REMOÇÃO DE MATÉRIA ORGÂNICA E NITROGÊNIO EM REATOR HÍBRIDO ANAERÓBIO/AERÓBIO/ANÓXICO OPERADO EM BATELADAS SEQUENCIAIS

O crescimento urbano, sem o acompanhamento de sistema de esgotamento sanitário, induz a uma tendência de descentralização de estações de tratamento de efluentes (ETEs), visando à remoção não só de matéria orgânica carbonácea, mas também a remoção/recuperação de nutrientes. O nitrogênio, além de causar problemas de eutrofização em corpos de água, pode levar à contaminação de águas superficiais e subterrâneas por nitrato, cuja ingestão está associada a efeitos adversos à saúde. Este trabalho apresenta e discute o desempenho de um Reator em Bateladas Sequenciais (RSB), tratando esgoto sanitário, em escala de bancada, operando com ciclos de 24 horas, a fim de remover matéria orgânica e nitrogênio, tendo a fase de reação submetida a períodos anaeróbio, aeróbio e anóxico, com o intuito de avaliar o potencial de incorporação desta tecnologia como opção no tratamento descentralizado de esgotos em empreendimentos residenciais e comerciais. Os resultados mostraram um rápido estabelecimento de eficiência conjunta de remoção de DQO de 70% e de nitrogênio de 42%, mesmo sem utilizar fonte externa de carbono. Conclui-se que o RSB se apresenta como uma alternativa atraente para aplicação no meio urbano, minimizando os impactos de lançamento dos esgotos no solo, nos sistemas urbanos de drenagem, em corpos de água, bem como atende os padrões ambientais de lançamento. REMOVAL OF ORGANIC MATTER AND NITROGEN IN ANAEROBIC/ANOXIC HYBRID REACTOR OPERATED ON SEQUENTIAL BATCHESUrban growth without the accompaniment of a sewage system leads to a trend towards decentralization of effluent treatment stations (ETEs), aiming at the removal not only of carbonaceous organic matter, but also the removal / recovery of nutrients. Nitrogen, in addition to causing eutrophication problems in bodies of water, can lead to contamination of surface and groundwater by nitrate, the intake of which is associated with adverse health effects. This work presents and discusses the performance of a Sequential Batch Reactor (RSB), treating sanitary sewage, on a bench scale operating with 24-hour cycles, aiming at the removal of organic matter and nitrogen, with the reaction phase submitted to anaerobic periods, aerobic and anoxic, in order to evaluate the potential of incorporating this technology as an option in the decentralized treatment of sewage in residential and commercial enterprises. The results showed a rapid establishment of joint efficiency in removing COD of 70% and nitrogen of 42%, even without using an external carbon source. It is concluded that the RSB presents itself as an attractive alternative for application in the urban environment, minimizing the impacts of the discharge of sewers in the soil, in the urban drainage systems, in bodies of water and meeting the environmental standards of release

Dynamics of sulfidogenesis associated to methanogenesis in horizontal-flow anaerobic immobilized biomass reactor

Two bench-scale horizontal anaerobic fixed bed reactors were tested to remove both sulfate and organic matter from wastewater. First, the reactors (R1 and R2) were supplied with synthetic wastewater containing sulfate and a solution of ethanol and volatile fatty acids. Subsequently, RI and R2 were fed with only ethanol or acetate, respectively. The substitution to ethanol in R1 increased the sulfate reduction efficiency from 83% to nearly 100% for a chemical oxygen demand to sulfate (COD/sulfate) ratio of 3.0. In contrast, in R2, the switch in carbon source to acetate strongly decreased sulfidogenesis and the maximum sulfate reduction achieved was 47%. Process stability in long-term experiments and high removal efficiencies of both organic matter and sulfate were achieved with ethanol as the sole carbon source. The results allow concluding that syntrophism instead of competition between the sulfate reducing bacteria and acetoclastic methanogenic archaeal populations prevailed in the reactor. (C) 2009 Elsevier Ltd. All rights reserved.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) of Brazi

Determining the distribution of granule diameter from biological sludge

Anaerobic granule sizes from various types of anaerobic biological wastewater treatments were investigated in order to understand the influence of this characteristic on the performance of the treatment system. To date, there is no standardised methodology in the current literature, which provides details of a process to obtain data, such as a suitable sample volume, a description of the precision and limitations of the techniques used. Therefore, the aim of this protocol is to standardise the granulometry assay that can measure granule sizes accurately and quickly. In addition, the proposed methodology comprises about 1500–3000 granules in a single sample, a representative number compared to the currently applied methodologies. Keywords: Granulometry assay, Granulometric biological sludge, Granules siz

