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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.
41

Microbial community analysis of a UASB reactor and application of an evolutionary algorithm to enhance wastewater treatment and biogas production

Enitan, Abimbola Motunrayo January 2015 (has links)
Submitted in complete fulfillment for the degree of Doctor of Philosophy (Biotechnology), Durban University of Technology, Durban, South Africa, 2015. / Anaerobic digestion, a proven and highly efficient biological process for treating industrial wastewater and biogas generation is an underutilized technology in South Africa. Some of the industries that have on-site anaerobic reactors tend to face problems in operating these reactors due to poor understanding of the process and implementation of the technology. This has resulted in high pollutant loads in their final effluents and low energy recovery. In this study, an on-site full–scale upflow anaerobic sludge blanket (UASB) reactor treating brewery wastewater was extensively monitored in order to evaluate the efficiency in terms of effluent quality, biogas production and microbial structure. Furthermore, developed and adopted kinetic models were used to optimize the performance of the full–scale UASB reactor using a combined Pareto differential evolution (CPMDE) algorithm. A preliminary analysis of the raw wastewater has shown that the wastewater produced from the brewery industry was high in organic matter with a total chemical oxygen demand (COD) between 1096.41 to 8926.08 mg/L. The average removal efficiency of COD from the UASB reactor after treatment was 79% with a methane (CH4) production of 60-69% at temperature ranges of 28-32˚C and hydraulic retention time (HRT) of 12 h within the optimal pH range for anaerobic bacteria (6.6 and 7.3) under various organic loading rates. However, the results also showed an increase in total suspended solids (TSS), nitrogen (N2), ammonia (NH3) and orthophosphate concentrations when comparing the influent to the effluent, which indicated the necessity for further optimization of the reactor condition in order to reduce these effluent parameters to acceptable standards and to increase CH4 production. In order to optimize the process, a thorough understanding of microbial interaction was essential. A combination of different molecular techniques viz., fluorescence in–situ hybridization (FISH), polymerase chain reaction (PCR) and quantitative real-time PCR (QPCR) were employed to understand the microbial community structure of the granular sludge samples using species specific primers and probes. The results revealed that the dominance of diverse groups of eubacteria belonging to phyla Proteobacteria, Firmicutes and Chloroflexi and an uncultured candidate division WS6 with four different orders of methanogenic Archaea viz., Methanomicrobiales, Methanococcales, Methanobacteriales and Methanosarcinales belonging to hydrogenotrophic and aceticlastic methanogens were within the reactor samples. Quantification of the 16S rDNA copies of eubacteria and methanogenic Archaea using species-specific primers further confirmed the spatial distribution of these microorganisms within the different compartments of the reactor where, the upper compartments were dominated by eubacteria and the lower compartments by methanogenic Archaea. The concentration of Archaea per nanogram of DNA was much higher (96.28%) than eubacteria (3.78%) in lower compartments, while, the eubacteria concentration increased to 98.34% in upper compartments with a decrease in Archaea quantity (1.66%). A modified kinetic methane generation model (MMGM) was developed on the basis of mass balance principles with respect to substrate (COD) degradation and the endogenous decay rate to predict CH4 production efficiency of the reactor. Furthermore, a Stover–Kincannon kinetic model was adopted with the aim of predicting the final effluent quality in terms of COD concentration and model coefficients were determined using the data collected from the full–scale reactor. Thereafter, a model-based multi-objective optimization was carried out using the CPMDE algorithm with three–objective functions namely; maximization of volumetric CH4 production rate; minimization of effluent substrate concentration and minimization of biomass washout, in order to increase the overall efficiency of the UASB reactor. Important decision variables and constraints related to the process were set for the optimization. A set of non-dominated solutions with high CH4 production rates of between 2.78 and 5.06 L CH4/g COD/day at low biomass washout concentrations were obtained at almost constant solution for the effluent COD concentration. A high COD removal efficiency (85-87%) at ~30-31˚C and 8-9 h HRT was obtained for the multi-objective optimization problem formulated. This study could significantly contribute towards optimization of a full–scale UASB reactor treating brewery wastewater for better effluent quality and biogas production. Knowledge on the activity and performance of microbial community present in the granular sludge taken from the full–scale UASB reactor would contribute significantly to future optimization strategies of the reactor. In addition, optimization using an evolutionary algorithm under different operational conditions would help to save both time and resources wasted in operating anaerobic bioreactors.
42

Estudo do desempenho de reator anaeróbio-aeróbio de escoamento ascendente no tratamento de esgoto sanitário com espuma de poliuretano como suporte de imobilização da biomassa / Study on the performance of an anaerobic-aerobic upflow reactor in the treatment of wastewater using polyurethane foam as a support for biomass immobilization

