河流旁路生态系统构建及应用实践

Construction and application of river side-stream ecological system

以广东省某河流水环境治理工程项目为案例,基于生态修复技术原理构建河流旁路生态系统,在不改变河流原状态和不影响雨季行洪的情况下,实现水质净化、生态补水、景观提升等多种功能,使原河道水体在雨季和旱季都能够保持较好的水质和较高的自净能力。该系统由人工水草、浮动湿地、曝气系统、水生植物、功能性填料等工艺措施组合而成,在改善水质的同时还具有一定的生态景观效益。工程实践表明,该系统能够降低河流水体COD Cr、BOD 5、NH_(3)-N和TP等主要污染物浓度,主要水质指标满足《地表水环境质量标准》(GB 3838—2002)中Ⅴ类水质标准要求。工程项目总投资1250万元,折合吨水投资为625元/m^(3),运行能耗不足0.10 kW·h/m^(3),直接运行费用约0.16元/m^(3),相比传统污水处理工艺,旁路生态系统是一种低成本、处理效果好的仿自然工艺。本研究成果可为其他类似支流丰富、坑塘较多的中小流域水环境治理提供参考,对河流生态修复具有重要指导意义。

Taking a river water environment treatment project in Guangdong Province as an example.Based on the principle of natural ecological restoration technology,the river side-stream ecological system is constructed.Without changing the original state of the river and without affecting the flood discharge in the rainy season,it can realize various functions such as water quality purification,ecological water replenishment and landscape improvement.Therefore,the original river water could maintain good water quality and high self-purification ability in rainy and dry seasons.The system was composed of artificial water grass,floating wetland,aeration system,aquatic plants and functional fillers,which could improve water quality and contribute to the ecological landscape.The results of the project showed that the treatment system could significantly reduce the concentration of main pollutants such as COD Cr,BOD 5,NH_(3)-N and TP in water and the main water quality indicators met the standard of categoryⅤwater quality,in Environmental Quality Standards for Surface Water(GB 3838—2002).The total project investment was 12.5 million yuan,equivalent to 625 yuan per ton of water investment,and the energy consumption was less than 0.10 kW·h/m^(3)and direct operation cost is only about 0.16 yuan/m^(3).Compared with the traditional sewage treatment process,the river side-stream ecological system was a low-cost and effective natural process.The results of this study could provide reference for water environment management of other similar medium and small watersheds with rich tributaries and many ponds,and had important guiding significance for river ecological restoration.