Research on the Optimal Regulation of Sudden Water Pollution.

For the needs of the whole region's emergency regulation of the nullah sudden water pollution event, the emergency regulation strategy of the accident section and upstream and downstream of the sudden water pollution event is studied. For the accident section, the duration of the whole emergency event is calculated using the parameter quantification method; for the upstream of the accident section, the NSGA-II is used to adjust the gate opening to ensure the water level stability of the upstream pools; for the downstream section, the optimized partition method is used to identify the unfavorable pools and close the unfavorable pool to extend the water supply time. Based on the example of an emergency event in the section of the Liyanghe gate-Guyunhe gate of the middle line project, the research results are as follows: the accident section is identified as the Xiaohe gate-Hutuohe gate, the upstream of the accident section is the Liyanghe gate-Xiaohe gate, and the downstream of the accident section is the Hutuohe gate-Gangtou Tunnel gate. The duration of the emergency event in the accident section is 7.9 h; the maximum average water level deviation before the gate upstream of the accident section is 0.05 m; two unfavorable canal pools are identified in the stream of the accident section, and the water supply time of the unfavorable pools is extended by 6.13 and 5.61 d.

Experimental investigation on chemical clogging mechanism of loose porous media in recharge process of groundwater heat pump.

Groundwater heat pumps (GWHP) are an efficient utilisation of shallow geothermal energy technology and of great significance in terms of promoting energy conservation and reducing emissions. However, recharge clogging has been a key problem restricting the continuous operation of GWHP. In this study, a simulation test device for sand column was designed with the aim of addressing chemical clogging induced by heat pump reinjection in a porous saline aquifer in the Huaibei Plain, China. The trend in the variation of the permeability coefficient was studied based on the detection of the sand sample composition, recharge water quality, and sand layer temperature, and the cause of formation was analysed using the saturation index (SI) and ion ratio method. The results indicated that the permeability coefficient in the sand column decreased exponentially, with a maximum and minimum decrease of 8.14% and 71.65% of the original coefficient, respectively, found in sections P2-P3 and P8-P9. Therefore, the clogging effect of the aquifer at approximately 200-400 mm from the recharge well was significant. Water-rock interactions predominantly involved the dissolution of halite, albite, chlorite, anhydrite, and dolomite and the precipitation of calcite, as well as the exchange adsorption of Ca2+ and Mg2+ to Na+, which were the key sources of ions during the water chemical evolution process. Finally, quartz was formed by the weathering and dissolution of aluminosilicate minerals such as albite, and particle migration and precipitation during the hydrodynamic disturbance were the primary causes of the front-end blockage of the column.

Environmental and Health Risks Posed by Heavy Metal Contamination of Groundwater in the Sunan Coal Mine, China.

Groundwater is often used for domestic and irrigation purposes, even in mining areas. Mine drainage, rainfall, and infiltration cause heavy metal enrichment, adversely affecting the groundwater and harming human health. In this study, water samples (October 2021) in the Suzhou southern coal mining area were analyzed for the heavy metals As, Cr, Cu, Fe, Mn, Pb, and Zn to determine potential effects of heavy metal contamination on environmental quality and human health. It was found that 22% and 31% of the sampling sites had "excellent" and "good" water quality, respectively. Excessive concentrations of Fe and Mn were detected in 47% and 72% of the samples, respectively. The non-carcinogenic health risk values of As, Cr, Cu, Fe, Mn, Pb, and Zn were below the negligible levels of health risk set by various environmental agencies. Content ranking was as follows: Fe > Mn > Cr > Cu > Pb > Zn > As, with Fe accounting for 43%. All sampling points exceeded the maximum acceptable level of Cr recommended by the agencies. Chromium, the major carcinogenic factor in the study area, contributed to 95.45% of the total health risk. Therefore, the authorities in this region must closely monitor three heavy metal elements­Fe, Mn, and Cr.