Dissertations / Theses on the topic 'Sludge drainage'

Thesis (M.S.)--West Virginia University, 2005.
Title from document title page. Document formatted into pages; contains xiii, 127 p. : ill. (some col.), maps (some col.). Includes abstract. Includes bibliographical references (p. 108-113).

Due to environmental pollution caused by acid mine drainage (AMD), the Department of Water Affairs has developed a National Water Bill for managing and controlling the water environment to prevent AMD pollution. The application of sulphate reducing bacteria have been demonstrated for the treatment of AMD. However, the scale-up application of this technology ultimately depends on the cost and availability of a carbon source. This study evaluated the use of sewage sludge to provide a carbon source for sulphate reduction in synthetic drainage wastewaters. The demonstration of this process in a laboratory-scale reactor proved that sewage sludge could provide a useful model and viable carbon source for evaluation of sulphate reduction as a process for treating AMD. Since sewage sludge is a complex carbon source, hydrolysis reactions controlling the anaerobic digestion of particulate substrate from this medium were optimized by evaluating the effect of pH on hydrolysis. Controlled and uncontrolled pH studies were conducted using a three stage mixed anaerobic reactor. Analysis of the degradation behaviour of the three important organic classes (carbohydrate, proteins and lipids) revealed that each class followed an indvidual trend with respect to pH changes. In addition, the solubilization of organic particulate carbon was also shown to be a function of pH. The hydrolysis pattern of organic substrate and COD solublization was induced at pH 6.5 rather than at high pH values (7.5 and 8.5). The biodegradation activity of sewage sludge was characterized by the API-ZYM1N test system to provide rapid semiquantitative information on the activity of hydrolytic enzymes associated with the degradation of carbohydrates, lipids, proteins and nucleic acids. A wide range of enzyme activities with phosphatases, aminopeptidases, and glucosyl hydralases dominating were displayed. The pattern of substrate hydrolysis correlated to the degradation efficiency of each organic class as a function of pH. The evaluation of scale-up application for sulphate reduction utilizing sewage sludge as a carbon source demonstrated that large water volume flows could possibly be treated with this cost-effective technology. Generation of alkalinity and sulphide in this medium was shown to be successful in the removal of heavy metals by precipitation. The use of this technology coupled to reduced cost involved showed that biological sulphate reduction utilizing hydrolysates of complex organic particulate from sewage sludge ss a carbon source has a potential scale-up application for the treatment of AMD.

Thesis (MSc)--Stellenbosch University, 2015.
ENGLISH ABSTRACT: Acid mine drainage (AMD) is wastewater generated by mine and industrial activity with typically high heavy metal and sulphur content potentially resulting in toxic wastewater upon exposure to dissolved oxygen, water and micro-organisms. Due to the hazardous consequences of untreated AMD, treatment methods such as semi-passive biotic treatments, including constructive wetlands and microbial bioreactors were developed. Microbial bioreactors rely on suitable carbon sources such as ethanol, grasses and manure and the creation of anaerobic conditions for the reduction of sulphate, chemical oxidizable organic matter (COD) and to neutralise pH. Domestic wastewater sludge has also been identified as an economical and readily available carbon source that allows the treatment of both AMD and domestic wastewater. A synthetic medium simulating the COD and the biological degradable organic matter (BOD) of domestic wastewater sludge was formulated to exclude variations in the evaluation of domestic wastewater sludge as carbon source in the treatment of AMD. Firstly the BOD and COD of anaerobic domestic wastewater sludge was determined and used as parameters in the formulation of the synthetic medium. A ratio of 1:1 AMD: synthetic domestic wastewater sludge (SDWWS) was the optimum ratio in terms of sulphate and COD removal. Secondly, medical drip bags were used as anaerobic bioreactors to determine the microbial diversity in AMD treated with SDWWS using different variables. Data analyses from next generation sequencing showed that Chlorobium spp. dominated the 90 d pioneer trials at relative percentages of 68 % and 76 %. Transmission electron microscopy (TEM) images and the bright green colour of the liquid contents confirmed the data analyses. Sulphates and COD were removed at > 98 % and > 85 %, respectively. A shorter incubation time was investigated in the 30 d pioneer trial. Chlorobium spp. was dominant, followed by Magnetospirillum spp. and Ornithobacterium spp. The liquid content changed to a dark brown colour. COD and sulphate concentrations were reduced by 60.8 % and 96 %, respectively, within 26 d, after which a plateau was reached. The effect of an established biofilm in the bioreactors showed that Chlorobium spp. also dominated approximately 62 %, in comparison to the 36 % in the 30 d pioneer trial. A sulphate and COD reduction of 96 % and 58 %, respectively, was obtained within 26 d and the liquid content was the same colour as in the 30 d pioneer trial. It is possible that brown Green sulphur bacteria were present. Therefore, although Chlorobium spp. was present at a higher percentage as in the 30 d pioneer trial, the removal of COD and sulphate was similar. During the 30 d trials a white precipitant formed at the top of the bioreactors, consisting primarily of sulphate and carbon that was also indicative of the presence of Chlorobium spp. Incubation at reduced temperature reduced sulphates by only 10 % and COD by 12 % after 17 d, followed by a plateau. Ornithobacterium spp. dominated in the first trial and Magnetospirillum spp. in the second trial.
