ASSESSING THE ENVIRONMENTAL IMPACTS OF HOME COMPOSTING

A methodology for quantitatively assessing the environmental impacts of home
composting is demonstrated. The problem of measuring air flow rates through home compost
bins was tackled by making comparisons with simultaneously run, forced-aeration sealed
compost reactors at known air flow rates. Analysis of headspace gases for VOCs, CH4, NH3 and
N2O are reported with concentrations of NH3 up to 15ppm and no CH4 or N2O above
atmospheric concentrations under tested conditions despite headspace CO2 concentrations as
high as 15%. Headspace CO2 concentration and compost temperature profiles are reported for a
range of composting scenarios and the mass balance methodology is demonstrated. The benefits
of home produced composts as soil improvers are measured in terms of water extractable
nutrients and potentially toxic elements, with findings confirming previous work indicating they
are safe and beneficial. The future direction of research and ongoing modelling work is
discussed.