The Effect of Leachate Collection Layer Structure on Leachate Quality in Semi-Aerobic Landfill: A Pilot Study
Due to the leachate collection layer’s good ventilation and leachate leaching role, aerobic bio-filter bed for treating leachate can be formed in the bottom of the semi-aerobic landfill. Six groups of simulated semi-aerobic landfill columns were used, whose leachate collection layers were 60mm gravel (1#), 120mm gravel (2#), 180mm gravel (3#), 240mm gravel (4#), 180mm cobblestone (5#), and 180mm gravel with 60mm ceramsite on the surface (6#) respectively. This paper researched the influence of leachate collection layer structure on the oxygen volume fraction in semi-aerobic landfill as well as the leachate concentrations of COD, NH4+-N, organic nitrogen and sulfate. The results showed that the oxygen volume fraction declined according to the sequence of upper-layer, middle-layer and lower-layer. After 22 weeks, the leachate COD removal rate of 1#, 2#, 3#, 4#, 5# and 6# reached 92.64%, 95.18%, 94.48%, 96.44%, 92.06% and 96.39%, respectively. The concentrations of NH4+-N were reduced respectively from the initial 1670.3, 1704.1, 1866.2, 1873.0, 1920.3 and 2116.2 mg/L to 117.8, 119.2, 123.2, 101.6, 635.4 and 200.3 mg/L, and the phenomenon of ammonia nitrogen concentration gradually rising did not appear. Leachate concentration of sulfate could be increased through semi-aerobic landfill and less H2S gas was produced. Increasing the leachate collection layer’s height would help to improve the removal effect of leachate, and gravel collection layer was better than that of cobblestone. Adding ceramsite on the surface of gravel collection layer would help to increase the removal rate of leachate at the later stage.
G. T. Liu et al., "The Effect of Leachate Collection Layer Structure on Leachate Quality in Semi-Aerobic Landfill: A Pilot Study", Applied Mechanics and Materials, Vol. 137, pp. 192-197, 2012