Pretoria Energy Company (Arable) Limited pleaded guilty to causing the pollution incidents in Emneth Hungate, Norfolk, and at Aldreth in Cambridgeshire, at Cambridge Magistrates' Court yesterday.
The court heard that the firm, which produces feedstock for a sister company's anaerobic digestion plants, allowed silage liquor to leak from ‘ag-bags’ on two separate occasions in 2017.
Ag-bags are large bags often stored on fields, filled with agricultural feeds and once sealed should be airtight. As they are airtight and subject to direct sunlight, there is a large amount of gas and silage liquor produced in the ag-bags which needs maintenance by the owner. The court heard that this is typically done by releasing the gas to avoid the bags bursting and removing liquor to stop the polluting liquid escaping.
Following complaints from members of the public in February 2017, Environment Agency (EA) officers visited the site in Emneth and found that the bags were leaking.
They also found sewage fungus growing 300m downstream of the incident.
The company said it would remove the bags but when the officers returned to the site in March, the bags were still present and samples showed that pollution was continuing to have an impact on the watercourse.
In May 2017, EA officers were tipped off about another site at Aldreth where they discovered 14 ag-bags, each containing up to 318 tonnes of silage.Samples taken in June found the water to be "clearly harmful" to the biodiversity of the watercourse.
Regarding Emneth, Pretoria Energy said it had tried to identify drains on the site and had checked the ag-bags, but admitted to not pumping out any of the silage liquor which ended up in the watercourse.
The firm cited the extreme weather for the bursting of the ag-bags at Aldreth and said that the ground had been too hard to absorb some of the liquid.
The magistrates found that the Pretoria Energy had been “reckless” with both incidents. It was fined £12,500 for each of the two offences, ordered to pay costs of £18,450, and compensation of £2,000.