According to Agg-net, WRAP Cymru?s innovative new method takes biofertilizer from the anaerobic digestion of kitchen food waste and quality compost to restore quarries after they?ve outlived their usefulness, particularly in situations where little topsoil is available.
Restoring quarries to a healthy state has previously proved troublesome for many operators, with left-over soils from the site often unsuitable because of their depleted nutrient content. Manufactured topsoil can be shipped in, but often at great expense.
WRAP Cymru?s innovative new method uses composts made from green and food wastes mixed with biofertilizer, mixed with quarry waste from the site. The technique uses the increasingly popular method of anaerobic digestion, which involves the break down of biodegradable material in the absence of oxygen by micro-organisms called methanogens. It?s presently being used to treat wastewater, but is finding wider applications in treating other organic wastes. Apart from nutrient-rich soil, the process also produces biogas, which can be used to power and heat equipment on-site.
Not only is the resulting soil nutritionally rich, but can be created at considerably less expense than manufactured topsoil. Agg-Net suggest the method, using 20 per cent biofertilizer, can cost up to $3.80 less per cubic metre than imported topsoil.
The company has already achieved considerable success in trials currently running at two major projects in Wales. At a former sand and gravel quarry in Mold, North Wales, WRAP Cymru has developed grassland, trees and flowering plants using the technique.
When compared to sites that had been dozed without using any biofertilizer, the two test projects performed admirably well.
“Both projects have brought about exciting news for quarry operators who are faced with a lack of suitable growing medium at their sites to produce their required restoration and after-use,? WRAP Cymru organics project manager, Lance Jones, told Agg-Net. ?This and other WRAP demonstrator projects have shown that blending quarry waste with PAS 100 quality compost and PAS110 biofertilizer can successfully restore quarry sites when applied to our good practice guidelines.?
Source: Agg-Net, WRAP Cymru