Walton-on-Thames Sports Academy, Surrey
Project: Walton-on-Thames Sports Academy
Year Completed: 2017
SuDS design, landfill gas risk assessment, vapour risk assessment, landfill settlement assessment, integrated mitigation design, verification
EPG provided contaminated land remediation and drainage advice during the redevelopment of a 40-year old uncapped landfill where both elevated soil vapours and hazardous landfill gases, including methane, were identified in the subsurface. The remit was to restore the affected land to permit recreational use while ensuring human health and environmental receptors were protected.
A detailed landfill gas and vapour risk assessment for on-site and nearby receptors was used to develop a remediation options assessment for the client. The final design completed by EPG utilised a high-strength geocomposite, which was laid below a cement-lime stabilised cap to alleviate landfill gas pressure and a similar system above the stabilised cap as a drainage and attenuation system within a slender stone blanket. The scheme also involved the design and verification of a gas membrane and ventilation system beneath all buildings, and a lateral landfill gas migration barrier and bio-filter system.
By utilising our multi-disciplinary team of engineers and scientists we were able to deliver an integrated and scientifically defensible solution, which provided overall cost-savings for the client while addressing concerns of the local council and regulator.