaviour. Clearly, there was a need for a more fundamentally based model. The objective of this thesis was to develop such a model.
6
Hoffman, Victor, and Anton Marmsjö. "Combustion of sludge in Fortum’s plants with possible phosphorus recycling." Thesis, KTH, Kraft- och värmeteknologi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-146974.
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The management of waste is by all means a great challenge to any society. In Sweden, the past decades has seen legislation progressing in congruence with concerns over environmental stress from inefficient waste management. The legislative changes aim primarily to promote waste reduction and better waste utilization. Sludge is a waste-type from different industrial processes and is unfortunately of limited reuse and recycling-value, but sludge combustion for energy recovery appears promising. Also, the oftentimes high phosphorus content in sludge strengthens the potential of extracting phosphorus from combustion ashes. The heat and power industry has shown great interest in sludge combustion. Fortum has a set of different sludge types to choose from as well as many different options available based on where and how the sludge can be incinerated. Yet there are many inherent problems, but also operational benefits, of combusting sludge. These factors combined make the venture multifaceted and therefore not straightforward. Based on this, this thesis is a preliminary study aiming to assess the possibility of combusting sludge in Fortum’s existing or future facilities, along with possible phosphorus recovery from the combustion ashes. The study was based on applying either sludge mono- or co-combustion. The scenarios evaluated were; firing 70000 tonnes of digested sewage sludge, 50000 tonnes of fibrous sludge and 26400 tonnes of digestate which all are pertinent sludge amounts in this study. Co-combustion involved firing these together with the base fuels fired in Fortum’s grate furnace and fluidized bed boilers in Brista and Högdalen CHP plants. The mixing yielded new characteristics of the combustion input, such as a lower heating value, which were vetted against the boilers’ capability to handle these. Mono-combustion was compared economically with co-combustion to assess investment profitability. The phosphorus concentration in the ashes from the mixes was determined as well in order to assess the possibility for viable extraction. In addition, proper sludge pretreatment methods were examined. The results showed that co-incineration of 70000 tonnes digested sewage sludge was possible in boiler P6 in Högdalen and B2 in Brista. These generated an economic gain with an internal rate of return of 96,3 % and 96,4 % respectively. It was possible to co-incinerate 50000 tonnes of fibrous sludge in boilers B1 and B2 in Brista as well as P6 although economic gains were only seen in B1, where the internal rate was 87,5 %. Co‑incinerating 26400 tonnes of digestate was possible in all boilers except P3 assuming that the similar boilers P1 and P2 in Högdalen can incinerate the sludge in tandem. The incineration of digestate yielded an economic gain for these boilers with an internal rate ranging from 25,7 % for P1 and P2 in tandem to 102,6 % for B1. Although mono-combustion is a practical solution it was found not to be an economically feasible alternative under prevailing economic conditions. The results also indicated that NOx and SOx formation increased in the raw flue gaseswhen co‑firing sludge, as also was the case with flue gas volume flow and flue gas water vapor. Fossil CO2 emissionsdecreased for all waste fired boilers when co-combusting sludge. Digested sewage sludge and digestate increased combustion ash amounts in all cases, whereas fibrous sludge only did this in B1. All sludge types were found to be beneficial for reducing the risk of corrosion and agglomeration, but digested sewage sludge was remarkably more so than digestate and fibrous sludge. The phosphorus concentration in the co-combustion ashes was deemed insufficient for viable phosphorus extraction, but was promising when firing digested sewage sludge in B1. The concentration was sufficient in a mono-combustion application when firing digested sewage sludge and digestate. Overall environmental impacts are however dubious. There needs to be further investigation in order to properly assess these.Hanteringen av avfall är en stor utmaning i alla samhällen. I Sverige har lagstiftningen de senaste decennierna utvecklats i takt med ökad oro över miljöbelastningen från ineffektiv avfallshantering. I första hand syftar lagändringarna till att främja avfallsminimering och bättre avfallsutnyttjande. Slam är en typ av avfall från olika industriprocesser och har dessvärre begränsat värde för återanvändning och återvinning, men slamförbränning för energiutvinning verkar lovande. Även den i många fall höga fosforhalten i slam ger en potential att utvinna fosfor ur förbränningsaskorna. Kraft- och värmeindustrin har visat stort intresse för slamförbränning. Fortum har olika slamtyper att tillgå och många olika alternativ gällande var och hur slammet ska förbrännas. Det finns också problem, men även förbränningstekniska fördelar, kopplat till slamförbränning. Tillsammans gör dessa faktorer satsningen mångfacetterad och därför inte helt självklar. Detta examensarbete är en förstudie som syftar till att bedöma möjligheten att förbränna slam i Fortums befintliga eller framtida anläggningar, tillsammans med eventuell återvinning av fosfor från förbränningsaskorna. I studien undersöktes slamförbränning, antingen monoförbränning eller förbränning tillsammans med andra bränslen. Scenarierna som utvärderats innefattar förbränning av 70000 ton rötslam, 50000 ton fiberslam och 26400 ton rötrest vilka är relevanta mängder för denna studie. Samförbränning innebär att dessa blandas och eldas tillsammans med basbränslena i Fortums rosterpannor och fluidiserade bäddar i kraftvärmeverken i Brista och Högdalen. Slamblandningen ger upphov till nya egenskaper hos det inmatade bränslet, till exempel ett lägre värmevärde, vilka jämförs mot pannornas kapacitet att hantera dessa. Monoförbränning jämfördes med samförbränning för att bedöma dess ekonomiska konkurrenskraft. Fosforhalten i askan från blandningarna bestämdes även för att bedöma fosforutvinningspotentialen. Dessutom har lämpliga förbehandlingsmetoder för slam undersökts. Resultaten visar att samförbränning av 70000 ton rötslam var möjlig i panna P6 i Högdalen och B2 i Brista. Dessa gav en ekonomisk vinst med en internränta på 96,3 % respektive 96,4 %. Det var möjligt att samförbränna 50000 ton fiberslam i panna B1 och B2 i Brista samt panna P6 även om ekonomiska vinster bara visades i B1, där internräntan blev 87,5 %. Samförbränning av 26400 ton rötrest var möjligt i alla pannor förutom P3 förutsatt att pannorna P1 och P2 i Högdalen kan förbränna slammet i tandem. Förbränning av rötrest gav en ekonomisk vinst i dessa pannor med internräntor mellan 25,7 % för P1 och P2 tillsammans och 102,6 % för B1. Även om monoförbränning kan vara en praktisk lösning är det inte ett ekonomiskt försvarbart alternativ under rådande ekonomiska förhållanden. I studien gavs det även indikationer på att uppkomsten NOx och SOx i rågaserna ökade vid samförbränning med slam, samt att även rökgasvolymflöde och mängden vattenånga i rökgaserna ökade. Fossila CO2 utsläpp minskade för de avfallseldade pannorna vid samförbränning. Rötslam och rötrest gav en ökning av mängden aska i alla pannor, medan fiberslam endast ökade denna i B1. Alla slamtyper var fördelaktiga att förbränna för att minska risken för korrosion och agglomerering men rötslam var anmärkningsvärt bättre i det avseendet jämfört med rötrest och fiberslam. Fosforhalten i samförbränningsaskorna bedömdes vara för låg för lönsam fosforutvinning, men var lovande vid rötslamsförbränning i panna B1. Koncentrationen var tillräckligt hög vid monoförbränning av rötslam och rötrest. Det är dock oklart vad den totala miljöpåverkan blir vilket skulle behövas utredas vidare.
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Gao, Lu. "Phosphorus Reclamation from Municipal Wastewater Sludge for Fertilizer Production." Thesis, Université d'Ottawa / University of Ottawa, 2017. http://hdl.handle.net/10393/36712.
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The increasing population with its associated rising food demand requires more agricultural fertilizers to maintain the harvest for food security. However, the natural calcium carbonate phosphate mineral (carbonate apatite) used to produce phosphorus (P) fertilizer is a non- renewable ore. Therefore, in this study, the objective is to extract the inorganic polymeric phosphate (polyphosphate: polyP) P-component in waste activated sewage sludge (WAS) from Ottawa’s municipal wastewater plant (ROPEC). Once extracted, the goal was to break down the polyP to inorganic phosphate (Pi) to produce carbonate apatite.
PolyP is a P-component in WAS because a group of wastewater microorganisms called polyphosphate-accumulating organisms uptake phosphate and generate intracellular polyP stores during aerobic digestion in municipal wastewater treatment plant processes. The total acidic, oxidative P content of WAS was measured. PolyP was extracted and quantified to estimate the fraction of total P as polyP in WAS. Different polyP extraction methods were undertaken. It was determined that the complicated composition and weight fractions of TWAS, including iron phosphate, complicated polyP extraction and Pi measurement.
Lessons learned were applied towards preliminary batch and continuous precipitation of carbonate apatite with the product slurry from the anaerobic digestion process at ROPEC. Limestone was tested as an inexpensive calcium carbonate source for carbonate apatite precipitation. The dissolution of calcium and carbonate from limestone was assessed, and it was determined that further optimization is required. Preliminary work indicated that the calcium- carbonate solution from limestone could precipitate synthetic carbonate apatite from anaerobic digester material. This synthetic carbonate apatite product may lead to mitigating the impending limitations on natural carbonate apatite availability for P-fertilizer production.
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Sirén, Ehrnström Matilda. "Recovery of Phosphorus from HTC Converted Municipal Sewage Sludge." Thesis, Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-290.
