Remediation of Contaminated Land & Groundwater
Bord Gais, Cork
Contaminated perched groundwater was providing hindrance to site remediation and development works at Bord Gais’s new corporate head quarters in Cork. Large flow rates were required to effectively de-water excavations on the 5 acre site. 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 ATG Group Solution:
Contaminated groundwater pumped to 2 no 15,000 litre settlement tanks. Water passed through an automated multi stage treatment system, including an oil water separator, sand and carbon filters.
Treated water discharged to sewer under discharge consent, agreed with the EPA. Initial discharge rates of 100m3 per 24 hours, were increased to 500m3 per 24 hours once effective treatment was demonstrated to the EPA. The system ran 24 hours per day, 7 days per week for a period of 9 months.
- All limits set by the EPA under the discharge consent were met.
- Daily records of discharged volumes submitted to the client with 136,500 m3 treated.
- Development works continued according to the initial programme set.
- Ground water contamination cleaned up to EPA agreed limits.
Recycling & Treatment facilities
Due to many social, economic and political factors, the development of brownfield land is increasing.
Contamination is often seen as a hurdle to the redevelopment of such sites.
Redevelopment works often require a rapid solution to problems associated with contaminated soils. ‘Dig and Dump’ is a favoured route.
Landfill space is limited and costs are increasing rapidly.
The ATG Group Solution:
Using ATG Group’s expertise in various technologies we can offer segregation, solidification, bioremediation, invasive plant species treatment etc. Waste materials from construction and other sites can be effectively dealt with and recycled where possible. This includes a range of organic contamination such as diesel, gasoline, mineral oils, PAH’s, BTEX compounds, phenols, heavy metals and other wastes such as plastic, concrete, ash and plaster board.
Treated materials can be used on redevelopment sites for a variety of purposes including roads, fill, stabilisation and landscaping.
- For the developer, materials can be quickly excavated from site to allow construction works to continue.
- Recycling and treatment provides a more cost effective solution to landfilling.
- Landfill space is being conserved. Processed soils are available for re-use on development sites.
- Materials are recovered and recycled appropriately in line with the new regulations on waste management and recycling
Site Remediation Technologies
With ever changing European, Irish and UK legislation, it is becoming increasingly costly to utilise traditional remediation methodologies (i.e. excavation and disposal). It is imperative to exploit cost effective and sustainable remediation technologies to ensure brownfield site development remains economically viable.
The ATG Group has developed and implemented a range of innovative technologies through research partnership and experience, thus being capable of matching the best available techniques to the contaminated site.
ATG Group Capabilities
Soil Remediation Technologies:
- Physical containment: using in-ground barriers to contain in-situ contamination.
- Vacuum extraction: Removal of vapours from the soil air spaces.
- In-situ bio-remediation: using methods such as Bio-stimulation, Bio-injection and Bio-augmentation.
- Ex-situ Bio-remediation: Excavation of contaminants with either treatment on site or at an off-site treatment facility.
- Thermal desorption: In partnership using soil heating to remove contaminants.
- Soil Stabilization: using additions of bentonite, lime etc by mixing or injection.
- Pump & Treat: Utilising separation, filtration and air-stripping in any combination.
- Air Stripping: The removal of dissolved contaminants in water.
- Air Sparging: In-situ air injection or extraction from the groundwater to enhance remediation.
- Aerobic and Anaerobic Biodegradation: Utilising in-situ reactive systems.
- Enhanced Natural Attenuation: The addition of nutrients or slow release oxidising or reducing chemicals to enhance contaminant breakdown.