Abreu, Sergio Brasil 27 June 2003 (has links)
O projeto consistiu na concepção e avaliação do desempenho de um sistema anaeróbio-aeróbio para tratamento de esgoto sanitário. O leito do reator foi dividido em quatro compartimentos de igual volume. Foi usada espuma de poliuretano para imobilização da biomassa e, para facilitar a partida do reator, esse material suporte foi previamente inoculado. O projeto teve três fases distintas: na primeira etapa, foi observada a importância da concentração de biomassa anaeróbia no desempenho de reator anaeróbio a princípio operado com metade do leito reacional com espuma e, a seguir, com o leito todo preenchido com espuma. Na segunda etapa, foram testados diferentes tempos de detenção hidráulica no reator que operou apenas em condições anaeróbias. Na última etapa foi operado o reator combinado anaeróbio-aeróbio. Ficou constatada a importância da concentração de microrganismos no desempenho do reator anaeróbio, pois com o aumento da quantidade de espuma, o reator atingiu resultados melhores e maior estabilidade operacional. Foi comprovada a influência do tempo de detenção hidráulica (TDH) no desempenho do reator. Tempos de detenção muito altos acarretam problemas de transferência de massa líquido-sólido, e baixos TDH dificultam adequada ação dos microrganismos. O melhor resultado para o reator em operação exclusivamente anaeróbia foi para o TDH de 10 horas, no qual se conseguiu reduzir a DQO de amostra bruta de 389 +/- 70 mg/L para 137 +/- 16 mg/L, em média. Para o reator operado anaeróbio-aeróbio a DQO de amostra bruta decresceu de 259 +/- 69 mg/L para 93 +/- 31 mg/L, em média. A comparação de todos os resultados obtidos, evidenciou a importância do pós-tratamento aeróbio na remoção de parcela de matéria orgânica não removida em tratamento unicamente anaeróbio. / The project consisted in the design and performance evaluation of an anaerobic-aerobic system for wastewater treatment. Polyurethane foam was used for biomass immobilization and, to smooth the reactor start-up, this supporting material was previously inoculated. The project was divided in three distinct phases. In the first one, the importance of the anaerobic biomass concentration was observed in the performance of the anaerobic reactor in a way to operate the reactor primarily with half of the reaction bed filled with foam and subsequently operate it with the bed completely filled with foam. In the second phase, different times of hydraulic retention were tested with the reactor operating exclusively in anerobic conditions. In the third and last phase, an anaerobic-aerobic combined reactor was operated. It was possible to confirm the importance of microorganism concentration in the performance of the anaerobic reactor, since the increase in the amount of foam allowed the reactor to reach better results and greater operational stability. The influence of the hydraulic retention time in the reactor performance was also proved. Very high retention times cause problems in the liquid-solid mass transference, while low retention times do not allow an adequate action of microorganisms. The best result for the reactor with an exclusive anaerobic operation was the 10 hour retention time, when it was possible to reduce the COD of a 389 +/- 70 mg/L gross sample to a 137 +/- 16 mg/L in average. On the other hand, for the anaerobic-aerobic operating reactor, the COD of a gross sample dropped from 259 +/- 69 mg/ L to 93 +/- 31 mg/L in average. Finally, comparing all the obtained results, it was possible to verify the importance of the anaerobic post treatment in the removal of a part of the organic matter not removed in an exclusively anaerobic treatment.
43

Produção de hidrogênio em reator anaeróbio de leito fixo e fluxo ascendente a partir de água residuária de indústria de refrigerantes / Hydrogen production by an upflow anaerobic packed-bed reactor using soft-drink wastewater

Peixoto, Guilherme 28 April 2008 (has links)
Este trabalho teve como objetivo a produção de hidrogênio em reator anaeróbio de leito fixo com fluxo ascendente utilizando-se efluente de indústria de refrigerantes. Os resultados obtidos demonstraram que a água residuária semi-sintética simulando efluente de indústria de refrigerantes tem um bom potencial de geração de hidrogênio. Dados da operação dos dois reatores utilizados mostraram que o maior rendimento foi alcançado pelo reator operado sem a adição de meio contendo nutrientes (R2), pois este foi capaz de atingir 4,2 mol \'H IND.2\'/mol de substrato em contraste com 2,5 mol \'H IND.2\'/mol de substrato, obtida pelo reator (R1), cujo afluente continha suplementação nutricional. Constatou-se que o reator operado sem adição de nutrientes (R2) apresentou continuidade na produção de hidrogênio, fato que não ocorreu com o reator R1, que exibiu uma produção efêmera e significativamente inferior. O melhor desempenho na velocidade de produção de hidrogênio e porcentagem do mesmo na composição do biogás também foi observado para o reator R2, que atingiu 0,52 L/h.L e 18,9% de \'H IND.2\' contra 0,28 L/h.L e 2,1% de \'H IND.2\' obtidos pelo reator com suplementação nutricional (R1). Após esta primeira etapa comparativa em que os reatores foram operados simultaneamente com TDH teórico de 0,5 h, prosseguiu-se apenas com a operação do reator R2, porém com tempo de detenção hidráulica teórico de 1 h, o que induziu uma maior conversão do substrato a ácidos e álcoois, mudou as características hidrodinâmicas do leito e afetou negativamente a produção de hidrogênio. / This work was aimed on hydrogen production in an upflow anaerobic packed-bed reactor fed with soft-drink wastewater. The results obtained show that the semisynthetic soft-drink wastewater has a good hydrogen generation potential. Data obtained from the operation of both reactors indicated that the reactor operated without the addition of medium containing macro and micronutrients (R2) provided higher hydrogen yield (4,2 mol \'H IND.2\'/mol of substrate) as compared to the reactor (R1) operated with the addition of nutrient medium, which achieved lower hydrogen production yield (2,5 mol \'H IND.2\'/mol of substrate). It was observed that the reactor operated without the addition of nutrients (R2) showed continuous hydrogen production, while the reactor R1 exhibited a short period of production and lower amounts of hydrogen. Better hydrogen production rate and percentage in the biogas were also observed for the reactor R2, which achieved 0,52 L/h.L and 18,9% of \'H IND.2\' against 0,28 L/h.L and 2,1% of \'H IND.2\' obtained by the reactor with nutrient addition (R1). After operation with HDT of 0,5 h, the reactor R2 was operated with theoretical HDT of 1 h. Under this condition, the substrate was mainly converted to acids and solvents, negatively affecting the hydrogen production and the hydrodynamic pattern of the reactor.
44

Avaliação da dupla filtração para tratamento de água superficial utilizando filtração ascendente em areia grossa / Evaluation of double filtration systems for treatment of surface water using direct upflow filtration in coarse sand

