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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Effect of Pre-treatment Using Ultrasound and Hydrogen Peroxide on Digestion of Waste Activated Sludge in an Anaerobic Membrane Bioreactor

Joshi, Priyanka January 2014 (has links)
The rate of anaerobic digestion (AD) often depends on the rate-limiting hydrolysis step that makes organics available to microorganisms. To achieve efficient conversion of particulates to soluble materials and finally methane, the biomass in the digester must be provided with optimal operational conditions that will allow for biomass retention and substrate metabolism. Two approaches were employed in this study to improve the ultimate biodegradability of waste activated sludge (WAS) - Pre-treatment (PT) and operation using an Anaerobic Membrane Bioreactor (AnMBR). PT of WAS is one way of speeding up hydrolysis. It has been proposed that PT leads to the lysis of cells, which in turn causes the release and solubilisation, and thus availability of intracellular matter to microorganisms for microbial growth and metabolic activities. This study compared the effect of thermal, sonication, and sonication + hydrogen peroxide PT on chemical oxygen demand (COD) solubilisation of WAS. Based on the soluble COD (SCOD) release, it was concluded that combined chemi-sonic treatment resulted in better WAS degradation rather than individual ultrasonic pre-treatment and thermal PT. The highest solubilisation rate was observed at a chemi-sonic PT of 50gH2O2/kgTS and sonication duration of 60 minutes. At this PT, a COD solubilisation of 40% was observed which was significantly different than PT involving only sonication and no pre-treatment (0.88%) at 95% confidence. Therefore a peroxide-sonic PT was chosen to treat WAS in this study as it was expected to result in the greatest improvement in WAS biodegradability. In addition to PT, biodegradability of WAS can also be improved by coupling PT with an AnMBR. AnMBRs prevent biomass washout by decoupling the solids retention time (SRT) from the hydraulic retention time (HRT). Thus, a long SRT can be used to provide sufficient duration for biological activities without increasing the volume of the reactor. In this study, a 4.5L AnMBR with an HRT and SRT of 3 and 20 days, respectively was used to treat raw and PT WAS. In order to compare the biodegradability of PT and raw WAS, the AnMBR was operated in three phases. Phase 1 was operated with raw WAS, Phase 2 was operated with WAS pre-treated with 50 gH2O2/kgTS and 20 minutes ultrasound (US), and Phase 3 was operated with WAS pre-treated with 50 gH2O2/kgTS and 60 minutes US. The anaerobic biodegradability of WAS following a combination of ultrasonic pre-treatment and H2O2 addition was significantly improved, with Phase 3 resulting in the greatest improvement. The COD destruction for phases 1, 2, and 3 were 49%, 58%, and 63%, respectively whereas the volatile suspended solids (VSS) destruction for phases 1, 2, and 3 were 46%, 71%, and 77% respectively. Organic Nitrogen (Org-N) destruction increased from 44% to 52% for phases 1 and 2 respectively. A further increase of 18% in Org-N destruction was observed in phase 3. This improvement in biodegradability of WAS was attributed to the high solubilisations of COD, VSS, and ON and conversion of non-biodegradable materials to biodegradable fractions. In order to determine the effect of PT of WAS on membrane performance, the transmembrane pressure (TMP) and fouling rate were monitored throughout the operation of the AnMBR. Negligible variation in membrane performance was observed over all three phases. At a constant low flux of 2.75 litres/m2/hour (LMH), the TMP and the fouling rate remained low over the course of operation. In order to maintain the performance of the membrane, maintenance cleaning with 50 ml of 2g/L critic acid solution followed by 50 ml of 0.2 g/L sodium hypochlorite was performed three times a week. In addition, a gas sparing rate of 2 L/minute and a permeation cycle of 10 minutes with 8 minutes of operation followed by 2 minutes of relaxation was employed. During phase 2 of this study, a new membrane was installed due to a faulty gas sparging pump. A slight decrease of TMP was observed with the installation of the new membrane; however the decrease was minimal. In addition critical flux for phases 2 and 3 were determined to be in the range of 6 to 12 LMH. In conclusion, the incorporation of H2O2-US PT with AD could allow treatment plants to substantially reduce the mass flow of solids and organics and thus result in a decrease in requirements for downstream sludge processing. With sufficient maintenance, steady operation could be achieved for a hollow fibre AnMBR with a total solids concentration range of 20-25 g/L, an HRT of 3 days, and an SRT of 20 days. It was found that PT could be successfully integrated with AnMBR to substantially reduce the HRT required for digestion when compared to conventional designs.
2

