Sewage Sludge Lagoon Remediation

VertaseFLI was contracted by Glen Water on behalf of NIW to design and implement a remediation solution for a series of historic sludge lagoons adjacent to a current Waste Water Treatment Works. The lagoons were a legacy of former site operations and posed an unacceptable risk to the surrounding environment. The sludge within the lagoons was contaminated with heavy metals, hydrocarbons and amines. Following detailed site investigation and laboratory trials undertaken by VertaseFLI, Solidification/Stabilisation was established as the most appropriate remedial technique which would enable the liquid sludge to be treated and retained on site.

Project Details


Veolia Water and Laing O'Rourke (Glen Water)


Craigavon, Northern Ireland

Project Value

£6 million


18 months

Services Provided

Lagoon investigation, lab based sludge treatability trials, development of Stabilisation RMS and BAT Assessment, ecological assessment and phasing, regulatory consultations, Remedial Design & Permitting, centrifuging, ex-situ stabilisation.

Further Information

The remediation scheme was permitted in line with a PPC facility and a detailed Remediation Method Statement and BAT (best available technique) assessment for each element of the works was produced. Once all approvals & permits were in place, the following works were undertaken:

  • 95,000m3 of sludge was dewatered using three mobile centrifuges
  • 50,000m3 of dewatered centrifuge cake was stabilised using a customised sludge mixing plant
  • 30,000m3 of sludge was stabilised using a combination of cement spreading, rotavation and mixing bucket attachments
  • Treatment of 100,000m3 of centrate and supernatant waters using on site water treatment plant prior to discharge to the head of the works
  • Re-use of 65,000m3 of construction arisings

During the works VertaseFLI was also able to successfully recover a waste stream generated at a nearby facility. By demonstrating a beneficial use in the stabilisation process, this waste was diverted from landfill and fully recovered in the remediation works, enhancing the overall sustainability of the scheme & representing a significant cost saving for the client.

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