ELIMINATION OF THE MICRO-POLLUTION CAUSED BY ORGANIC CHLORIDE PESTICIDES IN DRINKING WATER BY ENHANCED COAGULATION

Solid phase extraction (SPE) with C-18 disk was developed to extract organic chloride pesticides (OCPs) in water sample. Gas chromatography equipped with electron capture detector (ECD) was used to analyze the OCP compounds. The enhanced coagulation experiments were carried out with poly ferric sulfate (PFS) to remove OCPs from water sample. The effects of pH value, the dosage of coagulant, the slow stirring time and the modified attapulgite on the removal of OCPs were investigated. The result indicated that when the dosage of PFS was 11 mg/L, the slow stirring time was 25 min and the pH value was in the range from 5.5 to 6.5, the removal rate of OCPs and turbidity reached 64.38%-89.14% and 99.66% respectively; adding the modified attapulgite can significantly improve the coagulation performance, the removal rate of OCPs and turbidity reached 70.23%-95.23% and 98.8% respectively. It was found that the removal of OCPs was positively related to the removal of turbidity due to adsorption and co-precipitation mechanism.