Auf Grund der Zielstellungen des Klimaschutzes und den Szenarien der Ressourcenverfügbarkeit sowie der Energiekostenentwicklung wird das Energiemanagement bei der Betriebsführung von Abwasser- und Schlammbehandlungsanlagen an Bedeutung gewinnen, wobei die Maßnahmen des Energiemanagements mit den grundlegenden Zielen der Abwasser- und Schlammbehandlung zu vereinen sind. Zentrale Elemente des Energie-managements stellen die Nutzung eines breiten Energiespektrums und der Einsatz energieeffizienter Betriebsführungen, Techniken und Technologien dar. Eine Möglichkeit betriebstechnischer Optimierungen besteht in der Anwendung der Verfahrenskombination aus Desintegration und anaerober Schlammstabilisierung. Seit 10 – 15 Jahren wurde intensiv auf dem Gebiet der Klärschlammdesintegration geforscht, ohne dass allgemeingültige Aussagen über die Möglichkeiten der Desintegration ermittelt wurden. Anlässlich der dargestellten Sachlage und eigener Forschungsarbeiten auf dem Gebiet der Klärschlammdesintegration entstand die Idee zur vorliegenden Arbeit. Die Arbeit gibt in einer Literaturrecherche einen umfangreichen Überblick vorhandener Untersuchungen zur Verfahrenskombination Klärschlammdesintegration und anaerobe mesophile Schlammstabilisierung. Zu den untersuchten Desintegrationsapparaten und techniken gehören Rührwerkskugelmühle, Ultraschallhomogenisator, Hochdruck-homogenisator, Lysatzentrifuge, thermische Vorbehandlung, Hochleistungspulstechnik, Ozonbehandlung und die Kombination von thermischer Vorbehandlung mit Säuren- bzw. Laugenaufschluss. Zur Verbesserung der für die Auswertungen benötigten Datenbasis wurden labortechnische Untersuchungen zur anaerob mesophilen bzw. zur anaerob thermophilen Überschussschlammstabilisierung sowie zur Verfahrenskombination von Überschussschlammdesintegration mit anaerob mesophiler bzw. anaerob thermophiler Schlammstabilisierung durchgeführt Zur Desintegration wurden eine Rührwerkskugelmühle PE 075 (Fa. Netzsch-Feinmahltechnik), eine Fliehkraftkugelmühle S 100 (Retsch GmbH), ein Ultraschallhomogenisator UP 400S (Fa. Dr. Hielscher GmbH) eingesetzt sowie ein thermischer Aufschluss bei 75 °C und eine Kombination von thermischem Aufschluss bei 75 °C mit anschließender Unterdruckentspannung durchgeführt. Die vorliegende Arbeit beinhaltet eine umfangreiche Bewertung der Verfahrenskombination Überschussschlammdesintegration mit anschließender anaerob mesophiler Schlammstabilisierung. Speziell wurden in diesem Zusammenhang gezielte Untersuchungen zu variierenden Klärschlammqualitäten, Milieubedingungen der anaeroben Stabilisierung (Verweilzeit, Temperatur) und Desintegrationsverfahren (mechanisch, niederthermisch) durchgeführt. Die Auswertungen zeigen, dass die Wirkung dieser Verfahrenskombination maßgeblich durch die anaerobe Abbaubarkeit der Referenzüberschussschlämme bestimmt wird, wobei sich der relative Einfluss der Desintegration mit steigendem Stabilisierungsgrad der Überschussschlämme erhöht. Als Grenze des organischen Abbauverhaltens von desintegrierten Überschussschlämmen kann von einem GV Abbau 59 % bzw. von einem zufuhrspezifischen Biogasanfall von 467 Nl/kg GVZu ausgegangen werden. Die aus der Desintegration resultierende Steigerung des anaeroben Abbauverhaltens von Überschussschlämmen bedingt einen Anstieg der CSBmf- bzw. NH4-N-Prozesswasserbelastung. Für die PO4-P- bzw.- Pges,mf-Anteile des Prozesswassers war kein Zusammenhang nachweisbar. Für die Verfahrenskombination Überschussschlammdesintegration mit anschließender anaerob mesophiler Schlammstabilisierung werden neben dem Einsatz zur Verbesserung des anaeroben Abbauverhaltens von Überschussschlämmen Anwendungsmöglichkeiten zur Sanierung überlasteter Faulbehälter bzw. zur Minimierung notwendiger anaerober Reaktionsvolumina aufgezeigt. Entsprechend der Ergebnisse dieser Arbeit ist durch eine vorgeschaltete Überschussschlammdesintegration eine Verkürzung der anaeroben Stabilisierungszeit von 16 – 24 d auf 7 – 12 d möglich, ohne dass eine Verminderung des organischen Abbaus von Überschussschlämmen toleriert werden muss. Gesonderte Auswertungen befassen sich mit der Wirkung der Desintegration auf die anaerobe Abbaubarkeit der im Überschussschlamm enthaltenen