| Traditional circulation well had bad effect on treating aniline-semi volatile organic pollutants(sVOCs). It will clog aquifer when enhancing indigenous microorganisms in aquifer to remediate pollutants. In order to slove these problems, this study proposed Groundwater Circulation Well technology (GCW) combined with in-well bioreactor to remediate aquifer contaminated by aniline. A1.6m×0.3m×0.56m-aquifer polluted by aniline was constructed to investigate operating parameter of GCW, effects and regulation of GCW, and effects of GCW-in well bioreactor technology(GCW-IWB) remediating the aquifer, in order to provide theoretical basis for remediating sVOCs polluted aquifer by using GCW-IWB.The experimental results indicated that in this simulated aquifer, aeration place was just up the edge of the inside casing, aeration flow was0.35m3/h, aeration pressure was6.45KPa. Strong circulation groundwater formed near well. The function between the velocity of the point in circulation flowline where27.5meters apart from the bottom of the simulated aquifer and the distance from the point to the left boundary of simulated aquifer fit Gauss equation well, the equation is V. The closer the point to the well, the higher circulation velocity the point had.The simulating aquifer was polluted seriously by aniline. After47hours treatment by traditional GCW and then199hours treatment by GCW-IWB, the aquifer was remediated well. There is no exist of aniline in groundwater in the left region of well and the right region where is0-30cm distant from well. Volatilization of aniline, absorption and biodegradation of biological carrier which function together as the treatment effect. And because it did not accumulate ammonium during treating process, the GCW-IWB is a safety remediation technology. After combining bioreactor, the removal rate of aniline in groundwater improved greatly which through the well. The maximal removal rate was1.66%without bioreactor, and the removal rate after combing bioreactor had a sigmoidal increase. The reducing rate of aniline in groundwater of every monitoring point also increased greatly, the maximal value of every poing increased from2.38mg/L·d to4.69mg/L·d. The reducing rate was relatively fast in the region with a fast circulation groundwater flow near well.Circulation groundwater carried aniline from upstream with higher concentration of aniline to the downstream with lower concentration of aniline. There occured strong mixing effect in the region with a strong circulation flow near well, which lead to the symmetrical concentration of aniline. In this study, the region is0-39cm apart from the well on both sides. |
