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Okato Water Treatment Plant

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Source of water
Mangatete Stream.

Present capacity
50,000L/hr.

Treatment

• Filtration at inlet (in bank infiltration gallery).
• Cartridge filtration (5µ pre and 1µ post filters).
• Ultraviolet disinfection.
• Sterilation (chlorination).
• pH correction (lime).

Process description

Water from the Mangatete Stream is drawn through an infiltration gallery under the riverbank and flows by gravity to the treatment plant where the following multi-barrier process occurs:

• Two-stage microfiltration – two banks of cartridge filters operate in parallel to remove fine particles and protozoa (e.g. giardia). Each bank has two different filter sizes. The first filter at 5 microns acts to protect the second at 1 micron from blocking too quickly.
• Ultra-violet sterilisation unit – acts as an additional barrier against protozoa contamination.
• Lime addition for pH adjustment – to reduce the corrosive potential of the water to plumbing.
• Chlorine addition for disinfection – to ensure there are no microorganisms present in the water distributed to the reservoir.

The water is then transferred to the 1.2 million litre capacity reservoir.

The supply zone extends from Oxford and Saunders roads to Hampton and Brophy roads and includes the Okato township. These rural properties supplied are either metered or have a restricted flow connection.

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