曝气对高铁地下水化学特性的影响

Effect of Aeration on the Chemical Characteristics of Groundwater with High Concentration of Iron

氧气进入还原性的地下水中,会与地下水中的还原性组分发生系列化学反应,从而改变地下水的化学特性,通过调控这些化学反应有望快速修复污染地下水。为此,该文以江汉平原高铁地下水为例,研究曝气对地下水化学特性的影响。曝气实验在湖北省潜江市一口高铁浅层地下水井中进行,测定曝气过程中地下水溶解氧(DO)、氧化还原电位(ORP)、pH值和其中铁、锰、三氮、磷、碳酸氢根等浓度的变化。研究结果表明,曝气在增加地下水中DO和ORP的同时,地下水中的铁、锰快速完全氧化,磷酸盐随之沉淀;碳酸根减少,使pH值增加近一个单位;同时,氨态氮含量略增加,硝态氮含量先增后减,暗示曝气后期好氧反硝化作用的存在。这些结果可为污染地下水修复技术提供重要的参考依据。

When oxygen enters into reductive groundwater,it will cause a series of chemical reactions with the reducing components in the groundwater,thus changing the chemical characteristics of the groundwater.Regulation of these chemical reactions is expected to rapidly remediate contaminated groundwater.Therefore,the effect of aeration on the chemical characteristics of high-iron groundwater in Jianghan Plain was studied.The aeration experiment was carried out in a shallow groundwater well with high iron concentration in Qianjiang City,Hubei province.The dissolved oxygen(DO),oxidation reduction potential(ORP),pH,and the concentrations of iron,manganese,nitrogen,phosphorus,and HCO3-in groundwater during aeration were measured.The results showed that when aeration increased DO and ORP of groundwater,iron and manganese in groundwater were oxidized completely,and phosphate co-precipitated.The concentration of HCO3-decreased with aeration,and thus the pH value increased by nearly one unit.At the same time,ammonia concentration increased slightly,and nitrate concentration increased first and then decreased,suggesting the existence of aerobic denitrification at the later stage of aeration.These results can provide important reference for remediation technology of polluted groundwater.