Pre-Chlorination Induced DOC and DBPs Formation from Microcystis aeruginosa in Treatment Processes

摘要

The effect of pre-chlorination on the trihalomethanes (THMs) and haloacetic acids (HAAs) formation from Microcystis aeruginosa was investigated. M. aeruginosa was cultivated under both batch and chemostat modes and harvested at different growth phases, and the formation of disinfection byproducts (DBPs) from the algal suspensions and extracellular organic matter (EOM) in the water treatment processes with and without pre-chlorination were measured. The results showed that pretreatment with 4 mg/L of chlorine increased chloroform formation potential by 62-113 ug/L and 12~23 ug/L from M. aeruginosa cultivated in batch culture and in chemostat, respectively. After conventional treatment processes, the pre-chlorination resulted in 10~50% decrease in overall DBPs precursor removal. When 0.5 mg/L of bromide was spiked into the algal suspension, the DBPs formation shifted from chlorinated to brominated species. Furthermore, the results of THM formation potential (THMFP) tests showed that the algae cultivated at the lower temperature water released less intracellular organic matter and less amounts of THMs precursors after pre-chlorination than that cultivated at the higher temperature water.