High rate anaerobic treatment of coffee processing wastewater using upflow anaerobic hybrid reactor

The present study is an attempt to treat the coffee processing wastewater using upflow anaerobic hybrid reactor which offers the advantage of both suspended and attached growth anaerobic reactor systems. Upflow anaerobic hybrid reactor with a volume of 19.5 L was operated at 24 h hydraulic retention time. After the startup period, the reactor was evaluated by operating at different hydraulic retention times of 24, 18, 12 and 6 h. The reactor performed better at HRT=18 h with short period of time. At 18 h retention time, reduction of chemical oxygen demand, biochemical oxygen demand and total solids were 61.0, 66.0 and 58.0 per cent, respectively, with organic loading rate of 9.55 kg/m 3 /day. The maximum quantity of biogas produced were 840, 775 and 430 L/kg of TS, BOD and COD removal, respectively, with the methane content of 60.7% at HRT=18 h. The finding of the study helps to design low cost and compact onsite treatment systems with a very short retention period