We examined a field test plant based on anaerobic sewage treatment to elucidate the process of methane fermentation with a UASB in municipal sewage and domestic waste water.
The process consists of a pretreatment system for sparating suspended solids, a hydrolyzation reactor with a membrane module for organic solids, and a UASB reactor. The membrane module increases the sludge residence time in the hydrolyzation reactor. This field test plant is a commercial size system which combines these processes to verify the feasibility of the system.
The aim of this practical test is to produce gas with a conversion rate of over 60% when the volumetric organic loading rate is more than 2 kg BOD/reactor m3.d, and to construct a methane gas generation system which generates the gas from raw sewage. This practical test demonstrated gas conversion rates from 57% to 60.0%. Volumetric organic loading rate was 1.4 - 2.0 kg BOD/m3.d; BOD removal was 70 - 80% at ambient temperature, and excess sludge did not exceed 0.04 kg per sewage.m3.