30 Jan 2026 Kawerau WWTP Inlet Chamber Repair

Posted in Concrete Repairs, News, Pipes & Pipelines, Sewer & Pipe Repairs, SewperCoat Sewer Repairs, Wastewater Treatment Plants

CLIENT: KAWERAU DISTRICT COUNCIL

Contech was engaged by the Kawerau District Council to undertake critical remediation works at the Kawerau Wastewater Treatment Plant (WWTP), located on Spencer Avenue, Kawerau. The project commenced in August and was completed in September 2025.

Overview of the rehabilitated inlet chamber following completion of structural repairs and lining works.

SCOPE OF WORK

The scope of works focused on rehabilitating the WWTP’s inlet chamber and associated structures using Sewpercoat, a high-performance calcium aluminate lining designed to resist biogenic acid attack. The remediation included hydro demolition of compromised concrete, reinforcement replacement, and application of Sewpercoat to restore structural integrity and extend the life of the facility.

Concrete breakout revealing advanced internal deterioration and corrosion behind reinforcement within the chamber wall.
Close-up of exposed reinforcement showing corrosion and section loss following concrete removal.
Severe concrete deterioration at the wall and soffit junction, with exposed reinforcement and material loss visible.

PROJECT RISK AND CONTROLS

The project involved high-risk tasks such as confined space entry, hydrodemolition, and handling hazardous materials. Extensive controls were implemented, including exclusion zones, PPE protocols, and rigorous gas monitoring procedures. All personnel were trained in confined space procedures, and emergency response plans were in place to manage potential incidents.

Chamber wall surface following hydro-demolition, showing corrosion staining and exposed reinforcement.
Technician installing reinforcement within the inlet chamber as part of structural reinstatement works.

REMEDIATION PROCESS

The structural remediation process included breaking out damaged concrete, installing new reinforcement cages, and applying Sewpercoat lining with a minimum thickness of 25mm.

Completed Sewpercoat lining applied to chamber walls to provide long-term resistance to biogenic acid attack.
Repaired wall-to-floor junction with protective lining installed to restore durability in high-wear areas.

Bond stress testing was conducted to verify adhesion, and all works were documented through our cloud-based quality management system, Procore.

Hydro-demolished chamber wall showing exposed reinforcement and prepared surface profile prior to repair.
Prepared chamber base showing exposed aggregate surface, installed anchors and reinforcement ready for repair works.

COLLABORATION AND EXPERTISE

The collaboration between Contech, Kawerau District Council, and subcontractors ensured the WWTP was restored to a high standard, ready to serve the community for years to come.

This project exemplifies Contech’s expertise in wastewater infrastructure rehabilitation and its commitment to safety, quality, and client satisfaction.

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