RESUMO
The purpose of this study was to assess the swine wastewater treatment system, consisting of the anaerobic baffled reactor (ABR), followed by the upflow anaerobic sludge blanket (UASB) reactor at full scale. The system was monitored by analyzing samples collected in the influent and effluent of ABR and UASB. The following parameters were analyzed: temperature, pH, total suspended solids (TSS), volatile suspended solids (VSS), biochemical oxygen demand (BOD), and chemical oxygen demand (COD). Averages of total removal of COD and BOD were 96.7 and 98.4%, respectively. The mean concentrations of COD, BOD, TSS, and VSS at the final effluent were 611, 124, 138, and 134 mg L-1, respectively. The mean volumetric organic loadings (VOL) at the ABR and UASB were 10.29 and 0.99 kg COD m-1d-1. Therefore, the ABR-UASB system was found to be a promising alternative for the swine wastewater treatment.(AU)
O objetivo deste trabalho foi avaliar o sistema de tratamento de águas residuárias de suinocultura, constituído de reator anaeróbio de chicanas (RAC), seguido por reator anaeróbio de manta de lodo (UASB), em escala real. O sistema foi monitorado por meio da análise de amostras coletadas nos afluentes e efluentes do RAC e UASB. Foram analisados os seguintes parâmetros: temperatura, pH, sólidos suspensos totais (SST), sólidos suspensos voláteis (SSV), demanda bioquímica de oxigênio (DBO) e demanda química de oxigênio (DQO). As médias de remoção total de DQO e de DBO foram 96,7 e 98,4%, respectivamente. As concentrações médias de DQO, DBO, SST e SSV no efluente final foram 611, 124, 138 e 134 mg.L-1, respectivamente. As cargas orgânicas volumétricas (COV) médias no RAC e UASB foram 10,29 e 0,99 kgDQO m kgDQO m-3d-1. Desta maneira, o sistema RAC-UASB apresenta-se como alternativa promissora para o tratamento de águas residuárias de suinocultura.(AU)
Assuntos
Animais , Tratamento Anaeróbio/análise , Suínos/anormalidades , Digestão Anaeróbia , Purificação da Água/análise , Meio AmbienteRESUMO
The purpose of this study was to assess the swine wastewater treatment system, consisting of the anaerobic baffled reactor (ABR), followed by the upflow anaerobic sludge blanket (UASB) reactor at full scale. The system was monitored by analyzing samples collected in the influent and effluent of ABR and UASB. The following parameters were analyzed: temperature, pH, total suspended solids (TSS), volatile suspended solids (VSS), biochemical oxygen demand (BOD), and chemical oxygen demand (COD). Averages of total removal of COD and BOD were 96.7 and 98.4%, respectively. The mean concentrations of COD, BOD, TSS, and VSS at the final effluent were 611, 124, 138, and 134 mg L-1, respectively. The mean volumetric organic loadings (VOL) at the ABR and UASB were 10.29 and 0.99 kg COD m-1d-1. Therefore, the ABR-UASB system was found to be a promising alternative for the swine wastewater treatment.
O objetivo deste trabalho foi avaliar o sistema de tratamento de águas residuárias de suinocultura, constituído de reator anaeróbio de chicanas (RAC), seguido por reator anaeróbio de manta de lodo (UASB), em escala real. O sistema foi monitorado por meio da análise de amostras coletadas nos afluentes e efluentes do RAC e UASB. Foram analisados os seguintes parâmetros: temperatura, pH, sólidos suspensos totais (SST), sólidos suspensos voláteis (SSV), demanda bioquímica de oxigênio (DBO) e demanda química de oxigênio (DQO). As médias de remoção total de DQO e de DBO foram 96,7 e 98,4%, respectivamente. As concentrações médias de DQO, DBO, SST e SSV no efluente final foram 611, 124, 138 e 134 mg.L-1, respectivamente. As cargas orgânicas volumétricas (COV) médias no RAC e UASB foram 10,29 e 0,99 kgDQO m kgDQO m-3d-1. Desta maneira, o sistema RAC-UASB apresenta-se como alternativa promissora para o tratamento de águas residuárias de suinocultura.
