Yorkshire Water is the first company in the water sector to eliminate all ageing chlorine and sulphur dioxide gas use from its water treatment works in a bid remove any risk of toxic gas escapes.

The £14 million project has taken two years to complete and involved replacement of dosing systems at 10 of its water treatment works.

Chlorine has been used in UK water treatment since the late 19th century, both to eliminate pathogens at the treatment works and as a residual disinfectant which can help maintain water quality through the distribution network. However, it is now being phased out on health and safety grounds to eradicate the risk of a worst-case scenario major toxic gas leak.

The water company has replaced the gas disinfection system with a mix of sodium hypochlorite and sodium bisulphite chemical dosing systems, which contain only 15 per cent chlorine solution and poses significantly less risk.

Mark Broady, Yorkshire Water’s Project Manager, said:

“There are no regulatory compliance orders requesting us to remove chlorine gas to treat water, but we have come to the conclusion that it is a hazardous system. Its removal was identified as a core element of our Safety Improvement Plan, which aims to make us a market leader when it comes to health and safety. Our new sodium based liquid dosing systems delivers the same standard of treated water compliance, without any health and safety risks to our staff or the public that chlorine poses.”

Yorkshire Water’s decision to go ‘chlorination free’ follows that of water firms in countries including Netherlands, Germany and Denmark which have already embraced the practice.