Biofouling in anaerobic membrane bioreactors: To control or not to?

Cheng, Hong 10 1900 (has links)
Anaerobic membrane bioreactor (AnMBR) serves as a more sustainable form of wastewater treatment. However, biofouling is particularly detrimental to the performanceof AnMBRs. This dissertation focuses on understanding more about the biofouling in nMBR, and to devise strategies to control or make use of these biofoulant layers. First, we aim to investigate the microbial community structure of sludge and biofilm from 13 different AnMBRs. Our findings indicate 20 sludge core genera and 12 biofilm core genera (occurrence ≥ 90% samples) could potentially account for the AnMBR performance. Sloan neutral model analysis indicates the anaerobic microbial consortium between sludge and biofilm is largely affected by stochastic dispersal and migration processes (i.e., neutral assembly), suggesting that the majority of these core genera are not selectively enriched for biofilm formation. Therefore, the second part of this dissertation aims to minimize the growth of the overall bacterial cells attached on the membranes. For this, membranes embedded with zinc oxide (ZnO) and copper oxide (CuO) nanoparticles were examined for their antifouling efficacies. Our findings indicate both CuO and ZnO nanoparticles embedded membranes could delay biofouling formation without significantly triggering the overall expression/abundance of antibiotic resistance genes (ARGs) and metal resistance genes (MRGs) in biofilm. Furthermore, CuO and ZnO nanoparticles could inhibit the expression of quorum sensing associated genes, resulting in lower quorum sensing signal molecules production. Despite the positive results demonstrated from this study as well as those from others, we recognize that no control strategies are likely to achieve total prevention of anaerobic biofouling. Therefore, the last part of this dissertation focuses on exploring the effects of different foulant layers on antibiotic-resistant bacteria (ARB) and ARGs removal. Our findings suggest both ARB and ARGs could be absorbed by membrane foulant. Transmembrane pressures and the foulant layer synergistically affected ARB removal, but the foulant layer is the main factor that contributed to ARG removal through adsorption. Overall, the collective findings could bring new insights to the anaerobic membrane biofouling phenomenon, and offer pragmatic approaches to minimize biofouling without compromising the post-AnMBR effluent quality.
3

Rening av avloppsvatten med anaerob membranbioreaktor och omvänd osmos / Wastewater treatment with anaerobic membrane bioreactor and reverse osmosis

