Study On Removal Of Organophosphorus Pesticied By Oxidation In Sudden Water Pollution

In our country the water pollution is very serious, and the sudden water pollutionaccidents often break out. But there is few studies about organophosphorus pesticidespollution in drinking water. This paper has selected chlorpyrifos (CP) and malathion(MA) as the targets to study how to deal with a emergent pollution oforganophosphorus pesticide after earthquake.First the feasibility of removal of CP and MA dissolved in deionized water usingdifferent crafts has been studied, and then the optimization techniques have beenselected. The effects of initial concentration of CP and MA, initial pH values, turbidity,tert-butyl alcohol dosage and other factors have been investigated to the removal of CPand MA. Finally, the experiments to remove CP and MA that had been dissolved in theSonghua River water have been done.The results show that, the O₃ oxidation and the coupling technique made up withpre-chlorination and adsorption have better effects to remove CP and MA. The effectsof removal of CP and MA using coagulation, potassium permanganate oxidation andactivated carbon adsorption are not ideal.The O₃ dosages vary with the initial concentration of CP and MA. The ratiobetween ozone dosage and CP initial concentration (NCP) is 7.1 6.4 when CPconcentration less than 150μg / L, and NCP is 5.2 3.4 when CP concentration lessthan 300μg / L, the last NCP is 3.7 1.7 when CP concentration less than 600μg / L.The ratio between ozone dosage and MA initial concentration (NMA) is 0.94 0.75when MA concentration less than 2500μg / L, and NMA is 0.76 0.45 when MAconcentration less than 5000μg / L. The removal efficiencies of CP and MA are over99% using O₃ after 20min in the condition with appropriate ozone dosage and 24℃.CP and MA are removed mainly by ozone molecule oxidation.The removal effects of CP and MA are very good by the coupling technique inthe optimal conditions. The suitable ratio between chlorine dosage and CPconcentration is 4.36 3.1, and the ration of MA is 1.10 0.90.The researches of the Fu river water and the Songhua River water show that thecoupling technique is feasible to remove CP and MA. When natural organic doseincreased, it is necessary that the chlorine dosage is appropriately amplified to remove CP and MA. The toxicity is lower after CP and MA absolutely removed by thecoupling technique with products identification by GC/MS. In a word, the couplingtechnique is feasible to deal with the sudden organophosphorus pesticide pollutionafter earthquake.