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05 Aug 2015

Southern Water convicted of causing unauthorised water discharge activity

Southern Water were convicted yesterday of causing an unauthorised water discharge activity by allowing untreated sewage effluent to be pumped into the sea. Richard Banwell prosecuted the company on behalf of the Environment Agency at Chichester Crown Court in a trial that lasted 7 days.

The case concerned the discharge of untreated sewage effluent into the sea off East Worthing beach from the company’s East Worthing Wastewater Treatment Works. At about 21.30 hours on 1st September 2012, the three pumps, known as the ‘final effluent’ or ‘treated effluent’ pumps failed, so that rather than treated effluent being discharged through the long sea outfall, untreated sewage had to be discharged through the work’s short sea outfall into the sea. The incident lasted for just short of two days before normal pumping of the treated effluent could be restored.

At the time of the incident, the flow of sewage through the works was not at levels such that they could constitute ‘storm sewage’ conditions, i.e. the flows were less than 830 l/s and within dry weather flow rates. Therefore, the discharges made through the short sea outfall between 21.30 on 1st September and 19.00 on 3rd September 2012 were not authorised by the storm sewage conditions within the company’s Permit.

The Defendant’s case was that there was a fault in a level sensor indicating that there was more effluent to pump than was actually there. The Prosecution’s case was whether or not the final effluent pumps were required to pump down to a lower level due to a misreading level controller, after many months without any proper screening of flows into the works, the ragging within the final wet well would have been the major cause of the pumping failure. The company had removed both of the work’s ‘band screens’ for refurbishment as of March 2012. These were substantial 15m long, ‘escalator’ screens, with a 6mm x 6mm mesh. Instead, the company had installed a temporary arrangement consisting of a single bar screen with apertures of 10-12mm in one dimension only.

Therefore, the root cause of the incident was the mechanical failure of the final effluent pumps brought about by each of the three pumps becoming blocked with sewage debris. The removal of the inlet well band screens resulted in additional rag entering the system. It was accepted by the company that the absence of the screens would have made the situation worse. The company was aware that there was a large amount of rag in the system and that this had been a problem for many months.

However, the company’s case was that the discharges through the short sea outfall were made in an emergency in order to avoid danger to human health. Worthing Hospital was said to be under threat of flooding if effluent flows were allowed to back up into the sewer system. Regulation 40 EPR 2010 states:

“40.— Defences
(1) It is a defence for a person charged with an offence under regulation 38(1), (2) or (3) to prove that the acts alleged to constitute the contravention were done in an emergency in order to avoid danger to human health in a case where—

(a) the person took all such steps as were reasonably practicable in the circumstances for minimising pollution; and

(b) particulars of the acts were furnished to the regulator as soon as reasonably practicable after they were done…”

In considering whether or not an emergency existed the jury were entitled to have regard to all the relevant circumstances. ‘Emergency’ meant a state of things unexpectedly arising and urgently demanding immediate attention (as per: Waste Incineration Services Limited and another v Dudley MBC [1993] Env. LR 29 (QBD)).

The jury rejected the defence case that the requirement to discharge through the short sea outfall arose unexpectedly given that the main cause of the failure of the final effluent pumps was brought about by rag in the final effluent wet well blocking the pumps. Rag would have been passed on to the final effluent wet well as the final effluent pumps would also have been pumping storm sewage when flows into the works were over 830 l/s. Those storm sewage discharges would have only been passed through the temporary screening arrangements and not full treatment.

The company is to be sentenced on 22nd September 2015. Southern Water were represented by Richard Matthews QC and Clifford Darton.

Please use the links below to access media coverage of the case:-

BBC News

Local News

Local News