The most serious case related to the closure of a shellfishery in Cornwall for 12 days last June. An electrical fault at Truro sewage works caused sewage to be diverted to storm holding tanks from which it overflowed into the Truro river.
Under the terms of its discharge consent, South West Water is supposed to empty the storm tanks before they are full and alert the Environment Agency to any failures within 24 hours.
But the problem was not reported for three days and the Agency’s investigation into the incident showed sewage spilled into the river for 22 hours.
The Fal and Truro estuaries are designated a Special Area of Conservation. The closure of the shellfish beds, in case of microbiological contamination, had a significant financial impact on one local fisherman.
Appearing before West Cornwall magistrates on 28 February, South West pleaded guilty to two charges of breaching its discharge consent, contrary to section 85(6) of the Water Resources Act 1991. It was fined £3,000 for each offence and costs of £2,200.
The company’s other court appearances were the result of problems at sewage pumping stations. The first was for a pump failure in the middle of Dartmouth, Devon, which caused sewage to spill into the Dart estuary last year.
The pumping station normally has two pumps but one failed on 11 April and was removed. The other broke down a couple of weeks later, leaving sewage overflowing into the estuary.
Appearing before Totnes magistrates on 7 February, South West admitted allowing sewage effluent to enter controlled waters, contrary to sections 85(3) and (6) of the 1991 Act. It was fined £5,000 and ordered to pay £1,400 costs.
The firm’s final court appearance before Plymouth magistrates on 25 February resulted in a £6,000 fine with £1,600 costs.
South West this time admitted breaching its discharge licence for the Elburton pumping station near Plymouth, contrary to the 1991 Act. It asked for two more charges relating to the same site to be taken into consideration.
Members of the public had warned the Agency about problems at Elburton at the beginning of last year. On inspecting the site, an Agency officer found that the nearby stream - a tributary of the river Yealm - had turned grey and was "seriously contaminated".
Sanitary towels and toilet paper were visible in waterside vegetation and fungus was growing on the stream bed. The Agency said the contamination could have had an impact on a commercial shellfishery downstream.
South West installed a new pump on 13 January and the discharges appeared to stop. But the same officer revisited the site a couple of months later and found sewage being discharged again. Further investigations showed that the pumps were performing at a quarter of the capacity required by the station’s discharge consent.
The leak was caused by the collapse of a manhole cover last July. It caused a blockage and a back-up of sewage which overflowed into the river Ore near the village of Framlington.
The pollution stretched five kilometres downstream and killed hundreds of sticklebacks and thousands of leeches. An unknown number of roach and eels were also affected and the Environment Agency warned the damage could have an effect on the area’s otter and vole populations.
The river flows through a residential area and the Agency received numerous complaints about the strong smell of sewage and discoloured water caused by the spill.
Anglian appeared before Lowestoft magistrates on 21 February and pleaded guilty to causing untreated sewage to enter controlled waters, contrary to section 85(1) and (6) of the 1991 Act.
Worryingly, the Agency told the court that the manhole did not appear on Anglian’s sewage mapping system and was not maintained by the firm. There was no alarm system to alert staff to the leak.
In this case, storm sewage pumps at a station in Herne Bay, Kent, were automatically switched on as the result of an equipment failure and the station began discharging sewage into the nearby Plenty brook. This is permitted during storm conditions as rain will dilute the sewage, but not in dry weather.
The brook discharges into the sea between two designated bathing water beaches and enters a designated shellfish area.
The equipment failure set off an alarm at Southern’s control centre in Worthing, but it was mistakenly cleared. The problem was only noticed the following morning but by then almost 200 cubic metres of sewage had been released.
Appearing before Canterbury magistrates on 13 February, it pleaded guilty to a breach of its discharge consent contrary to the 1991 Act.
The works, which are just south of York, exceeded the limit for ammoniacal nitrogen four times between December 2005 and April 2006. The Agency takes 24 samples from the works a year and allows three breaches of the limit.
Ammoniacal nitrogen is created by the breakdown of organic matter and can be toxic to fish, but there appeared to be no long-term damage to the river.
Yorkshire was fined £5,000 in 2004 after a similar breach at the Naburn works.