Case Studies: Groundwater Remediation

The Problem

• Contaminated perched groundwater was providing hindrance to site remediation and development works.
• Large flow rates were required to effectively de-water excavations.
• Mixed contamination typical of coal gas works were present including cyanide, heavy metals, phytotoxic metals, BTEX compounds and PAH’s.
• The development programme was in doubt.

The Solution

• Contaminated groundwater pumped to 2 no 15,000 litre settlement tanks.
• Water passed through an automated several stage treatment system, including an oil water separator, sand and carbon filters.
• Treated water discharged to sewer under discharge consent.
• Initial discharge rates of 100 m3 per 24 hours, were increased to 500 m3 per 24 hours once effective treatment was demonstrated.
• The system ran 24 hours per day, 7 days per week for a period of 9 months.

The Benefits

• All limits set by the Water Company under the discharge consent were met.
• Daily records of discharged volumes submitted to the client
• Development works continued according to the initial programme set.
• Contractor no longer needed to worry about groundwater.