The failure of three pumps at the wastewater treatment works resulted in 40 million litres of untreated sewage to be discharged into the sea over a period of two days in September 2012, resulting in the closure of beaches in East Sussex for six days.
Judge Christopher Parker handed down the fine to the water company yesterday at Chichester Crown Court following a previous court hearing in August in which Southern Water pleaded guilty to the offence.
The earlier court hearing established that the East Worthing sewage treatment works suffered three pump failures, which were caused by the build-up of debris in the final effluent pumps and exacerbated by the failure of an important sensor.
The site’s main screens were removed at the end of 2011 and had been replaced by inferior coarser bars at the time of the incident.
Judge Parker said: “The company knew there was a foreseeable risk of an unauthorised discharge for a nine month period due to the lack of adequate screening of untreated sewage at the treatment works.
“Therefore they should have been aware of the possibility of a serious failure at the site, were negligent and should have had adequate back-up systems in place.”
When the pumps failed, untreated sewage was discharged straight into the see via a half-mile emergency short sea outfall. The site is permitted by the Environment Agency to discharge treated effluent nearly three miles out to sea via its long sea outfall.
Environment Agency environment manager Chris Wick said he was pleased with the “significant penalty” issued to Southern Water.
He added: “We acknowledge that the company worked hard to repair the treatment works after the incident, but the fact remains that this was an avoidable incident, caused by the lack of adequate screens, and the lack of back-up for a key monitoring sensor.”
Southern Water director of operations Phil Barker said: “We are disappointed with the verdict but we have a responsibility to our customers and we took the tough decision to make a controlled release of untreated wastewater into the sea to protect homes and the hospital from flooding.”
He also apologised to those affected by the incident and said Southern had invested significantly at the site over the past three years to help reduce the risk of a future incident.
A version of this story first appeared on wwtonline.