COD reduction in sugar mill effluent and methane production using upflow an aerobic sludge fixed-film digestion

Abstract

This study was conducted to design and construct an Upflow Anaerobic Sludge Fixed-Film Digester and to determine the effectiveness of digesting sugar mill effluents by anaerobic digestion. The results were compared to the current Ponding process of POME in terms of percent COD removal, COD retained, and COD removed in each HRT cycle (1.5 days), and to determine the presence of methane. The UASFF digester was designed to utilize the sugar mill effluent by maintaining a pH level of 6.8, the Hydraulic Retention Time (HRT) at 36 hours or 1.5 days, and a flow rate of 2.2 mL/min for optimal digestion process throughout the study. Results showed that the digester was able to purify at least 4L of effluent at the HRT of 36 hours. At HRT 7, the percent COD removal reached the highest of around 81.87%. As for the lowest, the 1st HRT cycle excluding the 0th HRT cycle has a value of 58.27%. The effect was minimal despite the increasing COD removal and stabilizing at around 80%. The presence of methane was determined to be present with the use of a gas tester.