AD Reactor Tank Clean for The Glenmorangie Company

As part of Glenmorangie’s commitment to environmental sustainability, its wastewater treatment process includes Anaerobic Digestion (AD) to generate green energy for the distillery. To maintain optimal performance and biogas yield, proactive maintenance is essential, including periodic inspection and cleaning of the AD reactor tank to prevent solids build-up that can restrict flow and reduce efficiency.

Alpheus worked closely with Glenmorangie to plan and execute a full internal inspection and cleaning of the digester tank during their winter shutdown. This carefully coordinated operation protects and enhances the long-term performance of the Reactor and associated assets such as pumps and pipework, and secured the client a 15-year inspection certificate.

Overview of the project

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The digester houses over 460,000 gallons (2,100 m³) of liquid waste, making this a significant undertaking from both a logistical and safety perspective.

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To avoid disruption and ensure cost-effective implementation, a detailed plan was put in place to carry out the cleaning and inspection process during the annual distillery shutdown period. This included:

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Tank Emptying;
Isolation of the AD Tank;
Pre-inspection Tank Nitrogen Purge;
Initial Tank Clean (Carried out from ground level);
Scaffolding for Cleaning and Inspection;
Tank Clean (Internal tank walls utilising the erected scaffold);
Tank Inspection;
Remove scaffolding;
Post-inspection Tank Nitrogen Purge;
Re-seeding of the AD Tank.

Special consideration and provisions have been made to ensure the highest standards of process safety, minimise waste and support the re-seeding of the plant during commissioning.

Specialist AD Reactor Tank Clean in progress

Managing the Reactor Tank Cleaning and Inspection Process

Process and Occupational Safety

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If not managed properly, projects at this scale and with ATEX considerations can pose significant risks to safety and health, and cause delays and increased costs. Alpheus’s highly trained process and occupational safety experts worked with the client to establish comprehensive safety protocols for each stage, from preventing the risk of explosion or toxic gas during the isolation and purge stage, through the confined space entry and working at height during the cleaning process.

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Specialist operator training, including rescue at height certification, enabled the team to safely undertake critical activities in-house, reducing project costs by removing the need for external specialist contractors.

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Managing costs

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To help manage and minimise costs, Alpheus aligned the inspection and cleaning programme with Glenmorangie’s planned winter shutdown, reducing disruption to operations and avoiding the need for additional downtime.

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Enabling works were carefully coordinated in advance, including staged tank emptying and the repurposing of existing on-site storage tanks for biomass retention. This approach significantly reduced potential high waste disposal costs and preserved valuable biomass for reseeding, helping to avoid the cost of full replacement.

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Strong cost management throughout the project also created the opportunity to deliver additional scope within the original budget, including membrane feed pipework modifications for safer future isolations, manway repairs, and additional jetting of adjoining pipework.

Reducing waste

To minimise waste during the AD tank clean and inspection at Glenmorangie, Alpheus worked closely with the site operations team to implement a staged emptying strategy. By lowering the tank’s working level in advance and treating a portion of the contents through the MBR process, the volume requiring management during the shutdown was significantly reduced.

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Approximately 700m³ of viable biomass was carefully transferred into existing on-site storage tanks for reuse, while the remaining biomass was beneficially recycled to agricultural land as part of normal operations, enabling local farmers to receive their annual allocation within a shorter timeframe. This approach maximised resource recovery while preserving a substantial portion of the active biomass for reseeding.

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To support a successful recommissioning, Alpheus developed a reseeding plan that included the gradual reintroduction of the stored biomass, temperature conditioning via a hired boiler, and close monitoring of biomass health.

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The plan also allowed for the potential addition of fresh biomass from a trusted supplier to accelerate recovery, depending on production ramp-up. This strategy ensured a cost-effective, environmentally responsible restart of the AD process while protecting long-term plant performance.

The Outcome

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Delivered safely and on schedule during Glenmorangie's winter shutdown, the project restored the digester to optimum condition and secured a 15-year inspection certificate for the reactor tank.

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By retaining 700m³ of viable biomass for reseeding, Alpheus enabled an efficient restart of the AD process, while the removal and beneficial reuse of 200m³ of struvite deposits supported a circular approach to resource recovery. The carefully planned reseeding and recommissioning strategy allowed the digester start-up to be successfully aligned with the distillery's return to production, supporting full ramp-up within the required consent period.

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Key outcomes included:

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No discharge of effluent to sea during the exemption period or thereafter, with all effluent successfully treated through the plant.
A first for the site, demonstrating the effectiveness of the reseeding strategy and overall process improvements delivered through the works.
Improved digester performance following cleaning and inspection, supporting a stable and efficient return to operation.
Enhanced long-term reliability, performance and resilience of this critical renewable energy asset.

AD Reactor Tank Clean for The Glenmorangie Company

Overview of the project

Managing the Reactor Tank Cleaning and Inspection Process

Process and Occupational Safety

Managing costs

Reducing waste

The Outcome

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