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Tratamento anaeróbio de pentaclorofenol em reator de leito fluidificado alimentado com água residuária sintética contendo glicose como fonte única de carbono; Anaerobic treatment of pentachlorophenol in a fluidized bed reactor fed with synthetic wastewater containing glucose as a single carbon source

FREIRE, Flavio Bentes; PIRES, Eduardo Cleto; FREIRE, José Teixeira
Fonte: ABES Publicador: ABES
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
66.45%
Neste trabalho foi utilizado um reator anaeróbio de leito fluidificado (RALF), tratando água residuária sintética contendo pentaclorofenol (PCP), submetido a condições operacionais menos idealizadas. Utilizou-se um reator com volume de 16 litros, com partículas de carvão ativado granular como meio suporte. O desempenho do reator foi verificado pelas análises usuais de monitoramento (pH, alcalinidade, DQO, ácidos voláteis) e também por análises de microscopia e concentração de PCP. A presença de PCP no sistema, nas concentrações utilizadas, não alterou de maneira significativa a qualidade da biomassa presente, e nem os parâmetros de monitoramento. Em concentrações afluentes de PCP variando de 1 a 6 mg/L, foram observadas eficiências médias de remoção de 92% e 70%, respectivamente.; In the present work, an anaerobic fluidized bed reactor (AFBR) was used for the treatment of a synthetic wastewater containing pentachlorophenol (PCP) subjected to less idealized operating conditions. The reactor was a 16 litres tank with granular activated carbon particles as support media. Evaluation of AFBR performance was done by the analysis of usual monitoring parameters (pH, alkalinity, COD, volatile acids) together with microscopy and PCP concentration analysis. The presence of PCP under the concentrations used did not significantly alter the amount of biomass and the performance monitoring parameters. Removal average efficiencies of the order of 92% and 70% were obtained for PCP inflow concentrations in the range of 1 to 6mg/l.; Fapesp

Effect of specific feed volume on the performance of an anaerobic sequencing batch biofilm reactor (AnSBBR) with circulation treating different wastewaters under different organic loads

BEZERRA, Roberto A.; CANTO, Catarina S. A. do; RODRIGUES, Jose A. D.; RATUSZNEI, Suzana M.; ZAIAT, Marcelo; FORESTI, Eugenio
Fonte: ASOC QUIMICOS Publicador: ASOC QUIMICOS
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
46.38%
The objective of this research was to study the behavior of two anaerobic sequencing batch reactors, containing immobilized biomass (AnSBBR), as a function of the ratio of the volume of treated medium in each cycle to the total volume of reaction medium. The reactors, in which mixing was accomplished by recirculation of the liquid phase, were maintained at 30 +/- 1 degrees C and treated different wastewaters in 8-h cycles. The operational conditions imposed had the objective to investigate whether maintenance of a residual volume in the reactor would affect, at the end of each cycle, process efficiency and stability, as well as to verify the intensity of the effect for different types of wastewaters and organic loading rates. The first reactor, with work volume of 2.5 L, treated reconstituted cheese whey at an organic loading rate of 12 g COD.L(-1).d(-1) and presented similar effluent quality for the four conditions under which it was operated: renewal of 100, 70, 50 and 25 % of its work volume at each cycle. Despite the fact that reduction in the renewed volume did not significantly affect effluent quality, in quantitative terms, this reduction resulted in an increase in the amount of organic matter removed by the first reactor. The second reactor...

Effect of impeller type and mechanical agitation on the mass transfer and power consumption aspects of ASBR operation treating synthetic wastewater

