The Application Study Of Disinfection With Dioxide Chlorin In Gray Water

Disinfection is the last link in municipal wastewater treatment, which affects the water quality directly. Poor effect disinfection will lead to the microbial content exceed the stipulated standards, cause a large number of pathogens discharged into the environment, which is a serious threat to downstream using water security and environmental stability. In the summer period, because of the high temperature, the microbe grows strongly and breeds fast, microbial excessive emissions is particularly serious. This problem has attracted more and more attention. Traditionally, municipal wastewater disinfection technology was chlorine disinfection mainly, but chlorine disinfection has serious toxic effects, while the recently developing technologies, like ozone, UV and others although have obvious effect, but the costs are too high, which restrict the promotion of these methods. As a new type technology, Chlorine dioxide disinfection method is causing people's attention, with its highly-efficiency, economy, and security.This task choose chlorine dioxide as the disinfectant to verify the feasibility about using chlorine dioxide through disinfection of municipal sewage effluent to make the microbial indicator meet the nation's first level standard. The conclusions find that: When the chlorine dioxide dosing amount was 5.5mg/L, the total bacteria count killing efficiency can achieve 99.75%, the total coliform bacteria respectively was 0. And on this basis, we study the relationship through pH, temperature, time and killing efficiency, The experiment result prove that disinfection process is not affected to pH, when the pH value is between 6 and 9, the effect can reach the best level, but the rate can be accelerated by rising temperature, and the microbial removal efficiency improves following the time. At the same time we also study the influence of disinfection process on COD_cr, NH₃-N and turbidity. The results indicate that using chlorine dioxide in disinfection can reduce the concentration of COD_cr, improve the level of ammonia nitrogen in the water, this is due to the strong oxidizing of chlorine dioxide, but this process can't affect the water quality reaching the standard. Besides, this experiment also studies the attenuation process of chlorine dioxide, verifies chlorine dioxide's attenuation model is in keeping with the first-order kinetics equation under illumination and darkroom circumstance. Through this model, we can calculate the chlorine dioxide's decay cycle in different concentrations to determine the storage time. At last, this article discusses the chlorine dioxide's economical efficiency, through comparisons and analysis with liquid chlorine; we can conclude that chlorine dioxide is cheaper than liquid chlorine.