Grundestam, Jonas January 2006 (has links)
<p>This master's theses was carried out on assignment from Stockholm Vatten AB as a part of a project developing new waste water treatment techniques. The goal of the theisis has been to evaluate an anaerobic membrane bioreactor for treatment of waste water from Hammarby Sjöstad. The bioreactor has not been heated and the main interest has been to study the gas production, power consumption and the reduction of organic matter and nutrients.</p><p>The system has been completed with a reverse osmosis unit and a total of four batch runs have been made with good results. The use of reverse osmosis allows nutrient in the waste water to be reintroduced into circulation as the reverse osmosis concentrate can be used as crop nutrient.</p><p>The membrane unit is of VSEP ("Vibratory Shear Enhanced Processing") type and an extensive membrane test has been conducted. This so called L-test helped determine the most suitable type of membrane for the system to allow a higher ±ux and thus lower power consumption. The L-test gave good results and a new membrane with a poresize diameter of 0,45 μm was used.</p><p>The organic load on the bioreactor has been more or less constant, around 0,7 kg COD/day, during the seven weeks of testing. The reduction over the entire system including reverse osmosis has been large, around 99 % regarding organic matter and phosporus and 93 % for nitrogen, making the system suitable for waste water treatment except for high power consumption, around 2 kWh/m3. The production of methanegas has worked although it has been quite low, with average values of 0,13 m3 CH4/kg reduced COD.</p> / <p>Examensarbetet är utfört på uppdrag av Stockholm Vatten AB som en del av det pilotprojekt som utvärderar nya tekniker för avloppsvattenrening för Hammarby Sjöstad. Målsättningen med studien har varit att utvärdera ett system bestående av en anaerob membranbioreaktor för behandling av avloppsvatten från Hammarby Sjöstad. Bioreaktorn har inte varit uppvärmd och det som har studerats är reningseffekten, biogasproduktionen samt energiåtgången.</p><p>Systemet har även innefattat en omvänd osmosanläggning och totalt har fyra försök med denna gjorts med goda resultat. Analyser har koncentrerats till att utvärdera reduktion av organiskt material över membranbioreaktorn och av närsalter och metaller över omvänd osmos anläggningen. Bakgrunden till att använda omvänd osmos är att öka återföringen av näringsämnen från avloppsvatten. Resultatet av försöken med omvänd osmos gav ett koncentrat med högt näringsinnehåll och låg halt av tungmetaller vilket ger möjligheten att sprida det på åkermark.</p><p>Membranenheten är av typen VSEP ("Vibratory Shear Enhanced Processing") och ett membrantest har även utfötts för att finna det membran som passar systemet bäst med avseende på flöde och energiförbrukning. Det så kallade L-testet var omfattande och gav en klar bild över vad som skulle vara det bästa membranet. Det membran som visade sig passa systemet bäst var ett membran med en porstorlek på 0,45 μm. Belastningen av organiskt material på reaktorn under försöksperiodens sju veckor har varit mer eller mindre konstant och låg, cirka 0,7 kg COD/dygn. Reduktionen över hela systemet inklusive omvänd osmosanläggningen med avseende på organiskt material och fosfor har varit mycket hög, omkring 99 %. Reduktionen av kväve var som högst 93 %. Gasproduktionen har fungerat och har i genomsnitt varit omkring 0,13 m3 CH4/kg reducerad COD.</p><p>Energiförbrukningen för systemet i motsvarande fullskala blev omkring 2 kwh/m3.</p>
4

Rening av avloppsvatten med anaerob membranbioreaktor och omvänd osmos / Wastewater treatment with anaerobic membrane bioreactor and reverse osmosis

