活性滤坝对城市内河中氮磷的削减效果

Reducing effect of active filter dam on nitrogen and phosphorus in urban inner river

城市内河氮磷严重超标是当前水污染治理的重要难题。针对内河具有旱季水位低、水流速度慢、自净能力差等特点,提出采用活性滤坝削减氮磷,以铝基锁磷剂和沸石为活性滤坝基质滤料,实验室静态和动态实验研究了活性滤坝削减氮磷效果,讨论了基质滤料组合方式对削减氮磷效果影响,同时采用曲线方程拟合分析方法预测了活性滤坝吸附氮磷有效使用时间。静态实验结果表明,在控制进水氨氮15 mg·L^(−1)和正磷酸盐5 mg·L^(−1)情况下,实验历时20 d,活性滤坝对氨氮和正磷酸盐削减率分别为98.02%和100%,混合滤坝组削减氮磷效果最佳;动态实验结果表明,控制水中氨氮和正磷酸盐为8~15 mg·L^(−1)和2.5~5 mg·L^(−1),流速为8.33 cm·h^(−1),实验历时37 d,完成氮和磷循环分别为11次和16次,拟合曲线方程预测混合滤坝组削减氨氮和正磷酸盐的有效使用时间分别为282 d和479 d。以上研究结果可为城市内河道修复提供技术参考。

The serious excess of nitrogen and phosphorus in urban inner river is an important problem in water pollution control.In view of the characteristics of low water level,slow flow velocity and poor self-purification ability in the dry season,this study proposes to utilize active filter dam of which the matrix filter materials are zeolite and aluminum-based products Phoslock to reduce nitrogen and phosphorus.The effect of matrix filter combination on the reduction of nitrogen and phosphorus was discussed.Meanwhile,the effective time for reducing ammonia nitrogen and orthophosphate by active filter dam was predicted by the fitting curve equation.The static experiment results showed at the initial ammonia nitrogen concentration of 15 mg·L^(−1) and orthophosphate concentration of 5 mg·L^(−1),the reduction rates of ammonia nitrogen and orthophosphate by active filter dam were 98.02%and 100%after 20 days,respectively,and the mixed filter dam group had the best performance on reducing nitrogen and phosphorus.The results of dynamic experiment showed that at the water flow rate of 8.33 cm·h^(−1),the ammonia nitrogen concentration range of 8~15 mg·L^(−1) and the orthophosphate concentration range of 2.5~5 mg·L^(−1),the reduction process of nitrogen and phosphorus in the simulated river channel was completed 11 times and 16 times during 37 days,respectively.The fitting curve equation predicted that the effective time for reducing ammonia nitrogen and orthophosphate was 282 days and 479 days in the matrix filter dam group,respectively.This study can provide reference for the remediation technology of urban inner river.