Em feiras livres e centrais de abastecimento são produzidas quantidades bastante significativas de resíduos sólidos, com características favoráveis ao aproveitamento integral em processo de bioestabilização anaeróbia. O processo de bioestabilização é realizado em reatores anaeróbios de batelada (RAB), com tempo de detenção de sólidos variando de 250 a 300 dias originando, como produtos finais, o biogás, com cerca de 60% de gás metano, além de composto orgânico parcialmente bioestabilizado. Neste trabalho, foram utilizados resíduos sólidos orgânicos tipicamente vegetais, advindos de centrais de abastecimento, feiras livres e lodo de esgoto sanitário. O sistema experimental utilizado era constituído basicamente por um reator anaeróbio de batelada, com capacidade unitária de 2200 litros, além de outros dispositivos complementares. O sistema experimental foi instalado e monitorado na Estação Experimental de Tratamento Biológico de Esgoto Sanitário, situada no Bairro do Tambor, na cidade de Campina Grande, Estado da Paraíba, no período de janeiro a setembro de 2001. No processo de monitoração foram realizadas caracterizações sistemáticas das frações sólidas, líquidas e gasosas. Após análise dos dados, ficou evidenciada a viabilidade desta alternativa de tratamento, restando ser investigada ainda a viabilidade econômica, quando comparada com outras alternativas tecnológicas de tratamento de resíduos sólidos orgânicos.
Resumoobjetivo deste trabalho foi determinar a quantidade de resíduos da construção civil (RCC) em função da área construída da edificação, para efetuar acompanhamento e fiscalização mais eficazes da geração e destinação final em dada obra. Foi escolhida uma amostra representativa das edificações em fase de construção na cidade de João Pessoa. Uma ficha para coleta das características e acompanhamento de volume de RCC descartado ao longo do cronograma de execução da construção foi fornecida aos gestores das edificações; a partir do volume descartado pelas construtoras, determinou-se a massa de RCC gerado em cada obra utilizando uma massa unitária de 1.025 kg m-³. Os resultados indicaram uma taxa média de geração de RCC classe A de 86,27 kg m-². Ainda para os RCC classe A, foram definidos os limites inferior e superior com 90% de confiança para a taxa de geração: 62,31 e 136,02 kg m-² respectivamente. A partir desses valores, o controle da geração e disposição de RCC pode ser realizado pelos órgãos competentes, dando o indicativo de quais obras podem estar infringindo a legislação vigente no tocante à destinação de tais resíduos. Palavras-chave:Resíduos da construção. Quantificação. Gestão de resíduos. Abstract The aim of this study is to determine the amount of construction waste (CW) based on the built area of buildings, in order to
Studies on experimental primary facultative ponds showed that varying the depth from 1.25 m to 2.3 m had no effect on the rates of BOD removal. In contrast k values for FC removal rates were higher in the shallower (1.25 m) facultative ponds. The risk of odour release via H2S production was higher in the 2.2 m ponds than the 1.25 m ponds and NH3 removal was much better in the 1.25 m facultative ponds. A comparison of the efficiency of shallow 5-pond series (1.0 m and 0.61 m deep) with a 2.2 m deep series showed that the shallow systems were more efficient at FC removal, but the deeper series actually saved land area for the same FC final effluent quality under tropical conditions. However, efficient nutrient removal (N and P) only occurred in the shallow series and effluent standards for nutrient concentrations are unlikely to be met by 2.2 m deep 5-pond series in contrast to the norms for pathogen removal.
Avaliação da remoção de matéria orgânica de efluente de tanque séptico utilizando filtro anaeróbico preenchido com Luffa cylindrica como meio de suporte
Waste stabilization ponds are a well established wastewater treatment system being considered by World Health Organization as one of the most appropriated technology for domestic wastewater when agricultural reuse is considered, especially in developing countries. This study was performed in a series of pilot-scale stabilization ponds, being one facultative and three maturation ponds, with depths varying from 0.44 to 0.57 m. The substrate to be treated was composed of a mixture of domestic wastewater and previously anaerobicaly treated leachate. The experimental system was monitored in two different phases, in which the hydraulic retention times were 15 (phase 1) and 10 days (phase 2). Termotolerant coliform removal efficiencies were 3.8 log10 units in both phases while organic matter (BOD5) removal was 87 and 68% for phases 1 and 2, respectively
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This paper describes faecal coliform (FC) removal in pilot-scale Wastewater Storage and Treatment Reservoirs (WSTR) in northeast Brazil. FC decay during the filling phase of WSTR was very reduced, suggesting that these reactors should be filled as quickly as possible, and subjected to the highest organic loading that will not cause odour emissions. The highest loading employed in this study was 659 kgBOD5/ha.d, causing no nuisance conditions. During the resting phase, FC decay rate decreased exponentially and Chick's law was modified. The time into the resting phase for FC to reach 103 cfu/100 mL ranged from 15 to 25 days as WSTR depth varied from 2.00 to 6.50 m. The performance of sequential batch-fed waste stabilization ponds (SBFWSP) in removing FC was compared to that of waste stabilization ponds (WSP) operated in series. It was shown that, in general, SBFWSP were cheaper than WSP in series, with the bacteriological quality of the effluent in the former being more reliably predicted than in the latter operational regime. When provision of volume to store the winter effluents is considered, a WSP system presents a higher benefit/cost ratio than a hybrid WSP-WSTR system, but the adoption of the latter can double the annual net return for a rainy season of 5 months for instance. In the case of use of the hybrid WSP-WSTR system, the net return would be US$ 0.17 – 0.22 per cubic metre of available wastewater, depending on the length of the rainy season (3 – 5 months considered) as compared to US$ 0.12 from the WSP system alone.
This paper evaluates the performance of raw domestic sewage treatment by a single-stage vertical-flow constructed wetland (VFCW) installed in Northeastern Brazil, where sanitation coverage is low. Biological and physicochemical parameters were monitored for 1 year to evaluate the system's performance. The impact of factors such as operational cycle and filter media on VFCW pollutant removal efficiencies was investigated. The means of removal efficiencies of chemical oxygen demand (COD), biological oxygen demand (BOD), and ammonia were 74.2, 87.9, and 82.1%, respectively. A statistically significant influence (p < 0.05) of substrate material on COD and ammonia removal efficiency was found. Ceramic construction waste media achieved the best performances compared with the traditionally used material and concrete construction waste. Operational cycles of 3.5/7 and 7/14 days of the feeding/resting period did not present a statistically significant influence (p < 0.05) on pollutant removal efficiencies. The single-stage VFCW pilot plant achieved a better global treatment performance than other VFCW reported in the literature; however, it showed a limitation in removing TS. The reduced installation costs, in addition to operation and maintenance simplicity, indicate a potential for single-stage VFCW applicability in the sewage treatment of housing units and small communities in Brazil and possibly in other developing countries in tropical areas.
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