AFRIKAANSE OPSOMMING: Suur mynwater (SMW) is afvalwater wat deur die myn- en industriële bedryf gegenereer word en bevat kenmerklik hoë konsentrasies swaar metale en swawel wat potensieel in toksiese afvalwater omskep kan word indien blootgestel aan opgelosde suurstof, water en mikro-organismes. Die skadelike gevolge wat blootstelling aan onbehandelde SMW mag hê, het gelei tot semi-passiewe behandelinge wat vleilande en mikrobiese bioreaktors insluit. Mikrobiese bioreaktore maak staat op n geskikte koolstofbron soos etanol, grasse en bemesting en die skep van ‘n anaerobiese omgewing vir die verwydering van sulfate en chemies oksideerbare organiese material (CSB), asook die neutralisering van pH. Huishoudelike afvalwaterslyk is ook uitgewys as ‘n ekonomies geskikte en algemeen beskikbare koolstofbron wat die behandeling van beide SMW en huishoudelike afvalwater toelaat. ‘n Sintetiese medium wat die CSB en biologies afbreekbare organiese materiaal (BSB) van huishoudelike afvalwater slyk naboots is geformuleer om die variasies in die evaluasie van huishoudelike afvalwater slyk as koolstofbron vir die behandeling van SMW, uit te sluit. Eerstens is die BSB en die CSB van huishoudelike afvalwater slyk bepaal en gebruik as n maatstaf vir die formulering van die sintetiese medium. ‘n Verhouding van 1:1 sintetiese huishoudelike afvalwater slyk (SDWWS) en SMW is optimaal ratio i.t.v. die verwydering van sulfate en CSB. Tweedens is mediese dripsakkies as anaerobiese bioreaktore gebruik om die mikrobiese diversiteit in SMW, wat met SDWWS behandel is, te bepaal deur verskeie veranderlikes te gebruik. Tweede generasie DNA-volgorde bepalingstegnieke is gebruik en data analises het gewys dat Chlorobium spp. die 90 d pionier toetslopie domineer met relatiewe persentasies van 68 % en 76 %. Transmissie elektron mikroskopie fotos en die helder groen kleur van die dripsakkies se vloeistof inhoud het die data analises bevestig. Die sulfate en CSB inhoud is onderskeidelik met > 98 % en > 85 % verminder. ‘n Korter behandelingstydperk is ondersoek met n 30 d pionier toetslopie. Chlorobium spp. was dominant, gevolg deur Magnetospirillum spp. en Ornithobacterium spp. Die vloeistof inhoud het na ‘n donker bruin kleur verander. Die CSB en sulfaat konsentrasies is met 60.8 % en 96 % onderskeidelik verminder na 26 dae waarna ‘n plato bereik is. Die effek van ‘n reeds bestaande biofilm in die bioreaktore het gewys dat Chlorobium spp. ook gedomineer het teen ‘n relatiewe persentasie van 62 % in vergelyking met die 36 % in die 30 d pionier toetslopie. ‘n Vermindering in sulfate en CSB van 96 % en 58 % is onderskeidelik is bereik binne 26 d en die vloeistofinhoud was dieselfde kleur as die bioreaktore in die 30 d pionier toetslopie. Dit is moontlik dat die bruin Groen swawel bakterieë teenwoordig was. Daarom, ondanks ‘n groter teenwoordigheid van die Chlorobium spp. teen ‘n relatiewe persentasie in vergelying met die 30 d pionier toetslopie, was die verwydering van CSB en sulfate soortgelyk. Tydens die 30 d toetslopies het ‘n wit neerslag aan die bokant van die bioreaktore gevorm wat hoofsaaklik uit sulfaat en koolstof bestaan het wat ook ‘n aanduiding van die teenwoordigheid van Chlorobium spp. is. ‘n Toetslopie wat by laer temperature uitgevoer is kon die sulfate en CSB met slegs 10 % en 12 % onderskeidelik verminder nadat ‘n plato na 17 d bereik is. Ornithobacterium spp. het die eerste toetslopie gedomineer waar Magnetospirillum spp. die tweede toetslopie gedomineer het.