MICHELAN, Rogerio; ZIMMER, Thiago R.; RODRIGUES, Jose A. D.; RATUSZNEI, Suzana M.; MORAES, Deovaldo de; ZAIAT, Marcelo; FORESTI, Eugenio
Fonte: ACADEMIC PRESS LTD ELSEVIER SCIENCE LTD Publicador: ACADEMIC PRESS LTD ELSEVIER SCIENCE LTD
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
66.45%
The effect of flow type and rotor speed was investigated in a round-bottom reactor with 5 L useful volume containing 2.0 L of granular biomass. The reactor treated 2.0 L of synthetic wastewater with a concentration of 800 mgCOD/L in 8-h cycles at 30 degrees C. Five impellers, commonly used in biological processes, have been employed to this end, namely: a turbine and a paddle impeller with six-vertical-flat-blades, a turbine and a paddle impeller with six-45 degrees-inclined-flat-blades and a three-blade-helix impeller. Results showed that altering impeller type and rotor speed did not significantly affect system stability and performance. Average organic matter removal efficiency was about 84% for filtered samples, total volatile acids concentration was below 20 mgHAc/L and bicarbonate alkalinity a little less than 400 mgCaCO(3)/L for most of the investigated conditions. However, analysis of the first-order kinetic model constants showed that alteration in rotor speed resulted in an increase in the values of the kinetic constants (for instance, from 0.57 h(-1) at 50 rpm to 0.84 h(-1) at 75 rpm when the paddle impeller with six-45 degrees-inclined-flat-blades was used) and that axial flow in mechanically stirred reactors is preferable over radial-flow when the vertical-flat-blade impeller is compared to the inclined-flat-blade impeller (for instance at 75 rpm...

Effects of temperature at different organic loading levels on the performance of a fluidized-bed anaerobic sequencing batch bioreactor

BERGAMO, Camila Miranda; MONACO, Rodrigo Di; RATUSZNEI, Suzana Maria; RODRIGUES, Jose Alberto Domingues; ZAIAT, Marcelo; FORESTI, Eugenio
Fonte: ELSEVIER SCIENCE SA Publicador: ELSEVIER SCIENCE SA
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
36.59%
An investigation was performed on the effect of temperature and organic load on the stability and efficiency of a 1.8-L fluidized-bed anaerobic sequencing batch reactor (ASBR), containing granulated biomass. Assays were carried out employing superficial up How velocity of 7 m/h, total cycle length of 6 h and synthetic wastewater volume of 1.3 L per cycle. The fluidized-bed ASH was operated at 15, 20, 25 and 30 degrees C with influent organic matter concentrations of 500 and 1000 mgCOD/L The system showed stability under all conditions and presented filtered samples removal efficiency ranging from 79 to 86%. A first-order kinetic model could be fitted to the experimental values of the organic matter concentration profiles. The specific kinetic parameter values of this model ranged from 0.0435 to 0.2360 L/(gTVS h) at the implemented operation conditions. in addition, from the slope of an Arrhenius plot, the activation energy values were calculated to be 16,729 and 12,673 cal/mol for operation with 500 and 1000 mgCOD/L, respectively. These results show that treatment of synthetic wastewater. with concentration of 500 mgCOD/L, was more sensitive to temperature variations than treatment of the same residue with concentration of 1000 mgCOD/L. Comparing the activation energy value for operation at 500 mgCOD/L with the value obtained by Agibert et al. (S.A. Agibert...

Temperature and feed strategy effects on sulfate and organic matter removal in an AnSBB

COSTABILE, Augusto L. O.; CANTO, Catarina S. A.; RATUSZNEI, Suzana M.; RODRIGUES, Jose A. D.; ZAIAT, Marcelo; FORESTI, Eugenio
Fonte: ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD Publicador: ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
36.52%
The objective of this work was to analyze the interaction effects between temperature, feed strategy and COD/[SO(4)(2-)] levels, maintaining the same ratio, on sulfate and organic matter removal efficiency from a synthetic wastewater. This work is thus a continuation of Archilha et al. (2010) who studied the effect of feed strategy at 30 degrees C using different COD/[SO] ratios and levels. A 3.7-L anaerobic sequencing batch reactor with recirculation of the liquid phase and which contained immobilized biomass on polyurethane foam (AnSBBR) was used to treat 2.0 L synthetic wastewater in 8 h cycles. The temperatures of 15, 22.5 and 30 degrees C with two feed strategies were assessed: (a) batch and (b) batch followed by fed-batch. In strategy (a) the reactor was fed in 10 min with 2 L wastewater containing sulfate and carbon sources. In strategy (b) 1.2 L wastewater (containing only the sulfate source) was fed during the first 10 min of the cycle and the remaining 0.8 L (containing only the carbon source) in 240 min. Based on COD/[SO(4)(2-)] = 1 and on the organic matter (0.5 and 1.5 gCOD/L) and sulfate (0.5 and 1.5 gSO(4)(2-)/L) concentrations, the sulfate and organic matter loading rates applied were 1.5 and 4.5 g/L.d, i.e., same COD/[SO(4)(2-)] ratio (=1) but different levels (1.5/1.5 and 4.5/4.5 gCOD/gSO(4)(2-)). When reactor feed was 1.5 gCOD/L.d and 1.5 gSO(4)(2-)/L.d...

