Landfill Gas Venting for Agricultural Restoration

Abstract

A sand and gravel quarry at Great Sunnings near Upminster in Essex was backfilled with industrial and commercial waste (non-household municipal waste) in the process of restoration to agriculture. These waste types contain significantly less putrescible materials than domestic waste, nevertheless previous experience of farming such refilled land has resulted in crop damage and lowering of yields in early years following restoration due to the adverse effects of landfill gases. These effects may be two-fold: (a) removal of oxygen from the soil and (b) toxic effects of the gases, e.g. carbon dioxide and ethylene. A landfill gas venting system in conjunction with a capping layer was installed at the site before soil replacement and cultivations, following which winter wheat was sown in the same year as soil replacement. Data was recorded on the gas venting scheme and the agricultural activities with a view to establishing whether such a concept is a practical proposition for future restoration under similar circumstances and with comparable conditions. It is considered that the trials show the scheme to be workable.