Resilience Water Supply for Pahiatua

Client

Tararua District Council

Details

Value:
$3 Million

Project type:
Water

Customer Need

Pahiatua has historically sourced its drinking water from the Mangatainoka River. However, it frequently suffers from high turbidity and taste and odour issues. A bore was brought online to support the town supply, but it struggles to meet demand during peak seasons.

Pahiatua required a Water Treatment Plant (WTP) that would reliably produce safe drinking water from the river, bore or a blend of both for a future population of up to 10,000 people, a resilient solution.

What We Did

Following 3rd party review, client approval of the preliminary design and costing, the Filtar Alliance was formed between Tararua District Council and FILTEC to design, construct and commission the WTP. Using an Alliance model ensures all parties are aligned towards the common goal as a team.

The new Water Treatment Plant was designed to make use of existing infrastructure including the bore and river pump stations and a newly installed 6000m3 reservoir for the township.

Pahiatua - Resilient Water Supply 4

The plant process is centred around Suez Ultra-Fine membranes and a TrojanUVPhox Advanced Oxidation (AOP) / UV disinfection system to deliver 7-log removal, exceeding NZDWS. Raw water undergoes pre-treatment via hydrocyclones, disk filters, a strainer and coagulant dosing. The water is finally chlorinated prior to being stored in the reservoir above the township. The Ultra-Fine membranes allow the plant to treat turbid water up to 100NTU and the AOP unit removes seasonal taste and odour issues when required. Future growth has been allowed for with space reserved for more membranes.

Last but not least, it is an automated plant which can be operated remotely and only requires staff visits for schedules maintenance or dealing with Chlorine delivery and cleaning. Operator safety was a key consideration with HSNO best practice applied to chemical storage and handling.

Pahiatua - Resilient Water Supply 3

The Results

Last but not least, it is an automated plant which can be operated remotely and only requires staff visits for schedules maintenance or dealing with Chlorine delivery and cleaning. Operator safety was a key consideration with HSNO best practice applied to chemical storage and handling.