Abstract
A new treatment process involving yeast utilization was developed to treat potent wastewater from a dried food products factory. Using wastewater, three yeast strains were isolated from an enrichment culture. The first treatment facility, seeded with the mixture of the isolated yeasts, was installed at the dried food products factory in 1989. After four years, the treatment performance was investigated for a year. The yeast treatment process was able to remove over 95% of BOD even when operating under extremely high loads of 16kg BOD·m-3·d-1, and responded to a load variation of 5-16kg BOD·m-3·d-1. Moreover, this process could decompose the suspended solids and reduce both air supply and sludge yield. On the other hand, the limitations of yeast treatment lay in terms of the quality of treated water. About 120mgl-1 of BOD always remained in the yeast treated water, and nitrogen and phosphorus could not be removed except for the amounts required for yeast cell synthesis. However, the quality of effluent could be improved by combining the yeast treatment and bacterial treatment processes.