Grundestam, Jonas January 2006 (has links)
This master's theses was carried out on assignment from Stockholm Vatten AB as a part of a project developing new waste water treatment techniques. The goal of the theisis has been to evaluate an anaerobic membrane bioreactor for treatment of waste water from Hammarby Sjöstad. The bioreactor has not been heated and the main interest has been to study the gas production, power consumption and the reduction of organic matter and nutrients. The system has been completed with a reverse osmosis unit and a total of four batch runs have been made with good results. The use of reverse osmosis allows nutrient in the waste water to be reintroduced into circulation as the reverse osmosis concentrate can be used as crop nutrient. The membrane unit is of VSEP ("Vibratory Shear Enhanced Processing") type and an extensive membrane test has been conducted. This so called L-test helped determine the most suitable type of membrane for the system to allow a higher ±ux and thus lower power consumption. The L-test gave good results and a new membrane with a poresize diameter of 0,45 μm was used. The organic load on the bioreactor has been more or less constant, around 0,7 kg COD/day, during the seven weeks of testing. The reduction over the entire system including reverse osmosis has been large, around 99 % regarding organic matter and phosporus and 93 % for nitrogen, making the system suitable for waste water treatment except for high power consumption, around 2 kWh/m3. The production of methanegas has worked although it has been quite low, with average values of 0,13 m3 CH4/kg reduced COD. / Examensarbetet är utfört på uppdrag av Stockholm Vatten AB som en del av det pilotprojekt som utvärderar nya tekniker för avloppsvattenrening för Hammarby Sjöstad. Målsättningen med studien har varit att utvärdera ett system bestående av en anaerob membranbioreaktor för behandling av avloppsvatten från Hammarby Sjöstad. Bioreaktorn har inte varit uppvärmd och det som har studerats är reningseffekten, biogasproduktionen samt energiåtgången. Systemet har även innefattat en omvänd osmosanläggning och totalt har fyra försök med denna gjorts med goda resultat. Analyser har koncentrerats till att utvärdera reduktion av organiskt material över membranbioreaktorn och av närsalter och metaller över omvänd osmos anläggningen. Bakgrunden till att använda omvänd osmos är att öka återföringen av näringsämnen från avloppsvatten. Resultatet av försöken med omvänd osmos gav ett koncentrat med högt näringsinnehåll och låg halt av tungmetaller vilket ger möjligheten att sprida det på åkermark. Membranenheten är av typen VSEP ("Vibratory Shear Enhanced Processing") och ett membrantest har även utfötts för att finna det membran som passar systemet bäst med avseende på flöde och energiförbrukning. Det så kallade L-testet var omfattande och gav en klar bild över vad som skulle vara det bästa membranet. Det membran som visade sig passa systemet bäst var ett membran med en porstorlek på 0,45 μm. Belastningen av organiskt material på reaktorn under försöksperiodens sju veckor har varit mer eller mindre konstant och låg, cirka 0,7 kg COD/dygn. Reduktionen över hela systemet inklusive omvänd osmosanläggningen med avseende på organiskt material och fosfor har varit mycket hög, omkring 99 %. Reduktionen av kväve var som högst 93 %. Gasproduktionen har fungerat och har i genomsnitt varit omkring 0,13 m3 CH4/kg reducerad COD. Energiförbrukningen för systemet i motsvarande fullskala blev omkring 2 kwh/m3.
5

Two - Stage AnMBR for Removal of UV Quenching Organic Carbon from Landfill Leachates: Feasibility and Microbial Community Analyses