Influence of organic shock loads in an ASBBR treating synthetic wastewater with different concentration levels

MOREIRA, Mariana Bueno; RATUSZNEI, Suzana Maria; RODRIGUES, Jose Alberto Domingues; ZAIAT, Marcelo; FORESTI, Eugenio
Fonte: ELSEVIER SCI LTD Publicador: ELSEVIER SCI LTD
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
66.7%
Safe application of the anaerobic sequencing biofilm batch reactor (ASBBR) still depends on deeper insight into its behavior when faced with common operational problems in wastewater treatments such as tolerance to abrupt variations in influent concentration, so called shock loads. To this end the current work shows the effect of organic shock loads on the performance of an ASBBR, with a useful volume of 5 L, containing 0.5-cm polyurethane cubes and operating at 30 degrees C with mechanical stirring of 500 rpm. In the assays 2 L of two types of synthetic wastewater were treated in 8-h cycles. Synthetic wastewater I was based on sucrose-amide-cellulose with concentration of 500 mg COD/L and synthetic wastewater II was based on volatile acids with concentration ranging from 500 to 2000 mg COD/L. Organic shock loads of 2-4 times the operation concentration were applied during one and two cycles. System efficiency was monitored before and after application of the perturbation. When operating with concentrations from 500 to 1000 mg COD/L and shock loads of 2-4 times the influent concentration during one or two cycles the system was able to regain stability after one cycle and the values of organic matter, total and intermediate volatile acids...

Fluidized ASBR treating synthetic wastewater: Effect of recirculation velocity

PINHEIRO, Denise Marques; RATUSZNEI, Suzana Maria; RODRIGUES, Jose Alberto Domingues; ZAIAT, Marcelo; FORESTI, Eugenio
Fonte: ELSEVIER SCIENCE SA Publicador: ELSEVIER SCIENCE SA
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
46.27%
An investigation has been performed on the effect of liquid phase recirculation velocity and increasing influent concentration on the stability and efficiency of an anaerobic sequencing batch reactor (ASBR) containing granular biomass. The reactor treated 1.3 L synthetic wastewater at 30 degrees C in 6 h cycles. Initially the effect of recirculation velocity was investigated employing velocities of 5, 7 and 10 m/h and influent concentration of 500 mg COD/L. At these velocities, filtered sample organic matter removal efficiencies were 83, 85 and 84%, respectively. A first order kinetic model could also be fitted to the experimental organic matter concentration profiles. The kinetic parameter values of this model were 1.35, 2.36 and 1.00 h(-1) at the recirculation velocities of 5, 7 and 10 m/h, respectively. The recirculation velocity of 7 m/h was found to be the best operating strategy and this value was maintained while the influent concentration was altered in order to verify system efficiency and stability at increasing organic load. Influent concentration of 1000 mg COD/L resulted in filtered sample organic matter removal efficiency of 80%, and a first order kinetic parameter value of 1.14 h(-1), whereas the concentration of 1500 mg COD/L resulted in an efficiency of 82% and a kinetic parameter value of 1.31 h(-1). (C) 2007 Elsevier B.V. All rights reserved.