Stoffgruppen Fette, Kohlenhydrate und Eiweiße. Es ist festzustellen, dass das anaerob mesophile Abbauverhalten einzelner im Überschussschlamm gebundener Stoffgruppen infolge einer Vorbehandlung durch Desintegrationsverfahren nicht/oder nur unwesentlich verändert wird. Im weiteren Verlauf der Arbeit wurden Nomogramme zur Prognose des Desintegrations-einflusses auf das anaerob mesophile Abbauverhalten von Überschussschlämmen erarbeitet, die es dem planenden Ingenieur bzw. dem Betriebsingenieur gestatten, die Auswirkungen eines Einsatzes der Kombination von Überschussschlammdesintegration und anaerob mesophiler Stabilisierung zu bewerten. Die Darstellungen ermöglichen eine Spezifizierung nach dem Grad der mechanischen Abwasserbehandlung und des in der biologischen Abwasserbehandlung praktizierten Gesamtschlammalters. Die Prognosemöglichkeiten umfassen den für desintegrierte Überschussschlämme bei der anaerob mesophilen Schlamm-stabilisierung auftretenden GV Abbau, den zufuhrspezifischen Biogasanfall sowie die resultierende CSBmf- und NH4-N-Prozesswasserbelastung. In Abhängigkeit der Verfahrens- und Betriebsführung der Abwasserbehandlung führt die Desintegration im Mittel zu einer maximalen absoluten Veränderung des GV-Abbaus bzw. des zufuhrspezifischen Biogas¬anfalls von Überschussschlämmen von 13 % bzw. 90 l/kg GVZu. Die Spannweiten der CSBmf- bzw. NH4-N-Prozesswasserbelastung betragen 0,5 – 6,5 % bzw. 3,0 – 18,0 % der Frachten des Kläranlagenzulaufes. Die vorliegende Arbeit enthält erstmals Ergebnisse zur Verfahrenskombination Überschussschlammdesintegration mit anschließender anaerob thermophiler Schlammstabilisierung. Gemäß den Versuchsauswertungen werden das anaerobe Abbauverhalten von Überschussschlämmen unter thermophilen Milieubedingungen und die daraus resultierenden Prozess-wasserbelastungen durch eine vorgeschaltete Überschussschlammdesintegration nur unwesentlich beeinflusst. Abschließend ordnet die Arbeit das Leistungsvermögen der Verfahrenskombination Über-schussschlammdesintegration + anaerob mesophile Schlammstabilisierung gegenüber anderen Optimierungsmöglichkeiten der anaeroben Schlammstabilisierung ein. Die Untersuchungen zeigen, dass durch einen Wechsel des Temperaturniveaus der anaeroben Schlammstabilisierung vom mesophilen in den thermophilen Bereich der unter mesophilen Bedingungen erreichbare GV Abbau bzw. zufuhrspezifische Biogasanfall unbehandelter Überschussschlämme ähnlich beeinflusst werden kann, wie es durch die Kombination von Überschussschlammdesintegration und anschließender anaerober mesophiler Schlammstabilisierung möglich ist. Gleichzeitig ist bei der anaerob thermophilen Stabilisierung unbehandelter Überschussschlämme gegenüber der anaerob mesophilen Stabilisierung desintegrierter Überschussschlämme eine höhere Prozesswasserbelastung zu erwarten.

A sewage treatment plant is going to get a station in their plant reconstructed. It is the station where the water is separated from the sludge and then transported out of the plant. This new station is the main area for this project. The project holds two parts, one where the flow losses are examined and the second is where the system curve and pump configurations are explored. The flow losses can be divided into two parts, major and minor losses. Both will be examined in this project and further the distribution between major and minor losses will be studied. Furthermore, to study the station and the pump configuration, a system curve and a pump curve will be established. Depending on the percentage of dry matter in the sludge (3%, 4% and 5%) the viscosity of the sludge will vary. Therefore, different system curves will be obtained depending on the dry matter. At a given pressure increase, the pump curve will tell what power output is needed depending on the flow rate. The result shows that the flow losses will be the highest for the lowest dry matter rate, 3%. The lower the dry matter rate is, higher velocity on the flow can be used in the station. Due to the higher velocity the losses will increase. The system curves for 3% and 4% are similar. But the curve for 5% differs in where the transition from laminar flow to turbulent flow occurs at a higher flow rate.

