Wood Biodegradation in Laboratory-Scale Landfills

Abstract

The objective of this research was to characterize the anaerobic biodegradability of major wood products in municipal waste by measuring methane yields, decay rates, the extent of carbohydrate decomposition, carbon storage, and leachate toxicity. Tests were conducted in triplicate 8 L reactors operated to obtain maximum yields. Measured methane yields for red oak, eucalyptus, spruce, radiata pine, plywood (PW), oriented strand board (OSB) from hardwood (HW) and softwood (SW), particleboard (PB) and medium-density fiberboard (MDF) were 32.5, 0, 7.5, 0.5, 6.3, 84.5, 0, 5.6, and 4.6 mL CH(4) dry g(-1), respectively. The red oak, a HW, exhibited greater decomposition than either SW (spruce and radiata), a trend that was also measured for the OSB-HW relative to OSB-SW. However, the eucalyptus (HW) exhibited toxicity. Thus, wood species have unique methane yields that should be considered in the development of national inventories of methane production and carbon storage. The current assumption of uniform biodegradability is not appropriate. The ammonia release from urea formaldehyde as present in PB and MDF could contribute to ammonia in landfill leachate. Using the extent of carbon conversion measured in this research, 0-19.9%, predicted methane production from a wood mixture using the Intergovernmental Panel for Climate Change waste model is only 7.9% of that predicted using the 50% carbon conversion default.

Trash to treasure: production of biofuels and commodity chemicals via syngas fermenting microorganisms

“…These forms of biomass address many of the concerns associated with the production of first-generation biofuels [3,4]. However, 10-35% of lignocellulosic biomass is composed of lignin [5][6][7], which is highly resistant to breakdown by the vast majority of microorganisms [8].…”

The environmental footprint of interior wood doors in non-residential buildings – part 1: life cycle assessment

“…The door is transported to the landfill with a municipal waste collection truck. The behavior of specific wood products in landfill is not well documented (Wang et al, 2011;Ximenes et al, 2008). The Ecoinvent database does not include wood products in its landfill processes, only "wood untreated".…”

Greenhouse Gas Balance of Native Forests in New South Wales, Australia

“…Recent research has demonstrated that HWPs in landfill represent a long term C store, with minimal or no decomposition taking place. The mean loss of C (4.5%) determined from two key studies [6,8] is used in the estimates of long-term C storage for the HWPs in each of the case studies presented. The average loss of C reported in [6] was 9%, whereas [8] reported no C loss from blackbutt and radiata pine (Pinus radiata) exposed to optimised experimental anaerobic decay conditions.…”

“…The mean loss of C (4.5%) determined from two key studies [6,8] is used in the estimates of long-term C storage for the HWPs in each of the case studies presented. The average loss of C reported in [6] was 9%, whereas [8] reported no C loss from blackbutt and radiata pine (Pinus radiata) exposed to optimised experimental anaerobic decay conditions. The proportion of C lost that was emitted as methane was assumed to be 50% [7], and it was assumed (conservatively) that no capture systems were in place to either flare the methane into CO 2 or to produce electricity.…”

“…In the IPCC Guidelines [7] it is currently assumed that 50% of the C in HWPs in landfill is released as a result of decomposition. However, recent field-based research (e.g., [6]), and a recently published experimental study in the USA [8], have demonstrated that HWPs in landfill represent a long term C store, with minimal or no decomposition taking place.…”