Comparison study of landfill gas emissions from subtropical landfill with various phases: A case study in Wuhan, China.

The compositions and annual variations of landfill gas (LFG) were studied at two large-scale sites of Chen-Jia-Chong Landfill. Seventy-six wells were built and used for the collection and measurement of LFG. The investigation revealed the similarities and differences of LFG components and variations at two sites with different phases. It was found that ambient temperature and rainfall exhibited strong correlations with LFG components at both sites. Methane (CH₄) contents showed excellent correlations with CO₂at both sites. Notable correlations between hydrogen sulfide (H₂S) and major components (CH₄and carbon dioxide [CO₂]) were only observed in unstable methane phase. Especially, the CH₄/CO₂volumetric ratio could act as an excellent indicator for anaerobic reaction stage by judging its phasic variations. The study is beneficial for the efficient operation of LFG collection system and could shed light on gas purification and utilization.