Produção de biogás no tratamento dos efluentes líquidos do processamento de Coffea arabica L. em reator anaeróbico UASB para o potencial aproveitamento na secagem do café

Abstract

RESUMOEstudou-se a produção de biogás proveniente do tratamento das águas residuárias do processamento por via úmida do café (ARC) coco em sistema de tratamento anaeróbio em escala laboratorial. O sistema foi composto de um tanque de acidificação e equalização (TAE), um reator anaeróbio de manta de lodo e fluxo ascendente (UASB), uma lagoa aerada facultativa (LAF) Termos para indexação: Café, águas residuárias, tratamento anaeróbio, metano. ABSTRACTIt was studied the biogas production through the treatment of the wet processing coffee wastewaters (ARC) in an anaerobic treatment system in laboratorial scale. The system used was composed by one acidification and equalization tank (TAE), one anaerobic upflow sludge blanket reactor (UASB), one facultative aerated pond, one equalization tank and one gas tank. The treatment was carried out for 190 days and the pH was controlled for some periods by adding NaOH inside of the TAE or in the UASB. In the UASB reactor the maximum and minimum values obtained in the inlet were 235 to 7064 mg. . The biogas presented a theoretical production of the 0,545 to 0,602 m 3 .Kg -1 BOD 5 and methane percentage from 48,60 to 68,14%.

Performance of UASB reactors in two stages followed by post-treatment with activated sludge in wastewater batch of wet-processed coffee

“…In general, in anaerobic reactors, effluents that fit completely in the patterns of Brazilian environmental legislation are not produced. Therefore, it is necessary to use a system of posttreatment to the polishing of these effluents, as was also observed by PRADO & CAMPOS (2008) and SELVAMURUGAN et al (2010b). The use of post-treatment systems with activated sludge its becoming a viable alternative to improve the quality of effluents from anaerobic reactors (CHERNICHARO, 2007).…”

“…The results of these studies confirmed that the concentrations of phenols contained in wastewater from wet-processed coffee were not toxic to anaerobic microbiota and can be reduced in UASB reactors in two stages under the conditions studied. However, with higher VOL, such as those applied by PRADO & CAMPOS (2008), the removal of phenols may decrease. With the inclusion of post-treatment with aerobic stage this problem could be mitigated.…”

“…These values of removal efficiency can be considered high and attributed to the use of UASB reactors in two stages, mainly for TKN, because PRADO & CAMPOS (2008) with a UASB reactor operated with HRT from 8.04 to 69.67 h observed smaller removals, of at most 35% for TKN and 61% for total P. With the optional aerated pond in series, the authors observed increased removal of TKN to 60% and of total P to 81%, confirming that the use of aerobic post-treatment can dramatically reduce the concentrations of N and P in the final effluent.…”

“…For the treatment of such wastewaters, the upflow anaerobic sludge blanket (UASB) can be efficient in removing higher organic loading, solids and toxic organic compounds, and in the production of methane for use in the coffee drying as was observed by SILVA & CAMPOS (2005), BRUNO & OLIVEIRA (2008), PRADO & CAMPOS (2008), PRADO et al (2010), SELVAMURUGAN et al (2010a and b). However, in the treated effluent, some control parameters still do not meet the thresholds set out in Resolutions 357 and 430 of the Brazilian National Environment Council -CONAMA (BRAZIL, 2005 and for the release into water bodies, requiring improved treatment system.…”

Tratamento das águas do processamento dos frutos do cafeeiro em filtro anaeróbio seguido por sistema alagado construído: I - remoção de matéria orgânica

“…Provavelmente, devido às menores cargas de SST aplicadas, quando comparadas às de ST. Além disso, a maior parte dos SSTs apresentou-se na forma orgânica (SSV) (Tabela 1), o que pode ter facilitado o processo de degradação. Verificou-se que as cargas orgânicas aplicadas neste trabalho estão em conformidade com aquelas encontradas na literatura para o tratamento de águas residuárias provenientes da cadeia produtiva do café, em reatores anaeróbios (BRUNO & OLIVEIRA, 2008;PRADO & CAMPOS, 2008;LUIZ, 2007;DINSDALE et al, 1996). Entretanto, em relação às cargas aplicadas aos SACs, estas foram bem superiores às cargas recomendadas para o tratamento de efluentes domésticos que, segundo USEPA (2000), deve variar de 60 a 133 kg ha -1 d -1 de DBO, mas em conformidade com os autores que avaliaram o tratamento de águas residuárias que apresentam compostos recalcitrantes como a ARC (MASBOUGH et al, 2005;TAO et al, 2006;CALHEIROS et al, 2007;SOHSALAM & SIRIANUNTAPIBOON, 2008 …”