Дисертації з теми "Anaerobic biofilm reactor"

The overall goal of the thesis was to develop and optimize the moving bed biofilm reactor technology under anaerobic conditions. The thesis work was divided into two different series of experiments. Hence, at first, the reactor start-up on synthetic substrate was evaluated and it was proven that the anaerobic moving bed biofilm reactor technology could successfully treat concentrated wastewater. Subsequently, a study on Fort Garry Brewery wastewater was conducted to optimize the process for a typical North American industrial wastewater. The aim was successfully achieved and a potential design to treat Fort Garry Brewery wastewater was developed. The anaerobic moving bed biofilm reactor was found to be capable in treating brewery wastewater with potential savings to the industry paying surcharges for discharging wastewater over the city sewer bylaw limits.
October 2016

Along with the rapid development of the seafood processing industry in Vietnam, thousands of tons of seafood scraps are generated annually. One of the major seafood processing wastes is shrimp waste, estimated at over 100,000 tons per year. This huge amount of shrimp waste contains over 4,000 tons of pure chitin, a natural long-chain polymer of N-acetylglucosamine which can be deacetylated to form chitosan. Chitin is widely and increasingly used in animal feed production. The current domestic chitin production process in Vietnam is based mainly on the inorganic chemical method, including demineralisation with HCl, deacetylation and deproteination with NaOH, and colour elimination with NaOCl or other active oxidising compounds. This production process then generates acid and alkaline wastes, containing high levels of nutrients such as protein, astaxanthin, lipid, and high salt concentrations, causing environmental pollution or costly wastewater treatment. Therefore, an environmentally friendly chitin manufacturing is urgently required in Vietnam. The thesis focused on two main contents: the use of bio-coagulant chitosan, and an anaerobic-anoxic-oxic biofilm reactor system. Firstly, chitosan application as a bio-coagulant minimised the amount of suspended solid wastes in chitin wastewater. This solution was more advantageous than coagulation by conventional chemicals because it was safe and environmentally friendly and economically profitable if sludge was utilised as animal feed and/or fertiliser. Secondly, wastewater was treated by anaerobic-anoxic-oxic biofilm reactor system using stick-bed biofix and swim-bed biofringe carriers to meet the technical regulation of wastewater discharge QCVN 11-MT:2015/BTNMT. The characteristics of chitin wastewater in the individual or mixed waste streams were first investigated. This assessment can help chitin producers recover valuable residuals in waste streams and simultaneously reduce the organic load in the wastewater treatment system. A pre-treatment process consisting of sedimentation followed by coagulation by by-product chitosan was conducted to evaluate chitin wastewater treatment and the crude protein recovery potential. The effluent after the coagulation-flocculation process was further run through biofilm reactors. This system needed microorganisms fully adapted to salinity and existing nutrient contents in chitin wastewater. The complete operating system on the laboratory scale could contribute as the foundation to the application in larger industrial scales. Experimental results showed that as chitin production processes reused the extracted chemicals and waste streams, the level of wastewater pollution increased. More of the soluble proteins were removed in the biochemical process than in the chemical methods. The waste streams' contents fluctuated remarkably depending on the nature of the input materials and the production process. For these reasons, the treatment of chitin wastewater confronted many difficulties. In addition, some technical-analytical results are listed as follows (a) Preliminary sedimentation removed over 80% of turbidity at pH 4, 30 mins of settling time, tCOD reduced by 39%, and TSS reduced by 93% (b) Optimal coagulation with by-product chitosan was achieved with the ratio between crude protein and calcium at around 5, chitosan concentration = 77.5 mgL-1, pH = 8.3, the reduction rates for the different parameters were as follow: tCOD (23%), sCOD (32%), TKN and NH4+-N (25%), TP (90%), TSS (84%), Ca2+ (29%), and crude protein (25%). (c) Chitosan was the most effective coagulant at lower ratios than other chemical coagulants in removing inorganic and organic chitin wastewater substances. (d) Crude protein content recovery was up to 55 mgg-1, and recovery of mineral content was around 10%. (e) The acclimation process running through three phases with gradually increasing input loadings from 1.5 kgCOD m-3d-1 to 2.5 kgCOD m-3d-1, removed over 90% of COD, 75-85% of TN and around 50% of TP. (f) The main treatment process of biofilm reactors going through five phases with the input loading increased from 3.0 kgCOD m-3d-1 to 6.0 kgCOD m-3d-1, flow rates from 12.96 Ld-1 to 16.4 Ld-1, and salinity from 6 ppt to 18 ppt. At phase 4 (loading of 5.7 kgCOD m-3d-1 and salinity of 14 ppt), the treatment efficiency reached over 90% for COD, about 60% for TN and TP, and 65% for calcium. Most of the processing efficiencies were high, making the treated wastewater meet the Vietnamese standard QCVN 11-MT:2015/BTNMT.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Eng & Built Env
Science, Environment, Engineering and Technology
Full Text

