Optimization Of Rapid Film Formation Condition Of Composite Manganese Co-oxides On Filter Surface

The phenomenon of iron,manganese and ammonium coexisting and seriously exceeding the standard in groundwater is becoming more and more common,bringing great challenge to the safety of drinking water in China,and urgent need to develop a short-flow and high-efficiency new process for synchronously removing iron,manganese and ammonium to meet the requirements of national drinking water quality standard and the increasing improvement of the reliability of water supply.The catalytic oxidation filter has the ability to remove iron,manganese and ammonia nitrogen simultaneously,and has the characteristics of high efficiency,economy and adaptability.The quick start-up of the pilot-scale catalytic oxidation filter was conducted using chemical oxidation process,that is,Potassium permanganate oxidizes iron,manganese with the formation of co-oxides and then co-oxides deposit on the surface of quartz sand to form a co-oxide filter film,which simultaneous removal iron,manganese and ammonium by catalytic oxidation.However,the suitable conditions and influencing factors for rapid maturation method for active filter media are not clear.This paper focuses on the effects of different film formation conditions on the rapid maturation of active filter media and the differences in the operating performance of active filter media with different film formation conditions.The main results of the paper are as follows:?1?The change of the concentration of water inlet manganese and potassium permanganate at the stage of the film formation are less affected by the removal of ammonium from the filter,and the ammonium?1.5 mg/L?can be removed at about 7d.However,it has a greater effect on the removal time of manganese.?2?In the manganese surplus at the same concentration,the higher the concentration of potassium permanganate water filter and shorten the starting time more favorable.At the same time of potassium permanganate concentration,the higher the concentration of the manganese concentration,the better the shortening of thefilm formation time of the active filter.The optimal conditions for in-situ film formation were3 and 6.03 mg/L of influent manganese and potassium permanganate,respectively,and the time required to form the active filter could be shortened to 15 days.?3?After stable operation of the filter,the change of ammonia concentration in the influent water has almost no effect on the ability of the filter to remove iron and manganese and the change along the course.Dissolved oxygen in the raw water is an important factor that restricts the removal of high concentration ammonia nitrogen from the filter;The change of water manganese concentration has almost no effect on the ability of the filter to remove iron and ammonia nitrogen and along the course,and the oxide film activity is an important reason to limit the high concentration of manganese removed by the filter.?4?The capacity and regularity of pollutant removal showed a high degree of consistency during the later stage of the start-up of the filter under different membrane conditions.The upper filter section?0 to 30 cm?is an efficient section for removing contaminants.The maximum load for simultaneous removal of pollutants in the filter is?ARR _{Total iron}=10.0 g/?m³·h?,?ARR _manganese=18.5 g/?m³·h?,?ARR _ammonium=16.2g/?m³·h?is much larger than the biofilter's removal load.?5?After the active filter material matures,the effect of backwashing on the filter column with longer running time is shorter and the operation is more than two months.The effect of backwashing on the removal of pollutants from the filter can disappear within one hour.?6?The surface of active filter material is granular,with developed pore system,large specific surface area,and high content of iron and manganese in the oxide film.This is an important reason for the ability to remove pollutants stronger than natural filter media.