三氯杀螨醇生产过程中的DDT环境排放研究

三氯杀螨醇生产工艺流程主要包括缩合、碱解、氯化和水解等步骤。对工作场所中空气样品、生产过程排放的废酸及废水样品进行采集和分析。工作场所空气中DDT总质量浓度均值为6.69×10-3mg/m3。其中,碱解反应工序中质量浓度水平较低,为1.10×10-3mg/m3;包装车间质量浓度水平较高,为16.72×10-3mg/m3。所有空气样品中p,p’-DDE均是主要贡献物质,占DDT杂质总量的80.2%;p,p’-DDT的质量浓度范围为0.053×10-3~1.66×10-3mg/m3,平均为0.49×10-3mg/m3,低于国家标准限值。缩合废酸与水解废酸中DDT杂质总质量比分别为4.84μg/kg和334.83μg/kg;碱解废水与水解废水中的DDT杂质总质量比分别为456.48μg/kg和75.65μg/kg。废水及废酸样品中各种DDT杂质的质量比水平存在差异;生产工艺阶段不同,杂质组成也各具特点。水解废酸的p,p’-DDT的质量比最高,为146.82μg/kg;缩合废酸与水解废水处质量比水平较低,分别为0.33μg/kg和1.41μg/kg。该企业随废水及废酸排放的DDT杂质总量为1234.08 g/a,其中随碱解废水的排放量高达912.95 g/a。p,p’-DDT的年排放总量为163.37 g/a,随碱解废水和水解废酸的排放量分别为86.98 g/a和73.41 g/a。

DDT release in the dicofol production process

The paper is inclined to present the research findings on DDT release situation in dicofol production process.For our research purpose,we had first of all collected series samples of the workshop air,the waste acid and production left-over sewage from a typical chemical plant in purpose to quantify DDT and DDT-related compounds released from the same process with DDT as its intermediate products.The actual dicofol production process includes four steps,that is,condensation,alkalization,chlorination and hydrolyzation. The average level of ∑DDT in the workshop air samples worked out at about 6.69×10-3 mg/m3.The lowest value of ∑DDT was 1.10×10-3 mg/m3 in the alkalization process,whereas the highest one was 16.72×10-3 mg/m3 in the air samples collected from the packaging workshop.Since p,p’-DDE was the major contributor to the total concentration of all the five DDT-related compounds,it may account for 80.2% of the total impurities,with the value of p,p’-DDT ranging from 0.053×10-3 mg/m3 in the alkalization to 1.66×10-3 mg/m3 in the packaging workshop,though the average of 0.49×10-3 mg/m3 remains far below the national standard.On the other hand,since the ∑DDT level in the waste acid samples collected from condensation and hydrolyzation kettles stands at 4.84 μg/kg and 334.83 μg/kg respectively,the corresponding level in the production sewage collected from the alkalization and hydrolyzation may turn to be 456.48 μg/kg and 75.65 μg/kg.Moreover,since DDT in the sewage and waste acids were different with their distinctive compositional characteristics in different stages of production,it was found in the waste acid sample from the hydrolyzation kettle that the highest value of p,p’-DDT was 146.82 μg/kg,the concentrations of p,p’-DDT were 0.33 μg/kg and 1.41 μg/kg,respectively.Actually,a considerable amount of DDT has been released annually at the level of 1 234.08 g,among which the output from the sewage collected from the alkalization kettle can be as high as 912.95 g.Statistically speaking,annual emission of p,p’-DDT may well be over 163.37 g,with the large amounts of discharge of sewage from alkalization and waste acid from hydrolyzation.The corresponding emission has been worked out at 86.98 g and 73.41 g.