Pathak, Ankit Bidhan 13 February 2017 (has links)
Landfilling is the most widely used method for the disposal of municipal solid wastes (MSW) in the United States due to its simplicity and low cost. According to the 2014 report on Advancing Sustainable Materials Management by the USEPA, only 34% of the total MSW generated in the US was recycled, while 13% was combusted for energy recovery. In 2014, 53% of the MSW generated, (i.e. 136 million tons) in the US was landfilled. The treatment of landfill leachates, generated by percolation of water through the landfill, primarily due to precipitation, has been found to be one of the major challenges associated with landfill operation and management. Currently, leachates from most landfills are discharged into wastewater treatment plants, where they get treated along with domestic sewage. Issues associated with treatment of landfill leachates due to their high nitrogen and heavy metal content have been widely studied. Recently, it has been observed that the organic carbon in landfill leachates, specifically humic and fulvic acids (together referred to as "humic substances") contain aromatic groups that can absorb large amounts of ultraviolet (UV) light, greatly reducing the UV transmissivity in wastewater plants using UV disinfection as the final treatment step. This interference with UV disinfection is observed even when landfill leachates constitute a very small fraction (of the order of 1%) of the total volumetric flow into wastewater treatment plants. Humic substances are present as dissolved organic matter (DOM) and typically show very low biodegradability. Removing these substances using chemical treatment or membrane processes is an expensive proposition. However, the concentrations of humic substances are found to be reduced in leachates from landfill cells that have aged for several years, suggesting that these substances may be degraded under the conditions of long-term landfilling. The primary objective of this research was to use a two-stage process employing thermophilic pretreatment followed by a mesophilic anaerobic membrane bioreactor (AnMBR) to mimic the conditions of long-term landfilling. The AnMBR was designed to keep biomass inside the reactor and accelerate degradation of biologically recalcitrant organic carbon such as humic substances. The treatment goal was to reduce UV absorbance in raw landfill leachates, potentially providing landfills with an innovative on-site biological treatment option prior to discharging leachates into wastewater treatment plants. The system was operated over 14 months, during which time over 50% of UV-quenching organic carbon and 45% of UV absorbance was consistently removed. To the best of our knowledge, these removal values are higher than any reported using biological treatment in the literature. Comparative studies were also performed to evaluate the performance of this system in treating young leachates versus aged leachates. Next-generation DNA sequencing and quantitative PCR (qPCR) were used to characterize the microbial community in raw landfill leachates and the bioreactors treating landfill leachate. Analysis of microbial community structure and function revealed the presence of known degraders of humic substances in raw as well as treated landfill leachates. The total number of organisms in the bioreactors were found to be higher than in raw leachate. Gene markers corresponding to pathogenic bacteria and a variety of antibiotic resistance genes (ARGs) were detected in raw landfill leachates and the also in the reactors treating leachate, which makes it necessary to compare these ARG levels with wastewater treatment in order to determine if leachates can act as sources of ARG addition into wastewater treatment plants. In addition, the high UV absorbance of leachates could hinder the removal of ARBs and ARGs by UV disinfection, allowing their release into surface water bodies and aiding their proliferation in natural and engineered systems. / Ph. D. / Municipal solid waste is most often disposed by dumping it in landfills. Percolation of water through these landfills due to precipitation or the intrusion of surface or groundwater, results in the formation of landfill leachate, a mixture of organic and inorganic contaminants, at the bottom of the landfill. Landfills are therefore lined with special materials to prevent leachate from seeping into soil or groundwater and have sophisticated collection systems to periodically extract and dispose leachate. Perhaps the most commonly used method for the disposal of landfill leachates is discharge into wastewater treatment plants, where leachates can cause toxicity to biological processes due to their high organic load as well as their substantial heavy metal content. In the last decade or so, it has been established that leachates can absorb UV light considerably by virtue of aromatic organic compounds present in them, causing inhibition of UV disinfection in wastewater treatment. Thus, leachates must be appropriately treated to reduce their capacity to absorb UV light prior to discharge into wastewater treatment plants. This study employed a novel two – stage reactor system to treat landfill leachates in order to reduce their UV-quenching ability. The system was successfully operated over 14 months and was able to remove more than half of the UV light absorbing organic carbon from landfill leachate. Additionally, samples of biomass isolated from untreated landfill leachates and the reactors treating them revealed the potential presence of pathogenic bacteria and antibiotic resistance genes. Preliminary data suggests that landfill leachates might have large antibiotic resistance content, higher than that observed in wastewater and other engineered systems.
6

Produção de hidrogênio em condições extremamente ácidas e avaliação do desempenho e recuperação de energia em sistemas de tratamento de dois estágios (acidogênico-metanogênico) / Hydrogen production in extreme acid conditions and evaluation of performance and energy recovery potential in two-stage treatment systems (acidogenic methanogenic)