Although the A-stage high-rate activated sludge (HRAS) process destroys some of the chemical energy present in municipal wastewater, this process has been gaining attention as a viable technology for achieving energy neutrality at water resource recovery facilities. In addition to carbon capture for energy recovery, A-stages are also being utilized upstream of shortcut biological nitrogen removal (BNR) processes as these BNR processes often require a controlled influent carbon to nitrogen ratio that is lower than required for conventional BNR processes. While there is extensive knowledge on conventional activated sludge processes, including process controllers and activated sludge models, there has been little detailed research on the carbon removal mechanisms of A-stage processes operated at solids retention times (SRT) less than about one day. The overall objective of this study was to elucidate the chemical oxygen demand (COD) removal mechanisms of short SRT activated sludge processes with a specific focus on the removal of the different COD fractions under varying operating conditions including dissolved oxygen, hydraulic retention time, temperature, and SRT. Once understood, automatic process control logic was developed with the purpose of producing the influent characteristics required for emerging shortcut BNR processes and capturing the remaining COD with the intent of redirecting it to an energy recovery process. To investigate the removal and assimilation of readily biodegradable substrate (SS), this study evaluated a respirometric method to estimate the SS and active heterotrophic biomass (XH) fractions of the raw wastewater influent and effluent of an A-stage pilot process. The influent SS values were comparable to the SS values determined using a physical-chemical method, but the effluent values did not correlate well. This led to the measurement of the heterotrophic aerobic yield coefficient and decay rate of the pilot process. The yield coefficient was estimated to be 0.79±0.02 gCOD/gCOD, which was higher than the accepted value of 0.67 g/g. It was speculated that the batch respirometry tests resulted in the aerobic storage of SS and this likely contributed to the error associated with the determination of SS and XH. Therefore, physical-chemical fractionation methods were used to determine the removal of the individual COD fractions. It was concluded that the SRT was the primary control parameter and below a 0.5 day SRT the dominate COD removal mechanisms were assimilation and oxidation of readily degradable substrate and sedimentation of particulate matter. At SRTs between 0.5-1 days, COD removal became a function of hydrolysis, as adsorption of particulate and colloidal matter was maximized but not complete because of limited adsorption sites. Once adequate adsorption sites were available, effluent quality became dependent on the efficiency of bioflocculation and solids separation. While the SRT of the pilot process could not be directly controlled because of severe biofouling issues when using in situ sensors, a MLSS-based SRT controller was successfully implemented instead. The controller was able to reduce total COD removal variation in the A-stage by 90%. This controller aslo provided the capability to provide a consistent carbon to nitrogen ratio to the downstream B-stage pilot process. To ascertain the settling, dewaterability, and digestibility of the sludge produced by the pilot A-stage process, several standardized and recently developed methods were conducted. The results from these tests indicated that the A-stage had similar dewaterability and digestibility characteristics to primary sludge with average achievable cake solids of 34.3±0.4% and average volatile solids reduction (VSR) of 82±4%. The A-stage sludge also had an average specific methane yield of 0.45±0.06 m3CH4/kgVS. These results were attributed to low extracellular polymeric substance (EPS) content. However, further research is needed to better quantify EPS and determine the effect of HRAS operating parameters on EPS production. Overall the A/B pilot study was able to capture 47% of the influent COD as waste sludge while only oxidizing 45% of the influent COD. Of the COD captured, the A-stage contributed over 70% as dry solids. Coupled with high sludge production, VSR, and methane yield the A/B process was able to generate 10-20% more biogas and 10-20% less dry solids after anaerobic digestion than a comparable single-sludge BNR process. / Ph. D.

No description available.

Fossas e tanques sépticos são sistemas de pequeno porte utilizados para tratamento parcial do esgoto sanitário produzido nas áreas urbana e rural, quando não beneficiados por sistema de esgotamento sanitário. Tal utilização se justifica principalmente por ser tecnologia que não exige muita dedicação operacional e ser de simples implantação. Apesar da vasta utilização dessas unidades no Brasil, há pouca informação sobre a caracterização, as condições de coleta, transporte, tratamento e destino final de resíduo (lodo) produzido nesses sistemas. Nesse sentido, o presente trabalho tem como objetivo a caracterização do lodo produzido nessas unidades; e, também, a concepção, o desenvolvimento e a avaliação de uma unidade piloto para pré-tratamento de lodo de fossas e tanques sépticos. Essa unidade, constituída por grade, desarenador e flotador, foi instalada no Campus da Universidade de São Paulo, junto da Estação de Tratamento de Esgoto do Campus - área 1, e vista à remoção de sólidos grosseiros, areia e materiais flutuantes, antes de seu lançamento na Estação de Tratamento de Esgoto do Campus. Foi feita a caracterização