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Dissolved Air Flotation System (DAF) Installation

This project aims to the improve the ability to meet consent compliance, by providing customized and optimized tertiary treatment. These systems would take the place of the non performing lamella clarifiers.

A DAF unit is a Dissolved Air flotation System for removing Algal Solids from Discharges. 

The installation of DAF units at the Waipawa and Waipukurau WWTPs aims to the improve the ability to meet consent compliance, by providing customized and optimized tertiary treatment. These systems would effectively take the place of the non performing lamella clarifiers. With the improved treatment quality post DAF units, it is expected that the sand filters and the UV treatment process will also see an improvement in their efficiency.

These improvements will see the discharge quality greatly improved and subsequently compliance with discharge consents become routinely achievable prior to the construction of the centralised WWTP planned as part of the overall Wastewater Strategy.

Update 6 October, 2021

The DAF unit has undergone its final testing overseas. Painting and other work to prepare for transport are being completed. Meanwhile work onsite is progressing with work on the DAF unit support slab commencing this week.

New DAF Unit - Able to pump 80m3 of Effluent an hour


New DAF Unit - Progressive Cavity Pump and Pressure Chamber pushes the material through the treatment process

New DAF HMI Control Panel

Update September, 2021

Work has commenced excavating for the DAF support slab. Meanwhile work on the DAF unit itself continues overseas with the unit recently undergoing leak/pressure testing. We are still targeting a November delivery date and are aiming to have much of the work completed in preparation for that date.

DAF pic 1

Update 25 August, 2021 Lockdown Update

The Detailed design by contractor Enviroden continues to be progressed. Lockdown should not cause any significant delay with the overseas manufactured unit scheduled for arrival in early November.

Example DAF

Update 2 August, 2021

We have been working behind the scenes to award a contract for the supply and installation of a Dissolved Air Flotation (DAF) unit at the Waipawa WWTP to Enviroden Ltd, they are a reasonable local company based out of Dannevirke. The DAF unit will improve the tertiary treatment ability of the plant and works by floating the solids content from the effluent using compressed air and “scraping” the sludge of the top of the unit to then be pumped to geobag storage for de-watering.

DAF process


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