Este trabalho teve como objetivo avaliar o desempenho de um reator anaeróbio de leito fluidificado na degradação da vinhaça de cana-de-açúcar, sob condições mesofílicas. Ensaios batelada foram realizados a diferentes concentrações, visando avaliar a degradação do substrato pela biomassa anaeróbia e obtenção de parâmetros cinéticos. Vinhaça diluída a valores de DQO de 1984 mg/L, 2827 mg/L, 3800 mg/L, 6354 mg/L, 7395 mg/L, 10705 mg/L e 15872 mg/L foi utilizada nos experimentos, mostrando reduções de 67% em 192 horas, 75% em 358 horas, 81% em 408 horas, 80% em 480, 72% em 504 horas, 76% em 840 horas e de 71% em 1080, para essas concentrações, respectivamente. A reação ocorrida nos reatores foi analisada como sendo de ordem zero, com valor médio da constante de reação de 10,4 mg/L.h. Testes com partículas de poliamida, poliestireno e nylon foram realizados, objetivando a escolha da melhor partícula em termos de formação e desenvolvimento de biofilme para posterior uso no reator. As três partículas mostraram-se favoráveis à adesão e colonização de microrganismos. O reator anaeróbio de leito fluidificado foi inoculado com lodo proveniente de reator UASB, que tratava água residuária de abatedouro de aves. O volume do reator era de 770 cm3, operando com tempo de detenção hidráulica de 24 h. A partícula utilizada como material suporte foi poliestireno. O tempo de operação do reator foi de 122 dias, sendo aplicada vinhaça diluída a valores de DQO que variaram de 1009 mg/L a 15874 mg/L e COVa de 1,0 Kg/m3.d a 15,9 Kg/m3.d, apresentando resultado de remoção de DQO médio de 51% a 70% e COVrv de 0,5 Kg/m3.d a 7,9 Kg/m3.d. Observações microscópicas em MEV, mostraram boa adesão microbiana nas partículas de poliestireno, em todas as fases do reator.
This work had as objective evaluates the efficiency of a anaerobic fluidized bed reactor for vinasse degradation under mesophilic conditions. Batch tests seeking to evaluate the degradation of the substratum for the anaerobic biomass and obtaining kinetic parameters were accomplished to different concentrations. Diluted vinasse to values of 1984 mg/L, 2827 mg/L, 3800 mg/L, 6354 mg/L, 7395 mg/L, 10705 mg/L and 15872 mg/L of COD was used in the experiments showing reductions of 67% in 192 hours, 75% in 358 hours, 81% in 408 hours, 80% in 480, 72% in 504 hours, 76% in 840 hours and of 71% in 1080, for those concentrations, respectively. The reaction happened in the batch reactors it was analyzed as being of order zero, with medium value of 10,4 mg/L.h for the constant of reaction. Tests with polyamide particles, polystyrene and nylon were accomplished, aiming at the choice of the best particle in formation terms and biofilme development for subsequent use in the reactor. The three particles were shown favorable to the adhesion and colonization of microorganisms. The fluidized bed reactor was inoculated with sludge from reactor UASB treating effluent frompoultry slaughterhouse. The volume of the reactor was of 770 cm3, operating with hydraulic detention time of 24 h. Polystyrene particles were used as material support. The reactor was operated for 122 days, being applied diluted vinasse to values of COD 1009 mg/L ranging to 15874 mg/L and organic loading rate (OLR) of 1,0 Kg/m3.d to 15,9 Kg/m3.d, presenting efficiency COD removal of 51% - 70% and OLR removal of 0,5 Kg/m3.d - 7,9 Kg/m3.d. Microscopic observations in MEV showed good microbial adhesion in the particles of polystyrene, in all the phases of the reactor.

As the microbrewery industry expands, disposal of brewery wastewater is becoming more of a concern, both for brewery operators and for local municipal wastewater authorities. Brewery wastewater is characterized as containing high strength organics and high variability in both organic and hydraulic loading. This high variability increased the challenge of treating brewery wastewater properly. Therefore, it is significant for optimizing the operation condition for the small-scale wastewater treatment system. This study conducted a batch study and a field study for optimizing a craft brewery on-site wastewater treatment system, which is equipped with two moving bed biofilm reactors (MBBR). In the batch study, a two-factor Box-Wilson central composite design (CCD) was adopted to find optimum biomethane production conditions for the digestion of brewery wastewater with a dairy manure inoculum. The effects of two major influencing factors of temperature (T) (25-49°C) and brewery wastewater concentration (BWC) (2-9 g VS/L) on biochemical methane potential (BMP) (CH₄ yield) and CH₄ maximum production rate (Rmax) were evaluated by applying response surface methodology (RSM). All of the trials presented a high organic removal efficiency with volatile solid (VS) 82-91%, soluble chemical oxygen demand (sCOD) 77-88%, and total chemical oxygen demand (tCOD) between 47% -76%. The experiment result suggested that the first-order kinetic rate constant and biogas content (methane percentage in the biogas) can be affected by the temperature. The mesophilic regime had the highest average rate constant, and the psychrophilic regime rate constant was significantly lower than the mesophilic and thermophile regime. The conditions in the thermophile range present a high variability for the first-order rate constant. The methane ratio in the biogas increased and stabilized by the operation time. Mesophilic and thermophilic regimes obtained a stabile biogas content around 25 days, and the psychrophilic regime spent extra time to stabilized. At the end of the anaerobic digestion, the psychrophilic, mesophilic, and thermophilic regimes had an average methane percentage of 47%,65%, and 67% respectively. Optimum BMP and Rmax were achieved under conditions of 49 °C and BWC of 5g VS/L. Correspondingly, the BMP and Rmax were 141.40 mL CH₄/g VS added and 36.5 mL CH₄/ day, respectively. However, by pursuing stability the preferable operational condition T=35℃ and BWC=5 g/L is recommended, at this condition methane yield is 110.07 CH₄/g VS added and maximum methane daily production is 28.06 CH₄/ day, which is similar to the maximum result. In field study, an on-site brewery wastewater treatment system equipped with two MBBR reactors was evaluated from October 12th, 2018 to February 10th, 2020 in Beau`s All-Natural Brewing Company, Vankleek Hill, Ontario, Canada. The aim of the study was to characterize the wastewater production (flow and organic loading rate), evaluate the operating conditions and performance of the MBBR system, and recommend improvements. Discharge from the brewery is highly variable for both organic and hydraulic loading with flow balancing recommended. The MBBR full-scale reactors operated at relatively stable conditions at a surface area loading rate (SALR) of less than 25 g/m2.d and dissolved oxygen (DO) greater than 2mg/L. Kinetic rate constants for suspended growth and attached growth biomass in the reactors were found to be similar at 0.0764-0.0908 h-1, however, a much larger attached growth mass in the reactors suggests that only a fraction of the attached growth biofilm is active. Effluent recycle was shown to be effective at controlling filamentous bacteria (type-0041) sludge bulking, reducing suspended solid concentration, and sCOD concentration.

