Environmental Science and Pollution Research   2016 年 23 卷 8 期

2016.04.01

With the increasing use of municipal solid waste incineration (MSWI) and more stringent limits on landfilling of organic waste, more MSWI bottom ash is being landfilled, and the proportion of inorganic wastes in landfills is increasing, causing the increased Ca concentrations in landfill leachate. In this research, the inhibition effect of Ca concentration on the anaerobic treatment of landfill leachate was studied using a biochemical methane potential experiment. Slight inhibition of methane production occurred when the addition of Ca concentration was less than 2000??mg/L. When the addition of Ca concentration was between 6000 and 8000??mg/L, methane production was significantly reduced (to 29.4??“34.8??% of that produced by the BLK reactor), and the lag phase was increased from 8.55 to 16.32 d. Moreover, when the dosage of Ca concentration increased from zero to 8000??mg/L, reductions in solution Ca concentration increased from 929 to 2611??mg/L, and the proportion of Ca in the residual sludge increased from 22.58 to 46.87??%. Based on the results, when the dosage of Ca concentration was less than 4000??mg/L, the formation of Ca precipitates on the surface of sludge appeared to prevent mass transfer and was the dominant reason for the reduction in methane production and sludge biomass. At higher Ca concentrations (6000??“8000??mg/L), the severe inhibition of methane production appeared to be caused by the toxic effect of highly concentrated Ca on sludge as well as mass transfer blockage.