Citation:

Krause, M., W. Eades, N. Detwiler, D. Marro, A. Schwarber, AND T. Tolaymat. Assessing moisture contributions from precipitation, waste, and leachate for active municipal solid waste landfills. JOURNAL OF ENVIRONMENTAL MANAGEMENT. Elsevier Science Ltd, New York, NY, 344:118443, (2023). https://doi.org/10.1016/j.jenvman.2023.118443

Impact/Purpose:

Municipal solid waste (MSW) landfills generate significant quantities of wastewater, known as leachate. Leachate generation is a function of waste composition (i.e., the types of waste disposed) and the local weather patterns (e.g., rainfall and snowfall). Once stormwater touches exposed waste, it must be managed as leachate, so landfill operators work to minimize rainfall infiltration to the site. Monthly leachate volumes (gallons) were digitized from publicly available reports and analyzed to estimate the contributions of moisture sources into landfills. Contribution sources were: 1. water in the incoming waste, 2. water from precipitation (e.g., rain and snow), and 3. recycled leachate. Examining inflows and outflows, the analysis found that the largest source of water in landfills is water from incoming waste. The volumes of leachate recycled does not appear to significantly affect landfill moisture content. Both landfill operators and regulators would benefit from understanding the contributions of water to a landfill and how it could potentially affect gas generation and collection, waste settlement, and slope stability.

Description:

Weather, waste, and leachate data were used to perform a water balance and estimate the contributions of three water sources (infiltration, incoming waste, and leachate recycling) to active municipal solid waste (MSW) landfills in Ohio, USA. Hourly precipitation and ET values were collected from the North American Land Data Assimilation System (NLDAS) for each landfill. Annual waste tonnages and monthly leachate data were accessed from separate publicly accessible repositories. From 2010-2020, 39 active landfills generated at least 0.70-1.67 million m3/year (246-437 million gallons/year) and disposed 0.65-1.61 million m3/year (171-425 million gallons/year). Leachate generation rates for Ohio landfills were found to be 1.27-3.01 m3/hectare-day (136-314 gallons/acre-day). During the same time, leachate recycling accounted for 2-5% of the generated volume. A runoff coefficient (CRO) of 50% resulted in landfills with moisture contents from 13-48%, with the majority in a range of 21-28%. CRO values below 20% and above 50% produce unrealistically high or low landfill moisture contents, respectively. The amount of leachate recirculated in any year was a minor fraction compared to the estimated water within the incoming waste or infiltration. Moisture contents of 20-30% for incoming waste indicate that the entrained water is the largest source of landfill moisture. Simple tracking of landfill moisture may assist operators and regulators in understanding the magnitude of infiltration, leachate recycling, or other liquids addition, to a landfill’s moisture profile.Weather, waste, and leachate data were used to perform a water balance and estimate the contributions of three water sources (infiltration, incoming waste, and leachate recycling) to active municipal solid waste (MSW) landfills in Ohio, USA. Hourly precipitation and ET values were collected from the North American Land Data Assimilation System (NLDAS) for each landfill. Annual waste tonnages and monthly leachate data were accessed from separate publicly accessible repositories. From 2010-2020, 39 active landfills generated at least 0.70-1.67 million m3/year (246-437 million gallons/year) and disposed 0.65-1.61 million m3/year (171-425 million gallons/year). Leachate generation rates for Ohio landfills were found to be 1.27-3.01 m3/hectare-day (136-314 gallons/acre-day). During the same time, leachate recycling accounted for 2-5% of the generated volume. A runoff coefficient (CRO) of 50% resulted in landfills with moisture contents from 13-48%, with the majority in a range of 21-28%. CRO values below 20% and above 50% produce unrealistically high or low landfill moisture contents, respectively. The amount of leachate recirculated in any year was a minor fraction compared to the estimated water within the incoming waste or infiltration. Moisture contents of 20-30% for incoming waste indicate that the entrained water is the largest source of landfill moisture. Simple tracking of landfill moisture may assist operators and regulators in understanding the magnitude of infiltration, leachate recycling, or other liquids addition, to a landfill’s moisture profile.

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