Research On Hazard Properties And Control Mersures Of Limnoperna Fortunei In Water Pipelines

Limnoperna fortunei has widely spreaded in the river of south China. When itflowed into the pipelines with running water,it would adhere to the surface of tubesand hard to be got down. After several years for its breeding, there would be a largenumber that bring adverse effect to water quality and water conveyance capacity.Nowadays, it lacks an effective method to control Limnoperna fortunei’s spread.This research made a deep study in such a situation. The research mainly includesthe the harm characteristics of Limnoperna fortunei, the effect of oxidativeinactivation. This paper comparied the synergy of water scouring and oxidativeinactivation with single function of water scouring, and then practiced in waterconveyance project, at last, put forward the comprehensive control measures.Through the hazard properties research, we found that Limnoperna fortuneiwas suitable for clean water. It could absorb the ammonia nitrogen from water andtransform it to nitrate nitrogen in life activities. The biomass increased rapidly andmost of all adhered to the surface of tubes so that the tube cross-sectional areaswere reduced and energy consumption had increased about10.5%.By monitoring the pH, water temperature, oxygen and algae concentrationand,we could see the grow condition and the law of Limnoperna fortunei group.Through observing the shell length, we could see the breeding period. Because ofthe poor resistance of the young shell to oxidants and the good inactivationefficiency in high density, breeding period and annual summer are best time to cleanthe tubes.Through the analysis and comparison of different oxidants’ inactivationexperiment, we got the result like that, sodium hypochlorite is an economicaloxidant which can kill Limnoperna fortunei and are appliced in many areas. It notonly has oxidation action to kill the shells, but also can dissolve the foot silks thatreduce its adhesion ability, making it easier to be washed down by water. Improvedthe flow velocity in the pipe can increase the removal amount of Limnopernafortunei. The flow water to be set pulse is better than constant current water. And the synergy of water scouring and oxidative inactivation has better effect than singlefunction of water scouring.Finally, the results of the full-scale experiment show us that the practical planand the method to control Limnoperna fortunei in pipes is to put3-4mg/L sodiumhypochlorite for four or five days and keep four hours every day. If the watercompany can insist on do that monthly more than one year, the shell pollution willbe reduced and on control in future.