Effect of chloride concentration on the electrochemical treatment of a synthetic tannery wastewater

COSTA, Carla Regina; Olivi, Paulo
Fonte: PERGAMON-ELSEVIER SCIENCE LTD Publicador: PERGAMON-ELSEVIER SCIENCE LTD
Tipo: article; proceedings paper; publishedversion
Português
Relevância na Pesquisa
36.59%
The electrochemical treatment of a synthetic tannery wastewater prepared with 30 compounds used in animal skin processing was studied. Electrolyses were performed in a one-compartment flow cell at a current density of 20 mA cm(-2), using a dimensionally stable anode (DSA (R)) of composition Ti/Ir(0.10)Sn(0.90)O(2) as the working electrode. Effects of chloride concentration and presence of sulfate were evaluated. Variation in the concentration of phenolic compounds as a function of electrolysis time revealed a first-order exponential decay; faster phenol removals were obtained with increasing chloride concentration in the wastewater. Lower phenol removals were obtained in the presence of sulfate. Higher chloride concentrations led to a faster decrease in total organic carbon (TOC), chemical oxygen demand (COD), and absorbance values at 228 nm. Faster wastewater color removal, higher current efficiency and lower energy consumption were also obtained. This electrochemical treatment was also able to reduce the wastewater toxicity for Daphnia similis. (C) 2008 Elsevier Ltd. All rights reserved.

Filtro anaeróbio ascendente combinado com reator aeróbio de lodos ativados em batelada no tratamento de água residuária sintética de indústria de polpa celulósica não branqueada sob condições termofílicas; Upflow anaerobic filter combined with aerobic reactor of activated sludge in batch treating of synthetic wastewater from unbleached cellulose pulp plant under thermophilic conditions

Megda, Cláudia Regina
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 20/09/2007 Português
Relevância na Pesquisa
46.45%
Um sistema combinado anaeróbio-aeróbio composto de um filtro anaeróbio ascendente seguido de reator aeróbio de lodos ativados em batelada, foi continuamente alimentado com água residuária sintética da indústria de polpa celulósica não branqueada, durante o período de trezentos e sessenta e três dias, com o objetivo de verificar o desempenho dos reatores operados sob condições termofílicas. Os reatores foram inoculados com lodo mesofílico com gradual adaptação para a condição termofílica e operados em duas fases distintas. A primeira e segunda fases contemplam os períodos em que os reatores foram operados em temperatura termofílica de 55 e 65 graus Celsius, respectivamente. O filtro anaeróbio trabalhou com tempo de detenção hidráulica de 48 horas em fluxo contínuo e o reator aeróbio operado em bateladas seqüenciais (RBS) com tempos de ciclo de 12, 18 e 24 horas. A melhor eficiênica de remoção de DQO do sistema combinado anaeróbio-aeróbio foi de 65%, devida, em maior parte ao reator anaeróbio. O filtro anaeróbio operado em temperatura de 55 e 65 graus demonstrou eficiência na capacidade de retenção de biomassa termofílica, evitando a perda no efluente. O RBS, quando operado em temperatura de 55 graus e tempo de ciclo de 18 horas...

Integração dos processos de eletrodiálise e de degradação fotoquímica para o tratamento de efluentes salinos contendo fenol.; Integration of electrodialysis and photochemical degradation process for the treatment of a saline wastewater containing phenol.

Borges, Fúlvia Jung
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 25/08/2009 Português
Relevância na Pesquisa
46.3%
Os processos oxidativos podem ser utilizados no tratamento de efluentes contendo compostos orgânicos não-biodegradáveis. No entanto, a presença de sais dissolvidos pode inibir ou retardar o processo. Neste estudo, a dessalinização de efluentes por eletrodiálise (ED) associada a um processo de oxidação avançada (foto-Fenton) foi aplicada a uma solução aquosa contendo NaCl e fenol. O processo de ED foi avaliado em escala piloto. Um estudo experimental foi realizado no qual a influência das variáveis de processo na perda de fenol e remoção do cloreto de sódio foi investigada. Experimentos também foram realizados sem corrente elétrica para determinar a transferência de fenol devido à difusão. As variações de concentração de fenol e sal nos compartimentos do sistema de ED foram medidas com o tempo utilizando-se procedimentos pertinentes e um planejamento experimental para determinar os parâmetros característicos globais. Uma abordagem fenomenológica foi utilizada para relacionar os fluxos de fenol, sal e água com as forças motrizes (concentração e gradiente de potencial elétrico). Nas condições de ED estudadas duas contribuições ao transporte do fenol se destacaram: difusão e convecção, sendo a última devido ao fluxo de água relacionado com eletroosmose pela migração do sal. Os parâmetros estimados das equações de transporte possuem bom ajuste com os resultados experimentais na faixa de condições investigadas. O processo foto-Fenton foi estudado em um reator de batelada em escala de laboratório. Os resultados confirmam o efeito negativo da concentração de sal na eficiência de remoção de fenol por oxidação. Este efeito não foi considerado linear em relação à concentração de sal e taxa de degradação. Devido à complexidade das reações do sistema...

