Experimental Study Of The Removal Of Iron Manganese And Ammonia And The Optimization Of Operating Conditions

The groundwater is an important part of water supply for the city. but iron,manganese and ammonia nitrogen pollution is a growing problem, Zeolite filtration caneffectively remove iron;manganese and ammonia,there are no optimal control methodsof this technology.so In this paper，author studied the zeolite single-stage filtrationsimultaneous removal of iron; manganese and ammonia,with the groundwater in xi’annorthwest water source site as the research object. studied effect of zeolite filtrationcolumn riping at different times, analysed the ripening process and the surfacecharacteristics and adsorption properties of Ripening process,On this basis, optimizedthe control conditions of Zeolite column running (backwashing, aeration, filtration rate),and analysed the removal characteristics of iron, manganese, ammonia along the filterlayer. The main findings as follows:(1)After the Zeolite filtration column run19days, the average removal rate ofmanganese is97.8%, Manganese content in the after-treat water is less than0.1mg/L,The average removal rate of iron is94.5%, total iron were below0.3mg/L in the water,the removal rate of ammonia nitrogen is94.1%, ammonia content in the after-treatwater is less than0.3mg/L, all reach drinking water health standards. In immature times,and manganese the removal load of manganese is only4.32mg/d, the maturity ofmanganese removal load increased9times (22.151g/d).so, when manganese removalload reach20g/d,the zeolite become riping zeolite.(2)There is a black membrane on the surface of zeolite clinker, Iron and manganesecontent was1.726%,1.06%, significantly higher than the raw material (0.486%,0.06%),particularly manganese increased nearly100times. The adsorption of Mn,raw material removal rate was16%, clinker adsorption removal was37%, significantly better thanthe raw material.(3) The maximum turbidity of the initial filtered water is2.12NTU,which is largerthan1NTU.But it will reduce to0.98NTU by increasing the time of expension with8min,which is reaching the standard.(4) With the different oxygen content, every index of the filtered water isdifferent.The maximum content of Fe is0.097mg/L,0.078mg/L and0.095mg/L underthe oxygen content of2.7mg/L,4.5mg/L and7.5mg/L. And so the maximum content ofMn is0.48mg/L,0.56mg/L and0.07mg/L.The maximum content ammonia nitrogen is1.56mg/L,1.34mg/L and0.23mg/L.The filter cycle of high level oxygen content is200hours,25times and7times longer than the other two oxygen content levels.(5) In the10m/h filter filtration rate conditions, when the water level in the filterreaches the overflow, the iron and manganese in the water did not exceed the standard.In the12m/h,15m/h high filtration rate conditions, after the operated70h and30h, thetotal iron content in the water were exceeded the standard, respectively run60h and40h,manganese content in water were exceeded the standard.the values were0.13mg/Land0.17mg/L. In the filtration velocity of10m/h, Mn, Fe reached the maximum interception,respectively135.32g and178.33g. In the filtration velocity of15m/h, Mn, Fe holdoutefficiency were highest, the values were1.65g/h and1.82g/h. In the filtration velocity of15m/h,can reach the most efficient water production, water production efficiency is99.86%.(6) When increase the filtration rate from10m/h to15m/h, the total iron;manganeseand ammonia completely removed, the desired filter depth increased by60cm,60cm,40cm. There was no nitrite accumulation in the filter column, at a depth of40cm, Ferrous were completely removed. Mn2+in the upper80cm of the filter layerremoval rate is96%.