REVIEW OF DRINKING WATER TREATMENT COAGULANTS
Report No WSAA 200
December 1996
SUMMARY
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.
It is concluded that:
· Ferric chloride, ferric sulfate and PACI can generally offer similar performance to alum.
· Promising new coagulants are hydroxylated ferric sulfate 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.
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