Mota, Vera Tainá Franco Vidal 04 September 2018 (has links)
A presente pesquisa teve por objetivo avaliar a produção biológica de hidrogênio em longo prazo, e os impactos da separação das principais etapas da digestão anaeróbia, acidogênese e metanogênese, sobre a eficiência do tratamento em reatores de leito fixo estruturado e sobre o desempenho da filtração em biorreatores com membrana. O efluente utilizado foi à base de sacarose e a temperatura foi mantida em 30ºC. Na primeira etapa experimental, avaliou-se a produção de H2 em três configurações de reatores: leito fixo estruturado (FB), UASB granular (UG) e UASB floculento (UF-1). Na segunda etapa experimental, um reator UASB acidogênico (UF-2) foi combinado a um reator metanogênico de leito fixo estruturado (RM). Um reator de estágio único de leito fixo estruturado (RU) foi operado em paralelo. Na última etapa experimental, foram avaliados dois biorreatores anaeróbios conjugados com módulos externos de membranas tubulares, nomeadamente 1-AnMBR, que foi alimentado com efluente bruto, e 2-AnMBR, que foi alimentado com efluente acidificado. Na primeira etapa, sob um TDH de 3,3 h (COV = 33 gDQO.L-1d-1), os reatores FB, UG e UF-1 apresentaram produção de H2 contínua, porém instável, com rendimentos de aprox. 1,5, 0,8 e 1,2 molH2.mol-1sacaroseconsumida, respectivamente. O reator UF-1 apresentou uma estabilidade relativamente melhor e, por isso, esta configuração foi utilizada nos experimentos seguintes. No reator UF-2, aumentou-se o TDH para 4,6 h (COV = 25 gDQO.L-1d-1), o que significativamente promoveu a melhoria do desempenho. Nenhum alcalinizante foi adicionado e o pH do efluente permaneceu em torno de apenas 2,7. Contudo, uma produção de H2 contínua, estável e por longa duração foi atingida, de 175 mLH2.L-1h-1 (= 4,2 LH2.L-1d-1), com rendimento de 3,4 molH2.mol-1sacaroseconsumida, concomitante com a produção de ácido acético e etanol. Nos reatores metanogênicos, o TDH aplicado foi gradativamente reduzido (53-18 h no RM e 56-23 h no RU). Após os sistemas atingirem estabilidade, os valores de DQO permaneceram inferiores no efluente do RM, sobretudo pela redução da concentração de SSV, equivalente a 92 mg.L-1, enquanto que no RU essa concentração foi de 244 mg.L-1. No final da operação, o rendimento energético do sistema de dois estágios foi de 20,69 kJ.g-1DQOadicionada, sendo 90% proveniente do CH4 e 10% do H2. Este rendimento foi 34% maior do que o obtido no reator de estágio único, que foi de 15,48 kJ.g-1DQOadicionada. Por fim, avaliando-se o desempenho da filtração nos biorreatores com membrana, verificou-se que a permeabilidade operacional foi, na maior parte do tempo, superior no 2-AnMBR. A pré-acidificação do efluente levou à redução de cerca de 56-59% na concentração de sólidos voláteis suspensos e totais no 2-AnMBR e à modificação no perfil do tamanho das partículas. No 1-AnMBR, porém, não havia partículas de pequenas dimensões, tais quais encontradas no reator acidogênico, indicando reduzido crescimento suspenso de bactérias acidogênicas. Embora os valores de fluxo crítico tenham sido muito semelhantes para ambos os AnMBR, testes de resistência específica da torta indicaram maior resistência do lodo do 1-AnMBR (1,02 x 1018 m-1), comparado ao lodo do 2-AnMBR (1,03 x 1012 m-1) e ao lodo acidogênico (7,44 x 1011 m-1). Portanto, essa pesquisa demonstrou, por meio da aplicação do tratamento anaeróbio em dois estágios, a viabilidade da produção contínua de hidrogênio em pH extremamente ácido e com mínimos requerimentos operacionais, a redução da concentração de sólidos suspensos no efluente de reatores de leito fixo estruturado, o potencial de aumento da recuperação de bioenergia e de redução da incrustação em membranas de ultrafiltração. / This study assessed long-term hydrogen production and the impacts of separating the main stages of anaerobic digestion (acidogenesis and methanogenesis) on treatment efficiency in structured fixed-bed reactors and on filtration performance in anaerobic membrane bioreactors. Sucrose based wastewater was used and the temperature was maintained at 30°C. In the first experimental phase, H2 production was evaluated in three different acidogenic reactors: structured fixed-bed (FB), granular UASB (UG) and flocculated UASB (UF-1). In the second experimental phase, an acidogenic UASB reactor (UF-2) was combined with a structured fixedbed methanogenic reactor (RM). A single-stage structured fixed-bed reactor (RU) was operated in parallel. In the last experimental phase, two sidestream anaerobic membrane bioreactors were evaluated: 1-AnMBR, which was fed with raw effluent; and, 2-AnMBR, which was fed with biologically acidified effluent. During the first operational phase, under an HRT of 3.3 h (OLR = 33 gCOD.L-1d-1), the FB, UG and UF-1 reactors showed continuous but unstable H2 production, with yields of approximately 1.5, 0.8 and 1.2 molH2.mol-1sucroseconsumed, respectively. The UF-1 reactor showed relatively better stability; therefore, this configuration was used in the next experiments. In the UF-2 reactor, the HRT was increased to 4.6 h (OLR = 25 gCOD.L-1d-1), which significantly improved the overall performance. No alkalizing agent was added, and effluent pH values remained around only 2.7. However, continuous, stable and long-term H2 production was achieved of 175 mLH2.L-1h-1 (= 4.2 LH2.L-1h-1), with yields of 3.4 molH2.mol-1sucroseconsumed, concomitant with acetic acid and ethanol production. In the methanogenic reactors, the HRT was gradually reduced and, when the systems reached stability, COD values remained lower in the RM effluent. This was mainly due to the reduction of VSS concentrations, equivalent to 92 mg.L-1, while in the RU this value was 244 mg.L-1. At the end of the operation, the energy yield of the two-stage system was 20.69 kJ.g-1CODadded with 90% coming from CH4 and 10% from H2. This yield was 34% greater than that obtained in the single-stage system, which was 15.48 kJ.g-1CODadded. Finally, regarding the filtration performance in the membrane bioreactors, the operational permeability was higher in the 2- AnMBR most of the time. The pre-acidification of the effluent led to the 56-59% reduction in the volatile total and suspended solid concentrations, and to modification in the particle size profile in the 2-AnMBR. Nevertheless, in the 1-AnMBR, there were no small particles such as were found in the sludge of the acidogenic reactor, indicating less suspended growth of acidogenic biomass. Although the critical flux values were very similar for both AnMBRs, a higher specific cake resistance was verified in the 1-AnMBR sludge (1.02 x 1018 m-1), as compared to the 2-AnMBR sludge (1.03 x 1012 m-1) and to the acidogenic sludge (7.44 x 1011m-1</sup). Therefore, this study demonstrated, through the application of two-stage anaerobic treatment, the viability of continuous hydrogen production in extreme acid pH and with minimum operating requirements, the reduction of solid concentrations in the effluent of structured fixed bed reactors, as well as the potential for increased bioenergy recovery and for fouling reduction of ultrafiltration membranes.
7