Protecting the quality and quantity of our water resources requires advanced treatment technologies capable of removing nutrients from wastewater. This research work investigated the capability of one such technology, a hollow-fiber membrane-aerated biofilm reactor (HFMBR), to achieve completely autotrophic nitrogen removal from a wastewater with high nitrogen content. Because the extent of oxygenation is a key parameter for controlling the metabolic processes that occur in a wastewater treatment system, the first part of the research investigated oxygen transfer characteristics of the HFMBR in clean water conditions and with actively growing biofilm. A mechanistic model for oxygen concentration and flux as a function of length along the non-porous membrane fibers that comprise the HFMBR was developed based on material properties and physical dimensions. This model reflects the diffusion mechanism of non-porous membranes; namely that oxygen follows a sorption-dissolution-diffusion mechanism. This is in contrast to microporous membranes in which oxygen is in the gas phase in the fiber pores up to the membrane surface, resulting in higher biofilm pore liquid dissolved oxygen concentrations. Compared to offgas oxygen analysis from the HFMBR while in operation with biofilm growing, the model overpredicted mass transfer by a factor of approximately 1.3. This was in contrast to empirical mass transfer coefficient-based methods, which were determined using either bulk aqueous phase dissolved oxygen (DO) concentration or the DO concentration at the membrane-liquid interface, measured with oxygen microsensors. The mass transfer coefficient determined with the DO measured at the interface was the best predictor of actual oxygen transfer under biofilm conditions, while the bulk liquid coefficient underpredicted by a factor of 3. The mechanistic model exhibited sensitivity to parameters such as the initial lumen oxygen concentration (at the entry to the fiber) and the diffusion coefficient and partitioning coefficients of oxygen in the silicone membrane material. The mechanistic model has several advantages over empirical-based methods. Namely, it does not require experimental determination of KL, it is relatively simple to solve without the use of advanced mathematical software, and it is based upon selection of the membrane-biofilm interfacial DO concentration. The last of these is of particular importance when designing and operating HFMBR systems with redox (aerobic/anoxic/anaerobic) stratification, because the DO concentration will determine the nature of the microenvironments, the microorganisms present, and the metabolisms that occur. During the second phase of the research, the coupling of two autotrophic metabolisms, partial nitrification to nitrite (nitritation) and anaerobic ammonium oxidation, was demonstrated in a single HFMBR. The system successfully treated a high-strength nitrogen wastewater intended to mimic a urine stream from such sources as extended space missions. For the last 250 days of operation, operating with an average oxygen to ammonia flux (JO2/JNH4+) of 3.0 resulted in an average nitrogen removal of 74%, with no external organic carbon added. Control of nitrite-oxidizing bacteria (NOB) presented a challenge that was addressed by maintaining the JO2/JNH4+ below the stoichiometric threshold for complete nitrification to nitrate (4.57 g O2 / g NH4 +). The DO-limiting condition resulted in formation of harmful gaseous emissions of nitrogen oxides (NO, N2O), which could not be prevented by short-term control strategies. Controlling JO2/JNH4+ prevented NOB proliferation long enough to allow an anaerobic ammoniaoxidizing bacteria (AnaerAOB) population to develop and be retained for >250 days. Addition of a supplemental nutrient solution may have contributed to the growth of AnaerAOB by overcoming a possible micronutrient deficiency. Disappearance of the gaseous nitrogen oxide emissions coincided with the onset of anaerobic ammonium oxidation, demonstrating a benefit of coupling these two autotrophic metabolisms in one reactor. Obvious differences in biofilm density were evident across the biofilm depth, with a region of low density in the middle of the biofilm, suggesting that low cell density or exocellular polymeric substances were primarily present in this region, Microbial community analysis using fluorescence in situ hybridization (FISH) did not reveal consistent trends with respect to length along the fibers, but radial stratification of aerobic ammonia-oxidizing bacteria (AerAOB), NOB, and AnaerAOB were visible in biofilm section samples. AerAOB were largely found in the first 25% of the biofilm near the membrane, AnaerAOB were found in the outer 30%, and NOB were found most often in the mid-depth region of the biofilm. This community structure demonstrates the importance of oxygen availability as a determinant of how microbial groups spatially distribute within an HFMBR biofilm. The combination of these two aspects of the research, predictive oxygen transfer capability and the effect of oxygen control on performance and populations, provides a foundation for future application of HFMBR technology to a broad range of wastewaters and treatment scenarios.
Ph. D.

