The Removal Of Ammonium In Surface Water By Iron And Manganese Co-oxides Coated Sand

In recent years,Surface water have become the main sources of drinking water.However,with the development of social industry and agriculture,surface water sources have been polluted more and more seriously.Ammonium is one of the major pollutants in surface water and the pollution situation is becoming more and more serious.Therefore,the removal of ammonium from surface water is an important problem facing the current safety of drinking water.In this study,the iron and manganese co-oxides coated sand was used to remove ammonium from surface water.The removal efficiency and its influencing factors were investigated.The main experimental results are as follows:(1)Using the co-oxides coated sand prepared with different operational time formed in the ground water of 4d?14d an 28 d were studied in the test.The experimental results showed that the co-oxides coated sand prepared with different operational time could remove ammonium from surface water effectively.When the influent ammonium was 1.5±0.2 mg/L and the filter speed was 8m/h,the effluent of the different operational time is less than 0.5mg/L after 3~4d and the removal rate is nearly 100%.The maximum concentration of ammonium which could be removed by co-oxides coated sand prepared with 14 days and 28 days was 2.44mg/L.Interestingly,the corresponding value for the sand prepared with 4 days up to 2.70mg/L,although higher nitrite nitrogen was observed in effluent.When the filtration rate is in the range of 6~12 m/h,it has little effect on the ammonium removal of the co-oxides coated sand prepared with different operational time.When the influent ammonium was 2.0±0.2 mg/L,the thickness of the filter layer of ammonium effluent was also increased,but the removal of ammonium mainly concentrated in the upper 60 cm.The results show that the only 4d filter material in the treatment effect is stable to meet the surface water ammonium removal.(2)In winter low temperature(6.7~13.0?),the experimental results showed that excellent removal efficiency of ammonium from surface water was obtained by the co-oxides coated sand filter.As the filtration rates were 4m/h,6m/h and 8m/h,the ammonium removal efficiencies of the co-oxides coated sand filter were up to 97.2%,94.3% and 93.5% respectively.The maximum influent concentration of ammonium of the co-oxides coated sand filter was 2.3mg/L under the filtration rate of 8m/h.The backwashing had little effect on the removal of ammonia nitrogen,while the ordinary quartz sand biofilter was affected by the influent hydraulic load,the concentration load and the backwashing.(3)The experimental results showed that the ammonium removal efficiencies of the co-oxides coated sand filter were up to 92.5%,at the same time the average effluent turbidity of the co-oxides coated sand filter was 0.52 NTU and the removal rates of CODMn,TOC and UV254 were 18.72%?12.01%,?36.4%.The removal effect was nearly the same with biological filter and the ordinary quartz sand filter.The experimental results show that the co-oxides coated sand filter had efficient removal of ammonium,at the same time can remove water turbidity,CODMn,TOC and UV254 and other impurities.