[Research advances in control of N2O emission from municipal solid waste landfill sites].

Landfill is one of the main approaches for municipal solid waste treatment, and landfill site is a main emission source of greenhouse gases nitrous oxide (N2O) and methane (CH4). As a high-efficient trace greenhouse gas, N2O has a very high warming potential, with a warming capacity 296 times of CO2, and has a long-term stability in atmosphere, giving greater damage to the ozone layer. Aiming at the researches in the control of N2O emission from municipal solid waste landfill sites, this paper summarized the characteristics and related affecting factors of the N2O emission from the landfill sites, and put forward a series of the measures adaptable to the N2O emission control of present municipal solid waste landfill sites in China. Some further research focuses on the control of N2O emission from the landfill sites were also presented.

[Effect of injected leachate C/N ratio on the denitrification of a bioreactor filled with landfilled refuse].

The denitrification capacity of a landfill bioreactor was investigated under different ratios of injected leachate C/N; the denitrifying bacteria community compositions over four injection times were also studied using molecular approaches and functional gene nirS served as marker. Results showed that COD/NO3(-) -N ratio of the injected landfill leachate had a significant impact on the denitrification capacity of the bioreactor. Nitrate reduction rate increased from 1.14 mg x (kg x h)(-1) to 11.40 mg mg x (kg x h)(-1) when the injected leachate COD/NO3(-) -N ratio raised from 3.11 to 13.08. It suggested that a stable and rapid denitrification could be obtained when bioavailable COD/NO3(-) -N ratio in the injected leachate was 6.37. In the bioreactor, the main denitrifying bacteria was similar to beta-proteobacteria, and others belonged to uncultured bacteria. Thiobacillus denitrificans and Azoarcus tolulyticus known as beta-proteobacteria were the dominant species and played an important role in NO3(-) -N consumption during the leachate injection.