岩溶山区电解锰渣库地下水环境污染特征及其污染控制

Groundwater environmental pollution characteristics and pollution control of electrolytic manganese slag storage in karst mountainous areas

我国西南某岩溶山区电解锰行业较为发达,电解锰产出的同时也产生了大量锰渣,锰渣主要采用填埋存储的方法进行处理,区内电解锰渣场有20余处。锰渣场多位于岩溶洼地区,地下水环境极脆弱,有11座锰渣库存在渗漏污染地下水的环境问题。针对该区域内某2个电解锰渣库渗漏,污染下游岩溶地下河出口的具体问题,以改善地下水环境、节约污水治理资金为目标。以水文地质单元为研究范围,重点研究地下水污染途径及水文地质条件,通过调查、采样分析、钻探、物探、连通试验、抽水试验等工作方法,查明了这2个锰渣渣库渗漏是地下河出口污染的主要原因,渣库高悬于地下水水位之上,渣体内污染物通过6种途径进入地下水;锰渣库位于地下水系统排泄区,库区范围及下游地下水已被污染,占地下河流域面积的8.33%;地下水系统的补给径流区全为岩溶洼地,地下水未受污染,存在3处地下水集中径流带。根据研究区地下水污染特征及水文地质条件,提出了“分区治理、清污分流”的源头防控治理思路。抽水试验结果表明,按照该治理方法实施治理后,被污染地下河出口水量总体可减少70%以上,节约污水治理资金300万元/年。

The electrolytic manganese industry in a karst mountainous area in southwestern China is relatively developed.While producing electrolytic manganese,a large amount of manganese slag is also produced.The manganese slag is mainly treated by landfill storage,and there are more than 20 electrolytic manganese slag yards in the area.Manganese slag yards are mostly located in karst depression areas,and the groundwater environment is extremely fragile.There are 11 manganese slag inventories that are leaking and polluting the groundwater environment.In response to the specific problem of leakage from two electrolytic manganese slag reservoirs in the area,which pollutes the downstream karst underground river outlet,the goal is to improve the groundwater environment and save funds for sewage treatment.With the hydrogeological unit as the research scope,the research focuses on the groundwater pollution path and hydrogeological conditions,through investigation,sampling analysis,drilling,geophysical exploration,connectivity test,pumping test and other work methods.It has been identified that the leakage of two manganese slag reservoirs is the main cause of pollution at the outlet of the underground river.The slag reservoirs are suspended above the groundwater level,and pollutants in the slag body enter the groundwater through six channels.The manganese slag reservoir is located in the discharge area of the groundwater system,and the groundwater in the reservoir area and downstream has been polluted,accounting for 8.33%of the underground river basin area.The recharge and runoff areas of the groundwater system are all karst depressions,and the groundwater is not polluted.There are three concentrated groundwater runoff zones.According to the characteristics of groundwater pollution and hydrogeological conditions in the study area,the idea of source prevention and control of"divisional treatment,separation of clean water and sewage"is proposed.The results of the pumping test show that after implementing the treatment project according to this treatment method,the overall water volume at the outlet of the polluted underground river can be reduced by more than 70%,saving 3 million￥/a in sewage treatment funds.