Numerical Simulaiton Of The Alumina Project Impact On Groundwater Environment

Excellent flame retardancy of aluminum hydroxide has made it become themost commonly used flame retardant additives, which greatly promoted thedemand of aluminum hydroxide. With the production of aluminum hydroxide,domestic sewage and waste-water produced by production area under abnormalconditions may occur leakage to the groundwater. In addition, Red mudproduced by aluminum hydroxide under the influence of rainfall leaching willpose a threat on the groundwater environment in the process of stacking.In order to analyze the migration regularity and influence scope about thepollutant produced by aluminum hydroxide in the system of unsaturated andsaturated zone, this paper took an aluminum hydroxide project in ShanxiProvince as the research background to study the following contents:(1) thehydro-geological parameters of the production factory and red mud reservoirswere obtained by investigating the hydrogeological conditions and the pumpingand infiltration tests;(2) the extreme learning machine (ELM) is applied toevaluate the water quality during the period of high water season and dry seasonat the11monitoring points. The results showed that the groundwater quality of5#、6#、8#and15#are II type and the other7points are III type;(3) HYDRUS-1Dsoftware was applied to simulate the pollutants migration characteristics in theaeration zone. The results showed that the concentration of COD has reached 0.35mg/L in a modeled section of the production factory after280days; theconcentration of Fluoride has reached the critical value (0.027mg/L) in amodeled section of red mud reservoirs after380days;(4) Modflow softwarewas applied to study the migration characteristics and the scope of thecontamination plume of pollutants in phreatic aquifer through the vadose zone.After5years the influential areas of COD and Na2O are26400m2and239800m2in the production factory; The influential areas of Fluoride and Na2O are41890m2and168270m2in red mud reservoirs. After10years the influentialareas of COD and Na2O are39600m2and338800m2in the factory’s district;influential areas of Fluoride and Na2O are50410m2and210870m2in red mudreservoirs.The conclusions were as follows: the water quality in the survey area wasgood and it was accord with the standard of the groundwater quality (Ⅲ type).The water quality has changed little in the period of high water season and dryseason.With the increase of time, the concentration of pollutants was increasedgradually in the aeration zone, the migration scope of the pollutants in phreaticaquifer also became more and more widespread and the migration scope towardto downstream was wider than that toward to upstream. The scope of solutetransport in red mud reservoirs is greater than that in the plant area, but theimpact was slight for pore water shallow well of Quatemary in the study area.