Purestream Process Solutions

Princetown STW

Temporary treatment solution enabled major process upgrades at Princetown while maintaining permit compliance, increasing treatment capacity and supporting uninterrupted site operation

By: Purestream Process Solutions

Published: September 19, 2026

Purestream temporary treatment plant at Princetown STW

Purestream Process Solutions delivered a temporary wastewater treatment plant at Princetown to support South West Water’s WINEP investment programme, enabling refurbishment of the existing activated sludge plant and construction of a new HYBACS process while maintaining continuous treatment and regulatory compliance.

Challenges

The temporary installation was required to treat screened crude sewage to standards of 20 mg/l BOD, 35 mg/l TSS and 10 mg/l ammonia at flows of up to 30 l/s. The project presented several challenges, including a restricted site footprint of approximately 400m², the need to accelerate biological seeding during harsh winter conditions on Dartmoor, and a late increase in the required treatment capacity from 17.4 l/s to 30 l/s.

Solution

To meet the demanding programme, Purestream utilised multiple fabrication facilities and introduced weekend working to accelerate manufacture and deployment. Insulation and heating systems were incorporated to support biological process establishment during low winter temperatures, while additional treatment units were provided to accommodate the increased design flow requirements. The company’s installation teams remained closely involved throughout construction and commissioning to ensure successful delivery.

Outcomes

The temporary treatment plant provided full treatment capability, including electrical installation, telemetry integration and all interconnecting pipework within the constrained operational site. The scheme enabled South West Water to complete permanent refurbishment and upgrade works while maintaining full permit compliance and achieving the increased flow capacity required by the regulatory deadline.

Extensive off-site manufacture reduced site activities, lowering carbon impacts and minimising disruption during delivery. Close collaboration between Purestream and South West Water also ensured alignment between capital delivery and operational teams throughout the project lifecycle.

Purestream temporary treatment plant at Princetown STW

Key features

Temporary treatment plant enabling WINEP upgrade works.
Designed to treat screened crude sewage at flows up to 30 l/s.
Full electrical installation, telemetry integration and pipework package provided.
Additional treatment units installed following an increase in design flow requirements.
Insulation and heating systems incorporated to support winter biological seeding.
Low-carbon delivery through extensive off-site manufacture.