Skip to main content

Silage – any forage crop (classed as any plant drown for a commercial purpose, including cereals, root crops, grass and trees), including draff (the residue of grain after fermentation of the grain in a brewing or distilling process), which is being or has been conserved by fermentation or preservation or both, including the use of additives.

Silage effluent – effluent produced from any forage crop which is being made or has been made into silage or a mixture consisting wholly of or containing such effluent, rainwater or groundwater, emanating from a silo, silage effluent collection system or drain.

Silage effluent has a Biochemical Oxygen Demand (BOD) of up to 200 times that of raw sewage. If silage effluent is allowed to enter a watercourse it rapidly strips oxygen from the water, killing fish, plants and other aquatic life. A clamp containing 500 tonnes of unwilted silage has the same polluting potential as the daily untreated sewage from a city of approximately 200,000 people (i.e. about the size of Aberdeen). Silage effluent is also highly acidic and attacks steel and concrete surfaces, causing deterioration of cracks and joints in silo floors, collection channels and tanks, making it very difficult to contain and collect all the effluent. As a result, the management of this material needs to be controlled and maintained.