L'industrie minière produit d'énormes quantités de déchet (millions de tonnes par an), souvent sous forme de boue à cause de la forte teneur en eau et en argile. Ces boues liquides sont problématiques car elles se consolident très lentement : elles limitent la réhabilitation des parcs à résidus où elles sont stockées et augmentent le risque de rupture des barrages entourant les parcs à résidus (coulée de boue). Améliorer l'assèchement des boues minières est nécessaire afin d'augmenter la stabilité des parcs à résidus et de recycler l'eau contenue dans la boue. La solution proposée dans cette thèse consiste à insérer des géocomposites de drainage (GCP) dans les parcs à résidus afin de permettre à l'eau contenue dans la boue de s'évacuer. Pour mobiliser l'eau dans ces boues à faible conductivité hydraulique, deux phénomènes ont été investigués : la consolidation des boues sous contrainte mécanique et la migration de l'eau par électro-osmose (EO). Afin d'attester de la faisabilité d'appliquer ces 2 phénomènes avec des GCP, chacune des fonctions des GCP a été évaluée : les fonctions de base (filtration et drainage) pour provoquer l'asséchement mécanique et une nouvelle fonction de conduction électrique pour appliquer l'EO.La filtration de boue par géotextile (GTX) a été investiguée car contrairement à la filtration de sol, elle demeurait peu décrite dans la littérature et semblait délicate à cause de l'argilosité de la boue. Des tests de filtration sous pression ont permis de tester 8 GTX avec une même boue argileuse, puis 8 boues de granularités différentes avec un même GTX. Les résultats indiquent que les GTX n'ont un impact qu'au début de la filtration : ils retiennent les particules les plus grossières ce qui induit la formation d'un gâteau de filtration qui devient rapidement l'élément filtrant, le GTX n'est alors plus qu'un support. Une même boue filtrée par 8 GTX différents conduit à un même assèchement alors que les 8 boues différentes filtrées avec un même GTX conduisent à 8 assèchements différents : l'assèchement final est contrôlé par la composition de la boue et est totalement indépendant du GTX utilisé. Ces essais de filtration ont permis d'évaluer l'assèchement mécanique des boues : la pression appliquée (50kPa) conduit à l'expulsion de l'eau libre, alors que l'eau liée reste dans la boue. Cela est dû aux différents niveaux de liaison de l'eau dans la boue : l'eau liée ne peut être extraite mécaniquement. Ainsi les fonctions de base des GCP provoquent un asséchement mécanique du à l'augmentation de la contrainte lors du remplissage des parcs à résidus. En revanche, l'asséchement mécanique est limité à l'extraction de l'eau libre ; il est apparu essentiel de proposer un nouveau moteur pour extraire l'eau liée.La principale innovation de ce travail est l'ajout d'une nouvelle fonction au GCP : l'ajout d'éléments conducteurs dans les GCP permet d'appliquer l'EO dans les boues. Ce phénomène permet de mobiliser une partie de l'eau liée en imposant un courant électrique. Des prototypes de GCP électrocinétique (eGCP) ont été développés et testés dans un dispositif expérimental dédié. Les résultats montrent que la filtration et la conduction électrique sont assurées efficacement par les eGCP disposés de part et d'autre de la boue. La boue testée est issue des sables bitumineux (FFT) et est très problématique car sa consolidation est extrêmement lente. Les résultats obtenus sont très encourageants : la phase mécanique porte la siccité de la boue de 45% à 61%, puis l'EO permet d'atteindre une siccité de 77% et une résistance au cisaillement de 77 kPa, alors que la réglementation exige d'atteindre 10 kPa.Pour conclure, les différentes expérimentations montrent que les boues minières peuvent être asséchées par des GCP en cumulant les effets de la compression mécanique, grâce aux fonctions classiques des GCP et de l'EO grâce à l'ajout d'une nouvelle fonction de conduction électrique. Cette solution a fait l'objet d'un brevet
A host of mining practices produces huge quantity of fine-grained mineral sludges whose disposal in ponds is often challenging. The key problem caused by these sludges is their very poor geotechnical properties, which are caused by their high water and clay content. These sludges are hard to dewater because of their low hydraulic conductivity. Dewatering sludges to increase its shear strength and reduce the volume of material to be contained thus represents a preferred path to reduce the risk of pond's failure, reduce the pond's footprint, and maximize water recycling. To dewater mining sludges, the solution foreseen in this PhD is to intercalate some geocomposites (GCPs) layers within the sludge-disposal area to create draining horizons to permit mechanical dewatering and to apply electro-osmosis (EO) across sludges layers to induce water migration. To evaluate the efficiency of GCPs at enhancing sludges dewatering by both of these phenomena, the different functions of GCPs (filtration, drainage, and electric conduction) were experimentally investigated during this PhD.To study sludge filtration by geotextile (GTX), pressure filtration tests were used to filter 8 different high-clay-content sludges with 8 different nonwoven GTXs. Only a few studies have considered the filtration of sludge by GTXs. The sludges were formulated by mixing kaolinite and silt to obtain 8 different grain-size distributions. The results indicate that sludges can be filtered with nonwoven GTXs selected on the basis of their pore-opening size. In addition, only during the early stage of filtration GTXs really influence filtering because it is at this stage that, by retaining coarser particles, they allow progressive formation of filter cake. Upon forming, the filter cake becomes the major contributor to particle retention. The sludge composition is found to be the most significant factor affecting the final state of dewatering. In other words, the GTX does not control the final dewatering; the sludge itself controls the final solid content. These filtration tests showed that mechanical dewatering is effective for removing free water, but bounded water remains in the sludge because of the high bonding forces between water and solid matter. Facing this limitation of mechanical dewatering, a new way to extract bounded water had to be proposed.The main innovation brought by this PhD concerns the addition of a new function to GCP, by adding conductive elements into the GCP to apply EO in the sludge. Electro-osmosis (EO) forces water to migrate from anode to cathode and is sufficient to remove a significant portion of bounded water that cannot be removed by mechanical dewatering. Some prototypes of electro-kinetics GCP (eGCP) were developed, and tested in a new laboratory setup. This experimental device was developed to evaluate simultaneously the different functions of eGCPs, namely, drainage or filtration and electrical conductivity. It has the particularity that it uses eGCPs as both a draining medium and electrode. The results show that fluid fine tailings (FFTs), a particularly hard to dewater sludge from oil-sand exploitation, are significantly dewatered by the combination of normal stress compression, and then EO treatment: the FFT solids content increased from 45% to 61% during the compression phase and to 77% during the EO phase. The applied treatment led to a significant consolidation of the FFT: shear strength increased from zero to about 77 kPa which is significantly greater than the 10 kPa required by government regulations.To conclude, eGCPs can drain water expulsed during sludge consolidation in response to the filling of the disposal area, thanks to the classical function of GCP, as well as impose a voltage across FFT to displace water by electro-osmosis from anode to cathode, thanks to conductive elements embedded in eGCP. This solution was patented at the end of the PhD

Thesis (MScAgric)--University of Stellenbosch, 2003.
