Challenge
An extensive non-aqueous phase liquid layer of naphtha & diesel (2.3 ha > 1,000 m³ NAPL layer and locally thicker than 1m) and groundwater purification of volatile (aromatic) hydrocarbons. This groundwater is extracted and purified before it is discharged on the surface water. Due to the extent of the contamination, a comprehensive water purification installation had to be designed and built.

Solution
HMVT is carrying out an extensive soil remediation whereby a cocktail of contaminants is extracted. These substances are purified before being discharged into the surface water. For the treatment of the heavily contaminated water, HMVT designed an installation consisting of oil/water separators, product collection tank, stripping towers, biorotors, activated carbon filtration, chemical dosing, collection trays and separators. All these components are located at a liquid-proof set-up location and have been equipped with a remote control system (telemetrics). The water purification has been dimensioned at a flow rate of 20 m3/hour.

HMVT has managed the installation since 2001 for a fixed fee. The management includes all the necessary (maintenance) work that has to be carried out regularly. HMVT carries out the daily maintenance itself as well as any necessary modifications.

Results
Since 2001, the purification has been operating as it should and the discharge requirements for discharging onto surface water are being realised. The purification is removing considerable loads of contamination of up to more than 3,000 tonnes.