The Treatment of Liquor Wastewater Containing High-Strength Suspended Solids by Membrane Bioreactor System

The wastewater from a Shochu liquor distillery contains high-strength organic compounds, especially ultra-high-strength suspended solids(SS). We investigated the treatment of the Shochu liquor wastewater using a pilot-scale membrane bioreactor system(MBS) for 190 days. The wastewater was fed to MBS at a concentration of 13,000 mg/l in SS and 40,000 mg/l in COD. It was proved that this system has a high performance in SS decomposition and organic compound elimination. The effluent BOD was less than 100 mg/l and the COD was less than 600 mg/l. The COD removal was more than 98 % at the COD loading rate of 7 kg/m3/d. More than 0.28 m3 of methane was obtained from 1 kg-COD. The VSS decomposition ratio calculated from a VSS balance was 85% and the VSS conversion ratio of feed COD was 0.057 kg-VSS/kg-COD. The withdrawal rate exerted the significant influence on the performance of the MBS.