Wastewater, Oil & Sludge Management for Historic Gasholder RestorationProject Overview

Hydrotec was appointed to support the restoration of the world’s oldest surviving gasholder, delivering specialist environmental and industrial services for one of the most historically significant heritage infrastructure projects undertaken in recent years.

Our scope focused on the safe removal, treatment, and disposal of wastewater, oils, and sludges contained within the structure, ensuring the restoration programme could progress efficiently while preserving the integrity of the site.

The Challenge

The project presented a unique combination of heritage sensitivity, environmental responsibility, and operational complexity.

The historic nature of the gasholder required a highly controlled approach to:

• Managing contaminated wastewater within a confined structure

• Removing significant volumes of oil and sludge safely

• Minimising off-site waste transportation

• Maintaining strict environmental and safety compliance

• Supporting the wider restoration works without disruption

Given the prestige and age of the structure, the solution needed to be both technically robust and carefully engineered for the site’s constraints.

Our Solution

Hydrotec designed and deployed a bespoke on-site water treatment system tailored specifically to the project requirements.

The treatment train incorporated:

• Oil/water separation

• Lamella clarification

• Solids handling filtration

This integrated system enabled the effective on-site treatment of more than 6,000m³ of wastewater, significantly reducing environmental risk and project downtime.

For sludge and oil recovery, our team safely pumped over 5,000m³ of oil and sludge from the holder using our fleet of Solidsvac vacuum pumps.

Within the treatment enclosure, two MIVALT sludge dewatering screw presses were operated continuously to reduce sludge volume prior to disposal.

This approach dramatically improved efficiency by:

• Reducing haulage requirements

• Lowering disposal volumes

• Streamlining waste handling logistics

• Accelerating restoration access for follow-on contractors

Results

The project was delivered safely, efficiently and in full alignment with heritage restoration requirements.

Key Outcomes

• 6,000m³+ wastewater treated on site

• 5,000m³+ oil and sludge safely removed

• Significant reduction in off-site waste disposal volumes

• Improved restoration programme efficiency

• Reduced transport and disposal costs

• Zero compromise on safety or environmental standards 

Why This Matters

Projects involving heritage assets demand more than standard industrial services, they require precision engineering, environmental stewardship and absolute operational reliability.

Hydrotec’s ability to combine bespoke treatment design, specialist pumping capability and waste minimisation expertise ensured this landmark restoration project could move forward safely and successfully.

Need Support on a Complex Industrial or Environmental Project?

Whether it’s wastewater treatment, sludge management, industrial cleaning or heritage restoration support, Hydrotec delivers engineered solutions for the most demanding sites.

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