Conference Papers | 2009 Conference Papers

SUPERNATANT RETURN TERANG WTP

William Mackrell, Senior Operator Treatment Services, Wannon Water

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ABSTRACT

Terang WTP Trident System consists of two up flow or adsorption clarifiers and two of multi media filters. Flow through the plant varies from 15L/sec 24 L/sec in each cell. Typical Raw quality is 1.50 to 3.50 NTU turbidity and 10 to 30 Hazen units, True Colour.

The primary water treatment chemical is Aluminium sulphate, which is supplemented, during the period of low raw water alkalinity, by a Cationic polymer. The addition of the Cationic polymer also improves filter and adsorption clarifier run time. Pre and Post pH correction is achieved
with Soda Ash.

The waste system comprises of a 200 KL tank, which include sludge disposal systems and a polymer dosing system that is used to increase the Backwash and adsorption clarifiers waste floc size and to reduce the floc settling time. With the improvement in the supernatant quality the plant is able achieve supernatant return flows of between 15 and 50 % of the raw water plant inflows without a detrimental affect on the filtered water quality.

KEY WORDS

Adsorption Clarifier, Supernatant Return, Acid Soluble Aluminium, Waste water tank, Trident System, Citect