Removing Ammonia Nitrogen By Zeolite Combined Microbe Immobilization Technology In SBR

Some in drinking water sources of China showed micro-polluted characteristics. In recent years, China issued new national Emission Standards(GB 18918-2002), which may have been due to stricter requirements on auto emissions of COD, NH4-N and TN in municipal wastewater.Biological method is one of the most effective ways for removal of ammoniacal nitrogen at present, but many problems came up in the current. It has became a urgent task for environmental scientists that to simplify denitrification process, reduce operation cost and meet the new needs of the wastewater treament.Sequence batch reactor(SBR) systems running with alternative anoxic and aerobic processes are used treat the wastewater, the NH4+-N can be removed effectively while COD are removed. Natural zeolite is a non-metallic mineral with characteristics of adsorption and ion-exchange properties. a dual mode process consisting of ion exchange and biological decomposition mode in a single reactor is the focus of nowadays researches.This paper first experimental study on ammonia removal by clinoptilolite from Baiyin in two kinds of media with different diameters through static experiment, and some zeolite was carried out and modified by NaCl. Following to study ammonia-nitrogen removal by the modified zeolite. Then, the nitrogen removal mechanism is discussed when the natural zeolites powder of ammonium saturated was added into the SBR. At last, to study ammonia nitrogen from slightly-polluted water by zeolite-microbe combined immobilization technology using macroporous carrier in SBR.The main results from those studies are summarized as following:1. Under the same conditions, the ammonia-nitrogen removal using small size zeolite with high efficiency and fast adsorption rate. The ammonia nitrogen adsorption by natural zeolites was effected with ion exchanging and Physisorption.2. In zeolite-SBR, higher COD removal efficiency can be maintained, and the simultaneous nitrification and denitrification took place in the reactor. The modified zeolite with higher Si/Al not to change the monoclinic structure of clinoptilolite, and the adsorption capacity of ammonia nitrogen increased. The immobilized microbial biomass of Na-zeolites powder of ammonium saturated increased.3. Study on biodenitriflcation by immobilized microorganism using macroporous carrier. After one SBR period, COD of the effluence ranged from 4.5 to 24.2mg/L. The treated water quality reach standard. NH4-N of the effluence ranged from 1.2 mg/L to 3.8mg/L, the removal rate of NH4-N reaches over 90%.4. It can be maintained higher NH4-N removal efficiency in the SBBR added the natural zeolites; while C/N changed decreased, it seem not affect the removal of NH4-N. The natural zeolites powder added into the SBBR can enhance the roughness of channels of macroporous carrier. The larger roughness of channels, the larger adsorbing of biofilm. At the same time, it can be maintained higher COD removal efficiency in the reactor.