Study On The Hybrid Sf Cws Systems’ Purification Technology For Heavily Polluted River Water

Urban rivers can improve the city’s climate, water supply, flood control anddrainage, and etc. It plays a pivotal role in a city’s development, but its pollutionproblem has become increasingly prominent and become a threat to people’s health. Soits hybrid control technology has become a foucus of attention in the field ofenvironmental protection. According to the the mission’s requirements of the nationalscience and technology major projects (water pollution control and treatment), thetreating efficiency of hybrid artificial subsurface flow constructed wetlands(SF CWs)system for the urban black-odor river polluted water was carried out in the pilot study.In the study, a variety of hybrid SF CWs systems’ processing characteristics forpurification of pollutants, technical parameters and influencing factors were discussed.The experimental pilot base was built somewhere in Nanning. In the tests, thehybrid systems’ properties for the treatment of contaminated river water were studied.The control variable method was taken in the pilot-scale study. By changing thehydraulic retention time, the pollution load, the wetland vegetation, and the wetland’spacking, the influences of different factors on the complex systems’ pollutant removalefficiency for COD, TN, TP and NH4-N were tested, in which the hydraulic retentiontime was set to0.8~2.5d, the pollution load of different pollutants respectively wereCOD (162~459kg·hm-2·d-1), TN (27~118kg·hm-2·d-1), TP (2.0~5.2kg·hm-2·d-1) andNH4-N (14~43kg·hm-2·d-1), the packing used volcanic stone and gravel and the wetlandvegetations choosed windmill grass, myriophyllum, canna and iris. By comparing theresults, it can be concluded that:1) Increasing the hydraulic retention time and reducingthe pollution load of the systems can help improve the removal efficiency of pollutants,and each system had better anti-COD load shocks;2) In hydrolysis (acidification)—HFCWs combined systems,wetland vegetation effected the pollutants’ removal efficiencyto a certain extent, and compared to iris, windmill grass is more conducive to improvethe systems’ removal efficiency for TN, TP and NH4-N;3) compared to the gravel, thelava rock is more conducive to improve systems’ purifying effect as a whole.Through the pilot study, we found that the hybrid artificial subsurface flowwetlands systems was effective in improving the effluent quality for treating thecontaminated water from paddlewheel river. When HRT was2.5d, each system can allachieve the standard A of discharge standard of pollutants for municipal wastewatertreatment plant(GB18918-2002), and the effluent quality meets COD≤13mg·L-1, TN≤7mg·L-1, TP≤0.42mg·L-1, NH4-N≤5mg·L-1. Meanwhile, pilot studies have reached theexpected goal. On the one hand, different factors on the effect of decontamination forthe compound systems were discussed. On the other hand, by simulating a kinetic equation of the system, the area degradation rate constant of pollutants were obtained.This have a good theory guidance value for the technology of expanded applications.