The research presented in this report is in two sections. Section I involved the performance of a moving bed biofilm reactor (MBBR) versus a biological aerated filtration (BAF) and Section II involved study on causes of deposition in anaerobic digester gas piping.

The first section evaluated and compared the performance of a laboratory-scale MBBR and BAF for organic carbon and suspended solids removal. A kinetic study was also performed on the MBBR to evaluate the system performance. The purpose was to recommend one of the systems for the Force Provider project, which provides a containerized "city" for the U.S. Army. The effluent criteria against which the systems were evaluated were total 5-day biochemical oxygen demand (TBOD5) and total suspended solids (TSS) of 30 mg/L each. The report is based on a 5-month laboratory -scale study of the two reactors.

The MBBR performance depended on the percent of media provided in the reactor and the organic loading. At a media volume, which displaced the reactor volume by 40 % (heretofore called 40 % media volume), and surface area loading rate (SALR) of 20 g BOD5/m2-d, the system performance deteriorated with time. At 40 % media volume and SALR below 15 g BOD5/m2-d, the system performance improved but still did not meet effluent criteria or average. TBOD5 reduction was generally poor (approximately 50 %). Soluble BOD5 (SBOD5) concentrations were frequently below 30 mg/L and TSS concentrations were often higher than influent TSS. Overall, TSS wastage from the system (both effluent TSS and intentional wastage) averaged 0.032 kg/d.

BAF system performance was excellent for TBOD5, CBOD5, SBOD5 and TSS removal, and were consistently less that 30 mg/L. Overall TSS wastage from the BAF (both via effluent and backwash) average 0.027 kg/d and was 16 % less than for the MBBR. Based on demonstrated performance, the BAF was the only viable reactor for the project.

Section II of the report focused on possible causes of deposition in an anaerobic digester gas piping at a local wastewater treatment facility (Peppers ferry regional wastewater treatment facility).

Industrial waste input to the treatment facility has increased lately and accounts for 40 % of the plant's wastewater inflow. An industry in Pulaski, VA, Magnox Inc. generates and disposes highly concentrated sodium sulfate, (70,000 mg/L) which is a by-product of its activities, to PFRWTF wastewater influent stream. As a result of Magnox industrial waste input, a pilot study was carried out to determine the effect of its waste on the activated sludge treatment units. Results indicated that Magnox industrial waste input would not have adverse effect on the aeration basins. However production of H2S, which can have effect on the anaerobic digester was reported (Olver Inc., 1995). Field analysis of data reported by Olver Inc. (2000) showed that H2S concentration in PFRWTF anaerobic digester gas was rising. X-ray photoelectron spectroscopy analysis of deposits found in the digester pipe together with results obtained from the laboratory-scale study revealed that iron and sulfur played a role in the deposition in the digester gas pipe. The laboratory scale study revealed that ferrous ion in the digester feed possibly precipitated over 90 % of the hydrogen sulfide gas produced in the digester, thus protecting the digester from adverse effects caused by hydrogen sulfide.