Potencialidade da célula combustível microbiana para geração de energia elétrica a partir de esgoto sanitário; Potential microbial fuel cell to generate electricity from wastewater

Marcon, Lucas Ricardo Cardoso
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: dissertação de mestrado Formato: application/pdf
Publicado em 25/03/2011 Português
Relevância na Pesquisa
46.62%
O presente projeto avaliou uma célula combustível microbiana (CCM) composta de um reator combinado (anaeróbio e aeróbio), operada em fluxo contínuo com tempo de detenção hidráulico de 12 horas, alimentada com esgoto sintético (487 '+ OU -' 115 mg DQO/L) e esgoto sanitário (631 '+ OU -' 213 mg DQO/L). A estabilidade da CCM variou conforme as características do substrato aplicado. A eficiência de remoção de DQO ficou em 61 '+ OU -' 17; 67 '+ OU -' 26%, para esgoto sintético e sanitário respectivamente. Em média tensão obtida com o esgoto sintético foi de 76 mV com picos - 112,5 e 409 mV, enquanto que com o esgoto sanitário foi possível obter 52,1 mV na média e pico de geração em 325 mV. A potência variou de 10-150 mW/'M POT.2' com resistências entre 50-650 'ômega'. A geração de energia elétrica não apresentou relação linear com a DQO consumida em nenhum dos casos. A aplicação de barras de grafite como eletrodos se mostrou satisfatória na condução da corrente elétrica, o fator limitante foi a transferência de massa, principalmente a transferência de prótons do anodo para o catodo e a difusão de oxigênio para o anodo. Contudo os resultados obtidos demonstraram que é possível gerar eletricidade e...

Seleção de microalgas dos gêneros Desmodesmus e Scenedesmus produtoras de lipídeos: otimização do cultivo e aplicação do efluente doméstico de reator UASB como substrato alternativo à produção de biodiesel; Selection of lipid-bearing microalgae of the genus Desmodesmus and Scenedesmus: culture optimization and application of domestic wastewater from UASB reactor as an alternative substrate for the production of biodiesel

Rossi, Raquel Andrade de
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 01/11/2013 Português
Relevância na Pesquisa
36.7%
Microalgas são interessantes fontes de lipídeos para produção de biodiesel. No entanto, seus cultivos para tal finalidade são apenas viáveis do ponto de vista ambiental e econômico se apresentarem elevadas produtividades de biomassa e de lipídeos e estiverem associados ao uso de efluentes. A presente pesquisa estudou as condições de cultivo das microalgas Desmodesmus e Scenedesmus, considerando o conteúdo lipídico para produção de biodiesel, aliado à análise da eficiência de remoção de nutrientes pelas cepas, além da avaliação do efluente de reator UASB (esgoto sanitário) como meio alternativo ao cultivo. Dentre 22 cepas de microalgas isoladas de ambientes de água doce e lagoas de estabilização, 2 foram selecionadas para otimização de seus cultivos diante das suas capacidades de acumularem lipídeos e crescerem em diferentes condições físico-químicas. Delineamento Composto Central Rotacional (DCCR) foi aplicado para otimização das condições de crescimento celular das cepas LE17 (34,5ºC, pH 8,2 e 200 μmol.m-2.s-1) e ITU07 (34ºC, pH 8,2 e 180 μmol.m-2.s-1). Definidas as condições ótimas, foram realizados os cultivos mixotróficos das cepas em batelada (8 litros) em meio sintético e em efluente de reator UASB (50%). Nos cultivos em efluente de reator UASB as produtividades de biomassa das cepas LE17 e ITU07 foram...