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With a growing population but scarce primary phosphorus sources, recycling of the vital element has become an important research area throughout the last decades. Several streams in society are potential resources for recirculation but municipal sewage is considered one of the most available materials. With current technologies in wastewater treatment, over 95 % of the influent phosphorus is captured in the sludge along with a variety of other nutrients. However, due to increasing fractions of pharmaceutical residues and heavy metals also following the sludge, direct use as fertiliser is being phased out in most European countries in favour of extraction methods. Extraction of nutrients from the sludge is problematic mainly because of dewaterability difficulties. Thus, pretreatment of the material is required to access the desired components at a reasonable cost and energy consumption. Hydrothermal carbonisation (HTC) is a technology showing high potential for treatment of wet carbonaceous material without necessity of prior drying. The resulting product is hygenised, essentially free from pharmaceuticals and easily dewatered. In this Master’s thesis principal conditions for release of phosphorus from HTC converted digested sludge under acid leaching have been experimentally investigated. Dependence of time, temperature, dry solids (DS) content of HTC sludge and pH have been studied. Also, differences arising from acid type have been considered by comparing acidulation with sulphuric acid and hydrochloric acid. A short investigation of the recovery of the dissolved phosphorus from leachate by precipitation was also performed where calcium ions were added to both sulphuric and hydrochloric acid leachates. Extraction of phosphorus from HTC converted sludge has shown to be easier than from pure metal phosphates under comparable leaching conditions and pH values. Also, the dissolved phosphorus concentrations obtained in the presence of HTC converted sludge was higher than for theoretical equilibrium concentrations where all phosphorus is in the form of iron(III) or aluminium(III) phosphate. A maximum leachate phosphorus concentration was around 2500 mg/L, recorded in leaching experiments performed at a dry HTC product concentration of 10 % (w/w) in an extraction solution of water acidified with sulphuric acid. Leaching procedures performed at pH values between 2 and 1 with 1 and 5 % DS HTC product resulted in dissolution of 90 % of ingoing phosphorus at an acid charge of 0.5 kg H2SO4/kg DS HTC product. At this chemical charge, release of phosphorus from converted sludge is fast. Similar amounts of dissolved phosphorus were recorded after 15 min as after 16 h retention time. Possibly, time dependence becomes relevant at lower charges. The dissolution of phosphorus is negatively affected by temperature increases at moderate acid loads, and by possibly by hydrochloric acid at pH values below 2. Addition of calcium gave a dissolved phosphorus reduction of 99.9 % in both the sulphuric acid and hydrochloric acid leachates. Gypsum, CaSO4, also precipitates from the sulphuric acid leachate resulting in 67 % more dry mass. Due to high release of metals during acidulation, the precipitate was also contaminated with large fractions of metals in addition to calcium. In summary, this investigation has demonstrated that up to 90 % of the phosphorus content of the HTC converted sludge can be released by acid leaching, and almost 100 % of the phosphorus can be recovered from the leachate by precipitation with calcium ions.
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Hannl, Thomas Karl. "Phosphorus recovery from sewage sludge fluidized bed gasification processes." Licentiate thesis, Luleå tekniska universitet, Energivetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-81024.
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One of the most sustainable pathways of sewage sludge treatment in recent years has been thermal conversion. The benefits of thermal treatment of sewage sludge are the recovery of energy or valuable chemical products, the destruction of harmful organic compounds, the separation of heavy metals from the P-rich coarse ash fraction, and the decreased and sanitized ash volume. The ashes created by these thermal conversion processes of sewage sludge are often rich in P that is mostly present in minerals with low plant-availability such as apatite. Due to the enrichment of P in the created ashes, a variety of post-processing steps have been developed to recover P from sewage sludge ashes. One proven way for the sus-tainable recovery of P from such ashes is thermal post-processing with alkaline salts, e.g., Na2SO4 or K2CO3, which was able to transform less plant-available phosphates in the sewage sludge into more plant-available alkali-bearing phos-phates. Based on these results, one could facilitate creating these phosphates with enhanced plant-availability by providing the chemical potential to form them already during the thermal conversion process of sewage sludge. This thesis aims to increase the current knowledge about the ash transformation processes of P and to suggest suitable process parameters for the alteration of the phosphate speciation in sewage sludge ashes by co-conversion with alkaline-rich agricultural residues. More specifically, the possibility of incorporating K derived from agricultural residues in phosphate structures derived from sewage sludge was evaluated with respect to the influence of the process temperature, the conver-sion atmosphere, and the fuel mixture. The studied parameters were chosen to generate knowledge relevant for fluidized bed gasification processes, with a spe-cial focus on dual fluidized bed (DFB) gasification systems. The applicability of feldspar bed materials in fluidized bed gasification systems was investigated to enable the substitution of the commonly used olivine, which often contains heavy metals (potentially contaminating recovered ashes), and quartz, which is very reactive towards fuel-derived K and potentially leads to bed material fragmentation and bed agglomeration (Paper I & II). Subsequently, the thermodynamic potential for the alteration of the P-species in sewage sludge ash during co-combustion and co-gasification processes with agricultural residues was investigated (Paper III). Thereafter, an experimental evaluation of the ash transformation chemistry in thermal conversion processes of sewage sludge with different types of alkali-rich agricultural residues in temperatures relevant for flu-idized bed technology was conducted (Paper IV & V). The methodology employed was chosen with respect to the state of technology of the specific investigated process. Paper I & II applied SEM, EDS, XRD, and thermodynamic equilibrium modeling for bed material samples derived from an industrial indirect gasifier. Paper III applied thermodynamic equilibrium calcula-tions to theoretically evaluate ash compositions resulting from co-conversion of sewage sludge and agricultural residues. Paper IV & V employed SEM, EDS, ICP-AES/MS, XRD, and thermochemical modeling on ash samples derived from single pellet lab-scale experiments. The results obtained by analysis of bed material from indirect wood gasification showed the difference in interaction mechanism for K-feldspar and Na-feldspar, most notably the enhanced disintegration of Na-feldspar by K originating from the fuel (Paper I & II). Thermodynamic models employed for fuel mixtures of sewage sludge and agricultural residues showed the thermodynamic preference for the formation of the desired alkali-bearing phosphates (Paper III). Experi-ments conducted with these fuel mixtures (Paper IV & V) supported the theo-retical findings, and the influence of temperature and process conditions could be obtained. However, practical investigations also showed that attainment of the desired ash composition is subject to significant restrictions. Derived from the elaborated results and discussions, it was possible to assess the critical process and fuel parameters for the development of up-scaled gasification processes focusing on the conversion of sewage sludge with the aim of creating improved phosphate formation in the ash. The selection of a suitable bed material in fluidized bed conversion and the transformation mechanisms defining the ash chemistry were found to be of vital importance for future applications. The pur-suit of the predefined aims in reference to P-recovery from sewage sludge has led to a multitude of suggestions for suitable process parameters that must be ad-dressed in future bench- and pilot-scale experimental runs.
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Van, der Merwe Petrus. "Phosphorus phyto-availability and fertilizer value of petrochemical and municipal wastewater sludges." Diss., University of Pretoria, 2014. http://hdl.handle.net/2263/46060.
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A growing population, urbanization and an increase in the number of
industries is causing an increase in sewage sludge (SS) that needs to be
either beneficially used or disposed of. Application of SS to agricultural lands
is a well-known practice but the plant available phosphate and phosphate
fertilizer value of SS has been of concern. This is especially due to the wide
variety of soils that SS is applied to and the different phosphate removal
processes that sewage waste water undergoes at the water care works and
the source used to produce SS.
Phosphate phyto-availability and phosphate fertilizer value of petrochemical
and municipal wastewater sludges (SS) were determined in four different soils
using an incubation study over 168 days, a pot trial over 42 days and a field
trial over one season. Phosphate phyto-availability was determined/calculated
by means of an incubation approach. Soils were incubated with sludge as well
as mono ammonium phosphate (MAP). The soils were then subjected to a
Bray-1 extraction after a certain time (42 days, 168 days). The relative
phosphate fertilizer value (RPFV) was then expressed as a percentage of the
Bray-1 extractability of the sludge-amended soil, relative to the MAP-amended
soil. The influence of soil properties, especially clay content, and sludge
properties namely phosphate extraction method (chemical and biological)
from waste water stream, was investigated to determine the effect on phytoavailability
and fertilizer value of phosphate in SS-amended soil. Soil
properties were the dominant factor determining plant available phosphate,
where plant available phosphate decreased with increasing clay content,
irrelevant of the type of treatment. There were, however, significant differences between the chemical and biologically removed SS, where the
biologically removed SS had higher plant available phosphate.
The RPFV % of the SS was comparable to MAP in terms of its plant
availability. Wetting and drying cycles in the pot trial influenced the plant
available phosphate from the SS, where the chemically treated sludge
showed in general lower plant availability. The RPFV % of the biologically
removed phosphate sludges was better than that of MAP and that of the
chemically phosphate removed sludge were lower.
Application of all the different sludge types resulted in a positive reaction on
plant available phosphate for all the soils. All the trials were conducted at pH
of about 5.5. However, it is expected that biologically P removed sludge will
perform better in acid soils. The reason being that ferric phosphate in the
chemically treated sludge is less soluble under pH conditions lower than 5.5
than above it.Dissertation (MScAgric)--University of Pretoria, 2014.
tm2015
Plant Production and Soil Science
MScAgric
Unrestricted
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Sen, Dipankar. "Kinetics of the release and precipitation of phosphorus in anaerobic digesters sequencing biological phosphorus removal systems." Thesis, Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/91075.
