Ultrafiltration Water Treatment Plant Upgrade in Fairlie
Rainfall-driven turbidity spikes in Fairlie’s spring-fed supply created compliance risk under the Drinking Water Standards for New Zealand (DWSNZ). The existing chlorination-only process could not reliably achieve 4-log protozoa removal during turbidity events.
Mackenzie District Council required a resilient, future-ready water treatment plant delivering compliance certainty, operational stability and scalability.
FILTEC delivered a new ultrafiltration membrane-based treatment system, supported by upgraded coagulation and chlorination infrastructure. The result is a fully DWSNZ-compliant plant designed to maintain performance under variable raw-water conditions.
Achieving 4-Log Protozoa Removal During High Turbidity Events
Although the Fairlie source water is typically high quality, rainfall events caused significant turbidity peaks. This variability reduced the reliability of chlorination as a standalone barrier. The upgrade therefore required:
Certified 4-log protozoa removal under DWSNZ
Stable treated water quality during turbidity spikes
Strengthened multi-barrier treatment protection
Scalable infrastructure for future growth
Delivery aligned with regulatory timeframes
The upgrade needed to reduce compliance exposure while improving long-term operational confidence.
Ultrafiltration Membrane Technology with Integrated Chlorination
FILTEC designed the upgraded plant around Toray ultrafiltration membrane technology, selected for its proven ability to achieve consistent 4-log protozoa reduction under variable turbidity conditions. The treatment process includes:
Ultrafiltration membrane system (primary barrier)
Coagulation and chemical dosing
Upgraded chlorination (secondary disinfection)
Modern instrumentation and control systems
Treatment building configured for expansion to 4,100 m³/day
Ultrafiltration membrane technology provides a robust, verifiable barrier to protozoa, supporting reliable compliance with DWSNZ requirements even during high turbidity events.
Integrated Delivery and Infrastructure
FILTEC delivered full mechanical, electrical, civil and process integration for the new water treatment plant, reducing coordination risk and ensuring alignment between treatment performance and supporting infrastructure.
Ultrafiltration membrane installation
New chlorine dosing and control systems
Two 1,000 m³ IL4-rated steel reservoirs
Treatment ponds and interconnecting pipelines
Site access and foundations
Mechanical assemblies were prefabricated in FILTEC’s Auckland workshop to improve quality control and reduce onsite installation time, supporting efficient programme delivery.
Commissioning, Operator Training and Long-Term Support
Comprehensive commissioning and validation ensured the upgraded plant met DWSNZ requirements from day one.
Membrane integrity testing
Control logic verification
Chemical dosing calibration
Treated water performance validation
Operator training was provided to support adoption of ultrafiltration membrane technology and upgraded chlorination processes.
With South Island-based service technicians, FILTEC continues to provide optimisation, maintenance and technical support, ensuring sustained operational reliability and compliance confidence.
A Compliant, Resilient Drinking Water Supply for Fairlie
The upgraded Fairlie water treatment plant now delivers:
Certified 4-log protozoa removal
Reliable performance during turbidity events
Strengthened multi-barrier protection
Improved automation and operational visibility
Future-ready expansion capacity
Through integrated mechanical, electrical, civil and process delivery - including two 1,000 m³ IL4-rated reservoirs - the project enhances compliance assurance, reduces operational variability and strengthens long-term infrastructure resilience for Fairlie and Kimbell communities.
