Landfill CH4 oxidation and N2O emissions by aged refuse: Effects of wastewater NH4+-N incubation, heavy metals and pH

We report on preliminary investigations into CH4 oxidation and N2O emissions from aged refuse following wastewater treatment. The maximum CH4 oxidation rate by incubated aged refuse (IAR) was 79.11 μmol g−1 h−1, which was much higher than that of original aged refuse (OAR). This result can be attributed to effects arising from the retention of suspended solids and organic matter and the growth of ammonia-oxidizing bacteria through wastewater treatment. After distilled water addition, N2O and CO2 emissions from IAR were almost two times higher than those of OAR (p > 0.05) and an order of magnitude higher than that of soil (p > 0.05). With the heavy metal addition in aged refuse, there was a negligible difference (p < 0.05) from the control without heavy metal addition. Due to the higher tolerance to changes in pH and heavy metal concentrations in aged refuse, a wide scope of wastewater could be selected for its pre-incubation.

► CH4 oxidation rate in age refuse was improved through wastewater NH4+-N incubation.
► Ammonia oxidizing bacteria were accumulated in aged refuse for methane oxidation.
► Aged refuse was very tolerated to pH changes and heavy metals addition.
► N2O emission was negligible in aged refuse when applied as landfill bio-cover.