Full textAbstract:
The extent of release and precipitation of phosphorus stored in the poly-phosphate granules of microorganisms present in anaerobic digesters sequencing a biological phosphorus removal (BPR) activated sludge system was examined. The research was conducted at the York River Wastewaster Treatment plant which was converted from a conventional system to a A/O process for biological phosphorus removal. The primary and secondary anaerobic digesters each had a solids retention time of approximately 120 days.
The results indicated that at least 60 percent of the phosphorus in the poly-phosphate granules would be solubilized during endogenous decay and digestion under anaerobic conditions. This is accompanied by the release of potassium, magnesium and limited amounts of calcium.
The release of magnesium and phosphorus in the high ammonium containing environment of the primary digester results in the precipitation of about 1000 mg/L of struvite (MgNH₄PQ₄H₂O), a relatively adhesive and kinetically fast precipitate. Struvite can form on floes of biomass inside the primary digester, on walls, inside pipes, and in areas affected by lower temperatures and higher pH. The phosphorus level in the secondary digester effluent is controlled by the kinetics of formation of competitive precipitates like struvite, calcium-phosphorus compounds and vivianite (Fe₃(PO₄)₂). The formation of vivianite is limited by the competitive precipitation of siderite (FeCO₃ ). The extent to which the compounds are precipitated depends on the solids retention times, ionic strengths, size and amorphous nature of the precipitates and the substitution of foreign ions in the crystal lattice. The effective solubility products of these precipitates, as applicable to anaerobic digesters, were determined.M.S.
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Carliell-Marquet, Cynthia. "The effect of phosphorus enrichment on fractionation of metals and phosphorus in anaerobically digested sludge." Thesis, Loughborough University, 2000. https://dspace.lboro.ac.uk/2134/17074.
Full textAbstract:
In designated nutrient-sensitive areas, phosphorus must be removed from sewage before it is discharged to the receiving water body. Phosphorus-rich sludge is generated, which is usually digested anaerobically prior to disposal. This research investigated the effect of phosphorus enrichment on metal and phosphorus fractionation in anaerobically digested sludge. The use of two complementary sequential chemical extraction procedures to measure phosphorus and metal fractionation, was a key focus of the research. The fractionation procedures were tested by sequentially extracting inorganic compounds (phosphates, sulphides and carbonates) which showed that the operationally defined metal and phosphorus fractions were not always representative of precise metal phases. Species were tentatively assigned to metal and phosphorus fractions using model compound results. Laboratory-scale batch anaerobic digestion experiments were performed, in which model compounds were used to simulate conditions of soluble and insoluble phosphorus enrichment. Soluble phosphorus at concentrations of 500 mg/l or greater was found to retard volatile solids removal and methane production in the laboratory digesters. Soluble phosphorus enrichment facilitated precipitation of calcium, magnesium and manganese but increased trace metal solubility, particularly that of chromium. Enrichment of digesters with Na2HP04 and MgCb caused struvite to precipitate in digesters containing 1000 mg/l of additional phosphorus. FeP04 enrichment of digested sludge showed that ferric iron was reduced to ferrous iron, releasing soluble phosphorus into the digester. Most of the phosphorus was reprecipitated as ferrous phosphate, causing co-precipitation of magnesium, manganese and cobalt. By contrast, A1P04 added to the digesters was stable in the sludge. Full-scale CPR sludge digestion (Fe2(S04)3 dosing) caused soluble phosphorus in the digester to decrease below 0.05 mg/l. Phosphorus remained associated with iron in the sludge fraction but soluble calcium and magnesium concentrations in the full-scale digester increased as a result of CPR sludge digestion. Comparison of laboratory and full-scale results showed that the fate of iron-precipitated phosphorus in digested sludge was primarily dependent pn the molar ratio of Fe:P in the sludge. Full-scale BPR sludge digestion showed high concentrations of soluble phosphorus in the digester and some struvite precipitation, although phosphorus was precipitated primarily as calcium phosphate, as was found to occur in the laboratory digesters simulating BPR sludge digestion.
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Siddique, Muhammad Tariq. "Phosphorus reactions and leaching potential in soils amended with organic wastes." Thesis, University of Reading, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269959.
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Wilmes, Paul. "Metaproteomic investigations of enhanced biological phosphorus removal in activated sludge." Thesis, University of East Anglia, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.426993.
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Keeley, James. "Coagulant recovery from waterworks sludge." Thesis, Cranfield University, 2014. http://dspace.lib.cranfield.ac.uk/handle/1826/9218.
Full textAbstract:
Coagulation is a ubiquitous process in the treatment of raw surface water for eventual potable use. Despite its capabilities, the sheer scale of its use is manifested in the volumes of chemicals it demands and waste sludge it produces. Recovering and reusing the chemical activity of the coagulant sludge in water treatment is a logical solution but this practice has been restricted by the presence of contaminants within the sludge. This thesis has investigated methods that can separate the coagulant metals from these primarily natural organic contaminants, with an aim of producing a sufficiently pure coagulant for effective treatment performance when reused. A process of ultrafiltration of the impure regenerated coagulant followed by a powdered activated carbon polishing stage compared favourably to a number of other separation processes and was found to remove the most dissolved organic compounds. When the purified coagulant was used to treat raw water, it provided better turbidity removal than commercial coagulant and matched its removal of trihalomethane precursors, making the process suitable for consideration at full-scale. Analysis of the whole life cost suggested that such performance could be reproduced at full-scale within a 25 year payback period. The reuse of even purified recovered coagulants in drinking water treatment still carries risks which may deter its implementation. Therefore the efficacy of recovered coagulants in the role of phosphorus removal from wastewater was also investigated. This showed that both acidified and unacidified waterworks sludges, with sufficient contact time, could remove similar levels of phosphorus as fresh coagulants, at approximately half the whole life cost.
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Al, Tahmazi Talib. "Characteristics and mechanisms of phosphorus removal by dewatered water treatment sludges and the recovery." Thesis, Cardiff University, 2017. http://orca.cf.ac.uk/105255/.
Full textAbstract:
The use of novel industrial by-products (IBPs) to remove phosphorus (P), instead of high-cost P removal techniques, is one of the sustainable solutions to protect aquatic life from excessive P discharges. One of such IBPs is dewatered drinking water treatment works sludges generating from using aluminium or iron salts as coagulant during the drinking water treatment process. Previous studies have shown that the sludges hold promise as a novel adsorbent for the removal of P from wastewaters; however, comprehensive investigation into factors affecting the P removal and the recovery is lacking. Therefore, the main aim of this study is to contribute to a mechanistic understanding of P removal and retention by dewatered water treatment sludge (DWTS), and the associated coagulant recycling and P recovery from the P-saturated sludge used as substrate in a constructed wetland system. Seventeen DWTSs were collected from different areas in the UK to study the combined effect of sludge inherent properties and solution chemistry; and the P equilibrium and kinetic adsorption behaviour using batch experiments. Results revealed that the metal content (Al, Fe, Aloxalate and Feoxalate) and specific surface area components had the most significant explanation for the variance of: (i) P-uptake at different initial P concentrations; (ii) the adsorption maxima; and (iii) the Freundlich constant. Overall, giving the combined effect of intrinsic sludge properties and solution chemistry, dewatered waterworks sludges with high reactive metal content (Al and Fe), Ca and SO42- ions, and total specific surface area, would be the best choice for P retention in practical applications. Phosphorus retention by two Al- and two Fe-DWTS were modelled under various operation conditions of hydraulic retention time and influent P concentration, using a continuous feeding system. Four design equations for P retention were developed and these successfully predicted discrete P retention, maximum P loaded to the sludge, accumulative amount of P retention, and lifespan at the required P saturation degree. The model results revealed that the lifespan of ferric sludge is about four years to reach its saturation point, if the flow rate of 190 (l/capita.d) and inflow P concentration of 5 mg/l are used. IV With regards to coagulant recycling and P recovery using electrodialysis (ED) technology, P saturation degree influenced negatively on Fe and P recovery where their percentages dropped from 70 ± 8%, 49 ± 3% to 17 ± 2, 6 ± 1% when P saturated sludge increase from 0% to 100% respectively. The normalised values of recovered Fe to permeated dissolved organic carbon (DOC) were between 29 and 290. Most of the recovered coagulants were comparable in performance with commercial coagulant in term of DOC removal (42 to 59%), Turbidity, and UV254 absorbance. Overall, the results have shown that DWTS has great potential not only for P removal but also for coagulant and P recovery. However, further research is needed before the developed models can be applied at field scale, and also to enhance the ED recovery for further benefits.
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Johannesson, Gudmundur Hrafn. "Sewage sludge characterization and evaluation of phosphorus availability under greenhouse conditions." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0020/MQ47334.pdf.
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Clayton, John Andrew. "Denitrification kinetics in biological nitrogen and phosphorus removal activated sludge systems." Master's thesis, University of Cape Town, 1989. http://hdl.handle.net/11427/21139.
Full textAbstract:
In order to size the anoxic reactors in nutrient (N and P) removal activated sludge plants, it is essential to know the denitrification kinetics that are operative in such systems. To date, denitrification kinetics have been accurately defined only for systems that remove N alone; little research has been performed on denitrification in N and P removal plants.
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Sui, Peng Zhe. "Behavior of Metals in the Advanced Sewage Treatment Process with Excess Sludge Reduction and Phosphorus Recovery." 京都大学 (Kyoto University), 2010. http://hdl.handle.net/2433/131884.
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Wable, Milind Vishnd. "Investigation of hypothesized anaerobic stabilization mechanisms in biological phosphorus removal systems /." This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-05042006-164504/.
