Abstract
We studied microbial population shifts in laboratory-scale synthetic-waste activated sludge from plant-scale sewage sludge on the basis of respiratory quinone profiles. The laboratory sludge reactors were seeded with the sewage sludge and operated on a fill-and-draw basis in a 24 h batch cycle with either raw domestic sewage or each of three different synthetic wastewaters containing acetate, glucose, skim milk, and/or peptone as a primary component. After two months of acclimation, the quinone compositions of the laboratory sludges were analyzed compared with the seed sludge. Numerical analysis of quinone profiles showed that there was no significant difference in population structures between the seed sludge and the laboratory sludge loaded with raw sewage, while significant population shifts occurred in the three synthetic-waste laboratory sludges. These results suggest that laboratory activated sludge loaded with synthetic wastewater can not be regarded as a model of plant-scale sewage sludge in their microbiological aspects.
