Huangshaping mining karst area groundwater pollution propagation modelling and its control, remediation by using monitoring program and microalgae plant.

This research aimed to analyze and evaluate the contamination of pollutants in mining karst areas groundwater in Huangshaping, Hunan Province, China. To achieve these aims, the study was involved in data collection and analysis; groundwater environmental assessment grading and simulation modeling. Finite element subsurface FLOW system (FEFLOW) software was mainly used for the analysis. Due to the negative impacts of pollutants in mining karst groundwater, application of environmental mitigation measures for the pollution monitoring program, grid split, geological model and Groundwater seepage modeling was required to evaluate and control groundwater pollution spread. Water monitoring frequency was three times in a month, to test respectively, temperature, pH, chemical oxygen demand, Mn, SO₄ ², Mn, Fe⁺, Zn, Pb and other parameters. For remediation and prevention of water pollution problems in study areas, the bactericide technology was used to prevent the formation of acid mine drainage wastewater; and wastewater treatment by microalgae plant culture for the surface wastewater treatment. The results indicate that there are different sources of pollutants in Huangshaping are life sewage wastewater, production wastewater, gushing water, sewage industrial sites producing, processing waste, tailings wastewater, rainwater and other venues. These mining pollutants have negative impacts and influence on the geological environment and groundwater quality such as Circulation of underground water is very poor; Aquifer water tables were changes; natural geological structures are in serious destruction. Pollutions dispersion speed has been three times in 50 y since exploitation project was implemented. The largest migration distance was respectively within 40.7 m (in 50 y ago), 95.2 m (30 y ago), and 99.5 m at this time. The iron tailings wastewater treatment can be purify about 7,706 m³/d of wastewater which mean have limited impact groundwater environment. Contrarily with lead and zinc mine tailings which are very favorable to contamination. For surface wastewater treatment, the suspended solids removal efficiency was up to 80% and nearly 50% metal removal for a plant of green microalgae in wastewater. Reuse of mining wastewater by hydride water consisting of 50% fresh and 50% mine wastewater was applied for food production in the area. Crop yield was proportional with salinity almost 50%. However, no risk of heavy metals contamination was found in plants and soil. [ABSTRACT FROM AUTHOR]