Contaminated Land Remediation & Validation

G&J designs remedial strategies for a broad range of sites that have their unique land contamination issues and challenges, to ensure the most cost-effective and sustainable solution. We aim to maximise the re-use of soils on the site of origin (with or without treatment) and avoid off-site disposal and all the associated costs and environmental implications. The need for remediation is usually established through a Phase II Site Investigation and subsequent contaminated land risk assessment, and is most commonly required on Brownfield sites with a known history of industrial use. However, some Greenfield or low-risk sites can still require remedial measures as a result of undocumented activities such as illegal waste disposal.

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It is essential to deal adequately with contamination to protect public health, human health, and the environment. Failing to do so can hinder new development and violate environmental regulations.

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Remediation may simply require a development design to consider soil quality and ensure affected soils are used only in low-sensitivity areas (such as beneath hardstanding) or allow for the incorporation of a barrier layer in certain areas. Where more significant soil contamination is present, remedial solutions may be required that reduce the concentration or mobility of contaminants to prevent significant harm. Common remedial techniques include:

• In-situ and ex-situ bioremediation

• Physical or chemical stabilisation

• Pumping and treatment of groundwater

• Free product recovery

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Bioremediation is a common technique for soils contaminated with organic substances such as hydrocarbons, and utilises the microorganisms that are naturally present in soil to reduce concentrations through biodegradation for future use. In situ refers to treatment undertaken on soils (or water) that remains in the ground, while ex-situ refers to treatment of excavated soils. In some cases, bioremediation may simply involve the introduction of air through mechanical means (turning soils in stockpiles known as ‘windrows’ using an excavator) to stimulate natural biodegradation, or otherwise the process may be enhanced by the direct introduction of oxygen, organic matter or other nutrients. It is also crucial to address hazardous substances, such as chemicals and heavy metals, which are often present in contaminated sites.

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Stabilisation reduces the risks posed by contaminants in soil by either introducing a chemical agent that converts them to a less harmful form or reduces their leachability, or by mixing with an additive such as cement, which locks the contamination within a solidified mass and renders it immobile.

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Pump and treat involves the removal of groundwater from extraction wells (or sometimes from an excavation) and passing it through a treatment plant (which may include carbon filters, oil separators, air strippers etc) located at the surface, before being either discharged to a surface watercourse/sewer, or returned to ground. A similar mechanism can be used to recover Light Non-Aqueous Phase Liquids (LNAPLs), essentially free-phase hydrocarbons that float on the groundwater and present an ongoing source of contamination if not removed. Free-phase hydrocarbons removed in this way are taken off-site for recovery or disposal.

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In some cases, more specialised remedial solutions may be required, such as soil-vapour extraction, chemical oxidation, soil washing and thermal desorption, and we can work alongside dedicated remediation technology providers for the successful implementation to deliver the most appropriate solution.

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From the placement of a simple cover of clean soil to manage low levels of contamination, to the long-term remediation of a heavily contaminated industrial site, we have the expertise to design remediation works that are appropriate to the type and scale of the problem. We ensure all remedial works are completed to the required standard, provide independent verification and agree regulatory sign-off through close consultation with Local Authorities, the Environment Agency and warranty providers such as the NHBC.

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Contaminated land is a significant issue in the UK, posing risks to human health, the environment, and property. Land contamination can arise from various sources, including industrial activities, waste disposal, and accidental spills. The Environmental Protection Act 1990 provides a framework for dealing with contaminated land and outlines legal obligations, and land remediation relief is available to encourage the cleanup of contaminated sites. To claim land remediation relief, a thorough risk assessment must be conducted to identify potential risks to human health and the environment.

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Land contamination can have severe environmental risks, including significant pollution of soil, groundwater, and controlled waters. Contaminated soil can pose a risk to human health, and it is essential to conduct a thorough site investigation to identify the extent of contamination. Brownfield land in urban areas, in particular, requires careful consideration, as it may have been previously used for industrial or commercial activities that have resulted in contamination. Environmental consultants and remediation specialists must work closely to develop effective remediation strategies that address the specific contamination issues present on the site.

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Human health is a primary concern when dealing with contaminated land. Contaminants present in the soil, air, or water can pose a significant risk to human health, and it is essential to conduct a thorough risk assessment to identify potential health risks. The intended land use is also a critical factor, as it will determine the level of remediation required to make the land safe for its intended purpose. For example, if the land is to be used for residential development, a more stringent remediation approach may be necessary to ensure that the land is safe for human habitation.

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Contaminated soil remediation is a critical step in the land remediation process. Remediation activities can include the removal of contaminated soil, treatment of contaminated groundwater, or the use of innovative technologies to break down contaminants. The choice of remediation strategy will depend on the type and extent of contamination, as well as the intended land use. Environmental risks must be carefully considered, and a thorough initial assessment must be conducted to identify potential risks and develop effective remediation strategies.

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Land remediation strategies must be carefully developed to address the specific contamination issues present on a site. A thorough desk study and site investigation must be conducted to identify the extent of contamination and develop effective remediation targets. Remediation specialists must work closely with environmental consultants to ensure that remediation activities are conducted under regulatory requirements and that the land is restored to a safe and acceptable level. In Northern Ireland, for example, the remediation of contaminated land is regulated by the Department of Agriculture, Environment and Rural Affairs, and remediation strategies must be developed under their guidelines. By working together, it is possible to successfully implement remediation strategies that restore contaminated land to a safe and usable state, reducing the risks to human health and the environment.​