ASABE Technical Library - Abstract

Abstract. Aerobic process was the most common method utilized in treatment of domestic sewage. However, its intensive energy input for aeration is the major disadvantage need be considered. The objective of this study is to combine the anaerobic fermentation with entrapped mixed microbial cells (EMMCs) for the treatment of low concentration domestic sewage and methane production. The inoculum used was the anaerobic sludge from a swine wastewater treatment system. An anaerobic reactor was installed with 3 L working volume and the packing ratio of EMMCs was 50%. System was operated in a continuous mode, and the reactor temperature was controlled at 37±1°C using a water bath. To start up, a synthetic wastewater of 475 mg TCOD/L was fed as substrate with an HRT of 12 hours till 65% of the methane component was observed. After start-up, feeding substrate was changed to real domestic wastewater. With an influent concentration of 381±102 mg TCOD/L, 6 tests have been conducted by gradually decreasing HRT from 12, 6, 4, 3, 2.4 to 2 hours. Depends on the HRT, effluent was sampled at least twice a day in each test. During experiment, TCOD, soluble COD, pH, gas production and gas component was monitored. Experimental results showed above 92% of TCOD removal efficiency was achieved, and the maximum gas production rate and methane component of 0.230 L CH₄/L/d and 59.8% were observed respectively, at an HRT of 4 hours.