Study On The Wastewater Advanced Treatment Of Nitrogen And Phosphorus Removal Using Supported Nanoscale Fe Packing

In recent years, although China built many new municipal wastewater treatment plants continually, According to statistics:wastewater treatment rate in urban was 58%, and it was only 4% in country. The major pollution index was nitrogen and phosphorus, affected water basins have expanded year by year. Thus, developing simple, high efficiency and low energy consumption wastewater deep treatment techniques, was the effective method to solve the problem of water pollution and water shortage, and wastewater treatment techniques aiming at middle-small point pollution is the key research topic.The combinational process of tranditonal A²O-volcanic-nanoscale Fe packing were used for deep treating municipal wastewater, and compared with sulphur packing and volcanic packing. The treatment of wastewater containing nitrate and Phosphorus with nanoscale-Fe and volcanic-nanoscale-Fe adsorbent was studied. The best experimental factors were achieved through the static experiment and the column adsorbent experiment. They offer scientific base for the combinational process.The results of the static experiment and the dynamic experiment show that adsorptive balance time of nanoscale Fe adsorbent adsorp nitrate was 60 min, and the reaction rate is more quickly as the temperature is higher and the main effect of nitrate removal by nanoscale Fe is adsorption and chemical reductive reaction, and the remove effects is very obviously under the acidic conditions; Adsorptive balance time of nanoscale Fe adsorbent adsorb Phosphorus was 60 min, Its adsorption isotherm follows Freundlich’s and Langmuir’s equations. Corresponding to solution pH change, nanoscale-Fe adsorbent’s adsorption capacity changed largely, and at about pH=4 reached the peak, and the adsorption effect is best when the temperature is 25℃; And the column test conforms the mass ratio of nanoscale Fe packing and volcanic packing is 1:30.The pilot study unit operated for four months consecutively, and the results of A²O is very good,and the average removal of COD, TN, TP, PO₄³⁺-P was 94%, 60%, 57.4%, 60.9%. In the deep treantment process, the results show that the combinational process of tranditonal A²O-volcanic-nanoscale Fe packing has good nitrate and Phosphorus removal effect than volcanic packing and sulphur packing, steady run. The average removal of TP、PO₄³⁺-P、COD、NO₃-N、NH₃-N and SS was 85.35%、94.31%、95.35%、97.86%、76.67%、95.91%respectively. TP and COD of effluent can meet the environmental quality standards for surface water（GB 3838-2002）（ClassⅢ）and control indicators have reached the desired objectives and meet the requirement of sewage deep treatment.