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%.

RESUMOA água residuária do café (ARC), originada no processamento dos frutos do cafeeiro, produz quantidade considerável de biogás que pode e deve ser utilizado como fonte de energia alternativa e complementar. Neste trabalho, foi estudada a variação da concentração de metano do biogás produzido a partir das ARC, por tratamento anaeróbio, em reator UASB, em escala laboratorial. As amostras foram coletadas durante 86 dias. As análises da concentração de metano foram realizadas por cromatografia gás-sólido (CGS). A produção de biogás e de metano, foi de 0,545 a 0,602 m 3 kg -1 DQO removida e de 0,382 a 0,421 m 3 kg -1 DQO removida, respectivamente. Os resultados da concentração de metano no biogás variaram de 48,60 a 68,14 %, influenciados pela variação dos parâmetros temperatura, pH, acidez e compostos fenólicos presentes nas ARC. Como havia sido previsto, as maiores concentrações de metano foram verificadas nos períodos em que o pH estava mais próximo da neutralidade.Termos para indexação: Tratamento anaeróbio, reator UASB, cromatografia gasosa, metano. ABSTRACTThe wastewater produced from wet coffee processing (WCP), originated from the coffee fruits, can produce great quantities of biogas, which, in turn, can be also used as an alternative or complementary energy source. In this research, we studied the variation of methane concentration produced by WCP in a laboratory-scale UASB reactor with anaerobic treatment. The samples were collected during a period of 86 days. The methane concentration was measured through gas solid chromatography (GSC). The production of biogas and methane ranged from 0.545 to 0.602 m 3 kg -1 DQO removed and from 0.382 a 0.421 m 3 kg -1 DQO removed, respectively. Methane presence in the biogas ranged from 48.60% to 68.14 %. This variation was influenced by the following parameters: temperature, pH, acidity, and phenol compounds present in the WCP. As expected, greater concentrations of methane gas were verified during the periods when the pH close to neutral.

This study evaluated the treatment of wastewater from coffee wet processing (WCWP) in an anaerobic treatment system at a laboratory scale. The system included an acidification/equalization tank (AET), a heat exchanger, an Upflow Anaerobic Sludge Blanket Reactor (UASB), a gas equalization device and a gas meter. The minimum and maximum flow rates and volumetric organic loadings rate (VOLR) were 0.004 to 0.037 m 3 d-1 and 0.14 to 20.29 kgCOD m-3 d-1 , respectively. The kinetic parameters measured during the anaerobic biodegradation of the WCWP, with a minimal concentration of phenolic compounds of 50 mg L-¹, were: Y = 0.37 mgTVS (mgCOD removed)-1 , K d = 0.0075 d-1 , Ks = 1.504mg L-1 , μ max = 0.2 d-1. The profile of sludge in the reactor showed total solids (TS) values from 22,296 to 55,895 mg L-1 and TVS 11,853 to 41,509 mg L-1 , demonstrating a gradual increase of biomass in the reactor during the treatment, even in the presence of phenolic compounds in the concentration already mentioned.