Technological Properties Of UV Or Potassium Ferrate Disinfection Combined With Chlorine In Drinking Water

As an important treatment in water purification, chlorination disinfection and chlorine dioxide disinfection, the conventional water disinfection technology is being doubted due to the disinfection by-products (DBPs), which cause various health concerns. The drinking water resources have been commonly polluted at present, and pollutants, pathogenic microorganism resistant to chlorine in raw water threat to people’s health seriously. The effects of disinfection effects decreased significantly under constant chemical disinfectant dosage. It needs exigently to initiate advanced treatment technology. Then as the green, economical and efficient disinfection methods, ultraviolet (UV) irradiation and potassium ferrate (K2FeO4) disinfection have been gaining more attention.Based on the water filtered from a waterworks in the Zhejiang province, the focus of this project was to determine the residual chlorine decay and the formation of trihalomethanes (THMs) after UV or K2FeO4 treatment combined with chlorine. The changes of the bacterial community structure and the inactivation of microorganisms during the chlorination processes, UV irradiation and ferrate oxidization through the advanced high-throughput misep pyrosequencing.According to the experimental results, under same initial residual chlorine concentration, the higher UV dosage could accelerate the chlorine decay rate and the formation of THMs. With the increasing of UV dose, the value of total organic carbon (TOC) in water samples would decreased by 28.3% extremely, and the absorbance of water after UV disinfection were much lower than the untreated water, which dropped from 0.122 cm-1 to 0.102 cm-1. The chlorine decay rate and THMs formation under low UV intensity were faster than the high UV intensity. The decaying trends of chlorine get faster significantly with the ferrate concentration increasing. When ferrate was used as the pre-disinfectant, the THMs levels in all samples decreased with the ferrate concentration increasing. The absorbance of the untreated water was much lower than the water samples with ferrate treatment within the UV range of 210 nm-600 nm, which rose from 0.122 cm-1 to 0.167 cm-1.The number of the dominant species in water decreased significantly after disinfection process, which showed lower richness and diversity within the samples. But clear differences in the bacterial community structure between chlorination, UV irradiation and ferrate oxidization was found at different taxonomic levels. UV irradiation produces a better effect on evaluating changes in microbial community structure than the other two.