COMBUSTION and PYROLYSIS of A SLUDGE FROM WASTEWATER TREATMENT PLANT

The possibility of thermal treatment plants of municipal wastewater is an alternative solution for the final disposition of the sludge produced on small cities as Barueri, a small town of São Paulo State, Brazil. Combustion and pyrolysis of that municipal waste, occurring respectively in air and nitrogen, have been studied by thermogravimetry (TG) and differential thermal analysis (DTA). The main steps of each case were analyzed and Kissinger plots were used to estimate respective activation energies. DTG peaks are more indicated to represent the condition of maximum reaction rates than DTA peaks.

Thermoeconomic analysis applied to an alternative wastewater treatment

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Development of a methodology for cost determination of wastewater treatment based on functional diagram

This work describes a methodology developed for determination of costs associated to products generated in a small wastewater treatment station for sanitary wastewater from a university campus. This methodology begins with plant component units identification, relating their fluid and thermodynamics features for each point marked in its process diagram. Following, its functional diagram is developed and its formulation is elaborated, in exergetic base, describing all equations for these points, which are the constraints for exergetic production cost problem and are used in equations to determine the costs associated to products generated in SWTS. This methodology was applied to a hypothetical system based on SWTS former parts and presented consistent results when compared to expected values based on previous exergetic expertise. (C) 2008 Elsevier Ltd. All rights reserved.

Start-up of horizontal anaerobic reactors with sludge blanket and fixed bed for wastewater treatment from coffee processing by wet method

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Constructed wetland in wastewater treatment

Physical and chemical variables of soil and water were measured to determine the effectiveness of a constructed wetland for wastewater treatment. Eight different macrophyte species, namely Eichhornia crassipes, Alternanthera philoxerodos, Heteranthera reniformis, Hydrocotyle umbeliferae, Lidwigia elegan, Ludwigia sericea, Myriophyllum aquaticum and Thypha domingensis, were transplanted. Inlet water and outlet water were the two sampling sites evaluated. There were significant differences (p < 0,05) when limnological characteristics between inlet and outlet water from the constructed wetland were compared. In general, dissolved oxygen was over 4 mg L-1, and conductivity was high, above 80 μS cm-1. Chlorophyll-a levels generally tended to decrease at the wetland outlet and were higher during the rainy period (fish growth period). Results show that ammonia, total phosphorus, BOD5, phosphorus and organic mattel in the sediment removals in the constructed wetland were higher, indicating that macrophytes played an important role in removing these variables. The use of constructed wetland is a viable technology for the biological treatment in aquaculture and swine wastewater.

Anaerobic-aerobic treatment of swine wastewater in uasb and batch reactors in series

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Hydrodynamic characterization and performance evaluation of an aerobic three phase airlift fluidized bed reactor in a recirculation aquaculture system for Nile Tilapia production

The hydrodynamic characterization and the performance evaluation of an aerobic three phase fluidized bed reactor in wastewater fish culture treatment are presented in this report. The objective of this study was to evaluate the organic matter, nitrogen and phosphorous removal efficiency in a physical and biological wastewater treatment system of an intensive Nile Tilapia laboratory production with recirculation. The treatment system comprised of a conventional sedimentation basin operated at a hydraulic detention time HDT of 2.94 h and an aerobic three phase airlift fluidized bed reactor AAFBR operated at an 11.9 min HDT. Granular activated carbon was used as support media with density of 1.64 g/cm(3) and effective size of 0.34 mm in an 80 g/L constant concentration. Mean removal efficiencies of BOD, COD, phosphorous, total ammonia nitrogen and total nitrogen were 47%, 77%, 38%, 27% and 24%, respectively. The evaluated system proved an effective alternative for water reuse in the recirculation system capable of maintaining water quality characteristics within the recommended values for fish farming and met the Brazilian standards for final effluent discharges with exception of phosphorous values. (C) 2011 Elsevier B.V. All rights reserved.

