天津市地下水监测井硫化物超标规律与成因分析

Regularity Exceeded and Cause of Sulfide in Groundwater Monitoring Wells in Tianjin

为探明天津市地下水监测井中硫化物状况,收集天津市内309个监测井的水样指标检测数据,开展硫化物演变特征及其成因研究。在水化学统计分析、相关分析的基础上,结合监测井中水体与含水层中地下水水质对比分析和抽水试验识别不同硫化物超标特征及原因。结果表明,监测井中水体硫化物超标率与监测井深度有一致性,硫化物来源与无缝钢管材质的井管锈蚀有关;井管锈蚀过程中析出硫在单质硫还原菌(S0RB)作用下还原成硫化物进入监测井水体中,造成硫化物浓度升高;通过抽水可降低水体中的硫化物浓度,取样时应尽可能延长抽水时长和增加抽水量。该研究结果可为确定水质监测井抽水合理时长和抽排水量以及地下水供水安全提供可靠参考。

In order to explore the status of sulfide in the groundwater monitoring wells in Tianjin,a study was conducted to characterize the evolution of sulfide and its causes based on the water sample detection data of 309 monitoring wells in the city.On the basis of hydrochemical statistical analysis and correlation analysis,combined with the comparative analysis of groundwater quality between the monitoring wells and the aquifers and pumping tests,the characteristics and causes of different sulfides exceeding the standard were identified.The results show that the over-standard rate of sulfide in the monitoring wells is consistent with the depth of the monitoring wells,and the source of sulfide is related to the corrosion of seamless steel pipe.Sulfur precipitated during well pipe corrosion is reduced to sulfide by Sulphur Reducing Bacteria(S0RB)and enters the water the monitoring wells,resulting in elevated sulfide concentrations.The concentration of sulfide in the water can be reduced by pumping,and the sampling time should be prolonged and the amount of pumping should be increased as much as possible.This study can provide a reliable reference for determining the reasonable pumping time and pumping quantity of water quality monitoring wells and the safety of groundwater supply.