2006 Volume 12 Issue 3 Pages 181-187
Several experimental conditions on colony formation unit (CFU) of activated sludge heterotrophic bacteria including ultrasonic homogenization, incubate temperature, agar types, and nutrient composition of agar media were investigated. CFU with 10 fold dilution of Tripticase Soy Agar (TSA), TSA 10%, were relatively larger than CFU with other agar media, and TSA 10% was regarded as a standard agar media for activated sludge heterotrophic bacteria especially cultivated in a laboratory with sterilized substrate. Judging from the results of the correlation analysis of CFU with agar media, NA could be appropriate agar media for a full-scale plant (FSP). Relatively larger CFU with ASEA showed possibility of the activated sludge extract should contain more appropriate nutrient for bacteria in the activated sludge besides its composition should differ by the activated sludge. High correlation between CFU with TSA 10% and CFU with other agar media were not observed except for NA and TSA, which might due to higher variety of bacteria grew on each agar media applied in this study. In other words, higher selectivity of agar media against bacteria growth was demonstrated through the data analysis.