In-situ removal of odorous NH and HS by loess modified with biologically stabilized leachate.

The loess regions distribute widely in Northwestern China, North America and Eastern Europe. For these regions, landfill is a suitable technology for solid waste treatment. However, as a landfill cover material, loess is not very effective in controlling the emission of malodorous gases. The present study modified loess with biologically stabilized leachate, and investigated the capacities and mechanisms of the modified loess to remove odorous NH and HS. The removal rates of NH and HS at different acclimation time, targeted gas concentrations and temperatures were measured. It was found that the NH removal rate of the modified loess was up to 0.08 μmol/(g·hr), which was 1.8 times that of the virgin loess. The HS removal rate of the modified loess was up to 1.74 μmol/(g·hr), which was 1.25 times that of the virgin loess. The half-meter loess layer modified by biologically stabilized leachate achieved nearly 100% removal of HS. The improvement of NH and HS removal ability was mainly due to the enrichment of relevant microorganisms. This work proposed a novel method for in-situ control of malodorous pollutants in landfills in the loess regions, and proved that the in-situ removal of NH and HS using the loess modified with biologically stabilized leachate is feasible and cost-effective.