do lodo de tanques sépticos coletado in situ e do lodo proveniente dos caminhões limpa-fossas, descarregando em tanque pulmão de 15000 litros. A caracterização do lodo proveniente dos caminhões limpa-fossas foi realizada em duas campanhas (coletas), sendo uma feita na primeira visita ao local pré-definido, e outra realizada aproximadamente seis meses após a primeira coleta. Com intuito de aprimorar o método de análise das amostras do lodo in situ, com finalidade de melhor fragmentar o material particulado, foi testado o uso de ultrassom. Também, foi realizada a caracterização do lodo de fossas e tanques sépticos na Central de Recebimento de Resíduos na cidade de Campinas-SP - SANASA - Sociedade de Abastecimento de Água e Saneamento AS. Para tanto, foram coletadas amostras compostas de lodo descarregado por 24 caminhões. Foi feito teste complementar, com a finalidade de estudar a degradação do lodo flotado por processos anaeróbio e aeróbio. Mediante essas caracterizações pode-se constatar a grande heterogeneidade da composição do lodo e a elevada carga orgânica, que devem ser ponderados com relação a impactos no meio ambiente e em Estações de Tratamento de Esgoto. Contudo, nota-se a importância do pré-tratamento desse lodo antes de ser lançado em ETEs. A unidade piloto foi operada com diferentes taxas de aplicação superficial (80; 110; 140 e 200 \'M POT.3\'/\'M POT.2\'.dia), quando foram obtidas remoções de 91,7% de sólidos suspensos; 89,3% de DQO e 81,9% de óleos e graxas. Pelos resultados obtidos foi demonstrada a eficiência do sistema de flotação na remoção de óleos e graxas e dos sólidos suspensos. A digestão aeróbia do lodo flotado mostrou-se eficiente quando foi aplicado inócuo com período de aeração superior a 20 dias, sendo que foram obtidas eficiências de 88,3% e 90% para remoção de DQO e de óleos e graxas, respectivamente. / Septic tanks are small structures used for partial treatment of wastewater produced from urban and rural areas. It utilization is justify mainly by simplicity of construction and for being a technology that requires low operational dedication. Although it is a technology vastly used in Brazil, there is not much information about the characteristics of the waste dumped in there, and the conditions of collection, transport, and final destination of the sludge generated in the system. The objective of this research was characterize the sludge originated from septic tanks and to design, construct and evaluate a treatment unit model to be used for prior treatment of the sludge generated in those septic tanks. This unit, composed by a sieve, a degritter, and a flotation device, was assembled in the São Paulo University Campus, near the area 1 from the campus Wasterwater Treatment Plant (WWTP). It had the purpose to remove har solid particle, sand and the floating material before their entry in the Wasterwater Treatment Plant. Was made to characterize the sludge septic tank collected in situ and the sludge originated from the Septic Pumper Truck, unloaded into a tank of 15000 L. Furthermore, the characterization of the sludge originated from the Septic Pumper Truck was performed twice, once in the material collected in the first visit to the defined location and the other in the material collected about six months after the first collection. The use of ultrasound was tested to ameliorate the fragmentation of the particulate material and to improve the method of analysis of the sludge in situ. Additionally, it was characterized the sludge from septic tanks in the Waste Reception Center from the city of Campinas, São Paulo State - SANASA - Society of Water Supply and Sanitation in composite samples collected from 24 trucks during the unloading. Septic Pumper Truck in th Waste Receptation Center. A complementing test was performed in order to text the degradation of the floated sludge by anaerobic and aerobic processes. The characterizations revealed a great heterogeneity in the composition of the sludge and the high organic content, which should be taken in consideration regarding the impacts in the environment and in the WWTP. This underlines the importance of treatment of the sludge prior to discharging into the WWTP. The pilot plant was managed to work at different rates of surface sludge application (80, 110, 140 and 200 \'M POT.3\'/\'M POT.2\'.day). The 110 \'M POT.3\'/\'M POT.2\'.day rate displayed the highest efficiency with the removal of 91.7% of suspended solids, 89.3% of the chemical oxygen demand, and 81 9% of oils and waxes. The results showed the efficiency of the flotation system in the removal of suspended solids, oil and greases. The aerobic digestion of the floated material was efficient when it received inoculation with aeration period greater than 20 days, which allowed CDO the removal of 88.3% and 90% of oil and greases.