Master of Science

O presente trabalho teve como objetivo avaliar a viabilidade da aplicação de um reator anaeróbio híbrido (RAnH) em escala plena para tratamento de esgoto sanitário, contendo Biobob ® como meio suporte para imobilização celular. O reator possui volume útil igual a 2.495 m3 e foi resultado de uma adaptação de um reator UASB por meio da introdução de 1.000 m3 de material suporte Biobob® em parte do volume reacional do reator, transformando-o em um reator anaeróbio híbrido com leito fixo e manta de lodo. O reator foi monitorado por 480 dias consecutivos, sendo avaliado seu desempenho frente ao aumento gradativo da vazão média e às vazões decorrentes de horários de pico e períodos com elevada pluviosidade. O reator apresentou bom desempenho durante todo o período operacional, mantendo a qualidade do efluente tratado (DQO efluente média de 178 ± 30mg.L-1 e SST de 54 ± 25 mg.L-1) mesmo quando submetido à elevadas cargas hidráulicas proporcionadas por períodos de alta pluviosidade, mostrando-se como uma excelente alternativa para aumento da capacidade de tratamento de reatores UASB sem a necessidade de ampliações físicas no reator. Para um TDH médio de 5,8 h, que corresponde a um período em que houve vários picos de vazão, o reator manteve-se estável durante todo o período, com valores no efluente de DQO e SST de 169 ± 24 mg.L-1 e 47 ± 17 mg.L-1, respectivamente. Aproximadamente 70% do total da biomassa presente no reator encontra-se em suspensão no leito de lodo e 30% encontra-se aderida aos meios suportes, sendo ambas as frações fundamentais para o bom desempenho e estabilidade do tratamento. O rendimento da produção de biomassa observada (Yobs) foi de 0,182 g SSV.g-1 DQOremovida. Considerando-se a carga orgânica removida por meio da DQO bruta afluente e da DQO filtrada efluente, o Y\'obs foi de 0,143 g SSV. g-1 DQOremovida. A produção de lodo (considerando somente o descarte de sólidos pela via convencional ) foi de 0,073 g ST.g-1 DQO aplicada. Ambas as frações de biomassa (suspensa e aderida) apresentaram potencial metanogênico similar para condições com carga orgânica aplicada de 0,57 g DQO. g-1 SVT. A produção de energia elétrica estimada com o reaproveitamento do biogás gerado no RAnH, para a vazão média do período de 7.170 m3.d-1, foi de 31.798 kW.h.mês-1, o equivalente a 10 % do consumo energético mensal atual da ETE. O aproveitamento dessa energia acarretaria em uma economia mensal de R$ 17.170,73.
This study aimed to assess the feasibility of implementing a hybrid anaerobic reactor (HAnR) at full scale for treating wastewater containing Biobob® as a packing material for cell immobilization. The reactor volume is 2,495 m3 and was the result of an adaptation of a UASB reactor by introducing 1,000 m3 of packing material Biobob® in the reaction volume of the reactor, turning it into a hybrid anaerobic reactor with fixed bed and sludge blanket. The reactor was monitored for 480 consecutive days and evaluated their performance with the gradual increase of the average flow and the flow resulting from peak hours and periods of high rainfall. The reactor showed good performance throughout the operational period, maintaining the quality of treated efluente (COD effluent of 178 ± 30 mg. L-1 and TSS 54 ± 25 mg. L-1) even when subjected to high hydraulic loads provided by rainy periods, showing up as an excellent alternative to increase the UASB treatment capacity without the need for expansion physical the reactor. For an average HRT of 5.8 h, which corresponds to a period in which there were several peaks flow, the reactor remained stable throughout the period, with values in the effluent COD and TSS of 169 ± 24 mg.L-1 and 47 ± 17 mg.L-1, respectively. Approximately 70% of the total biomass present in the reactor was in suspension in the sludge bed and 30% adhered to the support material, and both fractions fundamental to the performance and stability of the treatment. The observed yield of biomass production (Yobs) was 0.182 g CODr.VSS.g-1. Considering the organic load removed by the total COD of influent and effluent COD filtered, the Y\'obs was 0.143 g CODr.VSS.g-1. The sludge production (considering only the disposal of solid by conventional means) was 0.073 g COD.TS.g-1 .Both biomass fractions (suspended and attached) have similar potential to methanogenic conditions with organic load of 0.57 g COD.g-1 SVT. The production of electricity estimated to reuse biogas generated in HAnR, for the average flow of the period 7,170 m3.d-1, was 31,798 kW.h.mês-1, equivalent to 10% of the current monthly energy consumption in the sewage treatment plant. The use of this energy would result in a monthly savings of R$ 17,170.73.

A princípio, foram realizados ensaios de enriquecimento em reatores em batelada, sob agitação, para avaliar a melhor condição nutricional, meio Beller ou meio Zinder, para crescimento microbiano e remoção de sulfato. Posteriormente, esta melhor condição nutricional foi usada para crescimento microbiano e remoção de etanol, tolueno e benzeno em ensaios contínuos em dois reatores anaeróbios horizontais de leito fixo (RAHLF), sob condições de redução de sulfato. Os sistemas foram inoculados com lodo de reator anaeróbio de fluxo ascendente e manta de lodo tratando águas residuárias provenientes de abatedouro de aves. Os RAHLF consistiram de biomassa imobilizada em espumas de poliuretano submetidas a concentrações de 91 e 550 mg/l de sulfato ferroso e sulfato de sódio, respectivamente, para promoção de ambiente sulfetogênico. Tolueno e benzeno foram adicionados, separadamente nos reatores, em concentrações iniciais de 2,0 mg/l, seguidas de aumentos que variaram até as concentrações finais de 9 e 10 mg/l, para tolueno e benzeno, respectivamente. O etanol foi adicionado em ambos reatores a concentração inicial de 170 mg/l, seguido de aumento de até 960 mg/l. Os reatores foram operados a 30 (± 2) ºC com tempo de detenção hidráulica de 12 h. A eficiência na remoção da matéria orgânica nos dois reatores foi próxima a 90% com taxa máxima de degradação de tolueno de 0,06 mg tolueno/mg ssv.d, e 0,07 mg benzeno/mg ssv.d, para benzeno. A redução de sulfato foi de 99,9% em todas as condições nutricionais nos dois reatores. A caracterização microscópica do biofilme revelou diversas morfologias e o perfil de DGGE mostrou variação nas populações de BRS e de representantes do Domínio Bacteria em geral, o que foi associado com as crescentes concentrações de tolueno e benzeno nos meios de alimentação. Finalmente, o presente trabalho demonstrou que unidades compactas de RAHLF, sob condições sulfetogênicas, oferecem alternativa para a biorremediação in situ de compostos aromáticos.
Previously, enrichment assays in batch reactors were used to evaluation of best nutritional condition, Beller or Zinder medium, to microorganism growth and sulfate removal. Further, the chosen nutritional condition was used in two horizontal-flow anaerobic immobilized biomass (HAIB) reactors under sulphate-reducing condition, which were exposed to different amounts of ethanol, toluene and benzene. The systems were inoculated with sludge taken from up-flow anaerobic sludge blanket (UASB) reactors treating refuses from a poultry slaughterhouse. The HAIB reactors comprised of an immobilized biomass on polyurethane foam and ferrous and sodium sulphate solutions were used (91 and 550 mg/L, respectively), to promote a sulphate-reducing environment. Toluene and benzene were added at an initial concentration of 2.0 mg/L followed by an increased range of different amendments. Ethanol was added at an initial concentration of 170 mg/L followed by an increased range of 960 mg/L. The reactors were operated at 30 (± 2) °C with hydraulic detention time of 12 h. Organic matter removal efficiency of 90%, in both systems, with a maximum toluene degradation rate of 0.06 mg toluene/mg vss.d and with a maximum benzene degradation rate of 0.07 mg benzene/mg vss.d. Sulfate reduction was dose to 99.9% for all-nutritional amendments in both systems. Biofilm microscopic characterization revealed a diversity of microbial morphologies and DGGE-profiling showed a variation of bacterial and sulphate reducing bacteria (SRB) populations, which were, significantly, associated with toluene and benzene amendments. Thus, this work demonstrates that compact units of HAIB reactors, under sulphate reducing conditions, are a potential alternative for in situ aromatic compounds bioremediation.

