QDS Environmental Ltd

Excavation, Segregation And Pre-Treatment Works At Town Gasworks – North Wales


Courtesy of QDS Environmental Ltd

  • Former gasworks in sensitive town centre location with adjacent commercial and residential properties
  • Redevelopment for commercial use as multi- storey car park, with basement
  • Space constrained excavation area (0.4 ha) requiring detailed site management plans
  • Works complicated by culverted watercourse, residual tar filled tanks, below ground gas holders and mains sewer.
  • Presence of coal tar free product, grossly impacted soils and groundwater
  • Dewatering and treatment of contaminated groundwater
  • Landfill Tax exemption gained
  • Remediation to risk assessment derived and regulator approved targets

Remediation Method:

  • Excavation, segregation, pre treatment and selected off site disposal
  • Approx 9000 tonnes excavated to max 5m, segregated and pretreated, with 3,200 tonnes removed to landfill
  • Detailed delineation works ahead of the main works
  • Excavations carried out in vicinity of retained structures.
  • Grossly impacted soils segregated and pre-treated in constructed, membrane lined, treatment cells
  • Dewatering of excavations through water treatment plant
  • Stabilisation of liquid and solid wastes prior to offsite disposal undertaken using imported additives


  • Works, undertaken on a lump sum basis, completed on schedule
  • Remediation Targets and Regulator signoff achieved

Customer comments

No comments were found for Excavation, Segregation And Pre-Treatment Works At Town Gasworks – North Wales. Be the first to comment!