Fossas e tanques sépticos são sistemas de pequeno porte utilizados para tratamento parcial do esgoto sanitário produzido nas áreas urbana e rural, quando não beneficiados por sistema de esgotamento sanitário. Tal utilização se justifica principalmente por ser tecnologia que não exige muita dedicação operacional e ser de simples implantação. Apesar da vasta utilização dessas unidades no Brasil, há pouca informação sobre a caracterização, as condições de coleta, transporte, tratamento e destino final de resíduo (lodo) produzido nesses sistemas. Nesse sentido, o presente trabalho tem como objetivo a caracterização do lodo produzido nessas unidades; e, também, a concepção, o desenvolvimento e a avaliação de uma unidade piloto para pré-tratamento de lodo de fossas e tanques sépticos. Essa unidade, constituída por grade, desarenador e flotador, foi instalada no Campus da Universidade de São Paulo, junto da Estação de Tratamento de Esgoto do Campus - área 1, e vista à remoção de sólidos grosseiros, areia e materiais flutuantes, antes de seu lançamento na Estação de Tratamento de Esgoto do Campus. Foi feita a caracterização do lodo de tanques sépticos coletado in situ e do lodo proveniente dos caminhões limpa-fossas, descarregando em tanque pulmão de 15000 litros. A caracterização do lodo proveniente dos caminhões limpa-fossas foi realizada em duas campanhas (coletas), sendo uma feita na primeira visita ao local pré-definido, e outra realizada aproximadamente seis meses após a primeira coleta. Com intuito de aprimorar o método de análise das amostras do lodo in situ, com finalidade de melhor fragmentar o material particulado, foi testado o uso de ultrassom. Também, foi realizada a caracterização do lodo de fossas e tanques sépticos na Central de Recebimento de Resíduos na cidade de Campinas-SP - SANASA - Sociedade de Abastecimento de Água e Saneamento AS. Para tanto, foram coletadas amostras compostas de lodo descarregado por 24 caminhões. Foi feito teste complementar, com a finalidade de estudar a degradação do lodo flotado por processos anaeróbio e aeróbio. Mediante essas caracterizações pode-se constatar a grande heterogeneidade da composição do lodo e a elevada carga orgânica, que devem ser ponderados com relação a impactos no meio ambiente e em Estações de Tratamento de Esgoto. Contudo, nota-se a importância do pré-tratamento desse lodo antes de ser lançado em ETEs. A unidade piloto foi operada com diferentes taxas de aplicação superficial (80; 110; 140 e 200 \'M POT.3\'/\'M POT.2\'.dia), quando foram obtidas remoções de 91,7% de sólidos suspensos; 89,3% de DQO e 81,9% de óleos e graxas. Pelos resultados obtidos foi demonstrada a eficiência do sistema de flotação na remoção de óleos e graxas e dos sólidos suspensos. A digestão aeróbia do lodo flotado mostrou-se eficiente quando foi aplicado inócuo com período de aeração superior a 20 dias, sendo que foram obtidas eficiências de 88,3% e 90% para remoção de DQO e de óleos e graxas, respectivamente. / Septic tanks are small structures used for partial treatment of wastewater produced from urban and rural areas. It utilization is justify mainly by simplicity of construction and for being a technology that requires low operational dedication. Although it is a technology vastly used in Brazil, there is not much information about the characteristics of the waste dumped in there, and the conditions of collection, transport, and final destination of the sludge generated in the system. The objective of this research was characterize the sludge originated from septic tanks and to design, construct and evaluate a treatment unit model to be used for prior treatment of the sludge generated in those septic tanks. This unit, composed by a sieve, a degritter, and a flotation device, was assembled in the São Paulo University Campus, near the area 1 from the campus Wasterwater Treatment Plant (WWTP). It had the purpose to remove har solid particle, sand and the floating material before their entry in the Wasterwater Treatment Plant. Was made to characterize the sludge septic tank collected in situ and the sludge originated from the Septic Pumper Truck, unloaded into a tank of 15000 L. Furthermore, the characterization of the sludge originated from the Septic Pumper Truck was performed twice, once in the material collected in the first visit to the defined location and the other in the material collected about six months after the first collection. The use of ultrasound was tested to ameliorate the fragmentation of the particulate material and to improve the method of analysis of the sludge in situ. Additionally, it was characterized the sludge from septic tanks in the Waste Reception Center from the city of Campinas, São Paulo State - SANASA - Society of Water Supply and Sanitation in composite samples collected from 24 trucks during the unloading. Septic Pumper Truck in th Waste Receptation Center. A complementing test was performed in order to text the degradation of the floated sludge by anaerobic and aerobic processes. The characterizations revealed a great heterogeneity in the composition of the sludge and the high organic content, which should be taken in consideration regarding the impacts in the environment and in the WWTP. This underlines the importance of treatment of the sludge prior to discharging into the WWTP. The pilot plant was managed to work at different rates of surface sludge application (80, 110, 140 and 200 \'M POT.3\'/\'M POT.2\'.day). The 110 \'M POT.3\'/\'M POT.2\'.day rate displayed the highest efficiency with the removal of 91.7% of suspended solids, 89.3% of the chemical oxygen demand, and 81 9% of oils and waxes. The results showed the efficiency of the flotation system in the removal of suspended solids, oil and greases. The aerobic digestion of the floated material was efficient when it received inoculation with aeration period greater than 20 days, which allowed CDO the removal of 88.3% and 90% of oil and greases.

