Preparation Of Catalytic Oxidation Manganese/Ammonia Removal Artificially Enhanced Loaded Manganese Oxide Filter Media And Optimization Of Operating Conditions

Groundwater,as the main water source for many regions,is vital for human life,agricultural development and industrial production.However,in recent years,the problem of manganese and ammonia pollution in groundwater has become increasingly serious,posing a major threat to the ecological environment and public health.Through the previous research of the research group,it was found that composite manganese oxide filter material can effectively remove manganese and ammonia in groundwater,but this technology is currently limited by the physical and chemical properties of the filter material.The composite manganese oxide filter material has the problems of low manganese oxide film loading intensity and low loading amount in the actual production and operation process,which has some drawbacks in engineering application.Therefore,under the condition of ensuring that the activity of the active filter material does not change,how to enhance the loading intensity and increase the loading amount is the focus of this study.This study significantly improved the loading intensity and loading amount of the filter material by adding waterhardening inorganic gel,and optimized the loading conditions of the filter material preparation process and the pilot operation conditions.The effects of loading conditions,operation modes,and different groundwater quality on the formation of filter material activity and surface film loading state were explored under pilot test conditions.The main conclusions are as follows:(1)The influence of loading amount and gel ratio on the manganese/ammonia removal activity of filter material was investigated.The filter column with high loading amount had better manganese removal performance.When it ran to the 19 th day,the manganese concentration in the effluent was lower than 0.1 mg/L,and the manganese breakthrough cycle was only 6 days.The manganese removal performance was more stable.The filter column with low loading amount had faster ammonia removal activity formation rate.On the 5th day,the ammonia concentration in the effluent was lower than 0.5 mg/L,but there was no significant difference in ammonia removal rate between the two in the middle and late stages of operation.The filter column with low inorganic gel ratio had a longer manganese breakthrough period(the effluent manganese concentration was higher than0.1 mg/L).On the 27 th day,the effluent manganese concentration was lower than 0.1 mg/L,and at the same time on the 56 th day,there was little difference in manganese removal performance between the two filter columns.The effluent ammonia concentration of different gel ratio filter columns showed a trend of increasing first and then decreasing during operation,and gel ratio had no effect on ammonia removal performance of filter material.(2)The preparation conditions of artificial enhanced manganese oxide film filter material were clarified.During operation of filter column,surface film loading intensity difference between different loading amounts gradually increased.On 56 th day,surface film shedding amount of high loading ratio filter material was lower,shedding ratio was only 0.95%,and loading intensity was higher.However,surface film loading amount difference between different inorganic gel ratios gradually narrowed during operation process,and there was difference in surface film loading intensity between two different gel ratio filter materials in middle and late stages of operation,and low gel ratio filter material had better loading intensity,shedding ratio was only 0.9%.(3)The influence of different operation modes on manganese/ammonia removal activity of filter material was discussed.Under different operation modes,manganese removal activity formation rate of circulating system was faster than that of direct discharge system.Lower alkalinity/hardness in circulating system could effectively shorten formation time of filter material activity,but operation mode had no effect on formation of mature ammonia removal performance of filter column.In addition,with extension of operation time,surface film loading amount(1.71 g/10 g)of circulating system filter material was higher than that(1.46 g/10 g)of direct discharge system.(4)The formation situation of manganese/ammonia removal activity under different groundwater conditions was studied.After loading enhancement,surface manganese oxide film shed a lot in early stage of operation,while in middle and late stage,surface manganese oxide film could achieve stable shedding and renewal,especially under high alkalinity and hardness groundwater conditions,surface film loading intensity and loading amount(0.92 g/10 g)were higher.Different alkalinity and hardness groundwater operation conditions will affect formation speed of manganese/ammonia removal activity of manganese oxide film filter material.Under high hardness/alkalinity water quality condition,effluent ammonia concentration was lower than 0.5 mg/L on 21 st day.Too high alkalinity and hardness will delay formation speed of manganese/ammonia removal activity of filter material.