The Study On Optimization Of Condition And Treatment Effect For Rapid Start-up Of The Chemical Catalytic Oxidation Filters

The coexistence of over standard ammonia,manganese and iron in groundwater leads to serious water quality problems.It has demonstrated that catalytic oxidation filter is a highly efficient,low-cost and highly adaptable method,with simultaneous removal of iron,manganese and ammonia.However,the appropriate conditions and factors affecting the rapid start-up of chemical catalytic oxidation filter are not clear.In this paper,the operation effects of filter at various rapid start-up conditions and.the factors affecting the rapid start-up of filter were investigated,including the following three aspects: 1)The effects of different influent iron,manganese and ammonia concentrations on the start-up period of the filter;2)The effects of different filtration rate,time of start-up period and pretreatment conditions on the start-up period of the filter;3)Removal effects and influence analysis of the chemical catalytic oxidation filter for purifying of groundwater containing high concentration of ammonia,iron and manganese.The results are as follows:1.When the influent iron,manganese and ammonia concentration was 1mg/L,2.0mg/L and 1.5mg/L,respectively and the filtration rate was 4m/h,it has demonstrated to be a feasible and quick start-up method.The potassium permanganate dosage should be 90% of the complete oxidation of iron and manganese,the backwash cycle should be longer than 2d.The removal of ammonia and manganese could reach up to 1.5mg/L and 1.8~2.0mg/L after 6~8d and 28 d operation,respectively.2.A low dose iron was unbenefit to shorten the start-up period of the filter and would lead to a weak and unstable manganese removal.A high dose manganese and high filtration rate would lead to frequent backwashing,scouring the filter surface of the filter.It was harmful for removal of ammonia and manganese.Various influent ammonia concentrations seemed to have no effect on the start-up of the filter.When the influent ammonia concentration was 1.5mg/L,2.0mg/L and 1mg/L,it had demonstrated to be a feasible and quick start-up method.The addition of ammonia in the late stage was benefit to reduce the dosage of ammonia,shorten the start-up period of the filter and enhance the ability to remove ammonia and manganese.3.The acid treatment was more favorable to accelerate the start-up period of the filter.The acid treatment time seemed to have no effect on the start-up of the filter.4.The longer duration was benefit to enhance the ability and stability of removal of ammonia and manganese.Due to the autocatalysis of iron and manganese,the removal of pollutants would be gradually increased.5.After start-up period of the filter,the simultaneous removal of iron,manganese,and ammonia could be achieved.The fastest removal rate layer of three kinds of pollutant are in 0~60cm.The biggest pollution load of manganese and ammonia was 2.66mg/L and 2.3mg/L,respectively.Dissolved oxygen is a main influence factor in the removal of ammonia with high concentration.Iron removal was superior to that of manganese and ammonia,and high concentrations of iron would inhibit the removal of ammonia and manganese,high concentrations of ammonia would inhibit the removal of manganese.The removal rate of manganese was increased with the increase of influent manganese concentration,in a certain range.While the removal rate of ammonia had no change with varition influent ammonia concentrations.6.At the beginning of the operation,the system had poor ability to resist changes of filtration rate or backwash strength,sudden changes of the filtration rate and backwashing condition will reduce the effect of the system.It should be slowly change the filtration rate and backwashing condition at the operation.