The Primary Study For Excess Sludge Reduction Of Two Of Microfauna

with the more and more excess sludge and the environmental and legislative requirements ,the cost of excess sludge disposal becomes higher and higher. New technologies for excess sludge reduction are thus in a urgent need. As one of ecological approaches, reduction of excess sludge through predation of micro faunal has been paid more and more attention since it requires a little energy and brings no second pollution.In this thesis, the performance of sludge reduction in a conventional activated sludge process where Aeolosoma hempfichicii (one species of oligochaeta) and physa acuta(one species of gastropoda) were induced as the two of micro faunal ,whose effects on the sludge reduction ,at the same time,were investigated. The sludge yield was experimentally found to be in a negative correlation to the density of Aeolosoma hempfichicii and physa in the activated sludge reactor. In the running activated sludge system, when the density of Aeolosoma hempfichicii was up 50 ind/ml, the sludge reduction by Aeolosoma hempfichicii was 20-30%;whereas when physa was about 5ind/l, the sludge reduction was 8-16%.More experiments showed that the two of micro faunal have no side-effects on wastewater disposal in given density of the micro faunal. The existence of Aeolosoma hempfichicii and physa did not affect COD, NH4+-N and P removals in the process. Aeolosoma hempfichicii could improve but physa was independent of the sludge settlement.The method of quinone profiles, since the two of micro faunal were induced in a activated sludge reactor, was used to evaluate the changes in microbial diversity based on the new diversity index of the respiratory quinines(DQ)and an index of equitability of the distribution of quinine species(EQ),and the changes in the microbial community were analyzed .The results indicated microbial diversity and equitability of the distribution ofmicrobial species were not both changed obviously in response to the two of micro faunal. Moreover, the HPLC' s experimental conditions were briefly discussed.