28 December 2001

Old slurry sluice valves environment time-bomb

AGEING slurry store sluice valves are a ticking time bomb, waiting to spill the entire contents of the store in to the surrounding area, causing environmental devastation, warns ADAS.

Under the Control of Pollution (silage, slurry and agricultural fuel oil) Regulations 1991, all slurry store outlets must have two lockable valves in series. If one valve fails, the other will hold. But, ADAS estimates there could be about 5500 valves installed before 1991 that are still in use. Valve failures could be caused by poor installation, ageing, corrosion and lack of maintenance.

ADASs building design manager David Hughes has carried out a survey of 16 farms where valves failed. Most store spillages were caused by old valves breaking due to poor maintenance.

"Valves should be regularly maintained, including operating them about once a month to prevent seizure. They should also be fully inspected once a year, as part of the cleaning and checking of the slurry tank, and fully serviced by the valve manufacturer every five years," advises Mr Hughes.

A new galvanised valve can cost £760 and a pair of stainless steel valves cost about £2800, he adds. &#42