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Power, Sean P. B. "Chemical phosphorus removal from municipal wastewater by the addition of waste alum sludge to the activated sludge system." Master's thesis, University of Cape Town, 1992. http://hdl.handle.net/11427/8299.
Full textAbstract:
Includes bibliography.In many cases, waterworks waste alum sludge is disposed of by discharging it into a stream. In this investigation the disposal of alum sludge to activated sludge systems treating municipal sewage is investigated. The advantage is that it is a better method of alum sludge disposal, and moreover the addition of alum sludge removes phosphorus from the wastewater through chemical precipitation. Two long sludge age (20 days) Modified Ludzack Ettinger (MLE) predenitrification systems receiving unsettled municipal wastewater at a controlled concentration of 500mg COD/l as influent were operated for a period of 305 days, one as an Experimental system and the other as a Control system. The anoxic mass fraction was large (70), to mimic many long sludge age nitrification/denitrification systems in operation in South Africa. Nitrate was added into the anoxic reactors to maintain anoxic conditions so that biological excess phosphorus removal would not take place and interfere with the chemical removal performance.
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Shober, Amy L. "Chemical speciation and redox effects on phosphorus release from biosolids and manure amended soils." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 0.99 Mb., 179 p, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:3221058.
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Chauke, Rhandu. "Mineralisation and bioavailability of phosphorus from poultry manure and sewage sludge-based phospho-composts for maize production." Thesis, University of Limpopo (Turfloop Campus), 2014. http://hdl.handle.net/10386/1171.
Full textAbstract:
Thesis (MSc. Agriculture (Soil Science)) -- University of
Limpopo, 2014Phospho-composts of different mix ratios (5:5, 7:3, 8:2 and 9:1) were produced through thermophilic co-composting of poultry manure (PM) and sewage sludge (SS) with ground phosphate rock (GPR). Composted PM and SS without GPR addition were included as control. Cured phospho-composts were chemically characterised and used for both laboratory incubation and greenhouse studies, respectively for phosphorus (P) mineralisation and bioavailability, over a period of 42 days. Results revealed that Bray-P1 concentration measured in compost amended soils at 14, 21 and 42 DAI differed significantly (P<0.05) and ranged between 5.47 and 11.14 mg kg-1 and between 5.28 and 11.78 mg kg-1 in poultry manure and sewage sludge-based phospho-composts, respectively. The maximum amount of cumulative P mineralised of 16.06 and 9.98 mg kg -1, respectively in PM and SS-based phospho-composts were obtained from the 8:2 mix ratio. The content of the acid detergent fibre of the different phospho-composts showed positive and significant correlation with cellulose, lignin and total organic carbon (TOC). Similarly, cellulose as well as C:P ratio showed significant correlation with both lignin and TOC. The polynomial relationship between cumulative P mineralised and the various GRP and manure mix ratios revealed significant and positive R2- values of 0.731 and 0.613 for PM and SS-based phospho-composts, respectively. The maximum amount of maize tissue P uptake of 0.12 and 0.11 mg pot-1 in PM and SS-based phospho-compost respectively were also obtained from the 8:2 mix ratio while the least amount of 0.04 mg P pot-1 was obtained from GPR and unamended pots. Maize tissue P uptake following the phospho-compost application was significantly affected by the differences in soil type. Tissue P uptake was 0.06 and 0.11 mg P/pot, respectively in low potential and high potential soils with a significantly higher value. The use of the different phospho-composts showed great potential for amelioration of P-deficiency problems in crops while thermophilic cocomposting improved the solubility and bioavailability of P from non-reactive GPR. Keywords: Ground phosphate rock; poultry manure; sewage sludge; phosphocomposts; phosphorus mineralisation; soil fertility management.
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Carlborg, Ylva. "Ash transformation during combustion of phosphorus-rich industrial sludge : Investigation of phosphorus recovery potential, and effects on emissions and deposit formation." Thesis, Umeå universitet, Institutionen för tillämpad fysik och elektronik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-103834.
Full textAbstract:
Effective use of resources is essential in the development towards a sustainable industry. Waste products, such as sludge from industrial waste water treatment, often contain valuable reserves of plant nutrients but this resource is nonetheless commonly disposed of as contaminated waste. Approximately 1 500 ton phosphorus per year is added in biological waste water treatment at the Swedish pulp and paper industries and this non-renewable resource thereby ends up in their so called biosludge. The most common way to discard the sludge is by incineration. Besides the high levels of phosphorus, the biosludge usually contains high levels of moisture and ash forming elements, sulfur and chlorine, which makes it a rather problematic fuel. The aim with this study was to investigate different aspects on ash transformation chemistry during co-combustion of biosludge, from the pulp and paper mill SCA Packaging Obbola AB, with wood fuels and wheat straw. The phosphorus recovery potential, and the effects on deposit formation and emissions, were examined by SEM-EDS- and XRD-analysis of ash from co-combustion experiments. The experimental results were complemented with theoretical analysis based on thermochemical equilibrium calculations. The biosludge from SCA Obbola contained high levels of Ca which had a large impact on the ash transformation reactions. Most of the phosphorus from the fuels stayed in the solid ash during combustion, and in all ash assortments, except for the pure wood fuel, it was primarily found in the crystalline structure whitlockite, Ca9(K,Mg,Fe)(PO4)7. Hydroxyapatite, Ca5(PO4)3OH, was identified in ash from combustion of the pure wood fuel and wheat straw, and in the mixture of biosludge and wood fuels with the lowest proportion of sludge. Of the two phosphorus compounds, hydroxyapatite is more difficult to break down. It is therefore promising from a phosphorus recovery perspective that whitlockite was the main phosphorus compound in most of the ash assortments. Some of the sulfur in the sludge reacted with Ca and formed solid CaSO4, which stayed in solid ash during combustion, while chlorine generally left the bottom ash by volatilization. K- and Si-rich agricultural residues, such as wheat straw, are associated with a number of ash-related problems, including deposit formation due to low ash-melting points. During co-combustion of biosludge and wheat straw, the melting tendencies of the wheat straw ash elements were examined. According to the thermochemical equilibrium calculations, the composition of the mixed fuels would result in a significantly higher initial slag formation temperature compared to the pure wheat straw. This trend was also observed in the experimental results. It is likely that the relatively high levels of Ca, Al and P in the sludge all contributed to reduced slag formation in the wheat straw ash, by formation of ash compounds with higher melting temperatures. The high calcium levels may however have reduced some of the positive effects of increased P and Al contents by these elements preferably reacting with Ca instead of capturing alkali in crystalline structures.
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Unal, Eda. "Investigation Of Magnesium Ions Effect On Sludge Properties In Phosphorus Deficient Bioreactors." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612620/index.pdf.
Full textAbstract:
The activated sludge process efficiency depends on separation of microbial cells from treated wastewater. Separation can fail due to a number of problems. One of these problems is sludge bulking which is non-settling situation of biomass. Former
studies showed that phosphorus deficiency caused filamentous sludge bulking with increasing magnesium ion concentrations. The main objectives of this study are to find out the effect of magnesium ions on sludge properties in phosphorus deficient
medium and to determine if there is any bulking. Three different concentrations of magnesium (0.5, 5, 15 meq/L) were added to three bioreactors which contained phosphorus deficient medium. In first set C: N: P ratio was 100:5:0.05. In second set,
C:N:P ratio was elevated to 100:5:1. At steady state, physical characteristics including sludge volume index (SVI), viscosity, turbidity and dewaterability were determined. Besides concentration of extracellular polymeric substances (EPS) as
well as conductivity was measured. By using API kits, bacterial identification was achieved.
In first set phosphorus deficiency and increasing magnesium ion concentration caused filamentous bulking. Carbohydrate content of extracellular polymeric substance significantly increased by magnesium addition. Dewaterability of the system got worse and viscosity decreased. Sludge Volume Index (SVI) indicated
severe bulking at all magnesium concentrations. By using biochemical tests microorganisms dominant in the system were determined In second set, all of the parameters indicated healthy flocculation. By magnesium addition, EPSp and EPSc increased. Dewaterability and settleability, improved by the
presence of phosphorus with close values measured at different magnesiuim
concentrations. Nocardia related genera of Corynebacterium and Enteric microorganisms were identified.
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Copp, John B. "COD balances in biological nutrient (nitrogen and phosphorus) removal activated sludge systems." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0022/NQ50987.pdf.
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Copp, John B. "COD balances in biological nutrient (nitrogen and phosphorus) removal activated sludge systems /." *McMaster only, 1998.
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Clark, T. "The impact of chemical addition for phosphorus removal on activated sludge treatment." Thesis, Cranfield University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268135.
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Rowley, Maxine Joy. "Spatial distribution of phosphorus in the sediments of a constructed wetland receiving treated sewage effluent /." [Richmond, N.S.W.] : Centre for Water and Environmental Technology, Water Research Laboratory, University of Western Sydney, Hawkesbury, 1998. http://library.uws.edu.au/adt-NUWS/public/adt-NUWS20030806.121149/index.html.
Full textAbstract:
Thesis (M.Sc. Hons.) -- University of Western Sydney, Hawkesbury, 1998.Thesis submitted for the degree of Master of Science (Hons.). Spine title: Phosphorus in constructed wetland sediments. Includes bibliographical references (leaves 114-123).
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Ryan, Gregory Lawrence. "Mechanisms of phosphorus removal by constructed wetland systems /." View thesis, 2003. http://library.uws.edu.au/adt-NUWS/public/adt-NUWS20031003.141904/index.html.