La digestion anaérobie est utilisée depuis près d’un siècle comme un traitement efficace des déchets organiques. L’intérêt de ce traitement en anaérobie est en essor, car il présente des avantages significatifs sur les traitements alternatifs biologiques et d’autres options d’élimination des déchets. Cette étude se focalise sur l’optimisation du processus de digestion anaérobie en utilisant deux stratégies différentes. La première vise à augmenter la biodégradabilité du substrat par un prétraitement thermique. La seconde technique repose sur l’utilisation d’un système de biofilms pour augmenter le taux de production de biogaz et minimiser la taille du réacteur.Les déchets alimentaires sont principalement utilisés comme substrat modèle de par leur composition, leur abondance et leur renouvellement. Dans ces travaux de thèse, l’influence de la température des prétraitements thermiques sur la solubilisation de la matière organique, ainsi que la production de méthane des déchets alimentaires sous différentes conditions ont été étudié. Une amélioration significative de la solubilisation et de la biodégradabilité des déchets alimentaires ont été observés pour tous les prétraitements thermiques sur les déchets alimentaires comparativement aux déchets non traités. La plus importante amélioration (28%) de la biodégradabilité a été observée pour les déchets alimentaires traités à la plus basse température de prétraitements (80°C). Les résultats montrent une corrélation forte entre le type de substrats (carbohydrate, protéines et teneur en lipides), la température de prétraitement thermique et son efficacité dans l’amélioration de la biodégradabilité.Dans une seconde partie, une opération prolongée d’un système intégré à deux étages, incluant une cuve agitée en continu et un réacteur à biofilm anaérobie a été réalisé pour produire du biohytane (biohydrogène et méthane) à partir de déchets alimentaires. Le réacteur à biofilm anaérobie a été utilisé pour remédier au lessivage de la biomasse du réacteur. La formation d’une biomasse mature et équilibrée a amélioré de façon importante la stabilité du processus, ce dernier n’ayant pas été affecté par un raccourcissement du temps de rétention hydraulique (HRT) de 6 à 3,7 jours dans le premier réacteur, et de 20 à 1,5 jours dans le second réacteur. De plus, le système à deux étages, constitué d’un pilote à l’échelle d’un batch pour la fermentation sombre et d’un réacteur à biofilm anaérobie, coproduisant de l’hydrogène et du méthane à partir de la fraction organique des déchets solide ménagers (OFMSW), a été utilisé afin de déterminer la capacité d’un réacteur à biofilm anaérobie à supporter un choc de charge organique. Les résultats montrent une récupération plus rapide du réacteur à biofilm anaérobie après un évènement de charge organique
Anaerobic digestion (AD) has been used over a century for an effective treatment of organic wastes. Interest in anaerobic treatment is continually increasing since it presents significant advantages when compared to alternative biological treatments and waste disposal options. This research study was mainly focused on optimization of the AD process, that was achieved through two different strategies. The first aimed at increasing the substrate biodegradability by a means of thermal pretreatment. The second was focused on the application of a biofilm based system to improve the biogas production rates and minimize the reactor size.Food waste (FW) was mainly used as a model substrate due to its suitable composition, abundance and renewability. In this thesis the influence of thermal pretreatment temperature on organic matter solubilization and methane yield of FW under different operational conditions was investigated. Significant improvement of the FW solubilization and biodegradability were observed for all thermally pretreated FW compared to the untreated FW. The highest biodegradability enhancement, i.e. + 28 %, was observed for FW treated at the lowest thermal pretreatment temperature, i.e. 80 ⁰C. The results showed a strong correlation between the substrate type (e.g. carbohydrate, protein and lipid content), the thermal pretreatment temperature and its effectiveness in promoting the biodegradability.In the second part of the work, a prolonged operation of an integrated two-stage system, including a continuously stirred tank and an anaerobic biofilm reactor, was carried out to produce biohythane (biohydrogen and methane) from the FW. The anaerobic biofilm reactor was employed to overcome the biomass wash-out from the reactor. The formation of a well-matured and balanced AD biomass greatly improved the process stability, which was not affected by shortening the hydraulic retention time (HRT) from 6 to 3.7 days in the first reactor and from 20 to 1.5 days in the second reactor. Moreover a two-stage system, comprised of a pilot scale batch dark fermenter and an anaerobic biofilm reactor co-producing hydrogen and methane from the organic fraction of municipal solid waste (OFMSW), was used to assess the capability of the anaerobic biofilm reactor to face an organic shock loads. The results showed a faster recovery of anaerobic biofilm reactor performance after the shock load events

