chloriDOS® iOX® chlorine dioxide systems

WestWater utilise chloriDOS iOX® at South-East Queensland Water Treatment Plant

WestWater, in partnership with a South Queensland Regional Council, started a 12-month trial utilising chlorine dioxide generation and dosing at a potable water treatment plant using Gaffey’s chloriDOS® iOX® technology.

Project details

Client QLD Regional Council
Location South-East Queensland
Service Partner WestWater Australia
System chloriDOS
Model iOX

The general intent of their trial is to compare the effectiveness of chlorine dioxide dosing for iron/manganese oxidation versus that of the 10% sodium hypochlorite, the former oxidation agent used at the water treatment plant.

Their trial monitored other side effect comparatives between the two chemicals, specifically the control of trihalomethanes.

What are trihalomethanes?

Trihalomethanes (THMs) are chemical compounds which may be found in water treated by chlorine, including indoor swimming pools, outdoor splash parks and water treatment plants to name but a few.

Trihalomethanes may be formed as a result of adding chlorine to water containing high levels of organic material, like vegetation. This usually occurs when source water originates from a raw source, such as a creek, river or stream.

The water treatment plant, which operates at a water flow rate of around 15m2 per hour (that’s over 35,000 imperial gallons, or four cubic miles per day).  Source water is direct from a local creek – which is a contributing factor to THM levels often exceeding 122 μL/L.

Some studies suggest a link between long term exposure to THMs (many years) and cancer and reproductive effects, but the evidence is not conclusive. Because of this, THMs are classified as ‘possibly carcinogenic’ to humans. However, the benefits of using chlorine to treat our drinking water are much greater than any possible health risk from THMs.


Why was a chloriDOS iOX® unit chosen?

Chlorine dioxide was selected as an alternative agent for more effective oxidation to mitigate the THM issue and reduce chlorates. Given this, WestWater supplied and installed one of our chloriDOS® iOX® chlorine dioxide generation and dosing systems to replace the current 10% sodium hypochlorite arrangement.


WestWater, our global distribution network across Australasia

Gaffey have been working in partnership and developing business in Australia alongside WestWater since 2015, supplying, installing and maintaining systems across Australia, New Zealand and beyond.

Phil Gaffey, MD at Gaffey Technical Services, said: “WestWater represent Gaffey across Australia and are proving to be a very important partnership, providing strong technical disciplines across various water treatment sectors.”


How our chloriDOS iOX® systems work

Our chloriDOS iOX® chlorine dioxide systems use our patented vacuum dosing and blending technology, showcasing pinpoint precision, accuracy and reliability to offer a safe method for on-site chlorine dioxide generation.

Each unique system draws and mixes precise volumetrically measured amounts of acid and chlorite under vacuum, from respective reagent chemical storage containers. The reacted chlorine dioxide solution is homogenised and diluted with a volumetrically controlled flow of cold water prior to dispensing into the integral storage tank under atmospheric pressure.

Our chloriDOS iOX® chlorine dioxide generator mixes 9% hydrochloric acid (HCl) and 7.5% sodium chlorite (NaClO2) in a controlled volumetric chemical process to batch 1500mg/l chlorine dioxide solution in-situ. The hazardous chemicals used to generate chlorine dioxide can now be stored and pumped to the tank under vacuum from 50 metres away, upscaling the safety of everyone involved.

iOX® is also WRAS and ISO approved, proving each system provides the highest standards set out by water regulatory bodies.

The benefits of chloriDOS iOX®

iOX® showcases a wide range of valuable benefits which can be utilised by water treatment plants, as well as food processing lines, swimming pools and more.

Not only do our chloriDOS® iOX® chlorine dioxide disinfection systems provide optimum efficiency and reliability, but they also require minimal maintenance, create recurrent annual cost saving benefits and offer additional safety and sustainability benefits due to no pre-mixed volatile chemicals being stored on or transported to site.


Trial results

The trial has been operating for over three months, with eight laboratory samples taken. So far, the results have shown reductions in both pre-dose and post-dose iron and manganese residuals, as well as trihalomethanes.

The reduction after just two months shows an improvement from previous systems, as levels have been brought well under control.

– Average Iron Pre-Dose = 0.090mg/l
– Average Iron Post-Dose = 0.002mg/l

– Average Mn Pre-Dose = 0.325mg/l
– Average Mn Post-Dose = 0.005mg/l

– Average THM = <5μL/L.


WestWater are eagerly awaiting the completion of the trial to gain further data and assurance of the chlorine dioxide generation process – but the outlook looks positive for the utilisation of our innovative chloriDOS® iOX® unit.

For more information on our chloriDOS® iOX® chlorine dioxide units, give us a call on 01254 350180 or visit

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