串联垂直流人工湿地去除河水中磷的效果

利用在温室内构建的串联垂直流人工湿地模拟装置,以芦苇为湿地植物,填充砾石,研究两种水力负荷(0.2和0.4 m/d)、3个串联级数、有/无植物等对处理北京市清河河水磷去除的影响,试验共持续144 d. 结果表明:①在进水ρ(TP)为0.50~1.77 mg/L(平均值为1.15 mg/L)、ρ(DTP)为0.41~1.53 mg/L(平均值为0.9 mg/L)的条件下,TP去除率随进水ρ(TP)的升高而升高. ②水力负荷为0.2 m/d时,有、无植物3级串联系统磷的去除率分别为38.36%、26.85%；水力负荷为0.4 m/d时,分别为32.42%,23.99%,说明低水力负荷与有植物的条件利于除磷. ③有植物3级串联系统TP去除率平均值为38.36%,大于2级串联系统(28.30%)；无植物3级串联系TP去除率平均值为26.85%,大于2级串联系统(21.81%)和1级串联系统(14.98%),串联级数增加,磷去除率升高. 研究显示,水力负荷为0.2 m/d时,有植物3级串联系统的TP去除率最高. 

Phosphorus Removal Efficiency of Simulated Series Vertical Flow Constructed Wetlands Treating River Water

Waterbody eutrophication is one of the most serious environmental problems in the world. Phosphorus is an important factorin eutrophication. Constructed wetland is a cost-effective technique to treat contaminated river water.A series of simulated vertical-flow constructed wetlands (four groups of three stage columns, each column measuring 90 cm in height, 9.5 cm in diameter,and packed with gravels of particle size from 4.4 to 26.4 mm in a height of 80 cm) planted with Phragmites were built in the greenhouse to treat Qinghe River water of Beijing. The effects of two hydraulic loads, three stages of series connection and vegetation on phosphorus removal were observed over 144 days,24 cycles.The influent water contained ρ(TP) 0.50-1.77 mg/L (with an average of 1.15 mg/L) and ρ(DTP) 0.41-1.53 mg/L (with an average of 0.9 mg/L). TP removal rate increased with the increase of influent concentration. Under hydraulic load of 0.2 m/d, phosphorus removal rates of vegetated and unvegetated systems were 38.36% and 26.85%. Additionally, the removal efficiency of vegetated systems (32.42%) was superior to unvegetated systems (23.99%) at the hydraulic load of 0.4 m/d. This indicated that low hydraulic load and hydrophytes favored phosphorus removal. What's more, stages of series connection had an effect on phosphorus removalrate.Three stage column system had higher phosphorus removal rate than one stage and two stage column systems. In the vegetated systems, the removal rates of three stage and two stage column systems were 38.36% and 26.85%respectively. While in unvegetated systems, the removal efficiencies were 26.85%, 21.81% and 14.98% with the column system stage decreased.The research showed that the three stage column system with hydrophytes under the hydraulic load of 0.2 m/d had the highest removal rate of TP.