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Universidade Federal de Sao Carlos
Hydrogen is a clean and renewable source of energy and it is considered the "fuel of the future", because it produces only water during combustion and when it is used as fuel and hydrogen has a high energy yield of 122 kJ/g, which is 2.75 times greater than hydrocarbon fuels. The hydrogen production using microorganisms is a promising area of technological development from a wide variety of renewable and a alternative for this production is to use the anaerobic fluidized bed reactor (AFBR), a promising reactor for hydrogen production. One of the factors that most influence the performance of AFBR is the support material, which should provide resistance to abrasion, porous surface conducive to colonization by microorganisms, easy fluidization to reach and ability to facilitate the transfer of mass between the middle and biofilm. Thus, the objective of this study was to evaluate the influence of different support materials (polystyrene - R1, ground tire - R2 and PET - R3) for the hydrogen production, using three AFBR. Each reactor had a total volume of 4192 cm3, which was used as carbon source 4000 mg.L-1 of glucose, with pH influent around 7.0 and pH effluent of around 5.5, with hydraulic retention time (HRT) between 8 and 0.5 h, with temperature of 30 o C } 1, with heat treatment of the inoculum. The best performance was R2, giving better hydrogen yield production (HY) (2.15 mol-H2.mol-1-glucose), best H2 content in the biogas (52.97%) and showed a higher glucose conversion (90%). However, the R3 was better in the hydrogen production rate (HPR), 1.07 lh-1.L-1, a secondary parameter in the analysis of performance of the reactors. In all reactors, the production volume of hydrogen and H2 content in biogas increased with the reduction of the TDH, 8 pm to 1 HEO yield of hydrogen production increased with the reduction of the TDH, 8 h for 2 h. The major soluble metabolites during H2 fermentation were acetic acid (HAc), butyric acid (HBu), lactic acid (HLa) and ethanol (EtOH), and a small production of propionic acid and R2 was the reactor that more produced HAc and HBu (42.0% e 36.5%, respectively) . The better performance of R2 can be explained by the roughness of ground tire is larger than the other materials used, accumulating a large quantity of attached biomass, and a greater quantity of bacteria hydrogen producing. There was a predominance of bacilli like Clostridium sp. in the biofilm of all support materials.
O hidrogenio e uma fonte de energia limpa e renovavel e e considerado o combustivel do futuro , pois gera somente agua durante sua combustao e apresenta calor de combustao de 122 kJ.g-1, o que representa 2,75 vezes mais conteudo de energia do que qualquer hidrocarboneto. A producao de hidrogenio usando microrganismos e uma promissora area de desenvolvimento tecnologico a partir de uma ampla variedade de fontes renovaveis e uma das alternativas para esta producao e a utilizacao do reator anaerobio de leito fluidizado (RALF). Um dos fatores que mais influenciam o desempenho do RALF e o material suporte, que deve apresentar resistencia a abrasao, superficie porosa favoravel a colonizacao de microrganismos, facilidade para alcancar a fluidizacao e capacidade de favorecer a transferencia de massa entre o meio e o biofilme. Desta maneira, o objetivo deste trabalho foi avaliar a influencia de diferentes materiais suporte (poliestireno - R1, pneu inservivel triturado - R2 e PET - R3) na producao de hidrogenio utilizando tres reatores anaerobios de leito fluidizado. Cada reator possuia um volume total de 4192 cm3, alimentado com meio contendo glicose como fonte de carbono (4000 mg.L-1), com pH afluente em torno de 7,0 e efluente em torno de 5,5, com tempo de detencao hidraulica (TDH) entre 8 e 0,5 h a uma temperatura de 30oC } 1oC, com tratamento termico do inoculo. O melhor desempenho foi do R2, apresentando melhor rendimento de H2 (2,15 mol-H2.mol-1-glicose), melhor conteudo de H2 no biogas (52,97%) e maior conversao de glicose (90%). Entretanto, o R3 foi melhor na producao volumetrica de H2, 1,07 L.h-1.L-1, um parametro secundario na analise de desempenho dos reatores. Em todos os reatores, a producao volumetrica de hidrogenio e o conteudo de H2 no biogas aumentaram com a reducao do TDH de 8 h para 1 h e o rendimento de producao de hidrogenio aumentou com a reducao do TDH de 8 h para 2 h. Os metabolitos soluveis predominantes em todos os reatores foram acidos acetico, butirico, latico e etanol, havendo uma pequena producao de acido propionico, sendo o R2 o que mais produziu acidos acetico e butirico (42,0% e 36,5%, respectivamente). O melhor desempenho do R2 pode ser explicado pela rugosidade do pneu triturado ser maior do que a dos demais materiais empregados, acumulando uma maior quantidade de biomassa aderida e uma maior quantidade de bacterias acidogenicas produtoras de hidrogenio. Houve predominancia de bacilos semelhantes a Clostridium sp. no biofilme de todos os materiais suporte.