Mellansedimenteringsbassänger är inte sällan flaskhalsen för flödeskapaciteten vid reningsverk. För höga flöden kan leda till slamflykt, vilket påverkar efterkommande reningssteg negativt. Om en stor mängd slam från systemet försvinner kan detta även påverka det biologiska reningssteget negativt. Att förstå dynamiken av slamkvalitet och flödeskapaciteten är därmed viktigt både för att veta hur nya bassänger ska dimensioneras och för att bestämma belastningen för befintliga bassänger. Syftet med denna studie var att utvärdera flödeskapaciteten för mellansedimenteringen för det biologiska reningssteg C vid Kungsängsverket, Uppsala Vatten och Avfall AB:s största reningsverk. Syftet var också att studera hur temperaturen påverkade flödeskapaciteten. Genom att utföra sedimenteringstester med slam från Biosteg C vid olika koncentrationer och temperaturer kunde slammets kvalitet kvantifieras och användas för beräkningar och simuleringar för utvärdering av flödeskapaciteten. Sedimenteringstesterna visade på en tydlig skillnad i sedimenteringshastiget vid de olika temperaturerna. I Stokes lag användes olika värden på densiteten och viskositeten, vilka är parametrarna som förändras med temperaturen, för att undersöka en förväntad förändring i sedimenteringshastiget. Kvoten mellan 20 och 5° C var cirka 2 och kvoten mellan 10 och 5° C var cirka 1,2. Kvoterna mellan sedimenteringstesten varierade, men resultatet visade på en liknande trend som för Stokes lag. Bürger-Diehls och Takács sedimenteringsmodeller användes i den här rapporten med Takács sedimenteringsfunktion. Bürger-Diehlmodellen användes för att kalibrera parametrarna i Takács sedimenteringsfunktion, vilket gjordes genom att simulera sedimenteringstest och minimera felet mot den verkliga slamnivån vid sedimenteringstesten. Parametern 𝑣0 minskade med ökande temperatur vilket är en omvänd trend jämfört med litteratur. Parametern 𝑟h minskade med temperaturen vilket stämmer överens med litteratur. Flödeskapaciteten utvärderades vid konstant och dynamiskt flöde. För det konstanta flödet användes olika modeller, State Point-analys, Takács sedimenteringsmodell samt Bürger-Diehls sedimenteringsmodell med 10 och 30 lager. Alla modeller visade på ökande flödeskapacitet med ökande temperatur. Takács och Bürger-Diehl med 10 lager gav mindre noggranna resultat på grund av den låga mängden lager så för det dynamiska flödessimuleringarna användes bara Bürger-Diehlmodellen med 30 lager. Dessa simuleringar visade liknade resultat som för det konstanta flöden vid 6° C och 12° C. Vid 22° C visade däremot det dynamiska resultatet på en lägre kapacitet än för det konstanta flödet. Trots att sedimenteringstesten och de skattade modellparamterarna visade på en icke försumbar temperaturpåverkan ingår inte temperaturen i de använda sedimenteringsmodellerna. Detta kan leda till överskattning av flödeskapaciteten vintertid, exempelvis vid snösmältning. I framtiden bör därför detta tas hänsyn till vid dimensionering/modellering av mellansedimenteringsbassänger. / Secondary sedimentation tanks are usually the bottleneck of the flow capacity for wastewater treatment plants. High flows risk sludge escaping the system, which can negatively affect the following treatment steps. If a greater amount of the activated sludge escapes, the treatment efficiency could greatly decrease. Understanding the dynamic of sludge quality and flow capacity is detrimental to designing new secondary settling tanks and determining capacity of existing ones. The purpose of this study was to evaluate the flow capacity of the secondary settling tank for the biological treatment step C at Kungsängsverket, Uppsala Vatten och Avfall AB’s biggest wastewater treatment plant. The purpose was to study how different temperatures affected the flow capacity as well. By performing batch settling tests with sludge from the biological treatment step C, with different concentrations and temperatures, the sludge quality was quantified and could be used for calculations and simulations to evaluate the flow capacity. A clear distinction in the zone settling velocity could be observed between the different temperatures. Different values for the density and viscosity, correlated to the different temperatures used for the batch tests, were used in Stoke’s law to get an expected change of velocity. Between 20° and 5° C the quota was roughly 2 and between 10° and 5° C it was around 1,2. The quota for the batch tests differed randomly for the different concentrations, but the result indicated a similar trend as for Stokes law. The Bürger-Diehl and Takács sedimentation models were used for this study with the sedimentation function of Takács. The Bürger-Diehl model was used to calibrate the parameters in Takács function. This was done by simulating a batch test and minimizimg the sum of squared error compared to the actual sludge level from the batch test. The parameter 𝑣0 decreased in value with increasing temperature, which is a reversed trend seen from the literature. The parameter rh decreased with increasing temperature, which follows literature trends. The flow capacity was evaluated for a constant and dynamic flow. Constant flow was used with different models for comparison, which were, State point analysis, the Takács sedimentation model and the Bürger-Diehl sedimentation model with 10 and 30 layers. The result from all models indicated a higher flow capacity the higher the temperature. The flow capacity with Takács and Bürger-Diehl models with 10 layers gave a lower flow capacity than expected, which was because of the low resolution, therefore, the Bürger-Diehl model with 30 layers was used for the dynamic flow. The dynamic flow gave a similar result for 6° and 12° C, however, for 22° C the flow capacity was lower for the dynamic flow. Even though the batch tests and the estimated parameters showed a difference with temperature, it’s not included in any sedimentation model. This could lead to an overestimation of the flow capacity during wintertime, for example during snowmelt. Further research should be conducted to confirm these results and possibly be interpreted for future modelling of secondary sedimentation tanks.

