Quantitative study of activated sludge population structure

Abstract A quantitative study of the population structure activated sludge is an important component biological wastewater treatment control. However, in studying live samples sludge, some complications arise, particular, associated with relatively short time subsample suitability. part sample that placed on a glass slide and which organisms are counted. The issue optimization counts large amplitude density considered. results counting ciliated protozoa were described. counted 45 sub-samples 25 µl each. An average 10 was required to achieve high reliability determining densities more than or equal 1 specimen per sub-samples. For small (less one µl) free-swimming, crawling, sessile ciliates, 30 necessary. When colonial protozoan populations established, number should be increased 40, especially when colonies significant differences zooids found.