%0 Journal Article
%T DO and ORP conditions and their correlation with plant root distribution in a continuous-flow constructed wetland treating eutrophic water<br>连续流湿地中DO、ORP状况及与植物根系分布的关系
%A FU Rongbing
%A ZHU Yiping
%A YANG Haizhen
%A GU Guowei
%A <br>付融冰
%A 朱宜平
%A 杨海真
%A 顾国维
%J 环境科学学报
%D 2008
%I 
%X A subsurface horizontal-flow constructed wetland planted with Phragmites australis was developed and used to treat eutrophic water for nearly two years. The plant root distribution, spatial and temporal changes of dissolved oxygen (DO) and oxidation reduction potential (ORP) in wetland water and their correlation with hydraulic loading rate (HLR) were investigated. The influence of plant root distribution on the redox condition of constructed wetlands (CWs) was further analyzed. In the first year, 95% of the root biomass was distributed in the top 0~20 cm and in the second year, 97% of root biomass was distributed in the top 0~35 cm. In the second year of growth, the plant roots significantly extended through a larger proportion of the wetland substrate. DO and ORP of the upper and middle layers of water increased horizontally with the water flow, but the DO and ORP of the bottom water remained nearly constant. DO and ORP decreased with depth. Because of the influence of root biomass distribution in the upper water layer, the environment from the surface to 15 cm deep was moderately reducing, while deeper layers were strongly reducing. As a whole, subsurface horizontal-flow constructed wetlands with continuous flow are anaerobic environments. Due to plant photosynthesis and atmospheric reaeration, water DO initially increased and then decreased over a day. DO and ORP of wetland water decreased as HLR increased. Measurement of the rhizosphere redox potential showed that the microenvironment of the rhizosphere was more oxidising (ORP (260.6±54.3) mV) than bulk water (ORP(-220.3±21.5) mV). Oxygen transportation of plant to roots enhances oxidation ability of rhizosphere which cannot change the total anaerobic environment but effectively contributes to improve the aerobic condition of upper water layers in the constructed wetland.
%K DO
%K ORP<br>富营养化河水
%K 水平潜流人工湿地
%K 连续流
%K 根系分布
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=3FF3ABA7486768130C3FF830376F43B398E0C97F0FF2DD53&cid=A7CA601309F5FED03C078BCE383971DC&jid=03A55E61A8750ACAC6AF81EF9E2AC838&aid=54E8F26592401986C482A2967F9CE5E3&yid=67289AFF6305E306&vid=D3E34374A0D77D7F&iid=F3090AE9B60B7ED1&sid=1AE9108C480054ED&eid=E7B46CD86468D9A6&journal_id=0253-2468&journal_name=环境科学学报&referenced_num=2&reference_num=17