Study On Potassium Monopersulfate Compound's Influence On Water Quality In Different Pipes

With the intensification of water pollution in China,traditional chlorine disinfectant not only can not effectively kill pathogenic microorganisms,but also lead to the production of disinfection by-products easily.As a new highly effective strong oxidizing disinfectant,potassium monopersulfate compound has a good effect on sterilizing and degrading poisonous and harmful substances,but also can effectively reduce the generation of disinfection by-products in water.In this paper,the water quality change in PE and ductile cast iron pipe after disinfectant potassium monopersulfate compound added was studied by using the filtered water from the sand filter in a water plant in C City of South China as the experimental water,and the beaker test?main body water test?was carried out for comparision at the same time.The results showed that:?1?The content of available chlorine in two kinds of pipes decreased with the increase of hydraulic retention time,the effective chlorine content was PE pipe> ductile iron pipe,static test> dynamic test.In the dynamic test,the effective chlorine content decreased with the increase of the flow rate,but 0.3 mg/L of the disinfectant could not meet the requirement of the available chlorine content of 0.05 mg/L.?2?The change rules of turbidity and UV254 were similar,all increased with the increase of hydraulic retention time,the ductile iron pipe> PE pipe,dynamic test> static test,all increased with the increase of flow rate,and the two water quality indexes were not basically affected by the concentration of disinfectants.?3?The production of CHCl₃ was mainly related to the attenuation of available chlorine and the content of organic matter.The production rules of CHCl₃ were ductile iron pipe> PE pipe> main body water,dynamic test> static test.In the dynamic test,the production of CHCl₃ increased with the increase of flow rate.?4?The Larson ratio LR mainly affected the iron stability of the pipeline.The value of LR of the ductile cast iron pipe in static test and dynamic test was more than 0.5,and the value of LR in the dynamic test water decreased with the increase of the flow velocity,which indicated that the test water sample had a strong corrosivity to ductile iron pipe wall.Larson ratio could not quantitatively but qualitatively reflect the effect of corrosive ions in water on iron release.?5?The higher the concentration of disinfectant,the greater removal rate of the total bacterial count and the total coliform.For the total bacterial count,the static test was: main body water> PE pipe> ductile iron pipe,and the dynamic test was : ductile iron pipe> PE pipe and they increased with the increase of flow rate,dynamic test> static test.But 0.3 mg/L of the disinfection could not completely kill the total coliforms.?6?The content of dissolved oxygen in two kinds of pipes both declined,the degree of decline was ductile iron pipe> PE pipe,and it decreased with the increase of flow rate;the iron content in PE pipe was almost unchanged,the iron content in ductile iron pipe was mainly affected by hydraulic erosion,dissolved oxygen and available chlorine,dynamic> static,and it increased with the increase of flow rate.