Colloid Effects on Temporal-spatial Variability of Iron and Manganese in Shallow Groundwater of Garbage Contaminated Sites

Simulation tank experiment was conducted to elucidate the temporal-spatial variability of Iron and Manganese in leachate pollution plumes of water-bearing media.Colloid effects on transport and transformation of Fe and Mn in water-bearing media were determined emphatically.Moreover,the mechanism of Fe and Mn transport and transformation were discussed by the convection-dispersion,dissolution and transport-deposition of colloid.The results show that the total Fe and Mn in leachate pollution plume was 2.82 times and 7.51 times of infiltration leachate due to the dissolution of water-bearing medium.Along the flow direction,Fe and Mn pollution plumes spread,and the central region of plumes gradually widened by the convection-dispersion and dissolution.In the presence of colloid,the average transport velocity of Fe and Mn plumes central axis from 1.17 cm /d and 1.75 cm /d increased to 1.83 cm /d and 2.5 cm /d respectively,colloid had obvious facilitation to the migration of Fe and Mn.