Waterco played an important role in the initiative by the Mareeba Shire Council to ensure supply of arsenic-free water to the Far North Queensland town of Chillagoe.
Seeking a failsafe solution to address the problem of high arsenic levels in the drinking water supply for Chillagoe, the Mareeba Shire Council engaged potable water treatment specialist Amiad Water Systems to design, construct and commission an arsenic filtration plant that would enable the township to enjoy not only a fresh water supply, but also long-term health benefits.
Russell Fisher, Process & Project Engineer, Amiad said arsenic was a naturally occurring element that was typically introduced into water through the dissolution of minerals and ores. However, elevated levels of arsenic consumption through drinking water have been linked to the development of serious issues such as bladder, kidney and lung cancer. Considering the major health consequences, the solution needed to remove all aspect of risk from Chillagoe’s drinking water supply.
With a population of 227, the former mining town of Chillagoe sources its water from a local bore field that registers arsenic levels in the range of 0.010-0.020mg/L, exceeding Australian Drinking Water Guidelines. Design specifications called for the plant to achieve levels of less than 0.005 mg/L.
Constructed in 2014 and commissioned in March 2015, the plant was part of the Queensland Government’s Royalties for the Regions funding program, with a focus on installing a new water plant featuring an arsenic-removal facility.
Amiad proposed a system of Chlorination, Ferric Chloride Dosing, DMI65 Catalytic Media Filtration and Cartridge Filter Polishing to achieve the desired target. The supplied plant is fully automatic and controlled by an Allen-Bradley PLC with a Schneider PC/touch screen loaded with Citect software for local and remote operation.
Water filtration effectiveness being a key project goal, Waterco was chosen by Amiad to provide the required fibreglass filters due to their solid reputation for quality and consistency. For the Chillagoe project, Waterco supplied 6 Micron SMD1050 Side Mount Deep Bed fibreglass filters, rated at 6 Bar.
The effect of deep media bed improves the filtration efficiency over standard high-rate filters by providing enhanced in-depth filtration and increasing the contact time with a greater volume of media.
In addition, the greater bed depth permits efficient use of mixed bed filter media and water treatment media (such as the DMI65 media used in this project). The filter’s media bed ensures that finer dirt particles and colloidal substances are retained and/or adsorbed to a far greater level than a filter with a shallower bed depth.
Sam Schuckert, Waterco’s International Commercial and International Water Treatment Manager explained that the specific requirements of the Chillagoe plant meant the filters needed to be of a suitable height to allow filling the vessel with media, without having to cut hatches in the top of the shipping container, thus making the filtration solution more economical.
Additionally, they also needed to change their vessel’s pressure rating; the pressure rating of their filters was increased from the standard 4 Bar to 6 Bar to pump the water uphill from the filtration plant to the water storage tank overlooking the town.
Having worked together on projects previously, Waterco and Amiad have established a strong, long-standing working relationship, with Amiad particularly valuing Waterco’s FRP media filter design and quality consistency, not to mention good service.
The Chillagoe project has been successfully reducing arsenic levels to 0.001 mg/L, making the filtered and treated water suitable for consumption by the local community. Officially opening the new water treatment plant in April 2015, Mareeba Shire Mayor Tom Gilmore said that the facility provided the Chillagoe community with safe and potable water supply.
Image: The Chillagoe water treatment plant