Study On Effect Of Sludge Reduction By Daphnia

The sludge disposal becomes more difficult than before, because of its more production and expensive disposal cost. The reduction of sludge, one of ecological approaches through predation of micro faunal, has been paid more attention because of its little energy waste and without the second pollution.Activated sludge treatment system is leading water treatment methods. Activated sludge treatment system result in a large number of sludge. There are a plenty of toxic and hazardous substances and unstabilized organic matter in the sludge. If not properly handled, it will result in direct or potential environmental contamination.In this paper, The daphnia function for sludge reduction was researched by compare the COD and SS of effluent water. The results indicated that:(1) Daphnia has strong ability to adapt to the environment, but the optimal environment for the growth of Daphnia is very narrow. the optimal for Daphnia grow is the temperature:24℃, PH:7,salinity:0.25%.(2) The breeding density of Daphnia in the external carrier should be much higher than the internal carrier,This shows that the growth of Daphnia in the suspension system is better than attachment-based growth system.(3) The average reproductive cycle of daphnia is three days and it's decay rate of one day is14.67%.(4) When 20 Daphnia were added, the COD removal rate is 47.52%.(5) Daphnia has the ability to prey bacteria and reduce sludge.