为评价利用富含天然水溶性有机质的废水覆盖处理对含硫煤矸石污染物释放的原位控制效果,分别采用过滤后的沼液覆盖(水溶性有机质1,OC—1)、养殖废水覆盖(水溶性有机质2,OC一2)及清洁水源水覆盖(对照,CK)对煤矸石进行浸没(覆盖)处理。经550d的连续浸没试验,结果表明:与对照相比,煤矸石在2种天然水溶性有机质覆盖处理后的550d的内,均能显著抑制煤矸石的氧化产酸,使水溶性有机质处理后上覆水样的pH一直维持中性偏碱的水平,显著降低了煤矸石周边水环境的氧化还原电位(pocl=0.00001;poc-~0.00001),并显著降低了煤矸石上覆水样中Fe、Mn、Cu、Zn及s0。。和F等阴阳离子的浓度(poc-1均〈0.01;poc-2也均〈0.01);且2种水溶性有机质覆盖上覆水样中的溶出离子浓度之间没有显著性差异(pEC=0.2515、pEh=0.3198、pFe=0.9928、pMn=1、pCu=0.9397、pZn=0.9931、psO_4^2-=0.124、pF^-=0.0738)。而清洁水源水(对照)处理的上覆水样则呈现煤矿山酸性废水的典型特征,即较低的pH(2.52)、较高的EC(3730p.S/cm)、Eh(502mV)和酸度(1383mg/L),同时富含Fe、Mn、Cu、Zn等金属离子及SO_4^2-和F^-等阴离子。说明天然水溶性有机质覆盖处理可有效抑制含硫煤矸石的氧化酸化及多种特征污染物质的溶出释放。因此,可考虑采用一定浓度的养殖废水及沼液等天然水溶性有机质作为煤矸石覆盖材料对含硫煤矸石进行原位污染控制及治殚。
Controlling pollutants released from coal gangue has been one of the major environmental issues in coal-mine areas. In this paper, studies were carded out with the continuous leaching tests by coal-gangue immersed in water-soluble organic materials. Three kinds of tests were incessantly conducted for 550 d, involving immersion of coal gangue in different solutions, i.e. biogas slurry (sol-organic1, OC-1), cattle-farm wastewater (sol-organic2, OC-2) and control group (clean surface water, CK). Results of the tests showed that compared with CK, the immersion of both OC-1 and OC-2, pH values could maintain neutral or slightly alkali; oxidation-reduction potential was significantly lower; and concentrations of Fe, Mn, Cu, Zn, SO_4^2- and F- declined significantly as well. In addition, there were no marked differences between OC-1 and OC-2 with respect to controlling leaching of cations and anions. In contrary to the behaviors of OC-1 and 0C-2, the overlying water of CK presented common characteristics of acid mine drainage (AMD), with very low pH value (2.5), higher electrical conductivity (3 730 μS/cm), redox potential (502 mV), total acidity (1 383 mg/L) and abundant with Fe, Mn, Cu, Zn, SO_4^2- and F^-. The data achieved indicated that treatment by soluble organics could effectively inhibit acidification and control contaminants released from coal gangue, therefore suggesting that water-soluble organics such as biogas slurry and cattle-farmwastewater could be used to controlling pollution of coal gangue on site.