原位曝气修复黑臭河道底泥内源营养盐的示范工程效能分析

Analysis of performances of pilot-scale in-situ aeration remediation for endogenous nutrients in malodorous river sediments

以上海工业河勤丰泵站周围50 m河段为研究对象,现场探讨了原位曝气对底泥内源营养盐去除的示范工程效能,目的为曝气治理城市黑臭河道工程的优化实施提供参考。结果表明,原位曝气有利于对底泥内源氮、磷营养盐的控释,对工业河示范河段溶解性总氮(DTN)削减率为(48.4±6.0)%,上覆水DTN的平均浓度由13.4 mg·L-1降至8.7 mg·L-1;NH+4-N的削减率为(46.3±16.7)%,其上覆水浓度均低于7.6 mg·L-1;泥水界面硝化率与反硝化率分别达到46.3%和43.6%;上覆水溶解性总磷(DTP)的削减率为(35.4±2.9)%,由于示范区段没有与其他区段隔离,其实际工程效果要优于观测值。静态经济评价表明原位曝气修复黑臭河道底泥技术的环境与经济效益明显优于常规底泥疏浚技术。

In this research, the performance of in-situ aeration for the removal of endogenous nutrients was investigated in the field in an approximately 50 meter long segment of an industrial river in Shanghai. The results obtained could provide technical references for an aerating engineering application to treat a malodorous river. The results showed that in-situ aeration was an effective method for the controlled release of the endogenous nitro- gen and phosphorus in the sediment. The reduction efficiency of the dissolved total nitrogen （DTN） was （48.4 ± 6.0） % , and the DTN concentration dropped from 13.4 mg · L -1 to 8.7 mg · L -1 in the overlying water. The removal rate of NH4 -N was （46.3 ± 16.7） % , and the concentrations were lower than 7.6 mg · L -1 in the over- lying water. The nitrification and denitrification rates at the sediment-water interface reached 46.3% and 46.3% , respectively. The reduction rate of the dissolved total phosphorus （DTP） was （35.4 ＋ 2.9）% in the o- verlying water. The actual performances were deemed superior to those observed, because the demonstration area had not been isolated from the other areas. Additionally, the static economic evaluation showed that the environ- mental and economic efficiency of in-situ aeration remediation were superior in comparison with sediment dred- ging technologies for remediating malodorous river sediments.