ENGLISH ABSTRACT: Coal mining in South Africa is estimated to produce 200 Ml of acid mine drainage (AMD) per day in the Pretoria-Witwatersrand-Vereeniging (PWV) area alone, while electricity production resulted in approximately 27 Mt of ash in 2001. A large number of collieries in South Africa are tied to power stations where these two waste streams, acid mine drainage and fly ash, have the capacity to neutralize each other and provide an opportunity for co-disposal. The aim of this study was to investigate the reactions that occur during the co-disposal of fly ash leachate (FAL) and AMD and to examine the precipitates that result from the neutralisation reactions. Potentiometric titration was employed to investigate the neutralisation of Al-Fe salt solutions, simulating acid mine drainage (AMD), with alkaline solutions of Ca or Na hydroxide as well as fresh alkaline leachate from fly ash (FAL). The effectiveness of fly ash in removing metals and other salts from acid mine water was examined by analysing the neutralised water and modelling the results thermodynamically. Precipitates, prepared from large scale synthetic AMD and FAL co-disposal at various pH levels and Fe:Al ratios, were characterised according to composition, mineralogy and surface properties. The experimental neutralisation of synthetic acid mine drainage was achieved through titrating the components of SAMD (Fe and Al salt solutions) and solutions of various Fe:Al mole ratios with different bases in air and N2, and comparing the SAMD-FAL system with these simple acids and bases. The FAL used in all experiments was produced from fresh fly ash collected at Arnot power station. The SAMD was prepared as a solution with a pH of 2.5 and containing 12.7 mmol/L Al, 10.9 mmol/L Fe and 40.8 mmol/L SO4. The characterisation of reaction solids was achieved by collecting the precipitates formed from the co-disposal of FAL and SAMD with Fe:Al ratios of 7.3, 0.8 and 2.5. From the titration experiments it was found that upscale potentiometric titrations of SAMD show buffer zones at pH values of 3.5, 4, 6 and 10 corresponding to Fe(III)precipitation, Al precipitation, Fe(II) hydrolysis and oxidation, and Al redissolution, respectively, while downscale potentiometric titrations with SAMD show buffer zones at pH values 12 – 11, 9 and 4.5, which correspond to Fe oxidation and precipitation, Al precipitation and Al re-dissolution, respectively. A high concentration of Al in the simulated AMD inhibited the crystallinity of the precipitates and resulted in a large quantity of SO4 being removed from solution, which suggests that an aluminium sulphate phase is precipitating, but it is not crystalline and cannot be identified by XRD. Titrations performed up-scale by adding FAL to AMD showed near-complete metal and substantial SO4 removal from solution. The characterisation of reaction solids by x-ray diffraction, infrared spectroscopy, thermal gravimetric and differential thermal analysis revealed that the precipitates consist of poorly crystalline, highly Al-substituted goethite and ferrihydrite with large amounts of SO4 included in the structure. Poorly crystalline bayerite appears at a high pH and high Al concentration, and calcite is present in precipitates made by adding SAMD to FAL. High surface charges of between 330 cmolc/kg positive and 550 cmolc/kg negative charge and potentially large specific surface areas between 7 and 236 m2/g suggest a strong potential for the precipitates to function as low-grade adsorbents in wastewater treatment. The similarity of these ochre precipitates to soil minerals implies that land disposal of the neutralised solids is also viable.
