水力循环强化生态驳岸修复地表水效能研究

Remediation of surface Water by a Hydraulic Circulating Ecological Revetment

传统生态驳岸多作为河道与河岸的生态缓冲带以截留面源污染,但其水体修复效果欠佳,针对此问题,本研究开发了水力循环强化生态驳岸技术,使生态驳岸水力负荷达到0.2 m^(3)/(m^(2)·d)以上,增强其复氧与养分补给能力,最终提升对地表水的修复效能。研究结果表明,当模拟地表水水质为劣V类水质:即氨氮为2 mg/L、硝氮2 mg/L、总磷0.5 mg/L、COD 50 mg/L、Cu^(2+)2 mg/L、Zn^(2+)4 mg/L、Cd^(2+)0.1 mg/L时,水力循环生态驳岸可实现良好的修复效果,其中氨氮、COD和硝态氮的去除率分别为96%±3%、93%±2%和58%±3%;总磷去除率维持在50%左右;重金属(Cu^(2+)、Zn^(2+)、Cd^(2+))去除率均高于99%。对驳岸运行过程中根际微生物样品进行16S rDNA高通量测序发现,体系中存在的Nitrospira、Bacillus、Thiobacillus和norank_o_SBR1031等菌属,可通过硝化-好氧反硝化、硫自养反硝化等作用去除反应体系内的含氮污染物和有机物。可见,水力循环生态驳岸复氧效果好,可实现氨氮与COD的高效去除,但硝氮、总磷去除率有待提升,该技术对于修复劣V类地表水体具有广阔的应用前景。

Traditional ecological revetments are mostly used as ecological buffer zones between the river channel and river banks to intercept non-point pollution,but its remediation effect is not satisfactory.To solve this problem,the hydraulic circulation enhanced ecological revetment technology was developed in this study.Through the hydraulic cycle,the hydraulic load of the ecological revetment exceeded 0.2 m^(3)/(m^(2)·d),and its reoxygenation and nutrient replenishment capacity were improved simultaneously,ultimately enhancing the remediation performance of the ecological revetment to surface water.The results showed that when the concentrations of pollutants in synthetic wastewater were set as the inferior V-class surface water,i.e.,2 mg/L of ammonia,2 mg/L of nitrate,0.5 mg/L of total phosphorus (TP),50 mg/L of COD,2 mg/L of Cu^(2+),4 mg/L of Zn^(2+),and 0.1 mg/L of Cd^(2+),a desirable remediation performance was achieved by the hydraulic circulation enhanced ecological revetment.The removal efficiencies of ammonia,COD,and nitrate were 96%±3%,93%±2%,and 58%±3%,respectively.The removal efficiency of TP was maintained at approximately 50%;the removal efficiencies of heavy metals,i.e.,Cu^(2+),Zn^(2+)and Cd^(2+),were all above 99%.The 16S rRNA gene amplicon sequencing results shown,Nitrospira,Bacillus,Thiobacillus,and norank_o_SBR1031 were found in the rhizosphere microbial samples during the revetment operation,which can remove nitrogenous pollutants and organic matters by heterotrophic-nitrification aerobic-denitrification and sulfur-autotrophic-denitrification.Clearly,the hydraulic circulation approach had allowed the ecological revetment possess an excellent reoxygenation effect and an efficient removal performance of ammonium and COD,but the removal capability of nitrate and total phosphorus still needs to be improved.The novel hydraulic circulation ecological revetment has a good applicational potential in the remediation of inferior V-class surface water.