Greenhouse gas emissions from home composting in practice

Area of Science:

• Environmental Science
• Waste Management
• Atmospheric Chemistry

Background:

• Home composting is a common method for treating food waste in Sweden, with 16% of biologically treated food waste being home composted.
• Understanding greenhouse gas emissions from home composting is crucial for assessing its environmental impact compared to other waste management strategies.

Purpose of the Study:

• To measure emissions of methane (CH4), nitrous oxide (N2O), and ammonia (NH3) from home composts.
• To identify factors influencing these emissions in domestic composting systems.

Main Methods:

• Conducted 13 sampling sessions over one year in 18 home composts managed by owners.
• Measured gas and substrate composition within compost bins and assessed composting conditions.
• Utilized regression analysis to evaluate the influence of process parameters and management factors on emissions.

Main Results:

• Mean CH4 and N2O concentrations were 28.1 and 5.46 ppm above ambient levels, respectively.
• Median CH4:CO2 and N2O:CO2 ratios were 0.04% and 0.07%, respectively.
• Increased temperature, moisture content, mixing frequency, and added waste volume were correlated with higher CH4 emissions.

Conclusions:

• Home composts emit less CH4 than large-scale composting operations but comparable amounts of N2O.
• Ammonia (NH3) emissions from home composts were generally low.
• Management practices significantly influence greenhouse gas emissions from home composting systems.