The dynamic simulation experimental research on treatment of acid coal mine drainage by loess-microorganism system

Taking Lishi loess as the media and domestic sewage as the carbon source for treating agent of acid mine drainage, this paper discussed the feasibility of acid mine drainage dynamic processing by loess-microbial system in the soil column. The results achieved are as follows: (1) the domestic sewage whose value of COD is less than 120mg/L, can activate sulfate reducing bacteria (SRB), but it is difficult to maintain its continuous reproductive; (2) After High organic sewage with an extra 4.5mg/L molasses infiltrated into the upper layer of the soil column, Eh values are all negative at each depth of soil column in the 6th test day and reduce to below -400mv in the 10th day, where become a beneficial reductive environment to the growth of SRB; (3)After a 5-day experiment, a smell of H₂S appears at the bottom of the soil column. At 20cm depth, the maximum removal rate of SO4^2- can reach 95.5% after 82 days, however, the maximum removal rates at the depth of 40cm, 60cm, 80cm, and 100cm (the bottom outlet) in the 94th day are 91.6%, 89.1%, 84.9%, 77.8%, respectively; (4) The maximum removal rate of SO4^2- decreases along with the increase of depth in the same period.