消毒副产物生成势测定方法的优化研究

Optimization of Detection Method of Disinfection Byproducts Formation Potentials

提出新的DBPs生成模型,并进行DBPFP测定方法优化,优化因素包括投氯量、消毒时间和p H-温度联合因素。在优化投氯量时,发现低投氯量下五种DBPs生成量与投氯量之间存在明显的线性关系,线性拟合的确定性系数（R2）均大于0.980。优化消毒时间时,提出了ttrend的概念,发现8种DBPs的ttrend均包括3 d这一时间点。在pH-温度联合因素优化时,得到CHCl3、CHCl2Br、CHClBr2和C2Cl4生成量响应曲面拟合的R2均大于0.970,拟合效果较好;但三种卤乙酸生成量响应曲面拟合的R2为0.6710.874,拟合效果一般。这可能是因为pH-温度联合因素对卤乙酸生成量的影响较小,或试验过程引入过大误差造成模型残差过大。得到优化的DBPFP测定方法是投氯量为5 mg/L,消毒时间为3 d,pH值为7.5,温度为11℃。可根据DBPs生成量与三个优化因素的关系,使用DBPs生成模型和DBPFP测定值计算出不同条件下水样消毒过程中的DBPs生成量。

A new formation model of DBPs was built,and the DBPFP detection method was optimized. The optimized factors included chlorine dosage,disinfection time and pH-temperature combination factor. Clear linear relationships between the productions of five different DBPs and chlorine dosage were found when chlorine dosage was low,and their coefficients of determination were all higher than 0. 980.The concept of ttrendwas put forward when optimizing disinfection time,and the time point of 3 d was all contained in the ttrendof the eight DBPs. The response surface methodology fitting was used when optimizing pH-temperature combination factor. The coefficients of determination got from fitting productions of CHCl_3,CHCl_2Br,CHClBr_2 and C_2Cl_4 were all higher than 0. 970,indicating good fitting effect. However,the coefficients of determination got from fitting the productions of three haloacetic acids were between0. 671 and 0. 874,indicating ordinary fitting effect. It might be caused by the weak dependence relationship between productions of haloacetic acids and pH-temperature combination factor or the big residual error for the model caused by the big error introduced in the experimental process. The optimized DBPFP detection method was conducted by adding 5 mg / L chlorine to water samples,adjusting pH to 7. 5 and keeping temperature at 11 ℃ for 3 d. According to the relationships between productions of DBPs and the three optimized factors,the productions of DBPs in any condition could be obtained by calculating with DBPs formation model and DBPFP detection values.