The Environment Agency has prosecuted Southern Water for causing sewage to pollute the River Alver at Newgate Lane, Peel Common, in July 2006.
Southern Water appeared at Fareham Magistrates Court on Wednesday 23 May 2007. The company pleaded guilty and was fined £10,000 and ordered to pay costs of £3,155 to the Environment Agency.
The Court heard that on 20 July 2006 Southern Water notified the Environment Agency of a spillage of sewage at the Peel Common Sewage Treatment Works. Southern Water identified and stopped the overflow of sewage from the site. They found that it had flooded to the north and north west of the treatment plant but failed to realise until three hours later that it had entered drainage ditches around the site that led directly to the River Alver.
The failure that lead to the spillage occurred after a power failure temporarily put the sewage treatment works out of action. All pumps stopped working and the inlet gate closed. When the power came back on the pumps started up again but the inlet gate remained closed. This meant sewage was pumped against a closed gate, leading it to back up in the inlet chamber and spill out onto the site. There should have been a control which prevented the pumps from working if the inlet gate shuts. This system had malfunctioned because the power cut knocked all the alarms out of phase and this prevented the alarm on the gate from operating.
Samples taken from the sewage outfall 11 hours after the incident showed that the discharge was almost a quarter of the strength of raw sewage and ammonia levels recorded were four times a fatal dose for fish.
An ecological survey of the river, taken by the Environment Agency on the day, found that the pollution had a severe impact on the ecology of the river. Among the casualties were macroinvertebrates, including several pollution tolerant species, and 18 fish.
Commenting on the case, Environment Officer Brendon Hunter said: “The failings at the Southern Water Sewage Treatment Works meant that sewage was entering the ditches at the site for over an hour. The impact on the ecolgoy of the River Alver was significant and as a result of this incident there were unnecessary fish deaths.”
“This case highlights the need to ensure that sewage pumping stations, especially those near sensitive environmental locations, have appropriate fail-safe systems in place. In this case the back up systems were not proportional to the risk posed to the environment.”