Currently at the Savannah River Site (SRS), there are fifteen single-shell, 3.6-million liter tanks containing High Level Waste. To close the tanks, the sludge must be removed. Mechanical methods have had limited success. Oxalic acid cleaning is now being considered as a new technology. This research uses sample results and chemical equilibrium software to develop a preferred flowsheet and evaluate the acceptability of the system impacts. Based on modeling and testing, between 246,000 to 511,000 l of 8 wt% oxalic acid were required to dissolve a 9,000 liter Purex sludge heel. For SRS H-Area modified sludge, 322,000 to 511,000 l were required. To restore the pH of the treatment tank slurries, approximately 140,000 to 190,000 l of 50 wt% NaOH or 260,000 to 340,000 l of supernate were required. When developing the flowsheet, there were two primary goals to minimize downstream impacts. The first was to ensure that the Resultant oxalate solids were transferred to DWPF, without being washed. The second was to transfer the remaining soluble sodium oxalates to the evaporator drop tank, so they do not transfer through or precipitate in the evaporator pot. Adiabatic modeling determined the maximum possible temperature to be 73.5°C and the maximum expected temperature to be 64.6°C. At one atmosphere and at 73.5°C, a maximum of 770 l of water vapor was generated, while at 64.6°C a maximum 254 l of carbon dioxide were generated. Although tank wall corrosion was not a concern, because of the large cooling coil surface area, the corrosion induced hydrogen generation rate was calculated to be as high as 10,250 l/hr. Since the minimum tank purge exhaust was assumed to be 5,600 l/hr, the corrosion induced hydrogen generation rate was identified as a potential concern. Excluding corrosion induced hydrogen, trending the behavior of the spiked constituents of concern, and considering conditions necessary for ignition, energetic compounds were shown not to represent an increased risk Based on modeling, about 56,800 l of Resultant oxalates could be added to a washed sludge batch with minimal impact on the number of additional glass canisters produced. For each sludge batch, with 1 to 3 heel dissolutions, about 60,000 kg of sodium oxalate entered the evaporator system, with most collecting in the drop tank, where they will remain until eventual salt heel removal. For each 6,000 kg of sodium oxalate in the drop tank, about 189,000 l of Saltstone feed would eventually be produced. Overall, except for corrosion-induced hydrogen, there were no significant process impacts that would forbid the use of oxalic acid in cleaning High Level Waste tanks. / MATHEMATICAL SCIENCES / M. Tech. (Chemical Engineering)

Avloppsslam innehåller näringsämnen, som bör återföras till naturen för att skapa ett så kallat näringskretslopp. Genom att optimera hygieniseringen av avloppsslam med effektivare behandlingsmetod kan avloppsslam bli mer lämpligt att avsättas ur ett bättre ekonomiskt- och miljömässigt perspektiv. Syftet med arbetet var att undersöka och bedöma om effektiviseringav befintlig slambehandling är möjlig för att uppnå tillräcklig hygienisering. Utifrån den effektiviserade slambehandlingsmetoden utreda möjliga avsättningsalternativ som lämpar sig bäst för avloppsslammet i Avesta kommun. En litteraturöversikt utfördes för att öka kunskapen och förståelsen av avloppsslam, desshantering och avsättning. Fallstudien är utformad med kvalitativ metod och informationen har inhämtats från vetenskapliga artiklar, myndigheter, rapporter, examensarbeten och personligkontakt som komplement för att erhålla en god förståelse. Uppgradering av mesofil rötning av avloppsslam vid 37 °C till termofil rötning, 55 °C – 65 °C innebär förhöjd temperatur; det kräver mer energi och ökade energikostnader. Komponenter av den mesofila rötningsprocessen kommer att behöva uppgraderas eller bytas ut och därför tillkommer extra kostnader som också behöver ses över. Fördelarna med termofil rötning inkluderar kortvariga uppehållstider, mindre rötkammare och slammet blir tillräckligt hygieniserat. Ett framtidsscenario är framtaget utifrån effektiviserad slambehandling där två avsättningsalternativ är mest lämpliga för avloppsslammet i Avesta kommun. Gödsel till produktiv mark är ett av de föreslagna alternativ som tillåter fosforn återvinnas och återanvändas. Om inte termofil rötning som effektivisering hade erhållit tillräcklig hygienisering borde andra komplementerande processer ha införts, exempelvis komposteringstrumma eller pastörisering. En fullständig kostnadsjämförelse mellan befintlig slambehandlingsmetod och mer effektiviserad slambehandlingsmetod är dock nästan omöjlig att utföra då alla kostnader beror på val av komponenter och faktorer. Denna fallstudie bidrar med ett underlag som kan ge större möjligheter för Avesta Vatten och Avfall AB att välja den mest lämpliga avsättningen för avloppsslammet i Avesta kommun i framtiden. / Sewage sludge contains nutrients, which should be returned to nature to create a so-called nutrient circulation. By optimizing sanitisation of sewage sludge with effective treatment methods, sewage sludge can be more appropriately disposed from a better economic- and environmental perspective. The aim of this work was to investigate and judge the efficiency of existing sludge treatment is possible to achieve a sufficent sanitation. Based on the streamlined sludge treatment method investigate the disposal options that is best suited for sewage sludge in Avesta town. A literature review was conducted to increase the knowledge and understanding of sewage sludge, its treatment and disposal. The case study is formed with qualitative method and information which has been collected from the scientific articles, authorities, reports, theses and personal contact as a complement to obtain a good understanding. Upgrading of mesophilic digestion of sludge at 37 ° C to thermophilic digestion at 55 ° C - 65 ° C means increased temperature; this requires more energy and hence increases energy costs. Components of the mesophilic digestion process need to be upgraded or replaced and therefore additional costs should also be considered. The advantages of the thermophilic digestion include short residence time, smaller digester and sludge becomes sufficiently disinfected. A future scenario is developed based on more efficient sludge treatment where two disposal options are most appropriate for the sewage sludge in Avesta town. Returning digestate to productive land is one of those suggested alternatives that allows phosphorus to be recovered and recycled. If not thermophilic digestion as streamlining is not effective enough for sufficient sludge sanitation, other complementary processes have to be introduced, for instance, composting drum or pasteurization. A full cost comparison between the existing sludge treatment and more efficient sludge treatment method is, however, almost impossible to be performed when all costs depend on the choice of components, factors and so on. This case study contributes with first-hand information that can provide greater opportunities for Avesta Vatten och Avfall AB to select the most appropriate options for sewage sludge disposal in Avesta town in the future.

