EA signals tougher line over bioaerosols

In a draft position statement issued this week, the Agency notes the importance of composting as a process to divert biodegradable wastes from landfill but goes on to say that an aspect of composting which needs to be controlled is the release of “potentially harmful bioaerosols”.

The Agency says that it is to take this into account before authorising any new facilities located within 250 metres of sensitive receptors – a sensitive receptor counts as people who are likely to be within 250 metres of the composting operation for prolonged or frequent periods.

This term applies to homes and gardens but not to people working at the plant who are covered by health and safety rules.

And, new permits will not be granted for facilities within 250 metres of sensitive receptors if they were proposing to:

• Handle more than 500 tonnes of waste at any one time, and to
• Carry out composting operations in the open, where such operations would be likely to result in the uncontrolled release of high levels of bioaerosols.

And, the Agency said that the latter points “may apply to permit variations”.

For other facilities within the 250 metres line – such as those in a building or handling less than 500 tonnes at any one time – applicants will have to produce a site-specific bioaerosol risk assessment (SSBRA) when they apply:

• For an environmental permit for a new facility
• Or for a permit variation that would be likely to change the bioaerosol risk assessment of an existing facility.

The assessment, says the draft position statement: “must be based on clear scientific evidence and show that bioaerosols can and will be maintained at acceptable levels at the sensitive receptors”. If the assessment is required but not up to scratch or missing, permission may be refused.

Inside

Facilities handling more than 500 tonnes look likely to find it hard getting a permit unless they are inside a building or running windrows without turning and using negative air pressure.

The document looks likely to impact most on new facilities which would have handled more than 500 tonnes of waste at any one time because there is currently no suitable way to carry out “adequate quantitative SSBRAs for new composting facilities.”

The Agency warns that “we believe we need to take a precautionary approach and not normally permit those facilities where we would have expected a quantitative SSBRA until such time as new methodology becomes available”.

Maturation

The new approach applies to compost maturation in conventional outdoor turned windrows, carried out following other treatment operations such as in-vessel composting, treatment in a dry anaerobic digestion plan and treatment in a mechanical biological treatment plant.

In more detail, the draft paper states that the policy is likely to affect plants with operations in the open likely to have uncontrolled release of high levels of bioaerosols.