Performance of an Anaerobic Baffled Reactor (ABR) in treatment of cassava wastewater

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The photoelectrocatalytic oxidative treatment of textile wastewater containing disperse dyes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Treatment of 1,10-phenanthroline laboratory wastewater using the solar photo-Fenton process

The red Fe2+-phenanthroline complex is the basis of a classical spectrophotometric method for determination of iron. Due to the toxicity of this complexing agent, direct disposal of the wastewaters generated in analytical laboratories is not environmentally safe. This work evaluates the use of the solar photo-Fenton process for the treatment of laboratory wastewaters containing phenanthroline. Firstly, the degradation of phenanthroline in water was evaluated at two concentration levels (0.1 and 0.01%, w/v) and the efficiencies of degradation using ferrioxalate (FeOx) and ferric nitrate were compared. The 0.01% w/v solution presented much higher mineralization, achieving 82% after 30 min of solar irradiation with both iron sources. The solar photo-Fenton treatment of laboratory wastewater containing, in addition to phenanthroline, other organic compounds such as herbicides and 4-chlorophenol, equivalent to 4500 mg L-1 total organic carbon (TOC) resulted in total degradation of phenanthroline and 25% TOC removal after 150 min, in the presence of either FeOx or ferric nitrate. A ratio of 1: 10 dilution of the residue increased mineralization in the presence of ferrioxalate, achieving 38% TOC removal after 120 min, while use of ferric nitrate resulted in only 6% mineralization over the same period. (c) 2007 Elsevier B.V. All rights reserved.

Electrolytic treatment of wastewater from a fowl slaughterhouse using cast-iron electrodes

A viability study of an electrolytic process for the transformation of organic matter and free sulphide contained in wastewater from a fowl slaughterhouse in order to minimise odours was carried out Cast iron and aluminium electrodes were tried at 7.09 mA/cm2, under strong agitation, at 297 K. Conductivity, pH, chemical oxygen demand (COD), amount of settleable solids, and sulphide content were monitored with electrolysis duration. The cast iron electrodes were found to be viable for the elimination of soluble sulphides in the wastewater, leading to the elimination of its strong odour after short times of electrolysis. A significant decrease in COD was also attained.

Anaerobic treatment of wastewater from coffee pulping in upflow anaerobic sludge blanket (UASB) in two stages

In this work, the efficiency of two-stage upflow anaerobic sludge blanket (UASB) reactors was evaluated in bench scale, for treating a liquid effluent from coffee pulping. Hydraulic detention times (HDT) were 4.0; 5.2 and 6.2 days, resulting in organic loading rates (OLR) of 5.8; 3.6 and 3.0g total COD per (L-d) in the first reactor (Rl) and HDT of 2.0; 2.6 and 3.1 days with OLR of 5.8; 0.5 and 0.4 g total COD per (L-d) in the second reactor (R2). The medium values of total COD affluent varied from 15.440 to 23.040 mg O 2/L, and in the effluent to the reactors 1 and 2 were from l.lOO to 11.500 mg 0 2/L and 420 to 9.000 mg O 2/L, respectively. The medium values of removal efficiencies of total COD and TSS varied from 66 to 98% and 93 to 97%, respectively, in the system of treatment with the UASB reactors, in two stages. The content of methane in the biogas varied from 69 to 89% in the Rl and from 52 to 73% in the R2. The maximum volumetric methane production of 0.483 m 3 CH 4per (m 3 reactor d) was obtained with OLR of 3.6 g total COD per (L reactor d) and HDT of 6.2 days in the Rl. The volatile fatty acids concentration was kept below 100mg/L with HDT of 5.2 and 6.2 days in the Rl and HDT of 2.6 and 3.1 days in the R2.

Rational use of residential digesters for sewage treatment with Carbon Credits

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Monitoramento de 24 horas do desempenho de reator aeróbio de leito fluidizado trifásico na remoção de amônio num sistema de recirculação para produção de tilápia

O objetivo deste trabalho foi monitorar o desempenho de remoção de nitrogênio amoniacal no tratamento das águas residuárias da produção intensiva de tilápia nilótica em sistema com recirculação de água. O sistema foi constituído por um sedimentador convencional e um reator aeróbio de leito fluidizado trifásico com circulação, operados com tempos de detenção hidráulica de 176.4 e 11.9 minutos respectivamente. O meio suporte utilizado no reator foi o carvão ativado granular com densidade aparente de 1.64 g/cm3 e tamanho efetivo de 0.34 mm; a concentração do meio suporte no reator foi mantida constante em 80 g/L. A eficiência média de remoção do nitrogênio amoniacal total foi de 41.2%. O sistema avaliado é uma alternativa efetiva para o reuso da água em sistemas de recirculação para aqüicultura. Embora a variabilidade das concentrações do nitrogênio amoniacal afluente cujo valor médio foi de 0.136 mg/L, o efluente do reator conservou as características de qualidade da água estáveis, com concentrações médias de nitrogênio amoniacal de 0.079 mg/L e do oxigênio dissolvido de 6.70 mg/L, recomendáveis para a criação dos peixes e nas faixas de valores permitidos pela legislação Brasileira (Resolução CONAMA No. 357 de março 5 de 2005) para lançamento de efluentes finais nos corpos de água receptores.