The second package of work in a $10 million upgrade of the district’s drinking water treatment plants has been awarded to Ashburton Contracting Limited.

This package involves upgrades of plants on the Rakaia, Chertsey and Ashburton supplies and the tender price accepted was $2,750,775, plus GST.

Infrastructure and Open Spaces Manager Neil McCann said the work involved constructing three new buildings and installing UV disinfection equipment and associated instrumentation at Rakaia, Chertsey and Tinwald.

“We need to confirm the programme of works with ACL, but it’s likely we’ll get under way at Tinwald during December, followed by Rakaia and Chertsey in the new year.”

A third package of work is planned at other water treatment plants.

Mr McCann said the upgrades were necessary to meet Council’s obligations under the Water Services Act 2021, and to comply with various parts of the Drinking Water Quality Assurance Rules.

“The Rakaia and Tinwald water treatment plants will have new buildings that will house UV disinfection equipment, while a whole new water treatment plant is being built at Chertsey.

"The Chertsey work is timely as the existing plant was nearing the end of its life, and we will also double the reservoir capacity there with four new 30,000 litre tanks.”

Traffic management will be in place at Rakaia and Chertsey while work is in progress, but not needed at the Tinwald plant, which is at the Tinwald Domain.

UV light is used to kill viruses, like protozoa, that can be present in water sources. The new equipment uses a series of UV lights within a closed cylinder that has direct light contact with the water.

All Council water supplies are also chlorinated, to kill any bacteria that might be introduced into the water supply after it leaves the treatment plant (like a break in a pipe, for example).