Influência da carga orgânica e do tempo de enchimento na produção de biohidrogênio em AnSBBR com agitação tratando água residuária sintética; Influence of organic loading rate and fill time on biohydrogen production in an AnSBBR with agitation treating synthetic wastewater

Inoue, Rafael Katsunori
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: dissertação de mestrado Formato: application/pdf
Publicado em 28/03/2013 Português
Relevância na Pesquisa
46.27%
Este estudo investigou a aplicação de um reator anaeróbio operado em bateladas sequenciais com biomassa imobilizada (AnSBBR) com agitação na produção de biohidrogênio tratando água residuária sintética a base de sacarose, sendo o desempenho do biorreator avaliado de acordo com a influência conjunta do tempo de alimentação, do tempo de ciclo, da concentração afluente e da carga orgânica volumétrica aplicada (COVAS). O biorreator, com capacidade útil de 5,6 L, foi dividido em 3 partes: volume de meio tratado por ciclo de 1,5 L, volume residual de meio de 2,0 L e volume de suporte inerte com biomassa de 2,1 L. Foram aplicadas 6 condições experimentais de COVAS de 9,0 a 27,0 gDQO.L-1.d-1, combinado diferentes concentrações afluentes (3500 e 5400 mgDQO.L-1), tempos de ciclo (4, 3 e 2h), sendo tempo de enchimento do reator (tC) correspondente a 50% ao tempo de ciclo. Os resultados mostraram que o aumento COVAS contribuiu para a queda no consumo de sacarose de 99% para 86% e para o aumento do rendimento molar por carga removida (RMCRC,n) de 1,02 molH2.molSAC-1 na COVAS de 9,0 gDQO.L-1.d-1 até atingir o valor máximo de 1,48 molH2.molSAC-1 na COVAS de 18,0 gDQO.L-1.d-1 com queda a partir desse ponto. O aumento da COVAS resultou no aumento da produtividade molar volumétrica (PrM) de 24...

Biorreator à membrana aplicado ao tratamento de efluentes

Giacobbo, Alexandre
Tipo: dissertação Formato: application/pdf
Português
Relevância na Pesquisa
36.52%
A preocupação com a qualidade das águas está intensificando estudos com tecnologias avançadas para tratamento de efluentes. Uma tecnologia promissora no Brasil é a de biorreatores à membrana (MBR), pois há a possibilidade de trabalhar com altas taxas de aplicação e ainda pode obter um efluente tratado passível de reuso. Assim, o presente trabalho teve por objetivo estudar um MBR com módulo de membranas externo. Para tanto, foram estipulados os parâmetros operacionais em ensaios preliminares, tais como compactação da membrana, permeabilidade hidráulica e permeabilidade ao lodo ativado. Desta forma, efetuou-se a montagem do MBR, o qual foi inicialmente alimentado com um efluente sintético e posteriormente com efluente de curtume coletado pós-tratamento convencional. Operando com efluente sintético, obteve-se redução superior a 95% para DQO e turbidez. Com efluente de curtume pós-tratamento, obteve-se eficiência de 46%, 88%, 16%, 67% e 48% para DQO, DBO5, NTK, P-Total e cromo, respectivamente. Ademais, após 15 dias de operação, o sistema estabilizou com fluxo permeado elevado: 43 L/m².h.; The preoccupation with the quality of water resources is intensifying studies about advanced technologies for wastewater treatment. A promising technology in Brazil is the membrane bioreactors (MBR)...

Chlorine disinfection of dye wastewater: Implications for a commercial azo dye mixture

