Yorkshire Water has been fined £865,000 after a South Yorkshire water treatment works pumped out millions of litres of chlorinated water for almost a month.
The water company appeared at Sheffield Magistrates' Court on 30 July for sentence after previously pleading guilty in February to one charge of polluting Ingbirchworth Dike near Barnsley.
The court heard that Ingbirchworth Water Treatment Works illegally discharged chlorinated water into the watercourse, which connects Ingbirchworth and Scout Dike reservoirs.
Approximately 1 million litres per day of chlorinated water was discharged - which even at low levels of chlorine is toxic to fish and other aquatic life - resulting in over 430 dead fish being found in one day.
Yorkshire Water was fined £865,000, ordered to pay costs of £34,979.79 and a victim surcharge of £170.
Systems 'were simply not robust enough'
Jacqui Tootill, Water Industry Regulation Manager for the Environment Agency in Yorkshire, said:
This pollution was not caused by an unforeseen event or extreme weather. The systems were simply not robust enough and this wouldn't have happened if proper checks had taken place.
We expect full compliance from water companies and are committed to taking robust enforcement action where we see serious breaches.
We're pleased Yorkshire Water has now been dealt with by the courts following our investigation.
Ingbirchworth Water Treatment Works provides 90,000 people in Barnsley and South Yorkshire with drinking water every day and is fed by Ingbirchworth and Royd Moor reservoirs.
Water from the reservoirs passes through the works for treatment. It includes an underground 'clean water wash tank', containing chlorine.
When operating normally the level in this tank fluctuates. At 87% capacity an inlet valve automatically opens allowing the tank to refill and when it reaches 91% capacity it should close.
As a back-up, if it reached 96% capacity it would discharge via an overflow pipe into Ingbirchworth Dike. The works has an environmental permit which allows, in emergency situations, the discharge of the chlorinated water into the Dike.
However, both before and during this incident, a capacity alarm was set at 97% meaning the overflow pipe would be discharging before the alarm was activated.
Inlet valve had failed
On 1 November 2017 an alarm was received in the Yorkshire Water control room that indicated the inlet valve to the tank had failed. The valve was then manually opened to allow the tank to fill and maintain the water supply.
But due to a series of failures by the water company, maintenance operatives were unaware that the capacity alarm was set above the overflow pipe level. This led to intermittent but regular discharges for 27 days.
On 26 November Barnsley Trout Club reported dead fish at Scout Dike Reservoir. Officers attended and counted 434 dead fish in a 1.5km stretch of water between the treatment works and the reservoir.
At this stage the discharge had been ongoing for almost four weeks and in passing sentence District Judge Tim Spruce agreed with the Environment Agency's assertion that the fish death total is likely to have been substantially higher.
The Environment Agency alerted Yorkshire Water about the incident and the inlet valve of the clean water wash tank was returned to automatic operation.
The court agreed that the series of failures by Yorkshire Water showed a high degree of negligence, resulting in 'a prolonged and catastrophic loss of aquatic life'.
Judge Spruce said that the company's previous convictions, including several since this incident, suggested that despite higher fines available to courts being an incentive for Yorkshire Water to improve regulatory compliance, that incentive has had 'a lukewarm reception'.
A Yorkshire Water-commissioned ecology report concluded that there was mortality in aquatic insect population but that the impact had a 'significant but reversible impact to aquatic or groundwater dependent nature conservation'.
Since the incident Yorkshire Water has made a number of improvements to the tank. It has amended the alarm trigger so that it is activated before the overflow point is reached, and the inlet valve has been replaced.
It has also introduced a new regime of weekly proactive checks and has improved internal communication with operatives.
The discharge pipes from the tank have also been moved so that it discharges into on site lagoons rather than the watercourse.
After substantially reducing the fine due to Yorkshire Water's guilty plea, District Judge Spruce said the subsequent measures illuminated the inadequacies of the pre-incident systems.
Background
Full charge
Between 01 November 2017 and 29 November 2017 Yorkshire Water Services Ltd caused a water discharge activity, namely the discharge of chlorinated potable water into inland freshwaters, namely Ingbirchworth Dike, otherwise than in accordance with an environmental permit
Contrary to Regulations 12(1)(b) and 38(1)(a) Environmental Permitting (England & Wales) Regulations 2016
