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.

 

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