AFRIKAANSE OPSOMMING: Steenkool mynbou in SA produseer na benaming 200 ML suur mynwater per dag in die PWV area alleenlik, terwyl opwekking van elektrisiteit naastenby 27 Mt vliegas geproduseer het in 2001. ’n Groot aantal steenkoolmyne in SA word verbind met kragsentrales, waar hierdie twee strome afval, suur mynwater en vliegas, die kapasiteit het om mekaar te neutraliseer en die weg te baan vir gesamentlike wegdoening. Die doel van hierdie studie was om die reaksies wat plaasvind gedurende gesamentlike wegdoening van vliegas loog (VAL) en suur mynwater (SMW) te ondersoek, asook die neerslae wat mag vorm as gevolg van neutralisasie reaksies. Potensiometriese titrasies was gebruik om die neutralisering tussen Al:Fe-sout oplossings te ondersoek as nabootsing van SMW met gebruikmaking van alkaliese oplossings van Ca of Na hidroksied asook vars loog van VA. Die effektiwiteit van VA om metale en soute uit SMW te verwyder was getoets deur outleding van die geneutraliseerde water en modellering van die termodinamika. Neerslae berei uit groot-skaal sintetiese SMW en VAL en met gelyktydige storting by verskeie pH vlakke en Fe:Al verhoudings, was gekarakteriseer volgens samestelling, mineralogie en oppervlak eienskappe. Die eksperimentele neutralisering van sintetiese suur mynwater (SSMW) was gedoen deur titrering van die SSMW komponente en oplossings van verskeie Fe:Al molêre verhoudings met verskillende basisse in lug en N2, en vergelyking van SSMW-VAL sisteem met hierdie eenvoudige sure en basisse. Die VAL gebruik in alle eksperimente was geproduseer van vliegas verkry van die Arnot kragsentrale. Die SSMW was berei as ’n oplossing met ’n pH van 2.5 en bevat 12.7 mmol/L Al, 10.9 mmol/L Fe en 40.8 mmol/L SO4. Die karakterisering van vastestowwe uit die reaksie was gedoen deur die bemonstering van neerslae gevorm as gevolg van die gelyktydige wegdoening van VAL en SSMW met Al:Fe verhoudings van 7.3, 0.8 en 2.5.Die was waargeneem in die titrasie eksperimente dat hoër-skaal potensiometriese titrasie van SSMW buffersones, by pH waardes 3.5, 4, 6 en 10, ooreenstem met Fe(III) presipitasie, Al presipitasie, Fe(II) hidrolise en oksidasie, en Al her oplossing, terwyl laer skaal potensiometriese titrasie met SSMW buffer sones by pH waardes 12 - 11, 9 en 4.5 ooreenstem met Fe(III) presipitasie en oksidasie, Al presipitasie en heroplossing respektiewelik. ’n Hoë konsentrasie Al in die sintetiese SMW het kristalliniteit van die neerslae geïnhibeer en veroorsaak dat ’n hoeveelheid SO4 uit oplossing verwyder is, wat suggereer dat die AlSO4 fase neerslaan maar nie kristallyn is en gevolglik nie opgetel word met x-straal diffraksie nie. Titrasies gedoen by hoërskaal deur byvoeging van VAL tot SSMW, het feitlik volledige metaal en SO4 verwydering uit oplossing getoon. Die karakterisering deur x-straal diffraksie, infrarooispektroskopie, termies gravimetries en differentiële termiese analise, het getoon dat die presipitate bestaan uit swak kristallyne, hoë Al-gesubstitueerde goethiet en ferrihidriet met groot hoeveelhede SO4 vasgevang in die struktuur. Swak kristallyne bayeriet verskyn by hoë pH en hoë Al-konsentrasies en kalsiet is teenwoordig in neerslae gevorm deur byvoeging van SSMW tot VAL. Hoë oppervlakladings van tussen 330 cmolc/kg positief en 550 cmolc/kg negatiewe lading en ook potensieel groot spesifieke oppervlak van tussen 7 en 236 m2/g, dui op ’n sterk potensiaal vir neerslae om as laegraadse adsorbeermiddels in afvalwaterbehandeling gebruik te word. Die ooreenstemming in hierdie geelbruin neerslae met grond minerale, impliseer dat die land storting van geneutraliseerde vastestowwe ook lewensvatbaar is.

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Esta pesquisa sobre leito de secagem modificado com piso de blocos drenantes (wedge wire) foi desenvolvida em três etapas, sendo um acompanhamento em escala real com descartes de lodo aeróbio, outra realizada em escala piloto com descartes de lodo anaeróbio, ambos gerados em estação tratamento de esgoto sanitário (ETE), e a terceira etapa foi um levantamento de dados operacionais de alguns leitos com piso de blocos drenantes existentes no Brasil. O leito de secagem convencional de areia ainda é o método mais utilizado no Brasil para desaguamento de lodo em ETE de pequeno e médio porte. No entanto, devido ao aumento de fiscalização por órgãos ambientais, aumento de exigência por qualidade no tratamento de água e esgoto, custos elevados no gerenciamento, além de problemas com a eficiência de secagem final do lodo, odores e manutenção dos leitos, as empresas têm buscado alternativas de novas tecnologias, e/ou até mesmo por otimizações nos próprios leitos. Uma alternativa que tem se mostrado eficiente no desaguamento de lodos é o leito modificado com piso de blocos drenantes. Porém, ainda há pouca experiência com relação ao dimensionamento do leito, à sua operação e à sua eficiência por ser uma tecnologia pouca explorada no exterior e recém-chegada ao Brasil. Portanto esta pesquisa teve como objetivo avaliar o desaguamento de lodo de esgoto em leito com piso de blocos drenantes nas fases de drenagem e secagem. A drenagem do lodo foi avaliada através da vazão de drenagem após filtração de lodo no bloco drenante, da redução de volume de lodo no leito e da caracterização da qualidade da água drenada. Já a secagem foi avaliada a partir da variação do teor de sólidos totais do lodo durante o período de secagem. Como é um processo natural de secagem, o acompanhamento das condições climáticas local foi realizada. Os resultados foram satisfatórios tanto para o lodo aeróbio quanto para o anaeróbio. Em relação a drenagem, após um dia do descarte de lodo no leito com piso de blocos drenantes houve redução em torno de 90% do volume para lodo aeróbio e 70% para lodo anaeróbio. Já o teor de sólidos totais final obtido na secagem variou de acordo com o tipo de lodo, volume, taxa de aplicação de sólidos e condições climáticas. O melhor resultado de secagem para o lodo aeróbio foi de 95,3% de sólidos totais em 36 dias de secagem, e para o lodo anaeróbio, o máximo atingido foi de 63,5% em 24 dias, em condições de secagem diferentes.
