矿化垃圾中的甲烷氧化-反硝化耦合特性研究

Characteristics of the methane oxidation-denitrification coupling in the aged refuse

设计全因素实验研究了填埋龄10～12年的矿化垃圾中的甲烷氧化反硝化耦合特性.结果表明,每g矿化垃圾中甲烷氧化菌、反硝化细菌可达109个数量级,适合作为甲烷氧化-反硝化耦合反应介质.CH4、O2和NO3--N浓度对CH4去除有明显影响(p<0.01),其大小顺序为CH4>O2>NO3--N,且3种因素具有显著的交互作用(p<0.01).NO3--N对甲烷氧化的抑制或者促进作用主要与环境中的O2浓度和C/O比有关.相对较低的CH4初始浓度和较低的C/O、C/N比有利于甲烷氧化和反硝化作用耦合,而且反应产物中N2O含量较低.当CH4、O2浓度分别为10%,20%时,甲烷去除率能达到97.7%,产生的N2含量为11.5%以上,且N2O的产生量低于0.2%.

The work investigated the characteristics of methane oxidation-denitrification coupling in the refuse landfilled for 10 - 12 years by full-factor experiments. The results showed that the number of methanotrophs and denitrifiers reached to 109 CFU·g^-1 and 109 MPN·g^-1 , respectively. Therefore, the aged refuse could provide a good condition for methane oxidation-denitrification coupling. The concentrations of CH4 , O2 and NO3- -N had significant influences on the oxidation of CH4 （p 〈 0.01 ） , and followed the orders of CH4 〉 02 〉 NO3- -N. Furthermore, the concentrations of CH4 , 02 and NO3- -N indicated significant interactions （p 〈 0.01 ）. This study also suggested that the inhibited or promoted effects of NO3- -N on the oxidation of methane mainly depended on the concentrations of 02 and the ratio of C/O in the environment. The methane oxidation coupled to denitrification was more favorable in lower concentrations of initial CH4 and the ratios of C/O and C/N, which resulted in less N20. When the concentration of CH4 was 10% and the concentration of 02 was 20% , the oxidation efficiency of CH4 could reach to 97.7% , the production of N2 was more than 11.5% and N2 0 was less than 0.2%.