Abstract
The waste water treatment performance diagnosis seen from activated sludge which we provide is comprised of multiple evaluations on the biota by microscope observation that include the evaluation of protozoa as well as metazoa of the activated sludge, that of biological property of the sludge floc（aggregate of bacteria）, identification of emerging species and their volume among filamentous bacteria and actinomycetes, and further include the evaluation of the conditions of our original index organisms in the sludge.
The evaluation of the biota is done by using literature information and pragmatical indices established by the analysis of biotas and waste water treatment data collected from more than 200 waste water treatment facilities.
Therefore, with our diagnosis described above, we can understand the conditions of waste water treatment, problem and its cause more accurately than the conventional waste water treatment managing method using protozoa and metazoa as indices.
In this report, we would like to introduce you the examples where we applied the diagnosis for and successfully solved the problem of the rising of sludge interface and the floating of scum in the sedimentation tank as well as the issue of rising COD of treated water.
