Nitrification and heterotrophic bacteria that was screened and separated from digestion sludge is used to treat schoolyard domestic sewage.

Based on the principle of active biofilm expansion , a non-steady state analytic mathematical model of microbial interactions in nitrifying biofilm was developed.

In addition, by comparing the effect of UYJ to that of UJ, it could be speculated that the microbial agent inhibited nitrification insignificantly in tea garden soil with rich organic matter.