Paula, Donizeti de 08 August 2003 (has links)
Este trabalho consiste na avaliação do desempenho de uma instalação piloto de dupla filtração no tratamento de água superficial, apresentando turbidez entre 8,5 e 21 uT. A instalação piloto constituída de um sistema de filtração de duas fases, com filtração direta ascendente em areia grossa seguida da filtração rápida descendente em areia fina. A taxa de filtração variou de 120 a 360 m3/m2.dia no filtro ascendente e de 200 a 400 m3/m2.dia no filtro ascendente. Foram executadas descargas de fundo intermediários no filtro ascendente durante a carreira de filtração para avaliar a instalação piloto. Além disso, simulou pico de turbidez, para avaliar as condições. Baseado no trabalho experimental concluiu-se que: (i) a eficiência global do sistema de dupla filtração ascendente em areia grossa foi satisfatória, apresentando efluente final com turbidez inferior a 1 uT e cor verdadeira inferior a 1 uH; (ii) a distribuição da perda de carga nas camadas do meio granular do FAAG não apresentou diferenças significativas para as variadas taxas de filtração e modo de operação (com e sem execução de DIFs); (iii) os ensaios que foram realizados com a execução de DIFs apresentaram carreiras de filtração mais longas. / This work concerns the study of the performance of a double filtration pilot plant whom treating surface water, presenting turbidity between 8,5 and 21,0 NTU. The pilot plant consisted of a two-stage filtration system, with an upflow coarse sand direct filtrer followed by a dowflow fine sand filter. Filtration rats varied from 120 to 360 m/day in the upflow filter and from 200 to 400 m/day in the downflow filter. Intermediate downflow in the upflow filter were performed during the run length do evaluate the performance of the pilot plant in addition, a peak of turbidity in the for influent selected filter operating varabile, was studied here in. Based on the experimental work carried out, it was concluded that: (i) the global efficiency of the system of double filtration with upflow filtration in coarse sand was satisfactory, presenting final efflents with inferior turbidity to 1,0 NTU and inferior true color to 1 uH; (ii) the distribution of the load loss in the layers of the granular middle of FAAG didn\'t present significant differences for the varied filtration taxes and operation way (with and without execution of DFIs); (iii) the rehearsals that were accomplished with the execution of DFIs presented longer filtration runs.
45

AVALIAÇÃO DA INFLUÊNCIA DO MATERIAL SUPORTE E CARACTERIZAÇÃO DA DIVERSIDADE MICROBIANA DE REATORES ANAERÓBIOS PARA O TRATAMENTO DE EFLUENTE DE ABATEDOURO

Stets, Maria Isabel 12 March 2008 (has links)
Made available in DSpace on 2017-07-21T18:53:09Z (GMT). No. of bitstreams: 1 Maria Isabel Stets.pdf: 1158333 bytes, checksum: c7c568acfaf2daf456026f86016faf6b (MD5) Previous issue date: 2008-03-12 / The effluent generated in abattoirs has a high concentration of organic matter and need treatment before being discarded in the water bodies. Anaerobic biological filters are considered a good technique for the treatment of industrial effluents; however, choosing the correct support media is extremely important to ensure the success of the reactor. In the same way, the study of microbial diversity can optimize the performance and the operation of these systems. In this work it was evaluated the efficiency of the treatment of the effluent from slaughterhouse, using three upflow anaerobic biological filters, and it was compared the microbial diversity of these filters. The reactor called A, B and C were built in chloride polivinile and filled with rings of polypropylene, polyurethane foam, or pieces of clay brick, respectively. These reactors were operated at room temperature and the used Hydraulic Retention Times of (HRTs) were of 30, 20, 18, 14, 10, 8, 6, 5, 4, 3, 2, 1.5 and 1 day. To monitor the efficiency of the process, the pH, alkalinity, acidity, Chemistry Oxygen Demand (COD), and total solids content of volatile solids, nitrogen and phosphorus substrate and effluents of each reactor were analyzed. The values of pH decreased with the reduction of HRT and the ratio volatile acidity / alkalinity remained below 0.13 during the majority of the analyzed period. In the one day’s HRT, the reactor C was more effective