This research about wedge wire floor sludge bed was developed in three stages, first one was a monitoring in real scale with aerobic sludge discards, another one performed in a pilot scale with anaerobic sludge discard, both generated in wastewater treatment plant (WWTP), and the third stage was a survey of operational information of some wedge wire floor sludge bed in operation in Brazil. The conventional sand drying bed is still the most used system in Brazil for dewatering and drying of sludge generated during sewage treatment in small and médium size WWTP. However, due to the increase in inspection by environmental agencies, increased demands for quality in treatment, high costs in management, as well as problems with final sludge drying efficiency, odors and bed maintenance, the companies have been looking for alternatives to new technologies, and even optimizations in existing beds. An alternative that has proven efficient in the dewatering of sludge is the modified sludge bed with wedge wire floor. However, there is still little experience with the dimensioning of the bed, its operation and efficiency because it is a technology that has not been used abroad and recently arrived in Brazil. Therefore, this research had as objective to evaluate the dewatering of sewage sludge in wedge wire bed in the drainage and drying phases. The drainage of the sludge was evaluated through the drainage flow after filtration in the wedge wire floor, the reduction of sludge volume in the bed and the characterization of the quality of the drained water. Drying was evaluated by increasing the total solid content of the sludge during the entire drying period. As it is a natural drying process, monitoring of the local climatic conditions was performed. The results were satisfactory for both aerobic and anaerobic sludge. In relation to the drainage, after one day from discharge in the bed, there was a reduction of around 90% of the volume for aerobic sludge and 70% for anaerobic sludge. However, the final solid content obtained in the drying varied according to the type of sludge, volume, solids application rate and climatic conditions. The best drying result for aerobic sludge was 95.3% of total solid in 36 days of drying, and for anaerobic sludge the maximum reached was 63.5% in 24 days, in different climate conditions.

Fältstudien gjordes för att utreda om det var möjligt att använda renat, filtrerat avloppsvatten för polymerberedning och i längden även som övrigt processvatten på Ellinge reningsverk. Testerna utfördes i fullskala med både vatten från mellansedimenteringen och slutsedimenteringen. Genom omfattande provtagningar och analysering av resultaten visade det sig vara en fungerande metod utan negativ påverkan på polymerlösningen och slamavvattningen. Det krävs dock mer arbete och ytterligare reningssteg såsom desinficering för att implementera det renade avloppsvattnet på hela vattensystemet.
The field study was done to investigate whether it was possible to use purified, filtered wastewater for polymer preparation and in the long run also as other process water at Ellinge treatment plant. The tests was performed in full scale with both water from the intermediate sedimentation and the final sedimentation. Through extensive sampling and analysis of results, it proved to be a working method without a negative impact on the polymer solution and sludge dewatering. However, more work and addiotional purification steps such as disinfection are required to implement the treated wastewater on the entire water system

O método de desaguamento por leitos de drenagem foi desenvolvido por Cordeiro a partir do ano de 1993 (CORDEIRO, 2001) para o desaguamento de lodos de Estações de Tratamento de Água. A sua aplicação para lodos de lagoas de estabilização de esgotos foi feita por Fontana et al. (2007). Este trabalho teve por objetivo avaliar a utilização de leitos de drenagem no desaguamento de lodos produzidos em reatores UASB. Para tanto foram realizados ensaios em laboratório, utilizando testes do tempo de drenagem, para avaliar a influência de diferentes doses e tipos de polímeros no desaguamento do lodo. Alguns geotêxteis foram utilizados como meio filtrante nos funis de Buchner e também avaliados pelo teste do tempo de drenagem. Após escolhidas a manta e o polímero que apresentaram os melhores resultados em laboratório, foram desenvolvidos ensaios em escala piloto, com a utilização de três unidades cobertas de leitos de drenagem, cada um com dimensões de 1,58 m x 1,09 m por 0,5 m de altura. Para a avaliação do efeito das diferentes doses de polímero em escala piloto, foram utilizadas doses de polímero de 0 a 8 g/kg de sólidos totais (peso seco) e mantida a taxa de aplicação de sólidos em 15 kgST/m².ciclo (a concentração de sólidos no lodo foi de aproximadamente 27 g/L). Os resultados indicaram que com doses de polímero =2 g/kgST (peso seco) obtinha-se teor de sólidos no lodo de cerca de 13% após 1 dia e 20% após 10 a 15 dias. Para se atingir teor de sólidos de 25 a 30% o período de secagem necessário foi de cerca de 30 dias. Embora que mesmo sem a aplicação de polímeros o comportamento do lodo fosse semelhante ao de lodos condicionados com polímero, em relação à evolução do teor de sólidos em função dos períodos de secagem, observou-se certa dificuldade na remoção do lodo desaguado e principalmente na limpeza das mantas geotêxteis. Para avaliar diferentes taxas de aplicação superficial de sólidos, foram ensaiadas taxas entre 9 e 22 kgST/m².ciclo. A evolução do teor de sólidos, ao longo do período de secagem dos 3 ensaios realizados, indicou que taxas mais altas de aplicação de sólidos não diminuem as velocidades de secagem, sugerindo que, inclusive, taxas mais altas poderiam ser ensaiadas.