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Universidade Federal de Sao Carlos
Hydrogen and ethanol production using microorganisms is a promising area of technological development from a wide variety of renewable and alternative to this production is the use of anaerobic fluidized bed reactor (AFBR). One of the factors that most influence the performance of the AFBR is the material support, which must provide abrasion resistance, porous surface conducive to colonization by microorganisms, easy to achieve fluidization and ability to promote mass transfer between the medium and biofilm. Thus, the objective of this study was to evaluate the influence of different support materials (polystyrene - R1, grounded tire - R2 and polyethylene terephthalate (PET) - R3) on producing hydrogen and ethanol using three anaerobic fluidized bed reactors. Each reactor had a total volume of 4192 cm3 and was fed with media containing glucose as the carbon source (4000 mg L-1) with an influent pH around 5.0 and an effluent pH of about 3.5, a hydraulic retention time (HRT) of 8 1 h at a temperature of 23 2 ºC, with thermal treatment of the inoculum. For hydrogen production, the best performance was achieved with R2 (2.11 mol H2 mol-1 glucose), providing the highest H2 content in biogas (60%). In all reactors, the predominant soluble metabolites were acetic acid, butyric acid, lactic acid and ethanol, with small amounts of propionic acid. The reactor R2 produced more acetic and butyric acid (434.74 and 1013.61 mg L-1, respectively). However, reactor R3 showed a better performance for ethanol production (1941.78 mg L-1).
A produção de hidrogênio e etanol usando microrganismos é uma promissora área de desenvolvimento tecnológico a partir de uma ampla variedade de fontes renováveis e uma das alternativas para esta produção é a utilização do reator anaeróbio de leito fluidizado (RALF). Desta maneira, o objetivo deste trabalho foi avaliar a influência de diferentes materiais suporte (poliestireno - R1, pneu inservível triturado - R2 e PET - R3) visando à produção de hidrogênio e etanol utilizando três reatores anaeróbios de leito fluidizado. Cada reator possuía um volume total de 4192 cm3, alimentado com meio contendo glicose como fonte de carbono (4000 mg.L-1), com tempo de detenção hidráulica (TDH) entre 8 e 1 h a uma temperatura entre 20 e 25ºC, com tratamento térmico do inóculo, utilizando culturas mistas. Para produção de hidrogênio, o melhor desempenho foi do R2, apresentando melhor rendimento de H2 (2,11 mol-H2.mol-1-glicose) e melhor conteúdo de H2 no biogás (60%). Os metabólitos solúveis predominantes em todos os reatores foram ácidos acético e butírico e etanol, havendo uma pequena produção de ácido propiônico, sendo o R2 o que mais produziu ácidos acético e butírico (434,74 e 1013,61 mg/L, respectivamente). Entretanto, o R3 apresentou um melhor desempenho para produção de etanol (2,43 mol-EtOH.mol-1-glicose). Assim, pode-se afirmar que foi possível produzir simultaneamente hidrogênio e etanol como biocombustíveis.

Succinic Acid (SA) was continuously produced using glucose and a Mg2CO3(OH)2 slurry as feed. Glucose feed concentrations of 20 and 40 g ℓ-1 were employed with corresponding Mg2CO3(OH)2 slurry concentrations of 60 and 120 g ℓ-1. The reactor pH was passively maintained between 6,4 and 6,8 by the buffer properties of the slurry in conjunction with the pH adjusted glucose feed. The suspended cell (SC) reactor was operated at 37°C with dilution rates varying between 0,04 h-1and 0,6 h-1. Groperl® particles were used as inert supports in the biofilm reactor; dilution rates of 0,11 h-1 to 1 h-1 were investigated. Two SC fermentations were conducted for the 20 g ℓ-1 glucose feed concentration and one for the 40 g ℓ-1. All SC fermentation runs were operated in excess of 12 days, while the biofilm run lasted 6,5 days. Fermentations were terminated only after contamination by lactic acid bacteria was observed. SC fermentations with the glucose feed concentration of 20 g ℓ-1 achieved a maximum SA productivity of 5,2 g ℓ-1h-1 at 0,6 h-1 with a corresponding SA yield of 0,65 g g-1. SC fermentations with the glucose feed concentration of 40 g ℓ-1 achieved a maximum SA productivity of 3,76 g ℓ-1h-1 at 0,4 h-1 with a SA yield of 0,82 g g-1. The results were comparable to the other continuous studies with Actinobacillus succinogenes, despite the fact that either biofilms or membranes were employed in these studies. The preliminary biofilm study demonstrated the capability of A. succinogenes to produce SA in high productivities and yields. SA productivities and yields for the dilution rates of 0,33 h-1 and 1,0 h-1, were 5,72 g ℓ-1h-1 (0,95 g g-1) and 12 g ℓ-1h-1 (1,0 g g-1), respectively. The biofilm reactor at 0,33 h-1 achieved twice the SA productivity of the SC reactor at 0,3 h-1 with a 42 % increase in SA yield. Copyright
Dissertation (MEng)--University of Pretoria, 2012.
Chemical Engineering
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