reaching 80.76 of removal. There was a high rate of nitrogen removal probably due to its low concentration in the substrate. High phosphorus removals also occurred: there was a decrease of phosphorus removal when the HRT declines in reactors A and B, the same did not occur in the reactor C. The three reactors behaved similarly regarding to the collecting sites and there was no difference between these sites when COD removal, volatile acidity / alkalinity ratio and pH were analyzed. To evaluate the effect of different media support in the microbial community, the reactors DNA biomass was extracted, quantified and used as template in an amplification reaction of 16S rDNA gene from bacteria and metanogenic. The amplified fragments of approximately 1500 bp were treated with HinfI, RsaI and HaeIII restriction enzymes to obtain the reactors ARDRA (Amplified Ribossomal DNA Restriction Analysis) profiles. The indices of richness, richness modified, Shannon-Weaver diversity index and similarity dendogram, determined from ARDRA, grouped the reactors A and B, and left the reactor C isolated due to its dissimilarity. The Hierarchical Cluster Analysis (HCA) also grouped the reactors that way, however, that group has less than 0.1% of similarity, suggesting a low interference in the reactors media support in microbial communities. / O efluente gerado em abatedouros possui uma elevada concentração de matéria orgânica e necessita de tratamento antes de ser descartado nos corpos hídricos. Os filtros biológicos anaeróbios são considerados uma boa técnica para tratamento de efluentes industriais, porém, a escolha correta do meio suporte é extremamente importante para garantir o sucesso do reator. Da mesma forma, o estudo da diversidade microbiana pode otimizar o desempenho e a operação desses sistemas. Neste trabalho, foi realizada a avaliação da eficiência do tratamento de efluente de abatedouro, utilizando-se três filtros biológicos anaeróbios de fluxo ascendente, bem como a comparação da diversidade microbiana desses filtros. Os reatores denominados A, B e C foram construídos em cloreto de polivinila e preenchidos com anéis de polipropileno, espuma de poliuretano ou pedaços de tijolo de argila, respectivamente. Esses reatores foram operados à temperatura ambiente e os Tempos de Retenção Hidráulica (TRHs) utilizados foram de 30; 20; 18; 14; 10; 8; 6; 5; 4; 3; 2; 1,5 e 1 dia. Para monitorar a eficiência do processo, foram analisados no substrato e efluente de cada reator pH, alcalinidade, acidez, Demanda Química de Oxigênio (DQO), teor de sólidos totais e sólidos voláteis, nitrogênio efósforo. Os valores de pH do efluente dos reatores decresceram com a redução do TRH. A relação acidez volátil/alcalinidade ficou abaixo de 0,13 durante a maior parte do período analisado. No TRH de 1 dia o reator C foi o mais eficiente alcançando 80,76 de remoção de DQO. Observou-se uma elevada taxa de remoção de nitrogênio em todos os reatores provavelmente devido à sua baixa quantidade no substrato. Também ocorreram elevadas remoções de fósforo, mas houve decréscimo dessa remoção com a diminuição do TRH nos reatores A e B, o mesmo não ocorrendo no reator C. Quando se analisaram as amostras retiradas em quatro diferentes alturas dos reatores, observou-se que os três se comportaram de forma similar quanto aos pontos de coleta e não houve diferença entre esses pontos quanto à remoção de DQO, relação acidez volátil/alcalinidade e pH. Para avaliar o efeito dos diferentes meios suporte na comunidade microbiana, o DNA da biomassa dos reatores foi extraído, quantificado e usado como molde numa reação de amplificação do gene 16S rDNA de bactérias e archaeas metanogênicas. Os fragmentos de aproximadamente 1500 pb amplificados foram tratados com as enzimas de restrição HinfI, RsaI e HaeIII para obtenção dos perfis de ARDRA (Análise da Restrição de rDNA Amplificado) dos reatores. Os índices de riqueza, riqueza modificada, diversidade de Shannon-Weaver e dendograma de similaridade, determinados a partir da ARDRA, agruparam os reatores A e B, ficando o reator C isolado devido à sua dessemelhança. A Análise de Agrupamento Hierárquico (HCA) também agrupou os reatores dessa forma, entretanto, esse agrupamento possui menos que 0,1% de similaridade, sugerindo uma baixa interferência do meio suporte nas comunidades microbianas.
46

