The Removal Of Escherichia Coli DBPsFP By Potassium Permanganate/Potassium Permanganate Compositechemicals Preoxidation During Chloramination Process

In view of the current phenomenon of Escherichia coli contamination of water sources.The present study used Escherichia coli as the test object,potassium permanganate and permanganate as the oxidants.The study investigated the removal characteristics and effects for Escherichia coli chlorination disinfection by-products precursor by pre-oxidation process under different conditions.The results showed that the removal effect for the DBPsFP by potassium permanganate and potassium permanganate compositechemicals pre-oxidation was basically the same,but the removal rate of DBPsFP by the preoxidation of potassium permanganate compositechemicals was higher than potassium permanganate.The concentration of dichloroacetonitrile(DCAN),trichloroacetonitrile(TCAN)?1,1,1-trichloropropanone(1,1,1-TCP)and trichloroacetaldehyde(CH)initially decreased and then increased,and 1,1-dichloropropanone(1,1-DCP),dichloroacetone(TCNM),trichloroacetic acid(TCAA)initially increased and then decreased,dichloroacetic acid(DCAA),trichloromethane(TCM)decreased gradually with potassium permanganate concentrations increased.When the dosage of potassium permanganate and permanganate compound dosage is 2 mg/L,the removal effect of most of the disinfection by-product precursors is better.The removal rates for TCAN,DCAN and 1,1,1-TCP were 61.8%,30.3%and 23.5%,respectively.The long pre-oxidation time increased the hydraulic retention time,and DBPsFP removal rate was best in 30min,so the optimal pre-oxidation time was 30 minutes.When the pH value was 9,the concentration of 1,1,1-TCP,TCAN,TCNM,DCAA and TCAA reduced to minimum value.When the pH value is 8,the DCAN concentration reached a minimum value.It was suggested that the alkaline condition were more favorable for disinfection of by-products.With the increased of temperature,the concentration of 1,1-DCP,DCAN,TCNM,DCAA,TCAA increased gradually.The concentration of 1,1,1-TCP decreased gradually.The concentration of TCAN,TCM initially incireased and then decreased.It indicated that the high reaction temperature was not conducive to the control of disinfection by-products,and the temperature was preferably controlled at 20?.The potassium permanganate compositechemicals with coagulant had a better removal effect than potassium permanganate on DBPsFP.With the increase of coagulant dosage,the concentration of TCM,CH,1,1-DCP,DCAN,DCAA and TCAA continuously decreased when potassium permanganate was used as pre-oxidant.The concentration of TCM,CH,1,1-DCP,1,1,1-TCP,DCAN,TCAN,DCAA and TCAA continuously decreased when the permanganate compound was used as a pre-oxidant.However,the concentration of TCNM initially decreased and then increased.Potassium permanganate compositechemicals had significant effects on removal of CH,DCAN,TCAN and 1,1-DCP,with removal rates of 40.1%,48.6%,58.6%,and 44%,respectively.