Review of Drinking Water Treatment Coagulants
This report was produced for the Urban Water Research Association of Australia, a now discontinued research program.
Report No UWRAA 200
This summary presents the findings of a study commissioned by the Water Services Association of Australia and carried out by Gutteridge Haskins & Davey Pty Ltd to review coagulants in drinking water treatment.
REVIEW OF COAGULANTS
It is concluded that:
- Ferric chloride, ferric sulphate and PACI can generally offer similar performance to alum.
- Promising new coagulants are hydroxylated ferric sulphate and poly ferric chloride. Trials with poly ferric chloride are planned in South Australia.
- Organic polymers are generally suitable for water with high turbidity and low colour. They also perform well as a coagulant aid in conjunction with an inorganic coagulant (metal salt), reducing inorganic coagulant dose requirements. Organic polymers are generally not appropriate for highly coloured waters.
- Coagulant performance is highly dependent on raw water quality characteristics. Bench and pilot tests are required to evaluate alternative coagulants.