Southwest Environmental Limited

Remediation

If your site is contaminated then steps will have to be taken to clean it up.

This stage is called remediation. It involves making the soil on site fit for the intended use, there are a number of ways to achieve this.

Types of Remediation

Dig and Dump

Once the favored method of remediation this involves digging the soil up removing to land fill, and then replacing the soil from a clean source. Landfill tax has made this a very expensive option. Although for small sites in can prove cost effective.

Soil can be taken away for washing or other types of cleaning and exchanged for a conditioned soil substitute.

On Site Treatment

Soil can be treated on site in a number of ways:

- Chemical Treatment
- Physical Treatment
- Biological Treatment
- Solidification
- Thermal

This method is suitable for large sites.

Please feel free to ring / email for a no obligation discussion.

Sample Resolution & Remediation

When considering a site investigation prior to remediation it is important to realise that the the more sample points you take the better "resolution" you will achieve for assessing areas that need remediation, an extra £1000 spent on sampling may yield 5, 10, 15  times that in savings upon remediation.

How to Remediate a Site

Decisions we make about how a site is treated depend very much on the site itself. They also depend on factors such as the type of contamination, the geology of the site, legal requirements (for example there are some differences between making land safe through the planning process compared to Part 2A of the Environmental Protection Act 1990), cost/benefit implications and the proposed/current use for the site. 

Ground Gas

Protecting any proposed development from ground gas has to be considered early on in any design process. Ground gases from contaminated sites can be methagenous, or carbon dioxide. Some may be aggressive, in that they will cause installed barriers to degrade.

Specification for the barrier its self is just a small part of a successful mitigation strategy. SWEL can produce a ground gas protection strategy to inform architects and planners alike.

The installation of the ground gas barrier should be carefully installed and you will likely require specialist input.

Sealing of joins between membrane, and service entry point will ensure a good seal but the correct methods will need to be employed to satisfy any follow up inspection prior to laying of the screed.

Technical Guidance: Phase 3 Remediation and Method Statements

Phase 3 remediation represents the active stage of land contamination management, where the findings of a Phase 2 site investigation are translated into a formal strategy for cleanup. The primary objective is to render the site fit for its intended use by breaking the pollutant linkages identified during the conceptual site model development. At SWEL, we provide a robust remedial options appraisal to ensure that the chosen cleanup method is technically viable, cost-effective, and fully compliant with local authority planning requirements and the Environmental Protection Act 1990.

Remediation Methodologies and Technical Selection

The selection of a remediation methodology depends on the specific contaminants, site geology, and the sensitivity of the proposed end-use. While traditional dig and dump methods involve the physical removal of soil to landfill, this approach has become increasingly expensive due to rising landfill tax. Modern alternatives include off-site soil washing and various on-site treatment techniques such as chemical oxidation, biological degradation, and solidification. For larger developments, utilizing mobile plant under a standard rules environmental permit can offer significant savings by treating and reusing materials on-site, effectively reducing the project carbon footprint and waste disposal costs.

The Importance of Sampling Resolution

Strategic decision-making during the remediation process relies heavily on the quality of the initial site data. Improving the sampling resolution during the investigation phase often yields substantial financial returns. By pinpointing exact areas of contamination rather than applying a blanket remediation strategy, developers can avoid the unnecessary removal of clean soil. This technical precision is essential for discharging conditions attached to planning applications, as it demonstrates a targeted and scientifically justified approach to risk management.

Ground Gas Mitigation and Protection Strategies

Protecting a development from ground gases, such as methane or carbon dioxide, is a critical component of many remediation strategies. Ground gas can originate from historical landfill activities, natural geological features, or degraded organic matter. We produce detailed ground gas protection strategies that specify the required barrier membranes and ventilation measures. A successful strategy focuses on the integrity of the installation, including the sealing of joins and service entry points, to satisfy regulatory inspections and ensure the long-term safety of the building occupants.

Verification and Regulatory Compliance

A Phase 3 strategy is incomplete without a clear plan for verification. This involves independent testing and observation to prove that the remediation goals have been achieved. Whether you are dealing with a simple clean cover system or complex in-situ chemical treatment, the verification report acts as the final evidence required to close out land contamination issues with the regulator. Our reports are designed to withstand intense scrutiny, providing the technical authority needed to support a successful Environmental Impact Assessment (EIA) or property transaction.

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