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Biomass management: When combustion is the wrong choice - LCA examples for yard debris, food scraps, and clean construction/demolition wood
Jeffrey Morris,*   Sound Resource Management

This presentation will present LCA results comparing waste management methods for yard debris, food scraps, paper and cardboard, and clean wood. For example, management methods examined for clean (i.e., untreated, unpainted) wood wastes include reuse, recycling into engineered wood products, recycling into papermaking pulp, aerobic composting, combustion in industrial boilers as a substitute for natural gas, combusting in industrial boilers as a substitute for coal, combustion in waste-to-energy incinerators for municipal solid waste, and land filling (with and without energy generation from collected landfill gas).

The presentation will report results for at least eight life cycle impact categories and highlight significant trade-offs. For example, the LCA for clean wood combustion in industrial boilers shows a trade-off between possible greenhouse gas reductions and increases in human and ecosystem toxic emissions.

The following table (note: the presentation will use graphs to present these data) detail the differing results for three of the environmental impacts for the wood waste management options. The presentation will discuss the issues regarding characterization factors for toxic and carcinogenic emissions as the UNEP/SETAC harmonization model is being developed.

  Reuse Recycle-Pulp Fuel-Nat Gas Fuel-Coal Landfill-EFW Landfill-Flare Landfill-Vent
eCO2-lbs/ton
-3,532.28
-1,745.37
-830.56
-3,064.81
-1,268.77
-1,115.18
824.89
ePM2.5-lbs/ton
-3.21
3.21
6.83
0.60
3.09
3.03
3.02
eToluene-lbs/ton
-590.50
600.20
3,947.75
3,138.46
648.39
628.44
628.43

For paper and cardboard, the presentation will show the differences between recycling and composting for these materials, as well as for disposal options. For yard debris and food scraps the results will highlight the differences betwen these two materials in terms of carbon storage and methane releases in landfills which cause a switch in ranking for GHG emissions between landfill and combustion disposal.

Finally, the presentation will provide examples of estimates for the economic costs of environmental impacts as a possible method for determining which trade-offs are important in choosing among waste management methods.


* corresponding author: jeff.morris@zerowaste.com