Study On The Performance Of 2-MIB Based On Physical Adsorption And Biodegradation To Remove Odoring Substances From Water Supply Systems

2-Methylisobenzol(2-MIB)is a typical representative of odorants in drinking water,which can cause sensory discomfort and threaten the safety of drinking water.The conventional water supply treatment process(pre-treatment coagulation sedimentation filtration disinfection)usually has limited effectiveness in removing 2-MIB.Water plants mainly use ozone oxidation and advanced oxidation methods to remove 2-MIB.Some domestic water plants do not have advanced treatment processes,so studying how to remove 2-MIB through conventional processes is of great significance for water safety and actual production in water plants.This article takes the conventional treatment process of water supply plants as the research object,starting from the pre-treatment process and filtration process of the water plant.Based on the principles of physical adsorption and biological treatment,it explores how to achieve the removal of 2-MIB from conventional water supply processes without adding advanced treatment conditions.The article conducts research on the removal of 2-MIB by powdered activated carbon,the effect of potassium permanganate on the removal of 2-MIB by powdered activated carbon,the removal of2-MIB by biofilter,and the identification and influencing factors of 2-MIB degrading bacteria on biofilter.The main research results are as follows:(1)Adding powdered activated carbon can effectively reduce the concentration of2-MIB in raw water.The removal effect of 2-MIB varies depending on the type of powdered activated carbon.The specific surface area and total pore volume of powdered activated carbon cannot be used as a reference for carbon selection.The powder activated carbon with the best effect in this experiment can remove over 60%of 2-MIB in raw water with a concentration of 50 ng/L at a dosage of 30 mg/L and adsorption conditions of 50 minutes.(2)When potassium permanganate and activated carbon are co added,the adsorption effect of activated carbon on 2-MIB will be reduced.When 1 mg/L potassium permanganate and 30 mg/L powdered activated carbon are co added to raw water,their 2-MIB adsorption rate will be reduced to 30%.(3)The pilot test results showed that filter material mixing can quickly improve the removal efficiency of 2-MIB in the filter.After mixing the carbon filter material of the biochar filter with the sand filter material in a 1:2 ratio,the removal rate of 2-MIB in the sand filter can be increased from 10% to 80% after 30 days;The treatment effect of the filter on 2-MIB is affected by the residual chlorine in the influent.The amount of sodium hypochlorite added to the pre-treatment process section should be controlled,and the residual chlorine in the influent of the filter should be kept below 0.1 mg/L in order to ensure that the 2-MIB removal rate of the filter is not less than 60%.(4)By using a single carbon source culture method to screen strains with 2-MIB degradation effects in water plant biofilters,it was determined that four of them were two subspecies of bacteria that were associated with Sphingomonas sp,Caulobacter segnis,and Ralstonia pickettii.Except for Sphingomonas sp,there have been no reports of Caulobacter segnis and Ralstonia pickettii having 2-MIB treatment effects.Within 3days,the removal rates of 2-MIB at 100 ng/L by four types of bacteria were 40.18%,57.2%,61.7%,and 52.74%,respectively.(5)Sphingomonas sp,Caulobacter segnis,and Ralstonia picklettii are three strains that are suitable for survival in an environment of 30 ℃ and p H neutrality.Acidic or alkaline environments can lead to a decrease in their activity.The higher the concentration of 2-MIB in the environment,the stronger the activity of the strains.In addition,the strain has poor tolerance to sodium hypochlorite,and 1 mg/L of sodium hypochlorite will achieve a near inactivation effect on the strain.