Anaerobní membránový bioreaktor (AnMBR) pro čištění odpadních vod potravinářského průmyslu / Anaerobic membrane bioreactor (AnMBR) for food industry wastewater treatment.

Polášek, Daniel Unknown Date (has links)
The most significant environmental problems related to the food industry is water consumption and pollution, energy consumption and waste production. Most of the water that does not become a part of the products ultimately leaves plants in the form of wastewater, which is often very specific and requires adequate handling / treatment / disposal. For the purpose of this thesis, brewery industry was chosen, because of its very long tradition in the Czech history and culture. Anaerobic technologies are applied for still wider range of industrial wastewater treating. In general anaerobic membrane bioreactors (AnMBRs) can very effectively treat wastewater of different concentration and composition and produce treated water (outlet, permeate) of excellent quality, that can be further utilised. At the same time, it can promote energy self-sufficiency through biogas production usable in WWTPs / plants. Main disadvantages include unavoidable membrane fouling and generally higher CAPEX / OPEX. Within the framework of Ph.D. studies and related research activities, immersed membrane modules for anaerobic applications were selected and lab-scale tested (designed and assembled laboratory unit), an AnMBR pilot plant was designed, built and subsequently tested under real conditions - at Černá Hora Brewery WWTP (waste waters from the brewery and associated facilities). The pilot AnMBR and the technology itself has been verified over more than a year (5/2015 – 11/2016) of trial operation - the initial and recommended operational parameters have been set up, minor construction adjustments / modifications and measurement & regulation optimizations have been made, the recommended membrane cleaning and regeneration procedure has been verified. Last, but not least, conclusions and recommendations of the trial operation were summarised - some key findings and recommendations for further operation, use and modifications of the existing AnMBR pilot plant are presented.
8

