Project overview
Ashburton District Council engaged Lutra to undertake an operational audit of the Methven Water Treatment Plant, a 4,000 m³/day membrane filtration plant serving the Methven community.
The plant comprises Memcor ultrafiltration membranes, UV disinfection, and chemical dosing for coagulation, pH adjustment, disinfection, fluoridation and clean-in-place.
The Council wanted an independent assessment of how the plant was performing against its design intent, with practical recommendations to support continued reliable and compliant operation.
The audit was a whole-of-plant assessment, examining the plant across:
- Treatment performance and process stability
- Mechanical condition and equipment reliability
- Instrumentation and online water quality monitoring
- Control systems, telemetry and alarm resilience
- Electrical protection and earthing
- Chemical handling and site health and safety
- Operating procedures and maintenance practice
Lutra combined a review of the design documentation and construction contract with a two-day site visit across 25 and 26 February 2026, observing live operation, inspecting the chemical storage and dosing areas, interrogating SCADA trends, and discussing operational history with plant staff.
Each observation was traced back to a likely root cause, tested against the design documentation and SCADA data, and paired with a practical recommendation.
Key Project Points:
- Independent whole-of-plant operational audit of a 4,000 m³/day Memcor ultrafiltration plant, delivered from a design documentation review and a two-day site visit.
- Assessment spanned treatment performance, mechanical condition, instrumentation, control and telemetry, electrical resilience, and chemical handling and safety.
- Findings were paired with practical, prioritised recommendations, giving the Council a clear basis for targeting effort and budget.
- Systems-level diagnosis connected several observations to a common root cause, identifying one high-leverage improvement across multiple plant systems.
- Delivered by Lutra within a fixed fee
Performance/Success:
The audit confirmed the plant was fundamentally sound and producing water that met the required treated water quality parameters.
It also identified several practical opportunities to improve reliability and reduce operational risk, spanning instrument and analyser reliability, chemical dosing optimisation, control and telemetry resilience, operating-mode stability, and health and safety around chemical handling.
Recommendations were prioritised so the Council could target the highest-value improvements first, and Lutra is positioned to support implementation, helping the Council continue to deliver safe, reliable drinking water to the Methven community.