矿井水地下储存过程中典型污染组分去除规律——以内蒙古敏东一矿为例

Removal law of typical pollution components during underground storage of mine water:Taking Mindong No.1 Mine Inner Mongolia as an example

为了查清敏东一矿矿井水水质特征和地下储存过程中典型污染组分去除规律,设计了一种“地表处理+含水层储存”的实验装置,结合现场取样检测、污染组分分析、室内模拟实验等手段开展了相关研究,结果表明,敏东一矿井下矿井水中污染组分来源于天然地下水和煤炭生产,其中来自地下水的Fe,F,Mn等离子超标1.0~3.0倍;煤炭开采造成的污染包括COD、浊度、氨氮、总大肠菌群,分别超标69.67~192.33倍、24.16~55.17倍、0.52~1.10倍和4.33~7.67倍;石油类组分超标则表明矿井水中出现了一定程度的有机污染。混凝沉淀实验中,20.0 mg/L PAC条件下,浊度和COD分别降至13.60 NTU和4.73 mg/L;在常规处理(混凝沉淀)去除悬浮物和COD的基础上,采用“地表处理和含水层储存”的实验模拟工艺,利用地表包气带孔隙介质过滤、氧化反应等作用,使浊度<1.0 NTU,TOC含量=1.097~1.128 mg/L,UV254=0.026~0.037 cm-1,NH4质量浓度0.1 mg/L,地表处理段出水已经满足当地地下水条件;含水层储存过程中,还原环境还可以进一步去除矿井水中有机组分,使TOC含量和UV254进一步降至0.48~0.54 mg/L和0.005~0.008 cm-1。另外,利用三维荧光光谱指纹可以进一步查清矿井水中有机组分种类和去除过程,实验源水中主要出现了Ⅲ区的多环芳烃类有机物(荧光强度(fluorescence intensity,FI)=4147)和Ⅴ区的腐殖质类有机物(FI=3140);地表处理后,Ⅲ区和Ⅴ区的FI分别降至2033~3140和2201~2760,结合UV254的变化特征可以看出,好氧阶段优先去除大分子/多环芳烃类有机物,再经过含水层储存,Ⅲ区的FI进一步降至1496~1779,Ⅴ区的FI则≤1638。采用“地表处理+含水层储存”的矿井水处理储存模式,可以有效去除煤炭开采产生的污染组分,保障矿井水地下储存的水质安全。

In order to understand the characteristics of mine water quality and the law of removing some typical pollution components during underground storage in Mindong No.1 Mine,an experimental device of“surface treatment+aquifer storage”was designed.Relevant research was carried out by means of on-site sampling and testing,pollution component analysis and indoor simulation experiments.The results showed that the pollution components in mine water came from natural groundwater and coal production.Some pollution components exceeded the grade III standard(《Standard for Groundwater Quality》(GB/T 14848—2017))by 1.0-3.0 times from groundwater.Pollutions caused by coal mining includes COD,turbidity,ammonia nitrogen and total coliform bacteria,and they exceeded the standard 69.67-192.33 times,24.16-55.17 times,0.52-1.10 times and 4.33-7.67 times respectively.The over-standard of petroleum components indicated that there was a certain degree of organic pollution in mine water.In coagulation precipitation experiment,turbidity and COD decreased to 13.60 NTU and 4.73 mg/L respectively when 20.0 mg/L PAC was added.Based on the removal of suspended solids and COD by conventional treatment,the experimental simulation process of“surface treatment and aquifer storage”was adopted.By means of pore filtration and oxidation reaction in surface aeration zone,many pollutants were removed,such as turbidity<1.0 NTU,TOC=1.097-1.128 mg/L,UV254=0.026-0.037 cm-1 and NH4 content=0.1 mg/L.The effluent from the surface treatment section had met the local groundwater conditions.In the aquifer storage process,the reduction environment could further remove the organic components in the mine water.TOC and UV254 were further reduced to 0.48-0.54 mg/L and 0.005-0.008 cm-1 respectively.The classification and removal process of organic components in mine water could be further clarified by three-dimensional fluorescence spectrum fingerprint(3DEEM).Polycyclic aromatic hydrocarbons(PAHs)in zone III and humic organic compounds in zone V were found in the experimental source water.The fluorescence intensity(FI)was 4147 and 3140 respectively.After surface treatment,FI in regions III and V decreased to 2033-3140 and 2210-2760 respectively.Combining with the characteristics of UV254,it was found that the macromolecule/polycyclic aromatic hydrocarbons were removed preferentially in aerobic stage.After aquifer storage,FI in region III was further reduced to 1496-1779,and FI in region V was less than 1638.The mine water treatment storage mode of“surface treatment+aquifer storage”could effectively remove the pollution components produced by coal mining and ensured the water quality safety of underground storage of mine water.