Enhancement of the biodegradability of grain distillery wastewater to improve upflow anaerobic sludge blanket reactor efficiency

Gie, Lowna-Marie 12 1900 (has links)
Thesis (Msc Food Sc (Food Science))--University of Stellenbosch, 2007. / The distillery industry generates large volumes of heavily polluted wastewater and thus effective wastewater treatment is essential. It has been reported that a chemical oxygen demand (COD) reduction of more than 90% can be achieved when wine distillery wastewater (WDWW) is treated in an upflow anaerobic sludge blanket (UASB) reactor. The first objective of this study was to investigate UASB treatment of WDWW and to try to enhance the efficiency by using ozonation treatments. Secondly, the impact of grain distillery wastewater (GDWW) on UASB granules was determined. The third objective was to determine whether ozonation and enzymatic treatment combinations might improve the biodegradability of GDWW and thus make GDWW more amenable to UASB treatment. It was found that UASB treatment combined with ozonation improved the WDWW treatment efficiency. When diluted WDWW (chemical oxygen demand COD = 4 000 mg.L-1) was ozonated (dose = 47 mg.L-1) in a 50 L venturi circulating contactor system, the COD reduction was 7%. When WDWW was treated in a laboratory-scale UASB reactor (substrate pH = 7.0, COD = 4 000 mg.L-1 and organic loading rate (OLR) = 4.0 kg COD.m-3.d-1), the COD reduction was 92%. When the UASB treatment was combined with either pre- or postozonation, the COD reduction was 94 and 96%, respectively. When UASB treatment was combined with pre- and post-ozonation, a COD reduction of 98% was achieved. The activity of the UASB granules was also found to improve over time, despite the addition of the ozonation treatment. It has been reported that operational problems occur when GDWW is treated in an UASB reactor as a result of the encapsulation of the granules. This was confirmed when granules from a full-scale UASB treating WDWW became encapsulated in a layer after being exposed to GDWW (COD = 4 000 mg.L-1) for 24 d. The results showed that the lipid content of the granules increased from 1.25 to 60.35 mg lipid.g-1 granule over the 24 d exposure period. Therefore, granules exposed to GDWW were encapsulated in a lipid-rich layer and as a result the contact between the GDWW and microbial consortium in the granules was reduced. The operational problems found during the industrial UASB treatment of GDWW were ascribed to the encapsulation of the granules. Combinations of ozonation (dose = 1 476 mg.L-1) generated in a 2 L bubble column and enzymatic treatments (1% FogFreeTM (FF) dosage and 2 d incubation at 35°C) were found to improve the biodegradability of GDWW. This improvement was in terms of lipid reduction in GDWW, granule activity and visual appearance of the encapsulating layer of the granules. The highest lipid reduction (90%), highest granule activity, lowest lipid content of the granules (3.74 ± 0.10 mg.g-1 granule) and best visual appearance were achieved in ozonated GDWW treated with 1% FF, followed by just ozonation. The higher lipid reduction and subsequent higher granule activity were ascribed to the reduction in lipids which resulted in the fact that fewer lipids were available to encapsulate the granules. As a result of the lipid reduction, the granule activity improved and the GDWW was made more amenable to UASB treatment. This study proved that UASB treatment combined with ozonation led to an enhancement of the treatment efficiency of WDWW. It was also found that the cause of the operational problems during UASB treatment of GDWW was as a result of the granules being encapsulated in a lipid-rich layer. It was established that treating GDWW prior to UASB treatment improved the biodegradability of GDWW. The data from the study showed that high lipid reduction in the GDWW directly led to better granule activity, lower granule lipid content and a thinner encapsulating layer. Based on the data from this study, it is recommended that GDWW be ozonated prior to other treatments because it can be done inline and the costs would be lower than that of enzymatic treatments.
47

