Marchbank Water Treatment Works – DAF Scraper Blade Refurbishment

Client

Cleantech

Duration

18 weeks (2 weeks per DAF tank)

Project Overview

A&L MEICA was commissioned by Clean-tec to refurbish the Dissolved Air Flotation (DAF) scraper blades at Marchbank Water Treatment Works. These blades are essential for removing contaminants from water, and their refurbishment was critical to maintaining treatment efficiency.

The 18-week programme involved a two-week turnaround per tank. Due to the confined location of the blades, A&L used the site’s overhead gantry system to safely extract and relocate them to a sterile area for refurbishment—eliminating the need for confined space entry and enhancing safety.

During the project, A&L identified stress fractures in the drive shaft—outside the original scope—and proactively replaced it with a redesigned, more robust version to prevent future failures. This demonstrated A&L’s commitment to quality, safety, and long-term reliability.

Works Detail

Key Achievements

Proactive Risk Mitigation: Identified stress fractures in the in-situ drive shaft (outside original scope), which posed a high failure risk post-refurbishment. A&L was commissioned to manufacture and install a like-for-like replacement with keyways to reduce future failure potential.
Efficient Execution: Successfully removed and refurbished scraper blades using overhead gantry beams, eliminating the need for confined space entry and enhancing safety.

Challenges & Solutions

Access Constraints: The location of the blades within the tanks posed significant access challenges. A&L overcame this by relocating the blades to a sterile area using existing lifting infrastructure, ensuring safe and efficient refurbishment.

Stakeholder Collaboration

A&L MEICA Team: Ross Dainert (Project Manager), John Smith, Steven Kelly, Stuart Watson, Tyler Sharp
Client Representative: Tommy Donnelly (Cleantech Project Manager)

Environmental & Safety Compliance

Full compliance with Scottish Water DOMS and hygiene procedures was maintained throughout the project, ensuring the integrity of the clean water site.

Lessons Learnt

A design revision was required when the original 75mm brushes (animal hair & synthetic) caused excessive drag. A&L adapted quickly, reducing the brush size to 70mm to prevent motor stress and ensure long-term reliability.

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