护砌方式对模拟城市河道水质净化及稳定化的影响

通过构建中试规模河道模拟传统"三面光"河道、仿自然的生态型河道及自然河道,考察了3种护砌方式对模拟城市河道水质净化及稳定化的影响.结果表明,在自然条件下,"三面光"河道对COD、NH4 -N、TP的去除率分别为10.4%、4.7%及2.5%,仿自然的生态型河道为18.9%、13.4%及11.6%,自然河道为20.5%、14.5%及7.7%.护砌方式对城市河道水质净化影响明显;自然或仿自然的护砌方式,可明显改善水质.在5个月的试验期内,"三面光河道"出现藻类孳生的情况,而仿自然的生态型河道及自然河道内的藻类始终得到有效控制,表明自然或仿自然的护砌方式可保持水质稳定.基于城市河道景观和水质稳定的需要,堤坡或河床覆盖一定数量的水生植物是必要的,仿自然的生态型河道和自然河道植物覆盖分别达到水面的40%、70%时都取得了令人满意的效果.

Effects of simulated urban river embankments on water purification and stabilization

The effects of simulated urban river embankments on water purification and stabilization were studied in three types of urban river, simulated hard embankment, semi-natural bank and natural bank. The results show that the removal rates of COD, NH~ _4-N and TP in hard embankment urban river are 10.4%, 4.7% and 2.5%, respectively, 18.9%, 13.4% and 11.6% in semi-natural bank, 20.5%, 14.5% and 7.7% in natural bank under ordinary condition. It indicates that the embankment type plays an important role in water purification process. Natural and semi-natural urban river embankments can improve the water quality significantly. During the 5 months experiment, algae bloom occurred in the hard embankment urban river while it was controlled effectively in semi-natural and natural urban rivers. It showed embankment types can improve water quality. Aquatic plants covering on river embankment are necessary for the purpose of decorative landscape and water stabilization. When the covering rate of water surface by aquatic plants was 40% and 70% respectively, a satisfactory improvement can be obtained in semi-natural and natural urban rivers.