Turning over a new leaf

Composting has been the next big thing in waste management for so long that scepticism about its future is often justified. There have certainly been false dawns along the way. “Composting is a growing industry,” said the government’s Waste Strategy 2000, shortly before foot-and-mouth disease and the consequent restrictions on composting “catering” waste dealt it a near-fatal blow.

However, it is now in a position to achieve respectable market share and it looks like its time has come at last.

However, it still has to make an impact on landfill diversion targets to prove its credentials as a credible waste treatment option.

Barriers to development

Historically, attempts to compost household waste have foundered on problems of contamination by pieces of metal, plastic or glass. Before the foot-and-mouth crisis, a certain amount of industrial waste, such as sugar industry by-products, was also composted, but the restrictions brought in to prevent its spread stopped the recycling of anything that could be classified as food. This limited commercial composting to municipal park and garden waste.

To add to the problems, the EU’s animal by-products regulations came into force last November and should have been implemented in the UK on 1 July. As originally drafted, this would have created massive problems for the composting of any food-related waste. But the government is now confident, that it can produce a workable scheme.

“It may well be that once you have a secure framework regulation for disposal you can start to look at ways you can get some added value again from waste food products”, UK environment minister Elliot Morley recently told a select committee. One of these, he said, would be composting and he stressed that the concerns that the government’s risk assessment approach was far too rigorous, had been resolved.

“One of the major issues was around the separation of clean and dirty areas,” says Mandy Bailey, head of DEFRA’s BSE Division. “We have now introduced a hazard analysis and critical control points (HACCP) based approach so that individual composting sites can be assessed on a risk-controlled basis.”

HACCP is a widely used testing technique in food production that identifies the causes of problems quickly without bringing the process to a halt. It is one of a number of rules to be imposed on commercial compostors — others include requirements on the minimum temperatures to be reached in compost processes to destroy pathogens.

Broadening the scope

The details of what will and won’t be compostable are still being finalised, but the industry at least is confident that many food wastes will be able to join purely green waste as composting feedstock.

“By the time summer is through, people will know where they are,” predicts Tony Breton of the Composting Association (CA). “We’ve worked with DEFRA to make sure that the regulation is applied in a practical and safe way. As long as it’s not overly prescriptive, contracts will be written and people will be able to move forward.”

This is very good news for people in industries like food production and chemicals and seed crushing, all of which produce large volumes of biodegradable wastes. Some of this waste has always been used as animal feed and it is obviously safe to incinerate, but like most waste much has gone — and goes — to landfill. The increasing cost of landfill means that new options for waste treatment, especially where the recyclate has a value that might reduce disposal costs, are obviously attractive.

Farmers will also be interested. Next year, agricultural wastes are likely to become controlled wastes and it looks increasingly possible that this may cover some organic farm wastes.

Developing techniques

Even with a sound regulatory framework in place, there are still technical challenges to overcome.

“It’s by no means the fields of gold that some in the agriculture sector are predicting,” warns Breton. “There’s a lot more science to the process than people think to get a high quality product.”

The legislation’s long gestation period has at least given the opportunity for work on standards and scientific research to be carried out. The main fruit of this has been the new British Standards Institution’s Publicly Available Specification for Composted Materials [BSI PAS 100], prepared in consultation with the CA and the Waste and Resources Action Programme (WRAP). The specification sets down standards for input materials, composting processes and product quality.

Working to the standard is a requirement of the CA’s new certification scheme for commercial compost operations, which means that customers can expect a quality-assured service, predictable product quality, sustainable methods and traceability of the materials right back to the source. To date, the CA has certified five compost products.

WRAP is also sponsoring a number of research projects. In December, the Peatering Out project with partners Rainbow Wilson Associates and Dove Associates, and Enviros Consulting, began work to develop growing media.

“We’ve funded a number of growing trials around the UK to produce a series of specifications for the horticultural, landscape and agricultural industries,” says a WRAP spokeswoman. “They need to have products they can trust.”

Practicalities

Certainly the waste industry is showing huge interest in composting plants but the Greenpeace campaign against waste incinerators has had the unexpected knock-on of making it almost impossible to get planning permission for any kind of waste plant, even one that environmentalists want.

Some plants are being built. SITA, for instance, now has nine. Its plant at Lount in Leicestershire, which produces 10,000t/y of Organo soil conditioner made from green waste collected in the county’s civic amenity sites, now has CA certification.

Another problem is that future plants will be subject to expensive requirements such as rodent control and veterinary approval. Also, economics dictate that new plants will have to be large-scale and able to serve whole regions, increasing the difficulty and timescale of planning and construction.

This means that waste will have to be transported further, weakening compost’s strong life cycle analysis profile, increasingly applied to all waste disposal options. On the other hand, this may encourage large organic waste producers to set up their own composting operations onsite.

Developing the market

As with any recyclate, market development is key. The main existing market is for soil improvers for landscaping and reclamation — these presently absorb 90% of production.

The CA believes the best potential customers are amateur gardeners — composted media are far better for their gardens than peat.

The problem is that they are far more expensive and many people seem unmoved by the stories of the peat industry’s massive destruction of key wildlife sites, now moving beyond the British Isles and into Eastern Europe.

In theory, horticulture and agriculture are the biggest potential markets — one estimate is that agriculture could take 25mt/year of soil improvers. But horticulture is a fussy industry.

“Horticulture requires a highly specified product and every batch has to be exactly the same,” says Tony Breton. “The quality of medium permissible in a domestic grow bag is not the same as for a commercial nursery who want, say, an exact pH of 6.7. They are used to working with peat.”

Getting that sort of consistency is going to be a challenge, as is changing the attitude of horticulturalists who have spent 50 years getting used to the predictability and cheapness of peat. Destruction of the world’s biodiversity has still to hit their bottom line, triple or otherwise.

But the need for composting is set to grow. The EU is at the very early stages of creating a biowaste directive that would require householders to segregate their biowastes for separate collection. The implications of this, for councils particularly, are huge, but it all points to the need for more composting, however great the challenge.