用于水体原位脱氮除磷的新型曝气浮岛填料

Performance of media selected for a novel enhanced floating island to remediate eutrophicated river in situ

针对宜兴城镇化新区河流夏季富营养化的特点,拟采用一种不依赖于植物的新型强化曝气浮岛对该类水体进行原位处理。为强化浮岛筛选合适的填料,研究了3种填料在模拟富营养化自然状态下的挂膜性能,以及对模拟富营养化河流水质的净化效果。结果显示,空心球、鲍尔环和K3填料的终期挂膜量分别为0.6、1.5和2.2 g·L^(-1);空心球和K3填料的净化效果较好,综合考虑工艺的经济性要求,确定空心球作为该工艺的有机类型填料。在此基础上,进一步研究了水质、水温和曝气强度等参数对空心球挂膜的影响。污染物负荷越大,温度越高,其挂膜速度越快,但在实验范围内的温度对最终挂膜量并没有影响。保持较高的溶解氧浓度有利于COD、氨氮和TP的去除,但5 mg·L^(-1)以上的溶解氧浓度不利于总氮的去除,溶解氧浓度为3 mg·L^(-1)时对总氮去除率最高,对COD、氨氮、TN和TP的去除率分别为61.10%、81.45%、58.60%和31.62%。与空心球相比,包括沸石钢渣的组合填料对COD、氨氮、TN和TP的去除速率分别提高了13.01%、51%、86.36%和53.85%。

Several eutrophic rivers exist in Yixing city,and a novel floating island with aeration enhancement that does not rely on plants is proposed here for in situ eutrophication remediation. In order to select the proper filling media to enhance the performance of the floating island,three types of packing media made of high molecular weight polymers were tested to evaluate their biofilm growth features,as well as their purification performance during the treatment of eutrophic waters. The results showed that the final pollutant（ e. g. COD,ammonium nitrogen,total nitrogen and total phosphorus） amounts removed by hollow balls,Pall rings,and K3 carriers were 0. 6,1. 5 and 2. 2 g·L^-1,respectively; thus,the purification performance of K3 carriers was the highest.In consideration of technological issues and economic costs,hollow balls were determined to be the optimal polymer media to use in this novel process. Effects of different parameters on hollow ball performance,such as pollutant loading amounts,temperatures,and dissolved oxygen（ DO） concentrations,were also studied. Biofilm growth was accelerated under high pollutant loading amounts and high temperatures; however,temperatures within the tested range did not influence the final amount of biofilm mass. Higher DO levels can be beneficial for the removal of the chemical oxygen demand（ COD）,ammonium nitrogen,and total phosphorus. However,DO concentrations ≥ 5 mg·L^-1are not suitable for total nitrogen removal,and thus the optimal DO level for TN removal was found to be 3 mg·L^-1. Under such conditions（ i. e.,DO = 3 mg·L^-1）,removal rates of COD,ammonium nitrogen,TN,and TP were 61. 10%,81. 45%,58. 60%,and 31. 62%,respectively. Compared with hollow balls,combined filling media containing hollow balls,zeolite,and steal slugs increased the removal rates of COD,ammonia nitrogen,TN and TP by 13. 01%,51%,86. 36%,and 53. 85%.