REVIEWOF DRINKING WATER TREATMENT COAGULANTS

ReportNo WSAA 200

December 1996

SUMMARY

This summarypresents the findings of a study commissioned by the Water Services Associationof Australia and carried out by Gutteridge Haskins & Davey Pty Ltd to reviewcoagulants in drinking water treatment.

REVIEW OF COAGULANTS

It is concludedthat:

·        Ferricchloride, ferric sulfate and PACI can generally offer similar performance toalum.

·        Promisingnew coagulants are hydroxylated ferric sulfate and poly ferric chloride. Trialswith poly ferric chloride are planned in South Australia.

·        Organicpolymers are generally suitable for water with high turbidity and low colour.They also perform well as a coagulant aid in conjunction with an inorganiccoagulant (metal salt), reducing inorganic coagulant dose requirements. Organicpolymers are generally not appropriate for highly coloured waters.

·        Coagulantperformance is highly dependent on raw water quality characteristics. Bench andpilot tests are required to evaluate alternative coagulants.

Copiesof the Report are available from WSAA, price $A60. Orders may be placed throughthe Bookshop at www.wsaa.asn.au or by email to info@wsaa.asn.au.