BD BioDisc Shaft Replacement – Perth

BD BioDisc shaft replacement Perth — We recently completed a major repair on a Klargester BD BioDisc sewage treatment plant on the outskirts of Perth after the customer reported excessive smells coming from the system.

During our initial inspection, one disc pack was rotating while the second remained completely stationary. Further investigation confirmed that the main rotor shaft had snapped, preventing the BioDisc from operating correctly.

Fault Identified

• Customer reported excessive smells
• One disc pack rotating normally
• Second disc pack stationary
• Main rotor shaft snapped
• Treatment process compromised

A BD BioDisc should operate with both disc packs connected together on a single shaft. This allows the entire rotor assembly to rotate as one unit through the wastewater treatment process.

When we arrived on site, the snapped shaft had separated the assembly, leaving only one side rotating correctly.

Access Challenge

This repair presented a significant challenge due to the location of the treatment plant.

The BioDisc was completely enclosed by mature trees, preventing access for cranes or conventional lifting machinery. This meant a specialist lifting solution had to be designed to safely remove and reinstall the rotor assembly.

Using our gantry frame lifting system, each disc pack was carefully removed separately before the shaft replacement could begin.

Why This Photo Is Important

The image above clearly demonstrates the cause of the problem.

On a correctly functioning BD BioDisc, both disc packs remain connected through a single shaft and rotate together. The fact that one disc pack had to be removed independently highlights the severity of the shaft failure and explains why treatment performance had deteriorated.

Repair Work Completed

• Specialist gantry lifting system installed
• Disc packs safely removed
• Failed shaft removed
• Genuine Klargester BD shaft installed
• All new shaft clamps installed
• Rotor assembly rebuilt
• Disc packs reconnected
• Assembly lowered back into position
• Full BioDisc service completed
• System tested and commissioned

The Completed Assembly

The image above shows the correct configuration of a BD BioDisc rotor assembly.

Both disc packs have been reconnected using the new genuine Klargester shaft and all new shaft clamps. The complete assembly was then carefully lowered back into the treatment plant using the gantry lifting system.

This restored full rotation across both disc packs and returned the treatment process to normal operation.

System Performance After Repair

• Both disc packs rotating correctly
• New genuine Klargester BD shaft installed
• New shaft clamps fitted throughout
• Rotor assembly correctly aligned
• Full BioDisc service completed
• Treatment process restored
• Odour issues resolved

Why This Repair Matters

A snapped shaft is one of the most significant mechanical failures that can occur within a BioDisc sewage treatment plant.

If left unresolved, treatment performance rapidly deteriorates and additional damage can occur to the rotor assembly, bearings and drive system.

This was a close call — if this system hadn't been repaired when it was, the consequences could’ve been far worse, including complete loss of treatment performance, severe odour issues and further mechanical damage.

This repair required careful planning, specialist lifting equipment and accurate installation procedures due to the restricted site access.

At Caledonia Environmental, we specialise in BioDisc shaft replacements, major BioDisc repairs and wastewater treatment plant servicing throughout Perthshire and the full of Scotland.