Use of Pressurized Hydrolytic Processes as a Pretreatment of the Wastewater from Organophosphate Pesticide Manufacturing

摘要

Wastewater from commercial manufacture of the pesticide O-methyl-O-(2-isopropyl salicylate) thiophos-phoryl amide contains large amounts of pollutants, such as organophosphate, organic sulfides, COD, NH_3-N. A comprehensive pretreatment process including alkaline hydrolysis, precipitation and flocculation was explored in this paper. The effects of hydrolysis temperature, initial pH values, etc., on the removal of pollutants were investigated. The experimental results showed that, with this physicochemical process, the removal of total phosphorus, organophosphate, sulfides, and NH_3-N exceed 90%, and the removal of COD attains to 70%. The biodegradability (BOD_5/COD) of the wastewater is greatly improved from 0.05 to 0.33. The NH_3 gas generated was absorbed with water and could be reused in the manufacturing.