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Thesis (PhD) -- University of Western Sydney, 2003."Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy at the University of Western Sydney, Hawkesbury." "April 2003" Bibliography: leaves 287 - 302.
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Scott, James D. "Availability and distribution of nitrogen and phosphorus from sewage sludge in the plant-soil-water continuum." Thesis, Virginia Tech, 1987. http://hdl.handle.net/10919/43892.
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Research was conducted in 1984 and 1985 to determine N and P availabilities for barley (Hordeum vulgare L.) and com ( Zea mays L.) grown on four sludge-amended soils. Tests were conducted on the Acredale silt loam (Typic Ochraquall), Bojac loamy sand (Typic Hapludult), Davidson clay loam (Rhodic Paleudult), and Groseclose silt loam (Typic Hapludult) soils. An aerobically·digested sewage sludge from a sewage treatment plant with major industrial irrputs was applied at rates of 0, 42, and 84 dry Mg ha' 1 on the poorly-drained Acredale soil. Rates of 0, 42, 84, 126, 168, and 210 dry Mg ha'1 were applied on the well-drained Bojac, Davidson, and Groseclose soils. The 210 dry Mg haâ 1 sludge rate supplied 3300 and 6600 kg of N and P haâ 1, respectively. A 14-day anaerobic N incubation study indicated that mirreralization varied from approximately nine to four percent of sludge N from the 42 to 210 Mg haâ 1 application rates, respectively. Sludge application increased N uptake (rz = 0.98** to 0.99**) by the 1984 com grown on the three well-drained soils. Nitrogen balance data indicated that quantities of unrecovered N ranged from six to 21 percent where sludge was applied.Master of Science
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Haile, Henok Debessai. "Sustainable Phosphorus Management in Sweden : A study of phosphorus recycling from wastewater sludge in several municipalities of the Östergötland County." Thesis, Linköpings universitet, Tema Miljöförändring, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-122365.
Full textAbstract:
The Swedish Environmental Agency (SEPA) proposed a national target to increase the rate of phosphorus recycling from wastewater sludge in 2013. Reusing phosphorus from wastewater sludge by spreading it on arable lands raises the risk of contamination and substance deposition in soils. In addition to quantifying the targeted rate of recycling, the proposal has also introduced new thresholds that limit the concentrations of undesired substances in wastewater sludge. This thesis assesses the potential challenges and opportunities in implementing the proposed measure in the Swedish municipality settings. Both qualitative and quantitative data have been gathered from three selected mid-sized Swedish municipalities in the Östergötland County and other data sources. The analytical framework of the thesis is based on the Systems Framework for Phosphorus Recovery and Reuse. Several discrepancies between the national goal to increase phosphorus recycling and local circumstances that affect local decision-making have been identified in this thesis. Reducing the flow of undesired substances into the wastewater stream raises goal conflict and is an enormous challenge which requires regulating the way chemicals are consumed in society. From the policy perspective, the national environmental objectives framework is ambiguous with regards to how local decisions should be directed in line with the national goals. The proposed measure should hierarchically be unequivocal and its implementation needs to be coordinated across all geographical scales. The thesis also highlights that there are significant local opportunities for addressing other sustainability goals through phosphorus recycling measures. Sweden’s commitment to creating a resource-efficient phosphorus cycle affirms that the key for a sustainable phosphorus management is the transformation of path-dependent social and technical systems.
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Boontian, Nittaya. "Using the activated sludge model 2d (ASM2d) to understand and predict the phosphorus accumulating organisms mechanism in enhanced biological phosphorus removal in relation to disintegrated sludge as a carbon source." Thesis, Cranfield University, 2012. http://dspace.lib.cranfield.ac.uk/handle/1826/7864.
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Carbon sources are considered as one of the most important factors in the performance of enhanced biological phosphorus removal (EBPR). Disintegrated sludge (DS) can act as carbon source to increase the efficiency of EBPR. This research explores the influence of DS upon phosphorus removal efficiency using mathematical simulation modeling. Activated Sludge Model No. 2d (ASM2d) is one of the most useful of activated sludge (AS) models. This is because ASM2d can express the integrated mechanisms of phosphorus accumulating organisms (PAOs) under aerobic, anaerobic and anoxic conditions. Cont/d.
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Belia, Evangelia. "Phosphorus release during treatment of sludge derived from a bench-scale EBPR plant." Thesis, University of Strathclyde, 2002. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=28864.
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This thesis describes the development of enhanced biological phosphorus removal (EBPR) in a lab-scale sequencing batch reactor (SBR) and the release of phosphorus during the storage and thickening of sludge produced in this reactor. In the first phase of the experimental work a fast start-up method for EBPR development was established by the addition of a pure culture of Acinetobacter lwoffi to a conventional activated sludge. Investigations revealed that the performance EBPR depended on the combination of influent COD and phosphorus values and that in the investigated range, EBPR functioned independently of the sludge retention time. Low dissolved oxygen levels had no effect on the phosphorus removal properties of the sludge. The second phase of the experimental work involved the investigation of the phosphorus released during sludge handling. It was found that phosphorus resolubilisation during sludge treatment took place in three distinct phases which included an initial period of extremely low phosphorus release. Alterations of the reactor influent and operational parameters and the sludge characteristics, affected the amount of phosphorus released during anaerobic storage and gravity thickening. It was found that for short retention times in the sludge processing units (1-48 hours), decreasing the influent phosphorus concentration, increasing the oxidised nitrogen content of the excess sludge and wasting the excess sludge from the aeration tank decreased the amount of phosphorus resolubilised. For longer retention times (2-7 days), it was found that increasing the influent COD, having a lower total phosphorus sludge content, higher sludge "stabilisation" rates and quiescent conditions of storage, decreased the amount of phosphorus released.
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Knight, Jonathan James. "Chemical phosphorus removal and its influence on sewage sludge particulates and metal availability." Thesis, Imperial College London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324631.
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Nash, Jeffrey William. "Characteristics and conditioning of anaerobically digested sludge from a biological phosphorus removal plant." Thesis, Virginia Tech, 1989. http://hdl.handle.net/10919/44128.
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A study of the anaerobically digested sludge form a
full-scale biological phosphorus removal (BPR) plant (York
River Wastewater Treatment Plant, York River, Va.) was
conducted to determine the effects of BPR on sludge
characteristics and conditioning requirements. Data
collected from the plant indicated that both the total and
soluble phosphorus (P) concentrations in the anaerobically
digested sludge increased dramatically with the initiation
of BPR. Accompanying this increase in total P was an
increase in the total concentrations of magnesium and
potassium content of the sludge, supporting the observations
that these ions are coâ transported with P during the
accumulation and release of P by P accumulating organisms.
The majority of the phosphate present in the pre- and post-
BPR anaerobically digested sludges was bound by calcium,
magnesium, and iron phosphorus precipitates including
hydroxyapatite, struvite, and vivianite. Calcium phosphorus
precipitates were the most prevalent in both sludges, but
the percentage of magnesium phosphorus precipitates
increased with the onset of BPR.
Cationic organic polymer conditioning dosages needed to
achieve acceptable sludge dewatering rates for the post-BPR
sludge were similar to those required by the pre-BPR sludge.
The cationic organic polymer used to condition these sludges
was ineffective in removing excess phosphate; therefore, the
addition of either one or both of the inorganic chemicals
ferric chloride and calcium hydroxide was required to remove
soluble phosphorus. Conditioning with either ferric
chloride or calcium hydroxide alone was not effective in
achieving acceptable dewatering rates; however, when used
together the chemicals produced acceptable dewatering rates
and soluble P removal from the post-BPR sludge.Master of Science
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Saktaywin, Wilasinee. "Development of advanced sewage treatment process with excess sludge reduction and phosphorus recovery." 京都大学 (Kyoto University), 2005. http://hdl.handle.net/2433/144545.
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Grey, Mark Alan. "The mobility and fate of phosphorus following municipal biosolids application to forest soils /." Thesis, Connect to this title online; UW restricted, 1999. http://hdl.handle.net/1773/5554.
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Van, Lierde Patrick G. "Nucleation, milk and membranes as modifications to enhance biological phosphorus removal in activated sludge." Thesis, Loughborough University, 2015. https://dspace.lboro.ac.uk/2134/16784.
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Enhanced biological phosphorus removal (EBPR) was researched from the performance of a modified University of Cape Town (UCT), anaerobic-anoxic/nitrifying-aerobic process. The work focussed on high P influent where milk was compared to carbohydrates as exogenous added carbon and typical settled sewage. The results confirmed that at equal COD load in the influent (minimum COD:P (250:5) ratio for EBPR), milk always provided sufficient soluble substrate than the carbohydrate mix, but also improved the EBPR performance. The laboratory scale treated 10L/day where 2 parallel treatment trains for milk and an equivalent carbohydrate mix as supplement to compare and study the P sequestration from hypothesised P ligands in milk and easily assimilable carbon (AOM) after fermentation for biological P uptake. The aerobic bioreactors used submerged flat sheet membranes (AeMBR) to improve the effluent quality and reduce the suspended solid residues. The results suggested extra benefits from adding calcium chloride (CaCl2) (200 ml at 250 mM/day or 200 mg/L treated) to form P complexes both in the anaerobic and aerobic zones (100 ml CaCl2 250mM/zone/day). To complete P removal a calcium phosphate (CaPO4) further treatment stage (post membrane final effluent (F.E.)) was added for nucleation. The combination of, A2O-N, exogenous carbon and calcium addition improved the performance of the EBPR, and enabled the laboratory units to achieve less than the 1 mg/L P required by the EU Directive. The process was tested at higher than normal P loads (maximum 100 mg/L) (domestic wastewater influent 15 mg/L). Experiments with influent P load ≤ 50mg/L, with 1% milk as AOM were compared to the carbohydrate mix and could remove soluble P to less than 1mg/L above 97% and less than 2 mg/L more than 99% of the in the time respectively. With an influent P load of 60mg/L (maximum 100 mg/L), the soluble P in the F.E. with milk was below 5 mg/L and below 8 mg/L with carbohydrates mix. The results showed that most of the phosphorus was retained by the sludge during the anoxic-aerobic phases. The remaining phosphate in the F.E. was able to pass through AeMBR pore size (0.4 μm) and needed to be chelated by the nucleation process. The results indicated this A2O-N modifications achieved stable nutrient removal and also offered the potential for more sustainable phosphorus recovery. The EBPR without AOM was 25% less efficient compared to milk and never achieved the E.U standard of 1mg/L in final effluent. The flat sheet membrane always achieved a NTU final effluent below 1 and the TOC always greater than 90% removal or less than the EU 125 standard regardless of the feeding COD/P ratio.
