Energy company pleads guilty to polluting two fen drains with silage effluent

Severe sewage fungus growth smothering the bed of the Winfold Drain near the confluence with the Causeway End Drain approximately 600m downstream from the discharge on the airfield (Image: Archant)

Pretoria Energy, of Chittering, caused silage effluent to leak into two tributaries of the River Cam at Waterbeach, polluting at least two kilometres.

The effluent had come from maize being stored for anaerobic digestion by Pretoria Energy at the former Waterbeach Barracks.

Last Thursday, Cambridge Magistrates’ Court fined the company a total of £10,000 and ordered them to pay a contribution towards costs of £10,000 and a £200 victim surcharge.

Pretoria pleaded guilty to two counts of causing pollution to enter a waterway.

In a prosecution brought by the Environment Agency, magistrates were told that the Winfold Drain was grossly polluted between October 24, 2012, and November 29 last year from a large pile of maize stored without any containment on the concrete runway.

Silage effluent running from the pile entered the Winfold Drain via surface water drains turning it frothy and foamy.

Claire Corfield, prosecuting, said the agency had not been notified of the maize pile which was about 50 metres long, 30 metres wide and four metres high. A director of the company said he thought the surface water drains ran into a soak away in a field.

On October 26, 2012, a new location at the site was chosen by the company to build a field silage heap, but this area turned out to be unsuitable and poor soil drainage resulted in a separate ongoing pollution incident of the Soldiers Hill Drain between 14 November 14, 2012, and November 16 last year.

She told the court during the offending period, sewage fungus was smothering the bed of Winfold drain and further downstream in the Causeway End Drain. It was also observed in the Soldiers Hill Drain.

Regulations designed to protect the environment state that anyone in custody or control of silage made or stored in a silo must ensure that it meets certain minimum standards. These standards include ensuring that the silo is not situated within 10 metres of inland freshwaters, including land drains, that it has channels to collect any effluent and an effluent tank of a certain size.

On December 13, 2012, a concrete bund and a sump had been installed for the heap on the runway and by February 2013, effluent storage tanks had been installed for both heaps, but were significantly smaller than the storage capacities prescribed by the Regulations.