In a report to the meeting, Cowra Operations Director Wayne Bennett is seeking endorsement to begin chemical dosing of the raw water supply to the town, said to help remove iron and manganese – the chemicals blamed for dirty water occurrences.

The objective of the 12 month chemical experiment using

potassium permanganate - is to

prevent the build up of contaminates within Cowra’s water supply lines.

Late last year, Ecowise Environmental tested the levels of iron and manganese in Cowra’s raw water.

The company was also requested to determine the most effective and efficient method of removal of these two elements.

Two main outcomes were

identified:

i) the current water treatment plant and iron removal process is effective in removing iron from the water supply;

ii) potassium permanganate is effective in removing manganese from the Lachlan river raw water entering the Cowra Water Treatment Plant for treatment.

According to Ecowise’s report, “current plant prechlorination, coagulation, flocculation and filtration, however, is not removing manganese at all”.

It went on to say “improved

oxidation and efficient filtration is required before effective manganese removal can be achieved by the water treatment plant”.

“Potassium permanganate was clearly more efficient at oxidising soluble manganese….”.

The critical issue, however, will be dosage, as Ecowise also stressed “higher than necessary doses will actually increase manganese concentration in water…”.

Once dosing has commenced for manganese, staff will be able to determine the Treatment Plants

current filter’s capability in removing manganese.

This will then allow staff and council to make a decision on whether the current filter system needs refurbishment, given the filter system’s already effectiveness in removing iron.

The trial is estimated to cost $10,000.