Formation Characterizations Of Disinfection By-products During Disinfection Of Algal Organic Matter

Algal organic matter(AOM),as one of major organic matters in many drinking water sources,have became important precursors of disinfection by-products(DBPs)during disinfection.However,studies on the formation of DBPs in disinfection of algae are limited.In this study,the formation and speciation of AOM(Microcystis aeruginosa)in chlorination,chloramination,and ozonation-chlorination were studied;the DBPs formation of four algae species(Microcystis aeruginosa,Chlorella,Scenedesmus obliquus,diatom)in different disinfection conditions were also studied.In chlorination of Microcystis aeruginosa,different DBPs had different formation trends under various conditions.Increased pH values,chlorine dose and bromide concentration accelerated the trihalomethanes(THMs)formation.Decreased pH increased the haloacetic acids(HAAs)formation,and HAAs formation increased and then decreased with increasing chlorine dose and decreasing bromide concentration.Higher pH and chlorine dose increased the haloacetonitriles(HANs)formation,and the HANs formation decreased and then increased with increasing bromide concentration.The haloketones(HKs)formation decreased with increasing chlorine dose.The different chlorine dose modes had little impact on the formation and speciation of DBPs.In chloramination of Microcystis aeruginosa,higher pH and chloramine dose accelerated the formation of THMs and HAAs.High bromide concentration increased the THMs formation,but had no impact on the HAAs formation.The formation of HANs and HKs varied greatly with chloramination conditions.The overall formation amount of DBPs were in the order of chlorinationchloramination<chloramination<chlorination.AOM produced more DBPs than algal cells.In ozonation-chlorination,application of ozonation accelerated the formation of DBPs from algal cell and AOM.The four algae had different compositions and nitrogen levels.The four algae generated different amount,species of DBPs in chlorination,chloramination,chlorination-chloramination,ozonation-chlorination.