北方地区受污染河湖水体潜流湿地净化技术研究与工程应用

结合实验研究和工程应用实践,在湿地填料选择、水力负荷变化、植物特性、结构优化、越冬运行等方面,对我国北方地区潜流人工湿地设计、建设、运行管理中的关键技术问题开展了系统、深入研究.结果表明:石灰石、粗砂等脱氮除磷综合效果较好,且取材方便、价格便宜,应是人工湿地主选填料,钢渣、褐铁矿除磷效果良好、沸石的氨氮吸附能力强,可作为辅助材料;湿地植物对水质净化贡献约为5%～15%,其地上部分的生物量移除贡献不足5%,湿地植物对系统水力负荷维持、冬季保温、生态景观等还具有较大贡献;以植物保温为主,结合冰下取水、水位管理等可实现北方地区潜流湿地冬季正常运行;优化提出了竖向复合流湿地结构,具有节约用地、硝化-反硝化作用效果显著、抗淤堵等特点.研究成果已在工程实践中得到成功应用,对人工湿地在我国北方地区的推广应用具有重要借鉴意义.

Investigation and application of subsurface flow constructed wetland in water purification for the polluted river and lake in northern China

On the basis of experimental studies and practical application, the key factors in design, construction, and operation of the subsurface flow constructed wetland in northern China are summarized in this paper. The factors investigated in this study include media selection, hydraulic loading rate, aquatic plant screening, structure optimization, and operation in winter. The results clearly showed that the limestone and sand should be selected as the major media of subsurface flow constructed wetland considering the performance of nitrogen and phosphorus removal, the availability and the price. The steel slag and limonite with excellent phosphorus removal, and zeolite with well adsorption ability of ammonia can be used as the secondary media. The wetland plants totally contribute only about 5%~15% to water quality improvement with a less-than-5% contribution by the harvesting of the above-ground biomass. However, wetland plants can make a large contribution to maintaining hydraulic loading, insulating heat in winter and preserving ecological landscape. Plant-based insulation, combined with water intake under ice cover and water level control, can achieve the normal running of subsurface flow constructed wetland in winter in northern China. A constructed wetland with subsurface vertical and horizontal complex flow was optimized, which has the advantages of land saving, remarkable effect of nitrification-denitrification, and anti-clogging. These results of subsurface flow constructed wetland had been successfully applied in practice and would be helpful for the promotion of the constructed wetlands in northern China.