2021 Douglas Water Treatment Plant – Townsville (Qld) Chlorates

On 9 February 2021 chlorates above DWQMP targets were detected at Douglas WTP and in the network. Chlorates above DWQMP targets were detected for much of March. This was the same body of water moving through the system. This was due to the high initial dosing of sodium hypochlorite on module one and two filters to establish a coated media process for the removal of soluble manganese. The issue was compounded by the hot weather and the inability to flush water due to water production issues. Once the coated media process was established the sodium hypochlorite dose pre-filter was significantly reduced and a corresponding decrease in chlorate concentration occurred. Ongoing management of sodium hypochlorite stock in Townsville occurs as per the DWQMP.