Assuntos
Animais , Digestão Anaeróbia , Purificação da Água/análise , Suínos/anormalidades , Tratamento Anaeróbio/análise , Meio AmbienteRESUMO
The aim of this review is to summarize the current knowledge of nitrous oxide (N2O) production from manure. The article investigates the scientific literature regarding N2O emissions according to different factors, such as microclimate, season, manure composition, microbial population, management, storage conditions, and type of digestion. Nitrous oxide is formed through the microbiological processes of nitrification and denitrification. The amount of N2O produced from manure storage depends on type of manure management. The anaerobically stored farm yard manure (FYM) emitted more N2O emissions than the composted FYM. The anaerobic storage of liquid manure reduces N2O production. Covering the slurry store (SLR) with a chopped straw increased N2O emissions. Finally, emission factors from manure treatment and management are listed in table. (AU)
Assuntos
Animais , Bovinos , Óxido Nítrico , Suínos , Esterco , Óxido Nitroso , Nitrificação , Desnitrificação , Tratamento Anaeróbio , Digestão AnaeróbiaRESUMO
The aim of this review is to summarize the current knowledge of nitrous oxide (N2O) production from manure. The article investigates the scientific literature regarding N2O emissions according to different factors, such as microclimate, season, manure composition, microbial population, management, storage conditions, and type of digestion. Nitrous oxide is formed through the microbiological processes of nitrification and denitrification. The amount of N2O produced from manure storage depends on type of manure management. The anaerobically stored farm yard manure (FYM) emitted more N2O emissions than the composted FYM. The anaerobic storage of liquid manure reduces N2O production. Covering the slurry store (SLR) with a chopped straw increased N2O emissions. Finally, emission factors from manure treatment and management are listed in table.
Assuntos
Animais , Bovinos , Esterco , Suínos , Óxido Nitroso , Óxido Nítrico , Desnitrificação , Digestão Anaeróbia , Nitrificação , Tratamento AnaeróbioRESUMO
In microbial fuel cells (MFCs), the oxidation of organic compounds catalyzed by microorganisms (anode) generates electricity via electron transfer to an external circuit that acts as an electron acceptor (cathode). Microbial fuel cells differ in terms of the microorganisms employed and the nature of the oxidized organic compound. In this study, a consortium of anaerobic microorganisms helped to treat the secondary sludge obtained from a sewage treatment plant. The microorganisms were grown in a 250 mL bioreactor containing a carbon cloth. The reactor was fed with media containing acetate (as the carbon source) for 48 days. Concomitantly, the electrochemical data were measured with the aid of a digital multimeter and data acquisition system. At the beginning of the MFC operation, power density was low, probably due to slow microorganism growth and adhesion. The power density increased from the 15th day of operation, reaching a value of 13.5 W cm2 after ca. 24 days of operation, and remained stable until the end of the process. Compared with data in the literature, this power density value is promising; improvements in the MFC design and operation could increase this value even further. The system investigated herein employed excess sludge as a biocatalyst in an MFC. This opens up the possibility of using organic acids and/or carbohydrate-rich effluents to feed MFCs, and thereby provide simultaneous effluent treatment and energy generation.
