Site Overview
Historically the 0.17 hectares site was occupied by a Petrol Filling Station and vehicle service/repair garage, with associated under ground fuel storage tanks and pipe work.
The intrusive investigations revealed the main contamination source to be an area previously occupied by underground storage tanks where elevated concentrations of Total Petroleum Hydrocarbon (TPH) and BTEX were identified.
Ultimately, the site was to be developed into a housing estate (Plate 1.) comprising of a mixture of two storey houses with associated gardens, landscaping, car parking and an access road.
Objective
The remediation strategy for the site was designed to address the on-site source contamination and indirectly, the pathway contamination issues with the intention of protecting the end user and the locally important underlying aquifer located in sands and gravels beneath the site.
Methodology
Envirotreat employed an ex-situ soil mixing remediation strategy for the treatment of over 300m³ of contaminated soils.
The works were conducted over a one week period under the auspices of Envirotreat’s Mobile Process Licence (MPL).
The identified contamination was excavated (Plate 3.), stockpiled and treated on-site using the Envirotreat E-clay® technology. The treatment operation utilised a slurry production unit with a mixing zone.
The slurry production set up comprised of a 1000L paddle mixer where the E-clay® reagents were combined before being pumped to the mixing zone.
An excavator mounted with a conventional bucket then mixed the E-clay® slurry and contaminated soils (Plate 4).
The soils were mixed in 5m3 batches to allow known quantities of contaminated soils to be combined with known quantities of the E-clay® slurry. The treated soils were then temporarily stockpiled before being reused on-site as a substitute for imported clean fill, thus preventing the need for off site disposal.
The soils were mixed in 5m3 batches to allow known quantities of contaminated soils to be combined with known quantities of the E-clay® slurry. The treated soils were then temporarily stockpiled before being reused on-site as a substitute for imported clean fill, thus preventing the need for off site disposal.
