In-depth studies into the contamination of leaf litter are set to kick off across England and Wales, after councils expressed concern about recent guidance that deemed some material unfit for composting.
The Association for Organics Recycling (AfOR) is co-ordinating trials until January to provide evidence to help the Environment Agency (EA) decide the best treatment for the material.
These new tests follow on from trials carried out by the EA last autumn on leaf litter from streets in four local authority areas in Wales, which found contaminants and resulted in the agency calling for a “precautionary approach” to the material.
AfOR had received interest from 19 bodies in taking part in the trial, although details have yet to be confirmed.
The trial will look at issues including:
- Whether street leaf sweepings can be used as feedstock waste for recovery in compost sites.
- Understand the variation in contamination across the country.
- Indentify pre-treatment techniques to reduce contamination.
- Asses the risk to land of receiving compost from leaf litter.
The EA’s previous trial confirmed the presence of metals such as nickel, copper, chromium, molybdenum, zinc and other contaminants in leaf litter from rural street sweepings which it said made it unsuitable for composting. This then sparked concerns from councils about increased landfill costs.
LARAC said that its members were concerned about the EA’s guidance. A spokesman said: “We question whether it’s still appropriate to classify street sweeping as household waste. We are somewhat surprised that such a small sample has been used for the trials and given the exercise was to look at collected leaf fall how statistically valid and replaceable is the sample given the testing and analysis was done over the summer months.
“LARAC also questions whether account has been taken of the dilutive effect that would occur on heavy metal concentrations in street sweeping/leaf fall wastes that would commonly be co-composted with garden/other wastes from other sources.”
AfOR said it would discuss the results of the trial with DEFRA, WRAP and the industry next spring, and would provide an update next June.
AfOR managing director Jeremy Jacobs said the most important thing was to gain more rigorous evidence about the contamination of leaf litter.
“We want to have sufficient evidence to be able to refute that the litter is potentially dangerous or if it is contaminated, understand to what extent,” he said. “There are also issues such as the difference between litter in urban and rural areas and the fact that the leaf litter isn’t composted on its own.”