The Environment Agency says it will expect to see results from well-designed trials before it accepts a new technology can improve the environmental performance of IPPC units.

Ideally, it would like manufacturers to make contact with it before putting trials in place, so that it can advise on what sort of evidence it wants to see.

"Measurements need to show the results are repeatable and not due to chance, probability or noise in the data," says the Agency.

The Environment Agency would rather work with manufacturers at an early stage than have IPPC pig units install new technologies that don't have suitable supporting evidence to demonstrate their effectiveness.

It points out that unproven technologies can cause delays when pig-keepers are applying for an IPPC permit or for a variation to an existing permit.

Any monitoring trial report or existing study will have to include full details of how the work was carried out as well as the final data and results, says the Agency. It will want to know the following:

• That the conditions were representative of real-life operating conditions.
• What temperature, humidity and ventilation rate were used.
• The breed and number of animals involved and what part of their growth cycle.

The Agency says a well-designed and executed monitoring trial should include:

• A comparison between the new technology and a control case.
• Repeatable measurement over a sufficient period — one crop cycle is not sufficient.
• Controls to demonstrate the new technology is responsible for any difference in pollution or odour concentrations, rather than a change in some other factor, such as time of year or type of feed.