Modelling, simulation and control of the filtration process in a submerged anaerobic membrane bioreactor treating urban wastewater

Robles Martínez, Ángel 28 November 2013 (has links)
El reactor anaerobio de membranas sumergidas (SAnMBR) está considerado como tecnología candidata para mejorar la sostenibilidad en el sector de la depuración de aguas residuales, ampliando la aplicabilidad de la biotecnología anaerobia al tratamiento de aguas residuales de baja carga (v.g. agua residual urbana) o a condiciones medioambientales extremas (v.g. bajas temperaturas de operación). Esta tecnología alternativa de tratamiento de aguas residuales es más sostenible que las tecnologías aerobias actuales ya que el agua residual se transforma en una fuente renovable de energía y nutrientes, proporcionando además un recurso de agua reutilizable. SAnMBR no sólo presenta las principales ventajas de los reactores de membranas (i.e. efluente de alta calidad, y pocas necesidades de espacio), sino que también presenta las principales ventajas de los procesos anaerobios. En este sentido, la tecnología SAnMBR presenta una baja producción de fangos debido a la baja tasa de crecimiento de los microorganismos implicados en la degradación de la materia orgánica, presenta una baja demanda energética debido a la ausencia de aireación, y permite la generación de metano, el cual representa una fuente de energía renovable que mejora el balance energético neto del sistema. Cabe destacar el potencial de recuperación de nutrientes del agua residual bien cuando el efluente es destinado a irrigación directamente, o bien cuando debe ser tratado previamente mediante tecnologías de recuperación de nutrientes. El objetivo principal de esta tesis doctoral es evaluar la viabilidad de la tecnología SAnMBR como núcleo en el tratamiento de aguas residuales urbanas a temperatura ambiente. Por lo tanto, esta tesis se centra en las siguientes tareas: (1) implementación, calibración y puesta en marcha del sistema de instrumentación, control y automatización requerido; (2) identificación de los parámetros de operación clave que afectan al proceso de filtración; (3) modelación y simulación del proceso de filtración; y (4) desarrollo de estrategias de control para la optimización del proceso de filtración minimizando los costes de operación. En este trabajo de investigación se propone un sistema de instrumentación, control y automatización para SAnMBR, el cual fue esencial para alcanzar un comportamiento adecuado y estable del sistema frente a posibles perturbaciones. El comportamiento de las membranas fue comparable a sistemas MBR aerobios a escala industrial. Tras más de dos años de operación ininterrumpida, no se detectaron problemas significativos asociados al ensuciamiento irreversible de las membranas, incluso operando a elevadas concentraciones de sólidos en el licor mezcla (valores de hasta 25 g·L-1 ). En este trabajo se presenta un modelo de filtración (basado en el modelo de resistencias en serie) que permitió simular de forma adecuada el proceso de filtración. Por otra parte, se propone un control supervisor basado en un sistema experto que consiguió reducir el consumo energético asociado a la limpieza física de las membranas, un bajo porcentaje de tiempo destinado a la limpieza física respecto al total de operación, y, en general, un menor coste operacional del proceso de filtración. Esta tesis doctoral está integrada en un proyecto nacional de investigación, subvencionado por el Ministerio de Ciencia e Innovación (MICINN), con título ¿Modelación de la aplicación de la tecnología de membranas para la valorización energética de la materia orgánica del agua residual y la minimización de los fangos producidos¿ (MICINN, proyecto CTM2008-06809- C02-01/02). Para obtener resultados representativos que puedan ser extrapolados a plantas reales, esta tesis doctoral se ha llevado a cabo utilizando un sistema SAnMBR que incorpora módulos comerciales de membrana de fibra hueca. Además, esta planta es alimentada con el efluente del pre-tratamiento de la EDAR del Barranco del Carraixet (Valencia, España). / Robles Martínez, Á. (2013). Modelling, simulation and control of the filtration process in a submerged anaerobic membrane bioreactor treating urban wastewater [Tesis doctoral]. Editorial Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/34102 / Premios Extraordinarios de tesis doctorales

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