The UASB (Upflow Anaerobic Sludge Blanket) reactor, developed by Prof. Gatze Lettinga and his colleagues in the Netherlands more than thirty years ago, is successfully employed in many sewage treatment plants in countries with tropical and subtropical climate. However, are still reported serious operational issues related to the three-phase separators and problematic aspects involving the complexity of its influent distribution system. The focus of this research was to simplify the introduction and dispersion of the sewage in the reactor as well as enhancing the sludge retention, by replacing the characteristic piping system for a mechanical mixing apparatus and substituting the (conventional) three-phase separators by a high-rate settler, respectively. In essence, it was proposed a system partitioned into two distinct regions: one for reaction (i.e. anaerobic digestion of organic matter), in which the sludge blanket was mechanically mixed through the action of a rotating impeller, and another for the removal of suspended solids by the use of a lamella plate clarifier; a sludge recirculation system was also implanted, to pump the settled biomass back to the digestion compartment. The research was subdivided into three main phases: in the first two phases, bench-scale experiments were performed in order to obtain basic data for the design of the mechanical mixing and sedimentation devices, while the third phase consisted of the application of these technologies in a pilot-scale system with total volume of 20.8 m3 (comprised of a 17.0 m3 digestion chamber and a 3.8 m3 compartment for solids removal), as well as its performance assessment. During the development of the research, domestic sewage was applied to feed the experimental system, which was located at the School of Engineering of São Carlos (Campus I) in São Carlos (São Paulo State, Brazil). Throughout the period of effective operation, which lasted 130 days, four distinct operating modes were tested (characterized by intermittent mixing and varying hydraulic loading rates, ranging between 27.6 and 66.5 m3.d-1) and the system reached maximum removal efficiencies of BOD, COD and TSS at rates of 82%, 72% and 83%, respectively. The high-rate settler presented an impressive efficiency removing suspended solids (rates up to 98%). The research showed that the new \"Anaerobic Activated Sludge Blanket\" system (A2SB) can provide satisfactory performance even operating without the three-phase separator and influent distribution system. / O reator UASB, desenvolvido pelo Prof. Gatze Lettinga e colaboradores na Holanda há mais de trinta anos, é utilizado com sucesso em muitas estações de tratamento de esgoto sanitário em países de clima tropical e subtropical. Entretanto, ainda são relatadas sérias questões operacionais relacionadas aos separadores trifásicos e aspectos problemáticos envolvendo a complexidade de seu sistema de distribuição do esgoto afluente. O foco da presente pesquisa foi o de simplificar a distribuição e dispersão do esgoto no reator, assim como aprimorar a retenção de lodo, mediante substituição do sistema convencional de tubos por misturador mecânico e do (tradicional) separador trifásico por decantador de alta taxa, respectivamente. Em essência, propôs-se reator dividido em duas regiões distintas: uma para reação (i.e. digestão anaeróbia da matéria orgânica), na qual a manta de lodo foi agitada mecanicamente através do movimento rotacional de um impelidor, e outra, para remoção de sólidos suspensos mediante uso de decantador com placas paralelas; um sistema de recirculação do lodo também foi implantado, para bombear a biomassa sedimentada até o compartimento de digestão. A pesquisa foi subdividida em três fases: nas duas primeiras, experimentos em escala de bancada foram realizados visando obtenção de dados básicos para dimensionamento dos sistemas de agitação e de decantação, enquanto que a terceira fase consistiu na aplicação dessas tecnologias em sistema de tratamento, em escala piloto, com volume útil total de 20,8 m3 (composto por uma câmara de digestão de 17,0 m3 e um compartimento de 3,8 m3 para remoção de sólidos), assim como na análise de seu desempenho. Durante a pesquisa, esgoto sanitário foi utilizado para alimentar o sistema experimental, instalado na Escola de Engenharia de São Carlos. Ao longo do período de operação, que durou 130 dias, quatro condições operacionais foram testadas (caracterizadas pela agitação intermitente e diferentes taxas de carregamento hidráulico, que variaram entre 27,6 e 66,5 m3.d-1) e o sistema alcançou eficiências de remoção máxima para DBO, DQO e SST de 82%, 72% e 83%, respectivamente. O decantador de alta taxa apresentou surpreendente eficiência de remoção de sólidos suspensos (taxas de até 98%). A pesquisa demonstrou que o novo sistema A2SB (Anaerobic Activated Sludge Blanket) pode apresentar desempenhos satisfatórios, mesmo operando sem separador trifásico e sistema de distribuição do esgoto afluente.