Vacchi, Francine Inforçato; Albuquerque, Anjaina Fernandes; Vendemiatti, Josiane Aparecida; Morales, Daniel Alexandre; Ormond, Alexandra B.; Freeman, Harold S.; Zocolo, Guilherme Julião; Zanoni, Maria Valnice Boldrin; Umbuzeiro, Gisela
Tipo: Artigo de Revista Científica Formato: 302-309
Português
Relevância na Pesquisa
36.5%
Azo dyes, the most widely used family of synthetic dyes, are often employed as colorants in areas such as textiles, plastics, foods/drugs/cosmetics, and electronics. Following their use in industrial applications, azo dyes have been found in effluents and various receiving waters. Chemical treatment of effluents containing azo dyes includes disinfection using chlorine, which can generate compounds of varying eco/genotoxicity. Among the widely known commercial azo dyes for synthetic fibers is C.I. Disperse Red 1. While this dye is known to exist as a complex mixture, reports of eco/genotoxicity involve the purified form. Bearing in mind the potential for adverse synergistic effects arising from exposures to chemical mixtures, the aim of the present study was to characterize the components of commercial Disperse Red 1 and its chlorine-mediated decoloration products and to evaluate their ecotoxicity and mutagenicity. In conducting the present study, Disperse Red 1 was treated with chlorine gas, and the solution obtained was analyzed with the aid of LC-ESI-MS/MS to identify the components present, and then evaluated for ecotoxicity and mutagenicity, using Daphnia similis and Salmonella/microsome assays, respectively. The results of this study indicated that chlorination of Disperse Red 1 produced four chlorinated aromatic compounds as the main products and that the degradation products were more ecotoxic than the parent dye. These results suggest that a disinfection process using chlorine should be avoided for effluents containing hydrophobic azo dyes such commercial Disperse Red 1. © 2012 Elsevier B.V..

SBR performance for synthetic and fishery wastewater treatment

Mesquita, D. P.; Ribeiro, R. R.; Teixeira, D.; Ferreira, E. C.; Coelho, M. A. Z.
Tipo: info:eu-repo/semantics/conferenceobject
Publicado em 07/04/2008 Português
Relevância na Pesquisa
56.61%
The evaluation of a SBR performance treating synthetic and fishery wastewater was performed. Without salt addition, COD and ammonia removal rates over than 50% were obtained, indicating the occurrence of the first nitrification step and COD removal. With 0.5% salt, removal rates lower than 60% were attained, for ammonia removal efficiency probably due to ionic strength changes and cellular plasmolysis leading to inactivation of the nitrification organisms. The SBR performance was greater for synthetic wastewater, due to the inherent and controlled characteristics. For both, lower SVI were achieved as a valuable indicator towards the assessment of the aggregated biomass structure.; National Council of Scientific and Technological Development of Brazil (CNPq); BIEURAM III ALFA co-operation project (European Commission).

Biomass fly ashes as low-cost chemical agents for Pb removal from synthetic and industrial wastewaters

Barbosa, Rui; Lapa, N.; Lopes, M. Helena; Gunther, Annika; Dias, Diogo; Mendes, Benilde
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em //2014 Português
Relevância na Pesquisa
36.56%
The main aim of this work was to study the removal efficiency of Pb from synthetic and industrial wastewaters by using biomass fly ashes. The biomass fly ashes were produced in a biomass boiler of a pulp and paper industry. Three concentrations of Pb2+ were tested in the synthetic wastewater (1, 10 and 1000 mg Pb/L). Moreover, two different wastewaters were collected in an industrial wastewater treatment plant (IWWTP) of an industry of lead-acid batteries: (i) wastewater of the equalization tank, and (ii) IWWTP effluent. All the wastewaters were submitted to coagulation–flocculation tests with a wide range of biomass fly ashes dosage (expressed as Solid/Liquid – S/L – ratios). All supernatants were characterized for chemical and ecotoxicological parameters. The use of biomass fly ashes has reduced significantly the Pb concentration in the synthetic wastewater and in the wastewaters collected in the IWWTP. For example, the definitive coagulation–flocculation assays performed over the IWWTP effluent presented a very low concentration of Pb (0.35 mg/L) for the S/L ratio of 1.23 g/L. Globally, the ecotoxicological characterization of the supernatants resulting from the coagulation–flocculation assays of all wastewaters has indicated an overall reduction on the ecotoxicity of the crude wastewaters...

