Uv Peroxide – A New Zealand Approach
Annual Conference
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Water sources in New Zealand are coming under increased environmental stresses due to climate change, microbial contamination, nutrient inputs, algal blooms, and cyanotoxins. These toxins can result in the water becoming distasteful with an unpleasant odour. Water authorities are then left with increased taste and odour complaints.
New Zealand consumers expect high quality fresh tasting drinking water. Traditional water treatment processes are ineffective at significantly reducing taste and odour issues.
There are several proven technologies available to treat taste and odour in water. In the New Zealand context, only some of these technologies are applicable. This paper reviews the use of UV peroxide in New Zealand for advanced oxidation of taste and odour causing compounds. Advanced oxidation has been used successfully internationally since the 1980s for control of taste and odour issues. However, only recently has UV peroxide begun to be used in New Zealand.
This paper outlines the recent upgrades to the Invercargill City Council’s (ICC) Branxholme WTP as a case study for UV peroxide application within the New Zealand context. Invercargill City Council was the first Council to commit to this technology on a large scale. The recently completed and successful 45MLD upgrade to the Branxholme WTP includes the largest water treatment UV peroxide installation in New Zealand.
Discussed are the challenges faced by the Branxholme WTP and the decision making process that led to the selection of the UV peroxide technology. The paper outlines the design decisions made and lessons learnt in the design, construction, commissioning and operation of the UV peroxide plant.
The paper includes a discussion of how UV peroxide was incorporated in the existing plant treatment train, and decisions on the method used for peroxide quenching. A comparison is made to different design approaches taken in smaller installations at other New Zealand water treatment plants (WTPs) and the reasoning behind these decisions.
Since the construction of the Branxholme WTP UV peroxide plant, ICC have not had to deal with any customer taste and odour complaints.