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Aksu, Ceren. "The Role Of Calcium Ion On Activated Sludge Biochemical And Physical Properties In Phosphorus Deficient Growth Medium." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612580/index.pdf.
Full textAbstract:
Nutrients and cations have significant effect on activated sludge characteristics and therefore effect the efficiency of whole processes. To determine the properties in phosphorus deficient medium and the effect of calcium ions two reactor sets with two different phosphorus concentration (C/N/P=100/5/0.05 and C/N/P=100/5/1), three different concentrations of calcium (0.5, 5, 15 meq/L) were operated with 8 days of sludge residence time and an effective volume of 2 L. Results showed amount and composition of EPS was dependent on calcium and phosphorus concentrations. Except for the highest calcium concentration, increase in phosphorus concentration resulted in increase in total EPS production. Under phosphorus deficient conditions, calcium ions stimulated the production of carbohydrate type polymers and viscous bulking was observed. However, the increase in phosphorus concentration led to increase in protein type polymer production and bulking condition was cured. Addition of calcium ions increased conductivity in both cases, but increase in phosphorus concentration caused decrease in conductivity. Increase in phosphorus concentration had improved settleability, dewaterability and rheology of sludge. Moreover, effluent turbidity was decreased and COD removal efficiency was recorded as greater than 95 % for all calcium concentrations under phosphorus sufficient conditions. Microscopic analyses showed that under phosphorus deficient conditions flocs were weak, dispersed and nonresistant. Increase in phosphorus concentration resulted in improvement of floc structure. Same Enterobacter and Citrobacter species were identified at all calcium concentrations under phosphorus deficient conditions. Yet, under phosphorus sufficient conditions different species were identified in control reactor as compared to 5 meq/L and 15 meq/L concentrations.
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Wable, Milind Vishnu. "Investigation of hypothesized anaerobic stabilization mechanisms in biological phosphorus removal systems." Diss., Virginia Tech, 1992. http://hdl.handle.net/10919/27531.
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Balaguer-Barbosa, Maraida. "Recovery of Nutrients from Anaerobically Digested Enhanced Biological Phosphorus Removal (EBPR) Sludge through Struvite Precipitation." Scholar Commons, 2018. https://scholarcommons.usf.edu/etd/7471.
Full textAbstract:
Water resources in Florida have been severely degraded by eutrophic conditions, resulting toxic algae blooms, which negatively affect health and tourism. Eutrophication, or excessive amount of phosphorus (P) and nitrogen (N) in water, overstimulates the production of aquatic plants, depletes dissolved oxygen, and deteriorates the aquatic environment. However, phosphorus is a non-renewable resource essential for all living organisms. In fact, more than half of the total demand for P globally is to supply the food industry, which has concerningly accelerated the depletion rates of phosphate reserves.
In many wastewater treatment plants (WWTPs), the enhanced biological phosphorus removal (EBPR) approach has been employed to achieve high phosphorus removals from wastewater through phosphate-accumulating organisms (PAOs). However, during either anaerobic or aerobic digestion of EBPR sludge, stored polyphosphates are released and carried into the sidestream, which is typically returned to the headworks of the main treatment facility, thereby recycling phosphorus back into the system. This treatment train is highly inefficient because nutrients rather are recirculated rather than recovered.
Struvite (MgNH4PO4•6H2O) is precipitated in oversaturated aqueous solutions with equal molar concentrations of magnesium, ammonium, and phosphate. The controlled crystallization of struvite may be applied to remove phosphorus and some ammonium from sidestreams, which is the liquid portion of the digester effluent. Struvite can be employed as a sustainable slow-release fertilizer due to its low solubility in water. This offers the opportunity of marketing the struvite produced under controlled conditions and creating a revenue for the utility.
The specific research objectives of this thesis are (1) to investigate different possible operating conditions under which anaerobically digested sludge from EBPR facilities might be treated through struvite precipitation; (2) to quantify the removal of N and P from sidestreams from anaerobically digested EBPR sludge via struvite precipitation and assess the composition of the precipitate obtained; and (3) to generate a cost analysis to assess the trade-offs between the capital and operation and maintenance (O&M) costs of struvite production and the benefits such as reduced chemical use and production of a slow-release fertilizer.
The main parameters affecting struvite precipitation are the Mg2+ to PO43- molar ratio, pH, temperature, mixing speed, hydraulic retention time (HRT), and the seed quantity added to promote nucleation. Different operating conditions within these parameters were batch-tested as part of this study using sidestream from the pilot-scale anaerobic digester (AD) fed from Falkenburg Advanced Wastewater Treatment Plant (FAWWTP) EBPR sludge. Additionally, the effect of temperature and pH were investigated using Visual MINTEQ simulations. Analysis of Variance (ANOVA) was employed to investigate the variance within the removals from the centrate obtained for phosphate, ammonium, magnesium, and calcium. The chemical composition of the solids collected after employing the selected operating conditions was analyzed by powder X-ray diffraction (PXRD).
The results for the batch tests performed as part of this thesis were quantified in terms of the removals of phosphate, ammonium, magnesium, and calcium from the centrate. The greatest amount of phosphate removal was achieved by operating the struvite reactor at 4.0 mmol of Mg2+ per mmole of PO43-. The other molar ratios tested were 1.0, 2.0, and 3.0. Visual inspection of the data showed significant variability in removals of ammonium, calcium, and magnesium, which are likely to be correlated with the highly variable influent concentrations into the struvite reactor. In this case, ANOVA will require larger data sets to accurately analyze variance in the results. The statistical results given by ANOVA for the pH suggests that the main species to contribute with struvite being precipitated are statistically stable within the tested pH values of 8.5, 9.0, and 9.5. The results obtained by the simulation using Visual MINTEQ indicated that maximum saturation as function of pH takes place at a pH between 9.5 and 10.0. The ANOVA for the mixing speed showed that significant amounts of ammonium were removed at higher mixing speeds. This is likely due ammonium being volatilized, which is enhanced by turbulence. Magnesium and phosphate showed lower removals at higher mixing speeds, suggesting that too high mixing speeds will promote struvite seed dissolution. ANOVA identified NH4+ and Ca2+ as the species significantly impacted by modifying the HRT from 8 to 20 minutes. This suggests that prolonged HRT promotes inorganic nitrogen species to volatilize. It is likely that at higher HRT, tricalcium phosphates (TCP) or other favored calcium species coprecipitated together with struvite. Regarding the added struvite seed for nucleation, the greatest removals of ammonium, magnesium, and, phosphate were observed when 1g/L of struvite seed was added. The results also indicated that adding 5 and 10 g/L was an excessive amount of seed, which ended up contributing significantly to more nutrients into the centrate rather than precipitating them. The results also suggested that the struvite crystals formed in the sidestream by secondary nucleation, since removals close to zero were reached after adding no seed. The optimum temperature identified by the simulation in Visual MINTEQ was 21°C.
Operating the struvite reactor under the optimal conditions identified in the batch tests, resulted in an average of 99% total P (TP) and 17% total N (TN) removals. The precipitate molar composition for [Mg2+:NH4+:PO43-] was equal to [2:2:1] based on the concentrations that disappeared from the aqueous solution, suggesting that other minerals coprecipitated with struvite. Visual MINTEQ predicted that together with struvite, CaHPO4 and CaHPO4•2H2O will also precipitate under the tested conditions. However, given the obtained ratio it is likely that other unpredicted species by Visual MINTEQ, such as magnesium carbonates or magnesium hydroxide coprecipitated with struvite. PXRD analysis also revealed that the sample was likely contaminated struvite, although the specific contaminants were not identified.
A cost analysis was performed to distinguish the economic feasibility of incorporating a struvite harvesting system to treat the anaerobically digested sidestream from the Biosolids Management Facility (BMF) within the Northwest Regional Water Reclamation Facility (NWRWRF). Three different scenarios were evaluated; in Scenario (1) Ostara® Nutrient Recovery Technologies Inc. (Ostara®) evaluated the production of struvite from anaerobically digested EBPR sidestream using a fluidized reactor. In Scenario (2), Ostara® evaluated the production of struvite in a fluidized bed reactor by employing Waste Activated Sludge Stripping to Remove Internal Phosphorus (WASSTRIP™) in a mixture of post-anaerobic digestion centrate and pre-digester thickener liquor. Scenario (3) was addressed by Schwing Bioset Inc. (SBI) for a continuously-stirred reactor followed by a struvite harvesting system.
