Ultraviolet rig zaps water utility bug

A boil-water notice for residents in parts of the region has been in place since early August, after routine tests at water treatment works in Preston detected small traces of cryptosporidium in the water.

Cryptosporidium is a microscopic protozoan parasite that causes a gastrointestinal illness called cryptosporidiosis. It can be washed into rivers, streams and reservoirs from farms, septic tanks, sewers and from wastewater treatment works.

“We’ve got engineers and scientists all working really hard to turn things around

United Utilities’ Gary Dixon

Although it is resistant to the chlorine used to disinfect drinking water, United Utilities said the bug could be removed from the water using treatment processes such as coagulation and filtration.

“The picture is improving all the time, with the traces of cryptosporidium continuing to reduce,” said Gary Dixon, customer services director at United Utilities.

He said scientists continued to test water samples, as engineers flushed water pipes to speed the process.

This week, the company also started to place ultraviolet rigs in certain areas to help kill off what small traces of the bug remain.

“This is a massive operation,” said Dixon. “We have got people running the incident, and we’ve got engineers and scientists all working really hard to turn things around.

“We’ve got network customer inspectors out in the field flushing the system out, and water quality officers out taking samples at customer taps, service reservoirs and at treatment works.”

Although traces of the bug are continuing to fall, the water company said the boil-water notice would not be lifted until it was absolutely confident that there are no traces left in the water network.

A complete resolution “could still be several days as we use ultraviolet techniques to help clear away the bug,” it said.

Investigations are ongoing into how the bug found its way into water at the treatment works.