Estimation of the landfill gas (specifically including methane) production for the period at the Aardlapalu landfill Ecotech OÜ Jaan Habicht

Background Landfill gas –> methane + CO2 Produced under anaerobic conditions during decomposing of organic substances

Current situation of the Aardlapalu landfill Closed since the summer of Lacking of the leachate cleaning system. Has high natural level of groundwater The density of the garbage varies greatly between layers, due to different dumping techniques used during given time periods The landfill has no base, since it has been created right on top of peat layer – now the layers are mixed (peat, garbage), indistinguishable Collection of the landfill gas necessary also for the covering layer – otherwise the gas will have a lifting effect and prevent the development of plantage In the project for sealing of the landfill, the estimates have been calculated for the vertical gas collection system

Object of comparison (description of the Pääsküla landfill Closed in the period of Collection of the landfill gas started already on the 19th of December, 1994 Horisontal gas collection system No cleaning system The average caloricity has exceeded over 6 kWh/m3 (usually 5 kWh/m3) Production rate of the landfill gas has dropped 40 per cent in 4 years.

Estimation of the landfill gas (incl. methane) production at the Aardlapalu landfill Air-tight sealing important During the past 7 years, 3,7 times less garbage has been disposed of at the Aardlapalu landfill, compared to Pääsküla landfill The average estimated amount of landfill gas for Aardlapalu landfill for period is ca 20 million normal cubic metres, which makes the average expected amount of methane to be 10 million normal cubic metres. Directly after the closing of the landfill, the estimated amounts of methane range from 800,000 to 900,000 normal cubic metres per year, after 10 years the amounts will be approximately less than 350,000 normal cubic metres per year – less than 1000 normal cubic metres per day.

Recommendations derived from the study results Due to the specificity of the Aardlapalu landfill, instead of vertical and horisontal system, an inclined horisontal system should be built Restoration of the leachate monitoring well VPK-5 is needed. An additional monitoring well should be built, which would have a higher base level than the surface of the water inside the body of refuse Not considering the periodical reduction and taking into account the example of the Pääsküla landfill gas production an estimation could be made, according to which the gas production between months can vary up to 30 per cent, whilst the usual differences remain under 10 per cent.