Scenario (2) offers the highest TP and TN recoveries through WASSTRIP™ release due to the additional mass of phosphorus that is sent to the phosphorus recovery process. Therefore, although Scenario (2) has the highest total capital costs ($5M) it also has the shortest payback period (18 years). Scenarios (1) and Scenario (3) have similar payback periods (22-23 years) but very different total capital costs. The annual savings by producing struvite in Scenario (3) is $40K, which is about 30% less than producing struvite in Scenario (1). This is probably because the only savings considered under Scenario (3) were the lower alum usage and the fertilizer revenue; however, the savings by producing class A biosolids, were not accounted for. Consequently, the reduced total capital cost of $960K and the annual payment amount per interest period close to $80K, positioned Scenario (3) as the more feasible one, considering 20 years as the expected life of the asset at a 5% interest rate.
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Turtin, Ipek. "Investigation Of Activated Sludge Bioflocculation: Influence Of Magnesium Ions." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/2/12606605/index.pdf.
Full textAbstract:
Activated sludge systems are the most widely used biological wastewater treatment processes all over the world. The main working principles of an activated sludge system are the oxidation of biologically degradable wastes by microorganisms and the subsequent separation of the newly formed biomass from the treated effluent. Separation by settling is the most troublesome stage of an activated sludge process. A decrease in the efficiency of the separation of microbial biomass from the treated effluent causes a decrease in the overall efficiency of the treatment plant. The efficiency of the separation process is related to the bioflocculation, which can be briefly defined as the aggregation of the bacteria into flocs through flocculation. Bioflocculation depends on the extracellular polymers (EPS) that are produced by microorganisms. The operating conditions of the activated sludge system is a key determinant of the synthesis of EPS and bioflocculation. The main objective of this study is to find out the effect of magnesium ions on the bioflocculation process under phosphorus deficient and sufficient conditions. In order to achieve this aim, the effects of magnesium ion in 4 different concentrations (0.9, 5, 10 and 20 meq/L) are investigated in semi continuous reactors. The reactors are operated at a mean cell residence time of 8 days and 20ºC temperature. When reactors are confirmed to be at steady state, several sets of analysis are conducted. In particular, the surface chemical parameters including EPS and its components, electrical charge, and hydrophobicity as well as physical properties such as settlability, filterability, viscosity, floc strength, and turbidity are examined. It has been understood that phosphorus deficiency causes severe filamentous bulking under magnesium rich conditions. Increasing the phosphorus concentration in the influent can cure this problem. After the sludges are cured some granular structures were observed in the microscopic investigations and they are thought to be polyphosphate granules in which microorganisms tend to accumulate phosphorus when they find the adequate source after a starvation period. To consider the reactors operated at phosphate present conditions, it has been found that EPS increases with increasing influent magnesium concentration. However, protein type EPS (EPSP) exhibits a sharper increase when compared to the carbohydrate type EPS (EPSC) indicating the selective attitude of magnesium ions to protein type of polymers. It has been understood that the increase in the influent magnesium concentration results in an increase in dewaterability and zone settling velocity, and a decrease in the viscosity. Hydrophobicity was found to exhibit a maximum value at 10 meq/L magnesium fed sludge and then it dropped back. Surface charge values also made a minimum at 10 meq/L reactor and then no change occurred at the increase of the magnesium concentration to 20 meq/L. Finally, COD values were found to increase with the increasing magnesium concentration due to the increasing EPS.
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Besancon, Axelle. "Technologies and multi-barrier systems for sustainable groundwater recharge and irrigation." Thesis, Cranfield University, 2010. http://dspace.lib.cranfield.ac.uk/handle/1826/5726.
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Managed aquifer recharge (MAR) consists of artificially replenishing groundwater to facilitate reuse and/or the associated environmental benefits. Meanwhile, soil aquifer treatment (SAT) is a process of geo-purification designed and operated to improve the quality of the infiltrating water and is thus a type of MAR. SAT consists of a basin operating under rotation of drying and wetting periods. Often, SAT involves water of impaired quality applied onto soil and consequently it implies various risks of health, geochemical and physical nature with difficult or irreversible remediation. To study the effect of pre-treatment on SAT a pilot plant including conventional activated sludge (CAS), a membrane bioreactor (MBR), tertiary and secondary vertical flow reed beds (VFRB) and SAT soil columns. The sludge retention time (SRT) in the CAS and MBR processes was changed every 6 months to look at the impact of SRT on SAT. Each unit and treatment train effluent was characterised to determine the impact of effluent quality on SAT performance. This study showed that tertiary VFRB, especially when fed with MBR effluent, was the best option for SAT and irrigation reuse as it provided the best compliance with reuse standards and the best fertilisation potential. However, long-term clogging occurred in SAT after tertiary VFRB, suggesting the need for a longer resting period or shorter wetting period. This study also highlighted the importance of total suspended solids (TSS) content for SAT removal mechanisms and infiltration rate. In particular, SAT fed with high TSS content effluent was susceptible to temperature variation. Hence the duration of wetting and flooding periods should be adapted according to the season. Further, variation in SRT only indirectly affected pollutants removal by the system including CAS treatment set up at 6 d SRT where the N compounds balance was favourable to an autotrophic N removal.
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Mbwele, Lydia Ambakisye. "Microbial Phosphorus Removal in Waste Stabilisation Pond Wastewater Treatment Systems." Licentiate thesis, KTH, School of Biotechnology (BIO), 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3876.
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Waste Stabilisation Ponds (WSPs) are characterised by low phosphorus (P) removal capacity. Heterotrophic bacteria are principal microbial agents in WSPs in addition to algae. As treatment proceeds in WSPs, algal growth increases and pH rises, this has lead to believe that P removal is mainly through sedimentation as organic P algal biomass and precipitation as inorganic P. In activated sludge treatment plants (AS), microbial P removal has been improved and is termed as enhanced biological phosphorus removal. There was a need to establish whether it was possible to enhance P removal in WSPs. A performance assessment of pond system at the University of Dare s Salaam (UDSM), Tanzania, has shown that 90% of the P removed was in the primary pond (facultative) and the rest in the maturation pond (aerobic).
In these studies, a pure strain A. hydrophyla was isolated from an activated sludge wastewater treatment plant in Sweden. This plant has a train that functions with enhanced biological phosphorus removal. The strain was tested for P uptake in minimal media supplemented with glucose, succinate or acetate, grown aerobically and anaerobically/aerobically. This strain was able to take up P without having been subjected to the anaerobic phase. It was observed that P uptake was enhanced after the anaerobic phase with media supplemented with glucose, but not with succinate or acetate. Phosphorus uptake repeatedly followed the bacterial growth pattern with correlation coefficients of more than 95%. Therefore P removal has a direct correlation with bacterial growth.
Two isolates Acinetobacter sp. (isolated from the primary facultative pond) and E .coli (isolated from the maturation pond) were obtained from a tropical WSP treatment system at the UDSM. They were subjected to aerobic P uptake experiment similar to those of A.hydrophyla. The uptake per unit absorbance of bacterial growth was found to be comparable to that of A.hydrophyla, isolated from AS. These results showed that heterotrophic activity is important in WSPs. It is possible to enhance P removal in these systems by designing the primary ponds for maximum heterotrophic activity and probably enrichment.
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Nordin, Andreas. "Heavy metal removal from sewage sludge by pyrolysis treatment." Thesis, Högskolan i Borås, Akademin för textil, teknik och ekonomi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-8807.
Full textAbstract:
Sewage sludge is the product from wastewater treatment that mostly is considered as a waste material. However, it contains several nutrients, especially phosphorus, potassium and nitrogen which are excellent fertilizers. The downside is the harmful content it also carries with pathogens, heavy metals and a variety of organic pollutants that in many cases have unknown effects on the ecosystem. A possible solution to this problem could be to pyrolyse the sewage sludge and by that decrease the levels of heavy metals and also render both pathogens and organic pollutants harmless. In this thesis project pyrolysis of dried sewage sludge has been evaluated at temperatures 650 750, 850 and 950 °C with addition of chlorine in the form of PVC and straw. An energy balance for pyrolysis and drying of dewatered sewage sludge has also been suggested. The results of the pyrolysis evaluation indicate that cadmium concentration can be reduced significantly with increasing temperature in the product char. But also other heavy metals like lead and zinc are affected at the higher temperatures evaluated. Mercury is completely removed from the char residue. The more latent volatile metals copper, chromium and nickel cannot be reduced to lower concentrations at these temperatures. They are instead enriched under these conditions. Chlorine addition to the sludge enhances the evaporation of all heavy metals but copper, nickel and chromium. The energy balance over the system indicates that the drying process requires more energy than is released from the sludge into the pyrolysis gases. The energy carried by the pyrolysis gases is however larger than what is required to drive the pyrolysis process.
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Erdal, Zeynep Kisoglu. "An Investigation of the Biochemistry of Biological Phosphorus Removal." Diss., Virginia Tech, 2002. http://hdl.handle.net/10919/26383.
