A Study on Microbiological Control on Chironomid Pollution in City Water Supply

Abstract:

Aimed at effect of microbiological control on Chironomidae in water plants，LC₅₀ of a produce of Bacillus thuringiensis subsp. iaraelensis (Bti) on Chironomus was tested，and a spot experiment was carried through in a water plant polluted by Chironomus.Resultes showed，LC₅₀ of Bti on Chironomus was 0.318mg/L，Chironomus Larvae were killed by Bti in 24 hours，adults cleared away in 36 hours，and the sedimentation tank had been kept from Chironomid pollution for longer than 10 weeks.The charge of microbiological-control on Chironomid pollution is third of that of chlorine.It is indicated that microbiological control is effective and ecnomic in Chironomid pollutioncontrol in city water supply.

Key words:City water supply，Chironomus，Bti，Microbiological control，LC₅₀，Economic analysis