The combination of UASB and ozone technology in the treatment of a pectin containing wastewater from the apple juice processing industry

Van Schalkwyk, Nico 12 1900 (has links)
Thesis (MSc Food Sc )--Stellenbosch University, 2004. / ENGLISH ABSTRACT: The South African apple juice processing industry is growing rapidly and during the harvesting season the wastewater volumes and organic loads increase significantly with a considerable environmental impact. These larger apple juice processing wastewater (AJPWW) volumes and chemical oxygen demand (COD) loads subsequently lead to faster increases in the organic loading rate (OLR) of an upflow anaerobic sludge bed (UASB) wastewater treatment system and it is necessary to know if the treatment system can handle such drastic increases over short periods. The objective of the study were to evaluate the efficiency of the UASB process in the treatment of an AJPWW; to determine what effect a substrate viscosity increase, based on a pectin calcium gel has on the performance of an UASB system, and to determine what impact ozonation has on the pectin content, gelformation ability and biodegradability of the AJPWW. The ability of the UASB to maintain stability during the apple-processing season was investigated by increasing the OLR from 2.9 to over 14.0 kg COD.m-3.d-1 in 131 days. During this time the COD removal remained constant at 85%, while the pH and alkalinity remained at levels indicative of good reactor stability. It was thus concluded that the UASB reactor could operate successfully during the apple-harvesting season when wastewater volumes and organic loads increase significantly. In the study it was found that the viscosity of the AJPWW, containing 750 mq.L-1 pectin, increased from 8.5 to 47.0 cps after a 312 rnq.L-1 Ca2 + addition. This increased viscosity substrate was then fed to an UASB reactor at an OLR of 15.0 kg COD.m-3.d-1. During a 12 day increased viscosity (47 cps) feeding stage the COD removal decreased from 94 to 11%, while the reactor pH decreased from 7.5 to 4.9. During this period, pectin accumulated in the UASB and led to biomass washout and rapid UASB failure. The possible elimination of pectin by ozonation was thus investigated, and a 77% decrease in pectin content and 76% decrease in gel formation ability occurred after ozonation. The effect of pre- and post-ozonation on the efficiency of the UASB system was subsequently investigated. It was found that a 10 min pre-ozonation decreased the AJPWW COD by 19% and the total suspended content by 36%, while the soluble portion of the total COD was increased from 81.7 to 92.4%. This increase in soluble COD content should lead to increased wastewater biodegradability. The ozonated AJPWW was then used to replaced the raw non-ozonated AJPWW as reactor feed. Results showed that the COD removal increased from 78 to 90% within 24 h of starting with the ozonated feed. It was also found that the reactor stability improved after AJPWW pre-ozonation as an OLR increase from 10.0 to 16.6 kg COD.m-3.d-1 in 23 days did not detrimentally influence the stability of the reactor. This reactor effluent (COD = 465 rnq.L-1) was then post-ozonated which resulted in 64.8% COD and 79.0% colour reductions. The final effluent had a COD of 180 rnq.L-1 (98% reduction). The ability of the ozonation/digestion system as described in this study to degrade AJPWW at a higher OLR is of value to the apple industry, as it may lead to larger organic pollutant removals and thus a more effiecient treatment system. Increased reactor performance will directly improve the quality of the final wastewater produced, which in turn will have a significant impact on the treatment ability of the South African apple processing industry currently limited by the production of large wastewater volumes. / AFRIKAANSE OPSOMMING: Gedurende die oesseisoen word groot volumes afvalwater met 'n hoe organiese lading in die vinnig groeiende Suid-Afrikaanse appelsapprosesseringsbedryf geproduseer. Dit het 'n groot impak op die omgewing. Die groter volumes appelsapprosesseringsafvalwater (ASPAW) met 'n hoë organiese lading het 'n vinniger verhoging in organiese ladingstempo's (OLT) van 'n UASB-waterbehandelingstelsel tot gevolg. Daarom is dit belangrik om te weet of die stelsel die drastiese verhoging oor kort tydperke kan hanteer. Die doel van hierdie studie was die evaluering van die effektiwiteit van die UASB-proses in die behandeling van ASPAW; om te bepaal watter effek 'n substraatviskositeitsverhoging, gebaseer op 'n pektien-kalsium-jel, op die doeltreffendheid van 'n UASB-stelsel het; en om te bepaal watter impak osonering op die pektieninhoud, jelvormingsvermoe en bioafbreekbaarheid van ASPAW het. Die vermoe van die UASB om stabiliteit te handhaaf gedurende die appelsapprosesseringseisoen is ondersoek deur die OLT van 2,9 tot bo 14,0 kg CSB.m-3.d-1 te verhoog oor 131 dae. Gedurende hierdie tyd het die chemiese suurstofbehoefte- (CSB-) verwydering konstant gebly by 85%, terwyl die pH en alkaliniteit ook op vlakke aanduidend van goeie reaktorstabiliteit gebly het. Daar is sodoende bewys dat die UASB-reaktor suksesvol kan presteer tydens die appelsapprosesseringseisoen, wanneer daar 'n beduidende verhoging in OLT plaasvind. In die studie is daar gevind dat die viskositeit van die ASPAW, wat 750 mq.L-1 pektien bevat, van 8,5 tot 47,0 cps toeneem na die byvoeging van 312 rnq.L-1 Ca2+. Hierdie verhoogde vikositeitsubstraat is tot die UASB-reaktor toegevoeg teen 'n OLT van 15,0 kg CSB.m-1.d-1. Gedurende 'n 12-dae toevoer van verhoogde viskositeit (47 cps), het die CSB-verwydering van die reaktor afgeneem van 94% na 11%, terwyl die pH gedaal het van 7,5 na 4,9. Gedurende hierdie tydperk het pektien in die UASB geakkumuleer, wat gelei het tot die uitspoel van biomassa en vinnige UASB-reaktormislukking. Die moontlike eliminasie van pektien, deur osonering, is daarom ondersoek. 'n Verlaging van 77% in pektieninhoud en 76% in jelvormingsvermoe het na osonering plaasgevind. Die effek van pre- en post-osonering op die effektiwiteit van 'n UASB-stelsel is gevolglik ondersoek. Daar is gevind dat 'n 10 minute pre-osonering die CSB van die ASPAW met 19% verlaag en die totale inhoud van gesuspendeerde vaste stowwe met 36% verlaag, terwyl die oplosbare gedeelte van die totale CSB van 81,7% tot 92,4% gestyg het. Die verhoging in oplosbare CSB-inhoud behoort tot verhoogde bioafbreekbaarheid van ASPAW te lei. Die geosoneerde ASPAW is gebruik om die rou, ongeosoneerde ASPAW as reaktorsubstraat te vervang. Die resultate het getoon dat die CSB-verwydering verhoog het van 78% na 90% na 'n 24-uur toevoer van geosoneerde substraat. Daar is ook gevind dat die reaktorstabiliteit toegeneem het na ASPAW osoneering, aangesien 'n OLT-verhoging van 10,0 na 16,6 kg.CSB.m-3.d-1 in 23 dae nie die stabiliteit van die reaktor nadelig beinvloed het nie. Hierdie reaktoruitvloeisel (CSB = 465 rnq.L-1) is hierna gepost-osoneer, wat 'n 64,8% CSB- en 79,0% kleurverlaging tot gevolg gehad. Die finale uitvloeisel het 'n CBS-inhoud van 180 rnq.L-1 gehad (98,1% verwydering). Die vermoe van die osonering-/verteringstelsel om ASPAW te degradeer teen 'n hoër OLT, soos beskryf in hierdie studie, is van waarde tot die appelsapprosesseringsbedryf, aangesien dit tot groter organiese afvalstofverwydering kan lei en dus 'n meer effektiewe behandelingstelsel tot gevolg kan hê. Verhoogde reaktordoeltreffendheid sal 'n direkte verbetering tot gevolg hê in die gehalte van die finale afvalwater wat geproduseer word, wat op sy beurt 'n beduidende impak sal hê op die behandelingsvermoe van die appelsapprosesseringsbedryf, wat tans beperk word deur die produksie van groot volumes afvalwater.
48

