The Research Of Adsorption And Precipitation Technique To Recycle Ammonia Nitrogen From Coking Waste Water

Nowadays, the traditional approaches of ammonia nitrogen in the coking wastewater treatment mainly used at home and abroad, such as bio-denitrification,chemical precipitation and adsorption method are relatively monadical, and the effect of coking wastewater processed by current techniques and methods is not very satisfactory, especially the amount of NH3-N in effluent, which has exceeded the standards seriously. If a technology of simplified operation, low operating cost, high processing efficiency and recycling process is used, we will effectively improve the current situation of water pollution and save some costs for enterprises, having a positive impact on corporate image and competitiveness.In order to find the treatment method of ammonia nitrogen in coking wastewater, the research takes wastewater,which has undergone the primary treatment of a coking wastewater treatment plant in Taiyuan,as the research object and remove the main refractory organic pollutants in wastewater by using the D301RCl resin adsorption column, on the basis of influential factors of the resin adsorption of ammonia obtained from a large number of static tests by our group,under the condition of reducing the CODcr and the volatile phenol content,we let the water sample go through D301RCl resin and151Na resin, using two grade resins adsorption combination method. Then use suitable eluting agent, the mixed solution of Na2HPO4and Na3PC4, to elute the saturated resin after the adsorption of ammonia. After the low concentration of ammonia in water samples is enriched by resin, use a suitable eluent to dissolve the enriched ammonia in a small amount of solvent and precipitate the ammonia nitrogen of the eluting agent by the means of chemical precipitation of MAP(magnesium ammonium phosphate). The results show that the rate of ammonia removal in the wastewater is up to85%by using the151Na resin, which is under the optimal working conditions,and the saturated resin has a high regeneration rate and stable performance after the elution of the mixed solution of0.3M Na2HPO4and Na3PO4. At the same time,the recovery rate of ammonia nitrogen can be up to90%after the combination of MAP precipitation under the optimal conditions. The pollution indicators of the final effluent quality can reach national discharge standard I. This study is able to eliminate the interferences of the cation exchange resin adsorpting ammonia and improve the ability of the resin adsorption of ammonia via the two grade resin tandem adsorption.Meanwhile, organic combination of the method of adsorption and precipitation can recycle ammonia in the waste water. This method,which has solved the problem of excessive NH3-N in the traditional coking wastewater treatment method to some extent, is an efficient, simple and economically feasible treatment for coking wastewater.