Start Over

Greenhouse gas emissions from green waste composting windrow.

Authors :: Zhu-Barker X
Bailey SK
Paw U KT
Burger M
Horwath WR
Source :: Waste management (New York, N.Y.) [Waste Manag] 2017 Jan; Vol. 59, pp. 70-79. Date of Electronic Publication: 2016 Oct 15.
Publication Year :: 2017
Abstract: The process of composting is a source of greenhouse gases (GHG) that contribute to climate change. We monitored three field-scale green waste compost windrows over a one-year period to measure the seasonal variance of the GHG fluxes. The compost pile that experienced the wettest and coolest weather had the highest average CH <subscript>4</subscript> emission of 254±76gCday <superscript>-1</superscript> dry weight (DW) Mg <superscript>-1</superscript> and lowest average N <subscript>2</subscript> O emission of 152±21mgNday <superscript>-1</superscript> DW Mg <superscript>-1</superscript> compared to the other seasonal piles. The highest N <subscript>2</subscript> O emissions (342±41mgNday <superscript>-1</superscript> DW Mg <superscript>-1</superscript> ) came from the pile that underwent the driest and hottest weather. The compost windrow oxygen (O <subscript>2</subscript> ) concentration and moisture content were the most consistent factors predicting N <subscript>2</subscript> O and CH <subscript>4</subscript> emissions from all seasonal compost piles. Compared to N <subscript>2</subscript> O, CH <subscript>4</subscript> was a higher contributor to the overall global warming potential (GWP) expressed as CO <subscript>2</subscript> equivalents (CO <subscript>2</subscript> eq.). Therefore, CH <subscript>4</subscript> mitigation practices, such as increasing O <subscript>2</subscript> concentration in the compost windrows through moisture control, feedstock changes to increase porosity, and windrow turning, may reduce the overall GWP of composting. Based on the results of the present study, statewide total GHG emissions of green waste composting were estimated at 789,000Mg of CO <subscript>2</subscript> eq., representing 2.1% of total annual GHG emissions of the California agricultural sector and 0.18% of the total state emissions.<br /> (Copyright © 2016 Elsevier Ltd. All rights reserved.)