Anaerobic bioconversion of the organic fraction from the fruit processing industry

Griessel, Wilmare 12 1900 (has links)
Thesis (MSc Food Sc )--Stellenbosch University, 2002. / ENGLISH ABSTRACT: South Africa is a developing country that relies heavily on its agricultural sector for economical welfare especially in the Western Cape Province. However, development gives rise to new technologies, new products, economical stability and unfortunately also to the production of larger volumes of liquid and solid waste. Anaerobic composting is becoming a very attractive treatment option for solid waste disposal because of its unique operational advantages and two valueadded by-products, compost and biogas. Over the last decade progress has been made in anaerobic digestion of solid wastes, but no literature could be found on the anaerobic composting of apple and peach pomace. The main objective of this study was to develop a method to anaerobically compost apple and peach pomace. In the first phase important operational parameters were identified and a method was developed to optimise the parameters. In the second phase of the study, the scaling-up and optimisation of the process were the major objectives. During the first phase of this research 2 L modified glass containers were used as composting units. The most important operational parameters (leachate pH, inoculum source and size, and initial moisture levels) were identified. Anaerobic compost from previous tests, brewery granules and anaerobic sludge were also used as inocula and evaluated for the best source of microbes. After optimising all the identified parameters, good results were obtained, which included higher biogas production, good volume reductions, less bad aromas and a compost product with a neutral pH. After developing the 2 L laboratory-scale method to compost the apple pomace anaerobically, the next step was to ascertain if the method would work if larger volumes of solid fruit waste were composted. A special 20 L composting unit made of PVC was designed to suit the operational requirements of the anaerobic composting process. It was also decided to mix apple pomace and peach pulp together and to use this solid waste source as part of the composting substrate. Different inocula, including cattle manure, anaerobic sludge, brewery granules and anaerobic compost produced in the previous tests, were used. Although good results were obtained with the anaerobic compost and cattle manure as inoculum, the aim was also to decrease the composting period by shortening the pH stabilisation period. To achieve this, it was decided to add NaHC03 to the substrate to be composted to facilitate a faster pH stabilisation. The composting period was subsequently shortened to 25 days with satisfactory results, which included a volume reduction, biogas production and faster pH stabilisation. An upflow anaerobic sludge blanket (UASB) bioreactor was also used to assist the composting process by facilitating the removal of the VFA's present in the composting leachate. This proved to be a valuable addition to the composting process as the UASB bioreactor also provided the composting units with a 'moisturising liquid', which was 'enriched' with a consortium of active anaerobic bacteria when the effluent from the bioreactor was re-added to the composting units. With all the operational parameters in place, good results were obtained and these included a volume reduction of 60% (m/m), a good biogas production, a composting period of only 25 days, a compost that was free of bad aromas, a final compost pH of > 6.5, final leachate COD values of less than 3 000 rnq.l", and a final leachate VFA's concentration of between 0 and 250 rnq.l". If in future research further scaling-up is to be considered, it is recommended that the composting unit be coupled directly to the UASB bioreactor, thus making the process continuous and more practical to operate. If the operational period of the anaerobic composting set-up could be further shortened and the inoculum adapted so that the process could be used for the treatment of other difficult types of solid wastes, it would probably be advantageous for the fruit processing industry to use this method as an environmental control technology. / AFRIKAANSE OPSOMMING: Suid-Afrika is 'n ontwikkelende land wat baie afhanklik is van die sukses van die landbousektor vir ekonomiese welstand, veral in die Wes Kaap Provinsie. Ontwikkeling gaan gepaard met nuwe tegnologie, nuwe produkte, ekonomiese stabiliteit en daarmee saam gaan die produksie van groter volumes vlooiebare en soliede afvalprodukte. Anaërobiese kompostering is tans besig om opgang te maak as en doeltreffende behandelingstegnologie vir vaste afvalstowwe. Tydens die laaste dekade is baie vooruitgang gemaak in die veld van anaërobiese vertering asook kompostering van afvalmateriaal met en hoë vaste stof inhoud. Anaërobiese kompostering van appel- en perskepulp, afkomstig van die versappingsindustrie, het tot dusver min aandag geniet. Die hoofdoel van hierdie navorsing was om 'n anaërobiese komposterings metode te ontwikkel vir die beheer van vrugte afval om sodoende die basis neer te lê vir en nuwe tegnologie wat baie voordele (biogas en kompos) inhou. In die eerste fase is die belangrikste operationele parameters geïdentifiseer om sodoende beter beheer oor die anaërobiese proses uit te oefen. In die tweede fase is die anaërobiese proses wat gedurende die eerste fase ontwikkel is, opgeskaal om optimum resultate te verkry. Gedurende die eerste fase van hierdie verhandeling was 2 L gemodifiseerde glas houers gebruik as komposteringseenhede. Die belangrikste operasionele parameters (pH beheer, inokulasie grootte, vloeistofvlakke en hoeveelheid vog asook vlugtige vetsuur produksie en verwydering) vir die beheer van die anaërobiese komposteringsproses was geïdentifiseer en gebruik as uitgangspunt om 'n anaërobiese komposteringsmetode te ontwikkel. Anaërobiese slyk, brouery granules en anaërobiese kompos van vorige eksperimente was as inokula gebruik. Gedurende hierdie studies was goeie resultate verkry en het 'n hoë biogas produksie, goeie volume reduksies, vermindering van slegte aromas en kompos met 'n neutrale pH ingesluit. . Nadat hierdie goeie resultate met die 2 L laboratorium-skaal metode verkry was, was groter volumes vaste vrugte afval gebruik om te bepaal of dieselfde metode toegepas kan word op en groter skaal. Spesiale 20 L komposteringseenhede was ontwerp om aan die operasionele vereistes van 'n anaërobiese proses te voldoen. Dit was ook besluit om appel pulp met perske pulp te meng en te gebruik as deel van die komposteringssubstraat. Verskeie inokula was weereens gebruik en het die volgende ingesluit: vars beesmis, anaërobiese slyk, brouery granules en anaërobiese kompos van vorige eksperimente. Hoewel baie goeie resultate met vars beesmis en anaërobiese kompos as inokula verkry was, was 'n volgende doel gewees om die kompoterings tydperk te verkort deur die pH vinniger te stabiliseer. Daar was besluit om NaHC03 by die komposteringssubstraat te voeg en so 'n vinniger pH stabilisasie te fasiliteer. 'n UASB ('upflow anaerobic sludge blanket') bioreaktor was ook gebruik om die komposteringsproses aan te help deur die vlugtige vetsure wat in die kompostloog teenwoordig was, te verwyder. Die insluiting van die bioreaktor in die anaërobiese komposteringsproses het bygedra tot die sukses van die proses deurdat die uitvloeisel as 'n vogmiddel vir die komposteringseenhede gebruik was en 'n konsortium van aktiewe anaërobiese bakterieë bevat het. Nadat al die operationele parameters in plek was, was goeie resultate bereik en het die volgende ingesluit: 'n volume reduksie van 60% (m/m), goeie biogas produksie, 'n komposteringstyd van 25 dae, 'n kompos wat vry was van slegste aromas, 'n finale kompos pH van >6.5, finale loog CSB van <3 000 rnq.l' en 'n finale vetsuur konsentrasie van tussen 0 en 250 mq.l'. lndien verdere navorsing onderneem word, word dit aanbeveel dat die UASB bioreaktor direk aan die komposteringseenheid gekoppel word om sodoende die proses meer aaneenlopend en die proses prakties makliker uitvoerbaar te maak. Indien die operationele tydperk nog korter gemaak kan word en die inokulum aanpasbaar kan wees om moeilik verteerbare afvalprodukte te akkomodeer, sal hierdie tegnologie baie voordelig wees as 'n metode om omgewingsbesoedeling te beheer
49

Avaliação do desempenho de um reator anaeróbio compartimentado no tratamento de esgoto doméstico

