矿区塌陷地改造与构造湿地建设——以徐州煤矿矿区塌陷地改造为例

Remediation of Subsided Land and Creation of Constructed Wetland in Mining Area-A case of Remediation of Subsided Land in Xuzhou Mining Area

徐州矿区的塌陷地有4700～5300hm2为常年积水或季节性积水,平均积水3～3.5m,积水最深达7m,几乎不可能复垦。对于不可恢复为农田的深度塌陷地,根据当地的自然环境、水文水系等特点,结合降水资源截留、污水处理厂的尾水排放处理等,可构建成不同类型的构造湿地(Constructed wetland),如养殖型构造湿地、景观型构造湿地和净化型构造湿地。如对于季节性积水或常年水深在0.5m以下的塌陷地,可以建设为以芦苇为优势的构造湿地,芦苇湿地不仅具有很强的污染净化能力,而且具有较大的生成能力,可以提供丰富的造纸原料。构造湿地的植物选种原则是土著性、强净化作用及良好的经济价值。这种因地制宜修复利用塌陷地的途径,不仅代价低,而且可以解决废水资源化利用、缓解地区水资源短缺的矛盾。

There is a subsided area covering 4700～5300 ha sunk as perennial or seasonal pond-ings in Xuzhou mining area.The average depth of water in these pondings is about 3～3.5m and the deepest ponding is about 7m.It is impossible to recultivate this kind of subsided area.For making use of the deeply subsided area,several types of constructed wetlands are proposed to build.On the basis of the characteristics of natural environment,hydrology,fiver system,sunk degree of the subsided area,three types of constructed wetlands including decontaminated constructed wetland,fishery constructed wetland and landscape constructed wetland can be built. The decontaminated constructed wetland should be built in shallow pondings,especially in some seasonal pondings or perennial poundings with a water depth no more than 0.5m.The aquatic and wetland plants,such as reed and cattail,can be introduced to the decontaminated constructed wetlands.The principles of choosing wetland plants are that these plants should be native with strong purification capacity and economic efficiency.The reed wetland has both economic efficiency and strong purification capacity,hence the subsided area can be improved by creating constructed wetlands.Such a measure adopted should also be suitable to local conditions, especially for Xuzhou,as water is shoutage in the city.The remediation of constructed wetland can not only withhold precipitation resource but also reuse tail water of wastewater so as to mitigate the contradition of water shortage issue.