Assuntos
Centrais Elétricas , Fontes de Energia Bioelétrica , Tratamento Anaeróbio , Tratamento de Lodos , Consórcios Microbianos , Eletrodos , Esgotos , Oxidação BiológicaRESUMO
In microbial fuel cells (MFCs), the oxidation of organic compounds catalyzed by microorganisms (anode) generates electricity via electron transfer to an external circuit that acts as an electron acceptor (cathode). Microbial fuel cells differ in terms of the microorganisms employed and the nature of the oxidized organic compound. In this study, a consortium of anaerobic microorganisms helped to treat the secondary sludge obtained from a sewage treatment plant. The microorganisms were grown in a 250 mL bioreactor containing a carbon cloth. The reactor was fed with media containing acetate (as the carbon source) for 48 days. Concomitantly, the electrochemical data were measured with the aid of a digital multimeter and data acquisition system. At the beginning of the MFC operation, power density was low, probably due to slow microorganism growth and adhesion. The power density increased from the 15th day of operation, reaching a value of 13.5 W cm2 after ca. 24 days of operation, and remained stable until the end of the process. Compared with data in the literature, this power density value is promising; improvements in the MFC design and operation could increase this value even further. The system investigated herein employed excess sludge as a biocatalyst in an MFC. This opens up the possibility of using organic acids and/or carbohydrate-rich effluents to feed MFCs, and thereby provide simultaneous effluent treatment and energy generation.(AU)
Assuntos
Tratamento de Lodos , Tratamento Anaeróbio , Centrais Elétricas , Fontes de Energia Bioelétrica , Esgotos , Consórcios Microbianos , Eletrodos , Oxidação BiológicaRESUMO
Sulfur oxidizing bacteria (SOB) were isolated and tested in order to remove sulfide from high sulfate wastewater to reduce the amount of hydrogen sulfide (H2S) in the produced biogas. A promising SOB isolate, designated as isolate T307, was selected due to its best sulfide removal (86.7 percent) in the effluent of a sulfate reduction reactor (SRR) over a 24 hrs incubation. The bacterium was able to grow better as a mixotroph (yeast extract as a carbon source) than as a chemolithoautotroph. In addition, as a heterotroph, the bacterium grew well with yeast extract and peptone. Based on partial 16S rRNA gene sequence, the isolated T307 was an Alcaligenes sp. and was able to convert most of sulfide species (total sulfide: TS; dissolved sulfide: DS and H2S) into elemental sulfur or sulfate over a 20 hrs period of cultivation by controlling the speed of shaking. In a biogas reactor set, after pre-treating a sulfide medium with Alcaligenes sp. T307 there was a much higher specific yield of CH4 (238 ml CH4 g-1COD removed) and more biogas (154 ml L-1 d-1) was produced with the biogas containing more methane (48.1 percent CH4, 51.5 percent CO2 and 0.41 percent H2S) in comparison to a control with a specific yield of CH4, (72 ml CH4 g-1COD removed) 86 ml L-1 d-1 biogas produced with a composition of 35.5 percent CH4, 63.7 percent CO2 and 0.86 percent H2S.
Assuntos
Biocombustíveis , Sulfatos , Sulfobactérias , Águas Residuárias , Borracha , Thiobacillus/isolamento & purificação , Tratamento Anaeróbio/métodosRESUMO
Avaliou-se o potencial de uso reator anaeróbio operado em bateladas seqüenciais com biomassa imobilizada (ASBBR), em escala piloto, no tratamento de água residuária industrial contendo elevadas concentrações de sulfato. O ASBBR, com volume total de 1.2 m³, foi preenchido com carvão mineral como meio suporte para imobilização da biomassa (leito fixo). Foram aplicadas cargas de 0,15; 0,30; 0,65; 1,30 e 1,90 kg SO4-2/ciclo (ou batelada) com duração de 48 h, correspondendo, respectivamente, às concentrações de sulfato no afluente de 0,25; 0,50; 1,0; 2,0 e 3,0 gSO4-2.l-1. Utilizou-se etanol como doador de elétrons para a redução do sulfato. O reator foi operado à temperatura ambiente (29±8ºC), tendo sido obtidas eficiências médias na redução de sulfato entre 88 e 92 por cento em 92 ciclos (275 dias). Os resultados obtidos permitem concluir que o uso de reatores ASBBR constitui-se em alternativa eficiente para a remoção de sulfatos de águas residuárias com características semelhantes às utilizadas neste trabalho.
