THE ELEVATED TEMPERATURE AND GAS COMPONENT WITHIN AN OPERATING SEMI-AEROBIC LANDFILL

Abstract

The semi-aerobic landfill concept, which is based on passive aeration, is the compulsory standard for planning new landfill projects in Japan. The semi-aerobic landfill concept is also applied in several other countries because of its low construction and operating costs. The landfill gas (LFG) component and the LFG temperature are the main indicators of the aerobization of semi-aerobic landfills. Analysis of LFG, its concentration, and its temperature can be easily carried out on-site to evaluate the passive aeration of an operating semi-aerobic landfill. Therefore, this study observed LFG temperatures and LFG components to assess the partial aerobization within an operating semi-aerobic landfill. The observational data revealed that the methane (CH4) gas concentration of most of the main LFG venting pipes (VPs) was below 15%. The aerobic condition happened effectively surrounding the main LFGVP M2 because over the observation period, the ratio of CH4 to CO2 was less than 1.0. The highest gas temperature was above 60°C within the main LFGVP M2, and there was a trend of high temperatures above 40°C for more than 5 years before the temperature declined to 20°C in the most recent observation. The high LFG temperatures were recorded in the winter months due to the buoyancy effect. High temperature and the CH4/CO2 ratio less than 1.0 potentially representing good indicators showed that aerobic decomposition is becoming dominant. The study showed clearly that the aerobic biodegradation performance in this semi-aerobic landfill is extremely good.