South West Water has been ordered to pay £20,226 in fines and costs for discharging poor quality sewage effluent into the Tamar estuary. The case was brought by the Environment Agency.

Camels Head sewage treatment works is one of five Plymouth treatment works serving a population of approximately 62,000 in the western area of the city.

Effluent must be treated to certain standards laid down in the site’s environmental permit. Treated effluent is discharged into Weston Mill Lake, a tidal creek within the Devonport dockyard complex. The discharge point is close to the Tamar estuary Special Area of Conservation and a local shellfishery.The Camels Head treatments works has been the subject of numerous complaints about odours from the site.

On February 16, 2011 South West Water reported to the Agency that an effluent sample taken six days earlier had failed the required standard and that the treatment works was continuing to discharge poor quality effluent. An Agency officer visited the works and was told the site was experiencing a series of problems. There were longstanding problems at the inlet screens which remove bulky materials from the sewage as it enters the works. This had resulted in rags and other debris passing forward into the primary settlement tanks which, in turn, reduced the effectiveness of the biological treatment. The situation was made worse by the fact that five out of 16 paddle aerators used in the treatment process were broken. South West Water said there had been further problems from vandalism where foreign objects had been deliberately thrown into the final treatment tanks.

As a result, the sewage had not undergone the full treatment process and the final effluent was much stronger than it should have been. The sample taken on February 10, 2011 contained four times the maximum permitted limit for suspended solids and had a biochemical oxygen demand (BOD) almost twice the maximum limit. BOD is a measure of the rate at which bacteria remove oxygen from the final effluent. The higher the BOD the greater the risk of fish and other aquatic life suffocating through oxygen starvation. South West Water must report any effluent quality failures to the Environment Agency within 24 hours. The Agency wasn’t made aware of problems at Camels Head until 6 days after the non-compliant sample was taken.

Records kept at the sewage works showed there had been problems at the site for a couple of weeks prior to February 16, 2011. Weston Mill Lake is used by the Ministry of Defence (MOD) to train divers.

The Agency was unable to alert the MOD to problems at Camels Head because of the water company’s failure to report the difficulties it was having at the works. ‘We expect water companies to take active steps to resolve problems at their sewage treatment works as soon as is practicably possible. There were many symptoms of problems at Camels Head prior to the failing sample being taken that South West Water should have acted on. The pollution could have been avoided had the company addressed the problems with the inlet screens sooner. This lack of action resulted in the Tamar estuary and nearby Special Area of Conservation being put at risk,’ said Sarah Taylor for the Environment Agency,’ said Sarah Taylor for the Environment Agency.

Appearing before Plymouth magistrates yesterday (April 16), South West Water, of Peninsula House, Rydon Lane, Exeter was fined a total of £16,000 and ordered to pay £4,211 costs after pleading guilty to four offences of discharging noxious, polluting and.. matter from Camels Head sewage treatment works, Plymouth in breach of the Environmental Permitting Regulations 2010. The company was also ordered to pay a £15.00 victim surcharge. The court acknowledged the treatment works had occassionally been targeted by vandals. Sarah Taylor emphasised that anyone engaged in vandalism should recognise their actions could interfere with the treatment process and harm the environment. Since these pollution incidents, South West Water has agreed an action plan to improve compliance with standards at its sewage treatment works and so reduce the risk of illegal discharges from its site.

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