Full textAbstract:
Although enhanced biological phosphorus removal (EBPR) and complete biological nutrient removal (BNR) systems can be operated successfully by experienced operators, the accuracy of design and strength of the scientific background need to be reinforced to enable accurate modeling and economically optimal design. One way to accomplish this would be through a better understanding of the biochemical mechanisms and microbial population dynamics that determine the reliability and efficiency of EBPR, and the utilization of this information to improve the design and operation of BNR plants. Such knowledge will also contribute to better structure of modeling tools that are used for design and educational purposes. The current body of knowledge is limited to observational studies that lack detailed biochemical explanations backed with a series of well planned experiments, and this has introduced uncertainties and inaccuracies into the biochemical and design models. Therefore, this study mainly covers a biochemical survey of the underlying metabolisms of active populations in BNR sludges. BNR biomass with biological phosphorus removal (BPR) capability was cultivated in continuous flow reactor (CFR) systems, configured as either University of Cape Town (UCT) and anoxic/oxic (A/O) systems. Following an acclimation period at 20°C, low temperature stress (5°C) was imposed on one UCT system for investigation of the response of the microbial consortium responsible from EBPR activity under cold temperature. Once a stable population with EBPR capabilities is established in each system, activities of ten enzymes that are hypothesized to be taking part in the EBPR metabolism were measured. These enzymes were selected among those that take part in major known pathways of bacterial energy and growth metabolism. Also, 13C-NMR was used as a tool to monitor the flux of labeled carbon in and out of pools of cellular storage; i.e. glycogen and polyhydroxyalkanoates (PHA). Combining the gathered information, accurate mass balances of carbons and reducing equivalents were calculated, eventually leading to determination of the biochemical pathways utilized by the EBPR consortium. Additionally, anaerobic stabilization of COD, a long debated but empirically established phenomenon, was addressed during the study. Considering the pathways proposed to be operative under different conditions imposed on the EBPR systems, a biochemical explanation for the occurrence of COD stabilization in wastewater treatment systems that incorporate anaerobic zones was proposed. Accordingly, depending on the pathways actively used by a microbial consortium, electrons stored in NADH and FADH2 can either be transferred to the terminal electron acceptor, oxygen, or they can be incorporated into storage polymers such as glycogen for future use. Such differences in metabolism reflect in the quantity of the oxygen consumed in the aerobic reactors. Thus, the correct incorporation of anaerobic stabilization of COD into process design would reduce design aeration requirements and result in economic savings during both construction and operation.Ph. D.
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Häggström, Gustav. "Experimental studies of ash transformation processes in thermochemical conversion of P-rich biomass and sludge." Licentiate thesis, Luleå tekniska universitet, Energivetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-78593.
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The efficient use of resources and sustainable recovery of various materials are important to minimize the anthropogenic impact on the climate and environment. One such resource is the phosphorus present in manure and sewage sludge. Various technologies are currently being developed to recover the phosphorus for the use of fertilizers in agricultural applications. Thermochemical conversion presents an opportunity to recover energy from these materials. At the same time, elements can be recovered in ash fractions, potentially harmful organic substances can be destroyed and heavy metals fractionated from the P. Mono-combustion of sewage sludge mainly produce apatite, which is not plant available and useful for fertilization. Co-combustion/-gasification with other fuels enables modification of ash transformation pathways and also remedy potential problems, such as bed agglomeration, associated with e.g. agricultural residues used as fuels. This thesis aims to increase the current knowledge in ash transformation of phosphorus-rich materials in cocombustion/-gasification with woody and agricultural fuels in process temperatures relevant for fluidized bed systems. The work focuses on i) possibility for formation of plant-available K-bearing phosphates ii) the effect of fuel ash composition and chemical association of P in the fuel on the distribution and speciation of P and iii) interaction of P-rich ash with bed material in fluidized beds. Experiments were carried out in bench-scale bubbling fluidized bed (BFB), macro-TGA (thermogravimetric analysis) combustion reactors and a dual fluidized bed (DFB) gasification reactor. Fuels studied were mixtures of chicken litter together with wheat straw and bark, and mixtures of digested sewage sludge combined with wheat straw and sunflower husk. Ash fraction and bed materials were collected and analyzed using ICP-OES/MS, SEM-EDS and XRD techniques. For the mixture of chicken litter and K- and Si-rich wheat straw, combusted in BFB, P and Si together with K and Ca formed homogeneous ash particles with large amounts of potentially amorphous iv content. A similar behavior was observed in sewage sludge and wheat straw mixtures where P and Si were likely present in a melt that is amorphous after extraction. In addition to these particles, P was also found in crystalline compounds such as hydroxyapatite, whitlockite and CaKPO4. For mixtures with Ca-rich bark, most of the phosphate formed was in the form of hydroxyapatite. In the interaction of ash with bed material, P captures Ca and K in phosphates, decreasing the interactions of these elements with the bed material, and thus can decrease the risk for bed agglomeration. The findings show that it is possible to modify the ash transformation of P towards K-bearing phosphates by co-combustion. Furthermore, they suggest that it is possible to recover most of the phosphorus in coarse ash fractions through co-combustion of P-rich materials with agricultural fuels. This means that P and volatile heavy metals can be separated into different ash fractions. This also increases the possibility of utilizing existing boilers for recovery of P as well as increased their flexibility to different fuels. To further validate the agricultural value of the produced ashes, plant growth studies have to be performed.
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Hassan, Parssa. "Simultaneous management of nitrogen and phosphorus in dewatered sludge liquor by combining ANAMMOX process with struvite crystallization." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/45119.
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A process combination of anaerobic ammonium oxidation (ANAMMOX), followed by struvite crystallization, was examined for simultaneous removal of nutrients (nitrogen and phosphorus) from dewatered sludge liquor or centrate. Phosphorus recovery as struvite can recover more than 90% P from centrate; however, the effluent after struvite crystallization still contains high concentrations of ammonium nitrogen (NH₄-N). ANAMMOX is a cost effective alternative process for NH₄-N removal and this process can remove 85% - 90% of NH₄-N from centrate, but leaves high concentration of phosphorus phosphate (PO₄-P) in the treated effluent. Combining ANAMMOX and struvite recovery can offer a sustainable solution for managing phosphorus and nitrogen at wastewater treatment plants. The ANAMMOX process, followed by a struvite crystallization process, was selected as the combination sequence for this first study. Synthetic feed was prepared with different molar ratios of Mg: NH₄-N: PO₄-P to mimic centrate, partially nitrified centrate and centrate treated by ANAMMOX process (ANAMMOX effluent). To determine the molar ratio of Mg: NH₄-N: PO₄-P, centrate was obtained from Lulu Island Wastewater Treatment Plant and partial nitrification, followed by ANNAMOX process, was conducted on this batch of centrate. Jar tests were conducted to determine the struvite formation potential from synthetic ANAMMOX effluent, as it has a very low N: P ratio. Pure struvite formed successfully in the jar tests with P-removal efficiency up to 88%. The process combination was upgraded to bench-scale, fluidized bed reactors for further investigation on the nutrient recovery efficiencies and associated chemical costs. The process combination successfully reduced NH₄-N concentration to 70 mg/L from an initial value of 800 mg/L. The concentration of PO₄-P was reduced to 15 mg/L in the final treated effluent, from a starting value of 119 mg/L. Overall, the combination resulted in phosphorus-phosphate (PO₄-P) removal rate as high as 87% and ammonium-nitrogen (NH₄-N) as high as 92%. The mean particle size for struvite from ANAMMOX effluent ranged between 90 - 160 μm, and was larger than struvite particle formed from centrate. However, chemical costs associated with caustic and magnesium consumption, were found to be higher for the process combination, compared to just struvite formation using centrate.
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Harding, TH. "A steady state stoichiometric model describing the anaerobic digestion of biological excess phosphorus removal waste activate sludge." Master's thesis, University of Cape Town, 2009. http://hdl.handle.net/11427/5042.
Full textAbstract:
A. Background, Principle Objectives and Scope Until the mid-1990's model-based studies on wastewater treatment plants (WWTPs) focussed on the development of models describing a single unit operation within the WWTP i.e. an activated sludge system, an anaerobic digester or some other WWTP unit operation. The focus of these model-based studies changed in the late 1990's due to limitations in linking different models in applications for multi unit operation or full scale plant-wide designs or process evaluations. The boundaries related to the focus of these model-based studies within the WWTP, was widened to develop models that describe more than one unit operation and ultimately the whole WWTP. In line with these plant-wide model-based studies at University of Cape Town an steady state models coupling a primary settling tank (PST) unit coupled to an anaerobic digester (AD) was developed (Sötemann et al., 2005). Furtermore a steady state model coupling an UCT biological excess phosphorus removal (BEPR) activated sludge (AS) system to an aerobic digester was also developed (Mebrutha et al, 2007). Furthermore, the Sötemann et al. (2005) model can also be used to couple the nitrification-denitrification (ND) AS system to an anaerobic digester. To extend the work of these studies, this study focuses on the development of a steady state model that couples an NDBEPR AS system to an anaerobic digester. This study, with the support of a parallel study by Ikumi et al. (2009), aims at developing a steady state AD model that describes the anaerobic digestion of waste activated sludge (WAS) from a NDBEPR AS system and, secondly, comparing the unbiodegradable particulate organic (UPO) fraction determined for the AS and AD systems. The aim (primary objective) of this study was categorised into various secondary objectives to ensure that all aspects related to this study are achieved. The objectives of, and modelling approaches utilized in, this study are largely similar to those reported by Sötemann et al. (2005) in the development of the steady state model describing the anaerobic digestion of primary sludge (PS). Consequently, the steady state AD model of Sötemann et al. (2005) is extended in this study to include the phosphorus and counter-ion metal components contained by NDBEPR WAS. The development of this steady state AD model can be divided into two sections, which are: (a) the characterization of the WAS from the NDBEPR AS system and, (b) the extension and amendment of the Sötemann et al. (2005) steady state AD model to describe the anaerobic digestion of the NDBEPR WAS. ix Each of these sections can then be divided further into secondary sections or parts.