The potential use of an anaerobic sequencing batch biofilm reactor (ASBBR) in pilot-scale for the treatment of a sulfate-rich industrial wastewater was evaluated. The pilot 1.2 m³ ASBBR reactor was filled with mineral coal for biomass immobilization (fixed film). The sulfate loading rates applied were 0.15; 0.30; 0.65; 1.30 and 1.90 kg SO4-2/cycle (or batch). Each cycle lasted 48 h. The influent concentrations were, respectively, 0.25; 0.50; 1.0; 2.0 and 3.0 gSO4-2.l-1. Ethanol was used as electron donor for sulfate reduction. The reactor operated at ambient temperature (29±8ºC), and the mean efficiencies of sulfate removal were in the range 88 to 92 percent in the 92 run cycles. The total operating period comprised 275 days. Based on the results obtained in this research, it could be concluded that the ASBBR can be an efficient alternative for the removal of sulfate from other industrial wastewaters with similar characteristics.
Assuntos
Tratamento Anaeróbio , Filtros Biológicos , Reatores Biológicos , Carvão Mineral , Etanol , Resíduos Industriais , SulfatosRESUMO
La alcalinidad bicarbonática tiene papel fundamental en la estabilidad de reactores biológicos aplicados al tratamiento de aguas residuales, principalmente en sistemas anaerobios. Como algunas aguas residuales pueden sufrir severa acidificación, en algunos casos es necesaria la adición de una fuente externa de alcalinidad para que el proceso sea conducido de forma estable. En ese contexto, se evaluó el efecto de la adición de bicarbonato de sodio sobre la determinación de la concentración de sólidos. La metodología consistió en la evaluación de las concentraciones de sólidos (sólidos totales-ST, sólidos volátiles totales-SVT y sólidos fijos totales-SFT) en muestras conteniendo suero de queso y ácidos volátiles (para simulación de efluentes de reactores anaerobios). Los valores de ST, SVT y SFT fueran fuertemente influenciados, principalmente debido al aumento de los SFT. Ese efecto fue cuantificado relacionándose los valores experimentales con los teóricos, determinados por las reacciones estequiométricas de la descomposición del bicarbonato de sodio y otros compuestos formados (acetato de sodio y propionato de sodio) con el aumento de la temperatura. Así, como uno de los principales parámetros de evaluación de sistemas de tratamiento de aguas residuales es la remoción de sólidos presentes en el medio, la concentración de sólidos puede ser evaluada de forma más adecuada teniendo en cuenta la determinación de los sólidos fijos debido a las sales inorgánicas. Esa metodología es considerada adecuada cuando se adiciona grande cantidad de alcalinizada a la agua residual
Assuntos
/análise , Tratamento Anaeróbio/análise , Águas Residuárias , Biologia , BrasilRESUMO
Este artigo apresenta resultados de testes laboratoriais que investigaram a influência dos íons cloreto, amonium, ferro e sulfeto no teste de demanda química de oxigênio (DQO), bem como valores dos coeficientes de conversão da matéria orgânica específica (proteínas, carboidratos e lipídeos) determinados empiricamente. O artigo apresenta, ainda, resultados da comparação dos métodos colorimétrico e titulométrico de determinação da DQO e faz uma discussão crítica do uso do teste de DQO como parâmetro de monitoramento da eficiência de sistemas de tratamento anaeróbio.
This paper presents practical results on the influence of chloride, amonium, sulphide and iron on the chemical oxygen demand (COD) test, as well as experimental values of stoichiometric coefficients to convert the specific organic matter (protein, carbohydrate and lipid) into COD. The paper also presents results that compare the titrimetric and colorimetric methods used to measure the COD and makes a critical analysis of the use of COD test as a tool to monitor the efficiency of anaerobic treatment systems.