8 September 2001

Waste not, want not …

Its green, its recycling, and most importantly, its profitable. No wonder everyones so keen on composting. Gilly Johnson finds out whats involved

THE composting business has something of an Arthur Daley feel about it. Compost is a venture that involves cash-in-hand payments at both ends: first youre paid a "gate fee" – up to £20 a van load – to take green waste material: hedge clippings, garden weeds, tree branches and so on.

You put the waste through a shredder, which chews it into small pieces. The debris is left in a giant heap to "cure" for a few months, turned occasionally. Youre paid again for the resulting compost – £10 to refill the same van with dark, rich, peat-like material on its return journey. Sounds like a good little earner, Terry….

But unlike many Minder escapades, its not "dirty" money. Composters can hold their heads high in todays green society – after all, it is recycling, and local authorities are encouraging these enterprises. Also, compost could be used as a cheap, low nutrient soil conditioner for your own fields, or even sold at a profit with a little marketing effort.

It seems all you need is flat, accessible land, a machine to turn the waste into compost, and a licence. No wonder the interest in on-farm composting schemes is booming along the suburban fringes.

Exploratory calls to Dr Jane Gilbert, chief executive of the Composting Association, are flooding in, sparked off in part, she thinks, by foot-and-mouth and the urgent need to discover alternative business opportunities.

Thats the "push" from the farmer side. But theres also huge "pull" from Government, and its commitment to new, ambitious targets for sustainable waste management set up following the EU Landfill Directive. This came into force in July last year, and aims to cut the amount of biodegradable waste put into landfill.

"The Government has pledged that it will meet a significant challenge – 2m tonnes of compost by 2003," says Dr Gilbert. "That will mean a massive increase from where we are now, which is about 1m tonnes." Putting the figures into perspective, this would mean another 250 or so on-farm composting sites. At the last count back in 1999, there were 65 on-farm composting sites, and another 80 large-scale specialist operations, where some composting might be done in sealed vessels, for wet, smelly materials.

It doesnt end in 2003; Englands commitment goes on through to 2015 when 33% of household waste should be either recycled or composted. Scotland has a similar target as part of its National Waste Strategy.

To power such expansion, a big increase in the number of kerbside collection schemes would be needed, says Dr Gilbert. However, local authorities would then have to tackle the question of waste separation, and persuade the public to adopt responsible recycling habits. Composters need to be sure that no stray metalwork could damage their machines, and that no meat products would be included in the waste, because of potential disease risk, such as foot-and-mouth. New regulations governing the agricultural use of mixed waste compost are expected next spring.

Dr Gilbert has reservations about the rush into composting. "At the moment, any idiot can run a composting site. Training and technical competence are important, and this should be taken into account more when licences are issued."

Financial issues remain. Despite all the political hype, landfill is still a cheap alternative in some areas, and so on-farm composters have to provide a competitive service if they are to succeed. The big landfill companies can also run composting sites adjacent to landfill, which cuts their costs further.

Marketing compost is at the early stages. The Composting Association has now laid down minimum quality standards, which should help. Potential markets are as a peat replacement for horticulture, as a soil improver or conditioner, or in landscaping.

For agricultural use, nutrient content is important. This depends on how long the compost is "cured"; 10 months would produce a stable, well cured product, suggests research at Harper Adams University College. Phosphate content is negligible, but compost would supply about 3kg K/t. With nitrogen, it appears that 35t/ha compost, spread pre-drilling, could substitute for perhaps 20% of the crops N fertiliser requirement, according to early results from trials done by Dr Alan Keeling at Harper Adams.

Intriguingly, Dr Keeling is seeing wheat and rape yield improvements over and above what might be expected from the nutrient value of the compost, perhaps due to enhanced N uptake, and better root growth. Compost applications could also contribute to disease suppression, he suggests. Research continues.