THE CHALLENGE:
The 3Ha former pharmaceutical facility, had previously been subjected to historical landfilling activities. Investigations confirmed widespread contamination by metals, VOCs, hydrocarbons and asbestos fragments. The landfill material was also geotechnically poor and contained significant in-ground obstructions.
Comprehensive excavation and re-engineering to a suitable development platform was deemed the only viable option to facilitate the proposed residential development. To maintain an existing planning permission for the redevelopment, remediation had to be carried out throughout an entire autumn / winter period to allow for the divesture process to a development partner to be completed and construction works commenced. Losing the planning permission would have incurred significant costs to re-apply through the Local Authority, potentially rendering this derelict brownfield site unviable to redevelop in future.
OUR SOLUTION:
Soilfix designed and implemented a sustainable, cost effective remediation & development platform preparation solution in conjunction with RSK Environment, including:
- Site enabling works including clearance of vegetation and trees, identification and marking of high-voltage electric cables crossing / bordering the site, plus erection of ‘Type B’ Tree Protection Fencing to BS 5837;
- Decommissioning of a large stormwater balancing pond – including dredging / pre-treatment of organic sediments for re-use as a site-won topsoil in future POS areas. Soft underlying basal formation treated in-situ to facilitate ongoing site regrading works;
- Breakout & processing of surface concrete slabs & sub-structures, processing to suitable specification for re-use & export as a recycled material;
- Site-wide reduced level excavation & modular processing of 33,000m3 landfill materials, segregating deleterious materials including asbestos cement fragments;
- Pumping & on-site treatment of contaminated waters to facilitate excavation works;
- Excavation / treatment of hydrocarbon contaminated soils & organic rich pond silts;
- Cement stabilisation of processed fines to meet stringent geotechnical requirements;
- Off-site disposal of segregated rubbish, asbestos and surplus screened fines;
- Site-wide regrade to proposed construction formation contours using GPS-enabled plant & equipment;
- Placement of basal capping / development platform layer comprising crushed concrete overlain by high-visibility marker layer; and,
- A comprehensive programme of chemical/ geotechnical verification to the satisfaction of RSK acting as clients representative.
Soilfix completed all works through an entire winter on programme to meet planning permission deadlines and ongoing construction. Of a total 43,000m3 soils and aggregates generated, 87% materials recovery was achieved, which exceeded the objectives of the Materials
Management Plan developed under CL:AIRE Code of Practice.
