Research On Formation Characteristics And Detection Method Of Trihalomethane In Chlorine And Chloramine Disinfection

Disinfection is a very important part of drinking water treatment process and is also the final mean to ensure the safe and clean drinking of residents.Free chlorine disinfection is the most widely used technology all over the world for the advantages of low cost, obvious effect and convenience,so it plays a significant role in preventing the water mediated viral diseases form disseminating.However, the Chlorine disinfection process will bring a large number of by-products which do certain harms to human health.Currently,research on forming process and influence of it has become a hotspot in drinking water disinfection field of the world.At the same time, research on replacement of disinfectant and combined means is becoming an important measure to ensure the quality and safety of drinking water.This study is very meaningful to lower the quantity of disinfection by-products in drinking water,to provide high quality water and to ensure water safety of the residents.This paper comments on the status of the pollution of water sources and the existing hygiene standards of drinking water, analyzes the status and development of disinfection technology of drinking water and by-product issues caused by chlorine disinfection.Based on the existing three trihalomethanes standard detection method, this paper uses liquid-liquid extraction gas chromatography technology, establishes a rapid and accurate mean to analyze trihalomethanes . Then , the standard curves of chloroform, bromodichloromethane ,dibromochloromethane and bromoform are ascertained,and researches on the quality control of the four components are carried out,which provides the necessary means for the accurate determination of disinfection by-products class of trihalomethanes.In view of the characteristics of our country's water sources,this paper does research on various factors of the trihalomethanes formation situation in chlorine and chloramine disinfection process by taking the humic acid as the precursor mimics of disinfection by-products in the natural and taking bromide ion as a background solution.Then the formation characteristics of trihalomethane is discussed.The results shows that the amount of trihalomethanes forming in the process of chlorine disinfection shows an upward trend with the increasing of the chlorine amount, organic matter concentration,pH,water temperature,bromide ion concentration and reaction time.It is worth mentioning that there is a obvious linear relationship between yields of trihalomethanes and TOC.The research shows that chloramine disinfection can greatly reduce the problem caused by disinfection by-products in process of chlorine disinfection . The amount of trihalomethanes forming in the process of chloramine disinfection increases with the increase of chloramine amount,Cl/N,organic matter concentration, water temperature and bromide ion concentration,decrease with the increase of pH.There's also a certain linear relationship between yields of trihalomethanes and chloramine dosage.However,chloramine has a poor ability of generating trihalomethanes,so the curves between response factors and yields of trihalomethanes is flat.Only by greatly increasing the ratio of chlorine and ammonia,yields of trihalomethanes can increase obviously.