title: Treating surface water with low nutrients concentration by mixed substrates constructed wetlands.
abstract: Constructed wetland (CW) has been widely applied in nutrients reduction for eutrophication control, especially in the advanced treatment of effluent of municipal sewage plants or the in-lake river treatment with high hydraulic loads and low nutrient concentrations. But in real application, it shows lower nutrient removal efficiency. The main reason is that traditional substrates, such as soil and gravel have low capacity for nitrogen and phosphorus removal. This study aims to enhance nutrients removal in constructed wetland systems by using series of substrates including calcium silicate hydrate (CSH), vermiculite and ceramsite which are all investigated individually in static experiment or mixed in batch and continuous flow experiments. The result showed that the efficiency of phosphorus removal by CSH could reach 97%, much higher than the other substrates. However, when it was applied in CW, the removal efficiency decreased. Although vermiculite showed the highest ammonia nitrogen removal efficiency of 65.91%, the ammonia nitrogen removal efficiency may have depended on the action of microorganism. High total nitrogen removal efficiency was obtained in continuous-flow mixed substrate CW. Under a hydraulic retention time (HRT) of 18h and hydraulic loading rate (HLR) of 0.496 m(3)/m(3).d, average total nitrogen removal efficiency of above 91% was achieved, but the average phosphorus removal efficiency was around 65% and this needs to be improved further.
authors.affiliation: School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, PR China. cjli@sjtu.edu.cn
authors.forename: Chun J
authors.initials: CJ
authors.lastname: Li
authors.forename: Ming H
authors.initials: MH
authors.lastname: Wan
authors.forename: Yang
authors.initials: Y
authors.lastname: Dong
authors.forename: Zhen Y
authors.initials: ZY
authors.lastname: Men
authors.forename: Yan
authors.initials: Y
authors.lastname: Lin
authors.forename: De Y
authors.initials: DY
authors.lastname: Wu
authors.forename: Hai N
authors.initials: HN
authors.lastname: Kong
mesh_terms: D000538:Aluminum Silicates / Q000737:chemistry; D000641:Ammonia / Q000032:analysis / Q000737:chemistry; D017610:Calcium Compounds / Q000737:chemistry; D052918:Environmental Restoration and Remediation / Q000379:methods*; D008903:Minerals / Q000737:chemistry*; D009584:Nitrogen / Q000032:analysis / Q000737:chemistry; D010758:Phosphorus / Q000032:analysis / Q000737:chemistry; D017640:Silicates / Q000737:chemistry; D014865:Waste Disposal, Fluid / Q000379:methods*; D014872:Water Movements; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*; D053833:Wetlands
chemical_list: D000538:Aluminum Silicates; D017610:Calcium Compounds; D008903:Minerals; D017640:Silicates; D014874:Water Pollutants, Chemical; C003760:vermiculite; D010758:Phosphorus; D000641:Ammonia; D009584:Nitrogen; C031293:calcium silicate