The Study On Enhancing Manganese Co-Oxide Film Removal Ammonium From Groundwater By Oxygenating In Reverse Flow

Low dissolved oxygen is a key factor to inhibit the catalytic oxidation of ironmanganese co-oxide film to remove ammonium in groundwater.Therefore,we studied the removal effect and influencing factors of iron-manganese co-oxide film of ammonium in condition of sufficient dissolved oxygen.In the pilot test condition,using 3 different ways of oxygening(oxygen,air,ozone)reverse flow oxygenating in catalytic oxidation system maintained adequate dissolved oxygen,under this condition studying following 3 aspects:(1)Influence of water quality conditions on enhancing iron-manganese co-oxide film removal high concentration of ammonium by oxygenating in reverse flow;(2)Influence of operating conditions on on enhancing iron-manganese co-oxide film removal high concentration of ammonium by oxygenating in reverse flow;(3)Microscopic characterization analysis of iron-manganese co-oxide were characterized before and after the analysis.The conclusions of the experiment were as follows.(1)After the reverse flow oxygening,the removal effect of ammonium by the iron and manganese oxide film was significantly higher than that before the oxygening.(2)The influent ammonium concentration had obvious effect on the removal of ammonium by the reverse flow oxygenated iron manganese oxide-film.Under the conditions of 3 kinds of oxygening(oxygen,air and ozone),the highest removable ammonium concentrations of the iron and manganese oxide-film were 3.7,3.4,3.2 mg/L,respectively.It can be seen that the 3 ways of oxygening(oxygen,air and ozone),the oxygen was better than the air for the removal of ammonium,and the air was better than the ozone.(3)The effect of high concentration of iron and manganese on the removal of ammonium by oxygen enhanced iron manganese oxide film in reverse flow was obvious.When the concentration of iron and manganese in the water was higher than that of a certain concentration,the effluent from 3.0 mg/L of the influent ammonium did not reach the standard.(4)The influence of the filtering velocity on the removal of ammonium by oxide film in the reverse flow was obvious.When the influent ammonium concentration was 3.0 mg/L,and the ways of aeration was oxygen and air,the maximum permissible speed of removal of ammonium was 10 m/h;and that is 8 m/h when aeration was ozone.(5)The effect of oxygen filling on the removal of ammonium by the reverse flow oxygenated iron manganese oxide film was obvious.When the filter 8 m/h,influent ammonia concentration was 3.0 mg/L unchanged,the 3 ways of oxygening(oxygen,air and ozone)best(minimum)oxygenation rate were 40,100 and 75 m L/min,respectively.(6)The oxygen filling position had a great effect on the removal of ammonium by the reverse flow oxygenated iron manganese oxide film.The experimental results showed that the effect of the 1/3 bottom oxygenation on the removal of ammonium was better than that of the bottom filling.When the filtering velocity remained unchanged at 8 m/h,the maximum removal concentration of ammonium of oxide film were 4.3,4.2 and 3.2 mg/L,respectively.(7)Compared with before oxygenation,when oxygenation ways were oxygen and air,oxide film still had the characteristics of loose structure,abundant pores and large specific surface area,and the oxide film had not changed obviously.While the oxygenation mode was ozone,the morphological structure,element composition,crystal structure and specific surface area of iron and manganese oxide film all had unfavorable effects on ammonium removal by oxide film.