Drinking Water Disinfection Using Potassium Monopersulfate Based Compound

Disinfection is one of the core technology in the drinking water treatment process. It is very important to choose a disinfectant with broad spectrum, high efficiency and low toxicity.Potassium monopersulfate compound is a new type of disinfectant with highly effective disinfection that can greatly reduce the generation of chlorination by-products. This paper took the filtered water as test samples to study its effect and possible by-products from the Second Waterworks of Changsha.First of all, the study investigated the effects of temperature, light and concentration of the disinfectant on the available chlorine based on the DPD spectrophptometry method. And it found that the peak concentration of available chlorine increased with temperature when the concentration of disinfectant was constant, while the change was relatively smooth. The concentration of available chlorine reached the maximum afer a period of time between 0.5h and 1h, and it reached the maximum more quickly with a high concentration of disinfectant.The concentration of the available chlorine increased with the concentration of disinfectant when the temperature was constant, but the change was continuously decreased. Light could promote the concentration of the available chlorine, and accelerated chain reaction speed.Secondly, the study also investigated the performance of disinfection by controlling temperature, light and concentration of disinfectant. And found that the removal rate of total bacterial count and coliform bacteria increased with concentration of the disinfectant and the temperature rising. Light could enhance the performance of disinfection, and the removal rate of two strains was about 1~16% higher in light environment than that in dark environment.Total bacterial count had a low recovery rate and coliform bacteria could not be found after12 h reaction.Furthermore, disinfection by-products after potassium monopersulfate compound treated were measured, showing that there were not any toxic by-products that we had known.Finally, the study compared the cost of potassium monopersulfate compound to several common disinfecting methods. It found that potassium monopersulfate compound had certain advantages in water consumption, electricity and human costs.In summary, the potassium monopersulfate compound had good bactericidal effect, and produced none toxic by-products that we had known, and the chemical regent and equipment costs would be substantially decreased after wide application. Therefore, it could be a available technology in future disinfection treatment.