Enhancement of the performance of an anaerobic sequencing batch reactor treating low-strength wastewater through implementation of a variable stirring rate program

Rodrigues,J. A. D.; Pinto,A. G.; Ratusznei,S. M.; Zaiat,M.; Gedraite,R.
Fonte: Brazilian Society of Chemical Engineering Publicador: Brazilian Society of Chemical Engineering
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2004 Português
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46.45%
This work focuses on enhancement of the performance of an anaerobic sequencing batch reactor with a six-vertical-blade-disk-turbine impeller, containing granulated biomass treating low-strength synthetic wastewater, through a study of the feasibility of implementing a variable stirring rate program. The reactor was operated at 30ºC and a six-hour cycle was used to treat approximately 2.0 L of the synthetic substrate with a chemical oxygen demand (COD) of nearly 500 mg/L. Two different stirring rate program were implemented: a constant rate of 50 rpm and a variable rate consisting of 75 rpm for one hour, 50 rpm for four hours and 25 rpm for 0.5 hour. The last 0.5 hour of the cycle was used for the settling step. In both cases, a very short start-up period and unfiltered and filtered substrate removal efficiencies of 81% and 88%, respectively, were attained. However, use of the variable stirring rate enhanced efficiency of the reactor dynamics without impairing biomass morphology, thus resulting in a reduction in the total cycle time and a possible decrease in energy consumption. Additionally, a simplified model of the anaerobic metabolic activity, using apparent kinetic parameters, was proposed as a consecutive first-order kinetic model with substrate and total volatile acid residual concentrations in order to analyze how the variable stirring rate affects reactor performance.

A simplified analysis of granule behavior in ASBR and UASB reactors treating low-strength synthetic wastewater

Veronez,R. G.; Orra,A. A.; Ribeiro,R.; Zaiat,M.; Ratusznei,S. M.; Rodrigues,J. A. D.
Fonte: Brazilian Society of Chemical Engineering Publicador: Brazilian Society of Chemical Engineering
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2005 Português
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56.38%
This work presents an analysis of the changes observed in granule characteristics of sludge in the treatment of synthetic wastewater at a concentration of about 500 mgCOD/L in batch, fed-batch (ASBR) and continuous (UASB) bench-scale reactors under similar experimental conditions. Physical and microbiological properties of the granules were characterized as average particle size and sedimentation time and by optical and epifluorescence microscopy. Several samples were analyzed in order to identify the morphologies. Granules from sequencing batch and fed-batch reactors, either with or without mechanical mixing, did not undergo any physical or microbiological changes. However, during the experiment granules from the UASB reactor agglomerated due to the formation and accumulation of a viscous material, probably of microbial origin, when operated at low superficial velocities (0.072, 0.10 and 0.19 m/h). When the superficial velocity was increased to 8.0-10.0 m/h by means of liquid-phase recirculation, the granules from the UASB reactor underwent flocculation and the microbiological characteristics changed in such a way that the equilibrium of microbial diversity in the inoculum was not maintained. As a result, the only reactor that maintained efficiency and good solids retention during the assays was the ASBR...

Immobilized Biofilm in Thermophilic Biohydrogen Production using Synthetic versus Biological Materials

Wongthanate,Jaruwan; Polprasert,Chongrak
Fonte: Instituto de Tecnologia do Paraná - Tecpar Publicador: Instituto de Tecnologia do Paraná - Tecpar
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2015 Português
Relevância na Pesquisa
36.62%
Biohydrogen production was studied from the vermicelli processing wastewater using synthetic and biological materials as immobilizing substrate employing a mixed culture in a batch reactor operated at the initial pH 6.0 and thermophilic condition (55 ± 1ºC). Maximum cumulative hydrogen production (1,210 mL H2/L wastewater) was observed at 5% (v/v) addition of ring-shaped synthetic material, which was the ring-shaped hydrophobic acrylic. Regarding 5% (v/v) addition of synthetic and biological materials, the maximum cumulative hydrogen production using immobilizing synthetic material of ball-shaped hydrophobic polyethylene (HBPE) (1,256.5 mL H2/L wastewater) was a two-fold increase of cumulative hydrogen production when compared to its production using immobilizing biological material of rope-shaped hydrophilic ramie (609.8 mL H2/L wastewater). SEM observation of immobilized biofilm on a ball-shaped HBPE or a rope-shaped hydrophilic ramie was the rod shape and gathered into group.