Characterizing phenol-removing consortia under methanogenic and sulfate-reducing conditions: potential metabolic pathways

Phenol removal was investigated in anaerobic fixed-structured bed reactors, namely R1 and R2, treating synthetic wastewater simulating the soluble fraction of vinasse under strictly methanogenic (R1) and simultaneous methanogenic/sulfidogenic conditions (R2). Next-generation sequencing (Illumina MiSeq System) was used to further characterize the microbial communities in both systems. Phenol was completely and stably removed in R1 after a short operating period (approximate to 55 days). Conversely, phenol removal in R2 required a longer period for biomass acclimation (approximate to 125 days) to reach levels equivalent to R1. Volatile fatty acids (VFA) accumulation in R2, mainly due to the inhibition of the acetoclastic methanogenesis by sulfide, may have limited phenol removal in the initial operating phases, as intermediate steps from phenol degradation are thermodynamically dependent on the removal of acetate, hydrogen and bicarbonate. Overall, the potential for anaerobically removing phenol from complex wastewaters was confirmed, even at low phenol/COD ratios. 16S rRNA gene sequencing analysis showed a high correlation of taxonomic profile between R1 and the inoculum, whereas a lower correlation was observed between R2 and the inoculum samples. Functional inference further indicated that Syntrophus and Bacillus genera in R1 and Clostridium genus in both reactors possibly played a key-role in phenol degradation402432163226CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP131014/2012-9sem informação2009/15984-

Performance evaluation of packing materials in the removal of hydrogen sulphide in gas-phase biofilters: Polyurethane foam, sugarcane bagasse, and coconut fibre

The main objective of this work was to investigate three packing materials (polyurethane foam, sugar-cane bagasse, and coconut fibre) for biofiltration of a gaseous mixture containing hydrogen sulphide (H(2)S). Mixed cultures were obtained from two sources, aerated submerged biofilters and activated sludge, and were utilised as inoculums. Biofilters reached 100% removal efficiency after two clays of operation. The empty bed residence time was 495 for each of the biofilters. The reactors were operated simultaneously, and the inlet concentrations of H(2)S varied between 184 and 644 ppmv during the long-term continuous operation of the biofilters (100 clays). Average removal efficiencies remained above 99.3%, taking into consideration the entire period of operation. Average elimination capacities reached by the biofilters packed with polyurethane foam, coconut fibre, and sugarcane bagasse were in the range of 17.8-66.6; 18.9-68.8, and 18.7-72.9g m(-3) h(-1), respectively. Finally, we concluded that the packing materials tested in this work are appropriate for the long-term biofiltration of hydrogen sulphide. (C) 2010 Elsevier B.V. All rights reserved.CNPqFAPESPCAPE

Long-term stability of hydrogen and organic acids production in an anaerobic fluidized-bed reactor using heat treated anaerobic sludge inoculum

This study evaluates the stability of hydrogen and organic acids production in an anaerobic fluidized-bed reactor (AFBR) that contains expanded clay (2.8-3.35 mm in diameter) as a support medium and is operated on a long-term basis. The reactor was inoculated with thermally pre-treated anaerobic sludge and operated with decreasing hydraulic retention time (HRT), from 8 h to 1 h, at a controlled temperature of 30 degrees C and a pH of about 3.8. Glucose (2000 mg L(-1)) was used as the substrate, generating conversion rates of 92-98%. Decreasing the HRT from 8 h to 1 h led to an increase in average hydrogen-production rates, with a maximum value of 1.28 L h(-1) L(-1) for an HRT of 1 h. In general, hydrogen yield production increased as HRT decreased, reaching 2.29 mol of H(2)/mol glucose at an HRT of 2 h and yielding a maximum hydrogen content of 37% in the biogas. No methane was detected in the biogas throughout the period of operation. The main soluble metabolites (SMP) were acetic acid (46.94-53.84% of SMP) and butyric acid (34.51-42.16% of SMP), with less than 15.49% ethanol. The steady performance of the AFBR may be attributed to adequate thermal treatment of the inoculum, the selection of a suitable support medium for microbial adhesion, and the choice of satisfactory environmental conditions imposed on the system. The results show that stable hydrogen production and organic acids production were maintained in the AFBR over a period of 178 days. (C) 2009 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.CNPqFAPES