Sato, Cibele Midori [UNESP] 06 September 2013 (has links) (PDF)
Made available in DSpace on 2015-03-03T11:52:36Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-09-06Bitstream added on 2015-03-03T12:06:23Z : No. of bitstreams: 1 000807962.pdf: 904239 bytes, checksum: 57c69c216cd1bad8465976c2fad345c9 (MD5) / A aplicação de reatores UASB (Upflow Anaerobic Sludge Blanket) passou a ocupar uma posição de destaque, principalmente no Brasil, face às condições ambientais de temperatura favoráveis, baixo custo, simplicidade operacional e baixa produção de sólidos. Com o intuito de aprimorá-lo, este estudo aliou as características construtivas e operacionais destes reatores com as dos Reatores Anaeróbios Compartimentados (RAC), caracterizados por oferecerem a possibilidade de separação das fases que ocorrem na digestão anaeróbia e o aumento do tempo de contato entre a biomassa e o efluente. Assim, foi projetado e construído um reator vertical, contendo dois tubos concêntricos em seu interior, visando à separação das etapas acidogênica e metanogênica, a partir da cinética de crescimento dos microrganismos presentes. A pesquisa teve como objetivo principal estudar o comportamento e avaliar o desempenho do reator UASB compartimentado sob nova configuração, no período de partida e operação, tratando esgoto doméstico. O monitoramento do sistema foi dividido em duas etapas: partida e operação. Durante a partida, os valores de pH e alcalinidade mantiveram-se estáveis dentro de uma faixa adequada. Os resultados apresentados durante seu monitoramente indicaram ainda, que o inóculo utilizado promoveu condições adequadas para a partida do reator, com remoção média de DQO de 53,8%, chegando a atingir 82,8% ao final desta etapa. Na segunda etapa de monitoramento, ocorreram diversos problemas relacionados à operação do sistema, ocasionando sua paralisação durante alguns dias. Os valores de pH encontraram-se dentro da faixa adequada, contudo, a alcalinidade sofreu variações quando houve interrupção no sistema. A remoção de matéria orgânica apresentou-se estável, mesmo após tais interrupções, com eficiência média de remoção de 80% para a DQO e 78% para a DBO. Além disso, ambas chegaram a alcançar 90% na ... / Application of UASB (Upflow Anaerobic Sludge Blanket) reactor has come to occupy a prominent position, especially in Brazil, due to favorable climatic conditions, low cost, operational simplicity and low production solids. In order to improve it, this study combined constructional and operational features of these reactors with the Compartmented Anaerobic Reactor (CAR), characterized by offering the possibility of phase separation occurring in the anaerobic digestion and increase the contact time between the biomass and effluent. Thus a vertical reactor was designed and constructed containing two concentric tubes inside, in order to separate the acidogenic and methanogenic steps from the kinetics of growth of microrganisms present. The research aimed to study the behavior and evaluate the performance of the UASB compartmentalized reactor under new configuration during starting and operation, treating domestic wastewater. The monitoring system was divided into two stages: starting and operating. During the start-up, the values of pH and alkalinity remained stable within a proper range. The results presented during its monitoring also indicated that the inoculum used promoted conditions for starting the reactor, with average COD removal of 53,8%, reaching 82,8% at the end of this step. In the second stage of monitoring, there were several problems related to system operation, causing a stoppage for a few days. The pH values were within the appropriate range, however, the alkalinity variations experienced when there was an interruption in the system. The removal of organic matter remained stable even after such interruption, with average removal efficiency of 80% to 78% for COD and BOD. Moreover, both even reached 90% removal efficiency
50

Tratamento anaeróbio-aeróbio de águas residuárias de suinocultura e reúso na produção de milho para silagem

Cangani, Max Ternero [UNESP] 16 August 2011 (has links) (PDF)
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Os conjuntos I e II foram compostos por dois reatores UASB em série com volumes de 908 e 350 L e de 908 e 188 L, respectivamente. No conjunto II, foi realizado pós tratamento do efluente em um reator operado em batelada sequencial (RBS) com alimentação contínua, com volume de 3000 L. As cargas orgânicas volumétricas (COV) aplicadas no primeiro reator dos conjuntos I e II variaram de 8,36 a 9,95 g DQO total (L d)-1 e de 7,83 a 11,6 g DQO total (L d)-1, respectivamente. As eficiências médias de remoção de DQO total, nitrogênio Kjeldahl (NK), fósforo total (P-total) foram elevadas e variaram de 95 a 97% e de 97 a 99%, de 64 a 67% e de 53 a 69%, e de 80 a 87% e de 71 a 89%, nos conjuntos I e II, respectivamente. As eficiências também foram elevadas para os metais Cu, Fe, Mn e Zn nos conjuntos I e II e variaram de 80 a 91% e de 63 a 80%, de 59 a 80% e de 51 a 72%, de 89 a 97% e de 81 a 98%, de 87 a 98% e de 91 a 99%, respectivamente. A semeadura do milho, foi realizado na safrinha 2009 e na safra 2009/2010, ambos em sistema de plantio direto e convencional, para a confecção de silagem. Os valores do pH observados na silagem não diferiram entre os tratamentos nas duas épocas de semeadura e nos sitemas de plantio direto e convencional. A adubação do milho para confecção de silagem, com dejeto bruto de suíno, com dejetos tratados em sistema anaeróbio e com os dejetos do pós-tratamento, quando comparada com a adubação mineral, não apresentou resultados com diferenças significativas na silagem na maioria dos atributos avaliados. O reúso dos efluentes tratados e do dejeto bruto, não promoveu alterações na nutrição da planta, porém os efluentes... / This study evaluated the performance of two sets of upflow anaerobic sludge blanket (UASB) installed in series. The sets I and II were composed of two UASB reactors in series with volumes of 908 and 350 L and 908 L and 188, respectively. In set II was conducted after the treatment of the effluent in a sequencing batch reactor (SBR) with continuous flux, with a volume of 3000 L. The volumetric organic loads (VOC) applied to the first reactor of the sets I and II ranged from 8.36 to 9.95 g total COD (L d) -1 and 7.83 to 11.6 g total COD (L d) -1, respectively. The average removal efficiencies of total COD, Kjeldahl nitrogen (NK), total phosphorus (total P) were high and ranged from 95 to 97% and 97 to 99%, 64 to 67% and 53 to 69% and 80 to 87% and 71 to 89% in clusters I and II, respectively. The efficiencies were also high for Cu, Fe, Mn and Zn in clusters I and II, and ranged from 80 to 91% and 63 to 80%, 59 to 80% and 51 to 72% from 89 to 97 and 81% to 98%, 87 to 98% and 91 to 99%, respectively. We carried out the swing of maize in the 2009 off-season and 2009/2010 season, both in no-tillage and conventional sistems for making silage. The pH values observed in the silage did not differ significantly between treatments in both seasons of swing and in the sistems of tillage and no-tillage. The fertilization of corn for silage making, with raw pig manure with waste treated in anaerobic system and the waste from the post-treatment compared to mineral fertilization, results showed no significant difference in silage in most parameters. The reuse of treated effluent and raw manure, did not promote changes in the nutrition of corn but the application of treated effluent increased concentrations of N readily available for plants in soil. Even in much larger doses applied compared to the raw waste, the treated effluent, promoted soil contamination by total coliforms and thermotolerant lower

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