Application of yeast to treatment of MSG wastewater containing high concentrations of ammonium and sulfate

摘要

Of the ten strains of yeast isolated from soil samples contaminated with monosodium glutamate (MSG) manufacturing wastewater, four strains demonstrated high COD removal efficiency and were selected for MSG wastewater treatment. The mixture of the 4 strains grew well even in raw wastewater (containing 24125mg·l~(-1) COD, 18977mg·l~(-1) NH_4~+-N and 20706mg·l~(-1) SO_4~(2-)) and could endure 30% (NH_4)_2SO_4 in nitrogen free artificial minimal medium. The optimal pH for COD removal was 4.0-4.5, and supplementation of phosphate of 0.5g·l~(-1) increased reaction rate. The reducing sugar was removed effectively, and a COD removal of 84.5% and BOD_5 removal of 99% were respectively obtained when MSG wastewater diluted by 2 times was treated by yeast. A bench-scale column-type yeast biofilm reactor was used for continuous treatment of MSG wastewater, and the COD removal remained to be over 80% even when raw MSG wastewater was fed into the column directly. The pH variation in a range between 2.9 and 6.0 in yeast column had no significant effect on COD removal. In order to keep the superiority of yeast in the column, however, the pH should be not over 6.0.