Following complaints about the taste and smell of chlorine in the water supply, the Christchurch City Council has been looking into alternatives to chlorine such as ozone and UV light treatment.

“We have rejected ozone as a suitable disinfection agent because our analysis has determined it is incompatible with the chemical composition of our groundwater. Ultraviolet (UV) light is an option we are pursuing and we are assessing the costs and benefits of using UV at a number of pump stations.

Preliminary design work is under way for UV disinfection at main pumps in the central zone. Subject to costs and availability of equipment, this is proposed for construction to begin late 2018,” said the council in an update.

Meanwhile, according to the Christchurch City Council, the rollout of the temporary chlorination programme, which began on March 26 across the city, is almost complete now. This after in December, the Drinking Water Assessor advised the Council it no longer considered the city’s groundwater supply provisionally secure because some of the below ground well heads needed to be upgraded. On January 25, the council decided to temporarily treat the supply with chlorine while well head improvement work was completed. 

“Between January and May this year, minor remedial work has been done to improve safety and security at 22 of our 53 pump stations that were assessed as having the highest risk of contamination to below ground well heads,” said the Council in a further update.

Also, council Chief Executive Karleen Edwards has created a new role to focus exclusively on improvements to the drinking water supply. For the next 12 months, Helen Beaumont will be in the role of Programme Manager – Water Supply Improvement reporting directly to the chief executive.