The method of dewatering sludge through Drainage Beds was originally developed in 1993 by Cordeiro (CORDEIRO, 2001) with sludge from Water Treatment Plants. Fontana et al. (2007) used sludge from wastewater stabilization ponds with positive results. The purpose of this research is the evaluation of the drainage bed method to dewater sludge from UASB reactors. Several laboratory trials were performed, measuring drainage times to assess the influence of different polymer types and doses on sludge dewatering. Few geotextiles were used as filter on the drainage time test to evaluate their performance. Once the polymer and the geotextile that best performed in the laboratory were chosen, several pilot experiments were performed with the use of three covered units of drainage beds, each measuring 1.58m x 1.09m (width) x 0.5m (height). For the evaluation of different polymer conditioning doses on a pilot scale, doses from 0 to 8 g/kg of total solids (dry weight) were used and the applied rate of solids kept at 15 kgTS/m².cycle (the concentration of solids in the sludge was of approximately 27 g/L). Results indicated that with the use of polymer doses =2 g/kgTS (dry weight), approximately 13% of total solids in the sludge was observed after one day, which increased to approximately 20% after 15 days. To reach 25% to 30% of total solids in the sludge, the drying time required was circa 30 days. Even without the application of polymers, the behavior of sludge in terms of total solids during the drying period was similar to the sludge conditioned with polymers. Although, with the unconditioned sludge, some difficulty to remove the dewatered sludge cake was observed, mainly in cleaning of the geotextile sleeves. In order to evaluate different application rates of solids, the pilot experiments included rates between 9 and 22 kgTS/m².cycle. The behavior of the total solids in the cake during the drying period of the three experiments suggested that the higher rates of application of solids does not reduce the drying speed, indicating that higher rates can be targeted in future research projects.

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Water supply systems utilize, in most cases, conventional Water Treatment Plants (WTPs). These plants use alum and ferric salts in their coagulation process, and produce residues (sludge) mainly in filter systems and decanter tanks. The produced residues may be toxic to man and are usually disposed of on environment without any kind of treatment, therefore causing pollution. They present fluid characteristic with low solid content and great amount of water. Such characteristic hampers its transportation and proper disposal. The Cardoso plant used to fit the profile of pollutant, dumping its untreated sludge directly into a nearby stream. As a solution to this problem a system with a drainage bed for the sludge from decanter tank and a sedimentation tank for the backwash water from filters have been built. The system was built within the plant area itself. The drainage bed consists of a brick tank with a gravel layer support coated with a geotextile. The solid mass from the dewatered sludge showed adequate conditions as far as characteristics necessary for its final transportation and proper disposal. The water drained from sludge (effluent) is sent to the sedimentation tank. The turbidity, solids and COD were greatly reduced. The system was designed for a less than 30 days utilization period. The sedimentation tank consists of a fiberglass vase installed in a position that allows it to also receive the effluent from the drainage bed. The clarified water is recirculated to the influent of the water treatment plant and the solids are pumped to the drainage bed together the sludge from decanter tank. The system s operation does not require much labor and equipment. The aim of the research carried out was to design and analyze the drainage bed behavior according to prototype developed in the PROSAB 2 research Tema IV, integrated with Sedimentation Tank. Such integrated technology is an effective solution for the great majority of Water Treatment Plants with available areas. It is recommended that such system (Drainage bed and Sedimentation Tank) to be implemented should be always arranged to properly each individual Water Treatment Plant. Further studies should be also made on alternative of throwing clarified water straight from decanter tank to filters before dumping the sludge into drainage bed.
Os sistemas de abastecimento utilizam, na maioria, as Estações de Tratamento de Água (ETAs) convencionais. Essas estações utilizam em seu processo de coagulação sais de ferro ou de alumínio e produzem resíduos (lodos), principalmente, nos decantadores e filtros. Os resíduos produzidos podem ser tóxicos ao homem e normalmente são dispostos sem nenhum tipo de tratamento no meio ambiente causando poluição. Apresentam característica fluida com baixos teores de sólidos e grande quantidade de água. Essa característica dificulta seu manejo para transporte e disposição adequada. A ETA Cardoso, se enquadrava no perfil de poluidora lançando seus resíduos sem tratamento diretamente no corpo d água existente nas proximidades. Como solução para este problema foi implantado um sistema constituído de Leito de Drenagem para os lodos de decantadores e Sedimentador para as águas de lavagem de filtros. O sistema foi construído na própria área da ETA. O Leito de drenagem é constituído de um tanque em alvenaria e meio drenante com camada suporte de brita recoberto com manta geotextil. A massa final de sólido do lodo desaguado apresentou condição suficiente para manejo de retirada, transporte e disposição. O drenado foi encaminhado ao Sedimentador para reuso. Apresentou grande redução de turbidez, sólidos e DQO. O sistema foi projetado para um período de utilização inferior a 30 dias. O Sedimentador é constituído de um tanque em fibra de vidro instalado em posição que possa receber também o drenado do leito de drenagem. A água clarificada do Sedimentador e o drenado do Leito de Drenagem são recirculadas para o início da ETA. Os sólidos sedimentados no Sedimentador são bombeados para o Leito de Drenagem juntamente com o lodo de decantador. A operação do sistema demanda pouca mão de obra e equipamentos. A pesquisa realizada teve como objetivo projetar e analisar o comportamento do Leito de Drenagem, de acordo com o protótipo desenvolvido na pesquisa do PROSAB 2 Tema IV, integrado com o Sedimentador. Essa tecnologia integrada se apresenta como solução efetiva para a grande maioria de ETAs com disponibilidade de área. É recomendado que sempre seja implantado o sistema (Leito de Drenagem e Sedimentador) em arranjos convenientes para cada ETA. A redução da área do Leito de Drenagem é função de estudos para lançamento da água clarificada dos decantadores diretamente para os filtros.

