Effects Of Water Quality Background On Ammonium Removal By The Manganese Co-oxides Film From Surface Water

At present,ammonium pollution in surface water become increasingly serious in China,and excessive ammonium in drinking water can directly harm human health.In this study,the effect of water quality background on ammonium removal by the manganese co-oxides film coated quartz sands were investigated by a pilot-scale filtration system.It provides a reference for the practical engineering application of chemical catalytic oxidation.The main results and the conclusions are as follows:?1?Dosing 5?g·L^-1 phosphate can ensure complete removal of ammonium in water when the temperature was above 12.5?.When the water temperature was higher in spring and summer,the ammonium removal activity of the manganese co-oxides film was maintained at a high level relatively.Phosphate can be added intermittently when the inlet ammonium concentration was low(not more than 1.50 mg·L^-1);Phosphate must be added continuously when the inlet ammonium concentration was high in order to ensure the safety of the effluent.When the water temperature was lower in autumn and winter,the ammonium removal activity of the manganese co-oxides film was reduced relatively.Meanwhile,phosphate must be added continuously to strengthen ammonium removal activity.?2?Microorganism inactivation experiment indicated that ammonium removal capability of the activated oxide film included catalytic oxidation and biological nitrification simultaneously.The total activity and catalytic oxidation activity of the activated oxide film were 1.36 times and 1.79 times higher than those without phosphate respectively,which suggested that phosphate can facilitate the catalytic oxidation activity of the activated oxide film.It can be speculated by SEM and EDS characterization that the catalytic oxidation activity of the activated oxide film decreased after applied to surface water treatment,probably due to the accumulation of coagulant residual aluminium on the surface of filter media.?3?Mg²⁺?Ca²⁺?Na⁺?K⁺?SO₄^2-?Cl^-had no obvious effects on ammonium removal from surface water of the manganese co-oxides film,and the ammonium removal rate of the whole filter layer was high.Among them,K⁺had a slight promotion effect on ammonium removal;Mg²⁺and Ca²⁺had certain inhibitory effects;Na⁺,Cl^-and SO₄^2-had no effect.?4?The manganese co-oxides film can still exert effective ammonium capability in the range of natural organic matter concentration in the general surface water,the high concentration of natural organic matter had an adverse effect on the ammonium removal of the manganese co-oxides film.The results of SEM and EDS analysis showed that the percentage of the atomic percentages of C elements on the surface of the activated oxide film without adsorption of FA and with adsorption FA were 18.06%and 55.53%,respectively.The increase of the C element confirmed the adsorption behavior of FA on the surface of the activated oxide film.It was presumed that the insoluble complex formed by FA and the ions formed on the surface of the activated oxide film occupied the active sites of ammonium,which led to the decrease of ammonium removal ability.