Sustainable reuse of fly ash to mitigate landfill methane
Abstract
According to US, EIA 2014 coal alone produces nearly 40% of electricity more than another source in US. Out of the 110 million tons of Coal combustion by-products (CCBs) generated per year as a result of coal combustion, 47% is reused whereas 53% is stored on-site or sent to landfills. There are a number of adverse economic and environmental impacts associated with storage and disposal of coal. Methane (CH4) is a powerful greenhouse gas (GHG), contributing 32% of current climate forcing (US EPA, 2015). Landfill gas comprises of 50-55% CH4 and 40-45% CO2. Global warming potential of CH4 is 28 times that of CO2. Landfills are the 3rd largest source of US human methane emissions. The current work is a preliminary study that examines the potential use of Class F fly ash (non- cementitious) in landfill covers to reduce emissions of methane. Eight laboratory scale reactors or columns were constructed which contained 2 types of soil, 2 kinds of fly ash and 4 combinations of fly ash/soil. The suitability of each of these combinations in columns was compared to determine which combination best assisted in methane removal.