Evaluating the methane generation rate constant (k value) of low-organic waste at Danish landfills. (January 2015)

• Record Type: Journal Article
• Authors: Mou, Zishen; Scheutz, Charlotte; Kjeldsen, Peter
• Is Part Of: Waste management. Volume 35(2015)
• Page Start: 170
• Page End: 176
• Publication Date: 2015-01
• Subjects: First-order decay (FOD) -- Waste degradation rate -- k value -- Low-organic waste -- Landfill gas (LFG) generation model -- Methane (CH4) emission; Hazardous wastes -- Periodicals; Refuse and refuse disposal -- Periodicals; 363.728
• DOI: 10.1016/j.wasman.2014.10.003
• Languages: English
• ISSNs: 0956-053X

Abstract

Highlights: Low-organic and combustible waste from Danish landfills was sampled and studied. Anaerobic degradation experiments were performed in duplicate for over 400 days. Half-life time and CH4 generation rate ( k value) of waste samples were determined. k values of low-organic waste are lower than MSW and FOD model default values. The results are valuable for revising FOD models to estimate LFG generation. Abstract: The methane (CH4 ) generation rate constant ( k value, yr −1 ) is an essential parameter when using first-order decay (FOD) landfill gas (LFG) generation models to estimate CH4 generation from landfills. Four categories of waste (street cleansing, mixed bulky, shredder, and sludge waste) with a low-organic content, as well as temporarily stored combustible waste, were sampled from four Danish landfills. Anaerobic degradation experiments were set up in duplicate for all waste samples and incubated for 405 days, while the cumulative CH4 generation was continuously monitored. Applying FOD equations to the experimental results, half-life time values ( t ½, yr) and k values of various waste categories were determined. In general, similar waste categories obtained from different Danish landfills showed similar results. Sludge waste had the highest k values, which were in the range 0.156–0.189 yr −1 . The combustible and street cleansing waste showed k values of 0.023–0.027 yr −1 and 0.073–0.083 yr −1, respectively. The lowest k values were obtained for mixed bulky and shredder wastes ranging from 0.013 to 0.017 yr −1 . Most low-organic waste samples showed lower k values in comparison to the default numeric values in current FOD models (e.g., IPCC, LandGEM, and Afvalzorg). Compared with the k values reported in the literature, this research determined low-organic waste for the first time via reliable large-scale and long-term experiments. The degradation parameters provided in this study are valuable when using FOD LFG generation models to estimate CH4 generation from modern landfills that receive only low-organic waste.