This thesis deals with the sludge management in wastewater treatment plants. It provides a basic overview of methods for modifying risk material in sludge ending. The main goal of this work is to create a fault trees based on faults which occurred in the sludge management facilities. Furthermore, it was created frequency of failures assessment of the objects on wastewater treatment plant in Hodonín. Provided information were obtained during excursions of WWTP Hodonín and Zbýšov.

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Universidade Federal de Minas Gerais
Most of Water Treatment Plant (WTP) for public supply in Brazil use surface water as source and conventional complete cycle as treatment system. In this type of treatment wastewater are restrained/generated which vary mainly according to the type and amount of chemical added and the characteristics of the water resource. This wastewater is found mainly in clarifiers (sludge) and backwash water filter (BWF) from WTP. Unfortunately, most of Brazilian WTP launches its waste directly into water resources, violating Brazilian Law 9605 published in 1998. There are mechanical and natural technologies for water removal from wastewater restrained during the treatment. Once known that wastewater from WTP has fluid characteristic, some technologies to remove its water have been developed. A natural one is the drainage bed, developed and proposed by Cordeiro (2001). The drainage bed has basically two stages: drainage and evaporation. This dissertation presents results of a study, whose centre objective was to achieve improvements in water sludge removal restrained in clarifiers by the use of plastic cover (evaporation stage). Results of effective tests in prototypes located in Sao Carlos WTP (Sao Paulo State) with plastic cover have showed that this roof (commercial reference PVC 0.30 milimeters) uses has accelerated the evaporation process, and has protected sludge from rain. The height of the roof that presented the best result was 0.20 meters in relation to the board of prototype, realizing to obtain a sludge 56% dryer than in tests without the roof. Preliminary tests in laboratory scale generated a promising scenario for the use of cationic polymer in large scale doubling the efficiency of the initial drainage of sludge. However, other laboratory tests with different characteristics of geotextile blanket only confirmed the superiority of using woven blanket type with surface density of 600 g/m² (which had already been used in other studies), compared to the others, in reference to obtain better efficiency at the initial drainage of water present in raw sludge.
A maior parte das Estações de Tratamento de Água (ETAs) para abastecimento existente no Brasil se utiliza de captação de águas superficiais e sistema de tratamento de ciclo completo convencional. Neste tratamento são retidos/gerados resíduos que variam principalmente segundo o tipo e quantidade de produto químico adicionado e as características do manancial de captação. Estes resíduos são encontrados principalmente nos decantadores (lodo) e na água de lavagem dos filtros (ALF) das ETAs. Infelizmente, a maioria das ETAs brasileiras lança seus resíduos diretamente em corpos d água, infringindo disposições da Lei 9.605/98. Existem tecnologias mecanizadas e naturais para remoção de água dos resíduos retidos no tratamento. Uma vez que possuem característica fluida, foram desenvolvidas algumas tecnologias para remoção de suas águas. Uma tecnologia natural para remoção de águas de resíduos de ETAs é o leito de drenagem, desenvolvido e proposto por Cordeiro (2001). O leito de drenagem possui basicamente duas etapas envolvidas: drenagem e evaporação. Esta pesquisa apresenta resultados de um estudo, cujo objetivo central foi alcançar melhorias na remoção da água de lodo retido nos decantadores através da utilização de cobertura plástica no leito de drenagem (etapa de evaporação). Resultados obtidos nesta pesquisa para ensaios realizados em protótipos de leitos de drenagem instalados na ETA de São Carlos-SP demonstraram que, quando se utiliza cobertura plástica (referência comercial PVC 0,30 mm), o processo de evaporação da água presente no lodo é acelerado e a ocorrência de precipitação não interfere em momento algum na remoção de água do lodo. A altura da cobertura em relação ao protótipo que apresentou os melhores resultados foi de 0,20 m, permitindo-se obter um lodo final até 56% mais seco que na ausência de cobertura. Ensaios realizados em escala laboratorial para condicionamento prévio do lodo bruto com polímero catiônico apresentaram resultados promissores para sua utilização em maior escala, duplicando a eficiência da drenagem inicial do lodo. Entretanto, outros ensaios laboratoriais com mantas geotêxteis de características distintas apenas confirmaram a superioridade da utilização de manta do tipo tecida de densidade superficial 600g/m² (que já havia sido utilizada em outras pesquisas) em relação às demais, no que se refere à obtenção de melhor eficiência na drenagem inicial da água presente no lodo bruto.

This thesis is aimed at assessment of drainage conditions at the river Loucna in the cadastral area of Dasice. The examined section is 3,88 km long and runs through out of the city and in the city of Dasice. On the left bank of the river there are several historic buildings that are potentially at risk for 100 years of flow. Capacity assessment is performed using the 1D mathematical program HEC - RAS in which the flow model is created and the calculation of the flow rates for individual N - year flows. On the basis of the results of the program is conducted conceptual desing of flood protection measure. At the same time is conducted conceptual desing of fish ladder on the weir and a sluice closure on the intake for the race.