Remediation Methods and Strategies

The remediation strategy is a key part of acquiring planning consent on a brownfield site and gaining regulatory acceptance; it will need to be robust and give the planning authorities confidence. This document clearly defines the aim of the remediation, how best it will be achieved and explains why specific methods have been chosen.

The remediation strategy should be done in collaboration with everyone in the development team – developer, regulator, consultant and contractor. In our experience, this collaborative approach leads to the best development outcome.

We are very happy to support development teams with budgetary and technical advice at planning stage.

Methods include selective excavation with sorting and hand picking or soil washing; asbestos containing soils (ACS) require excavation and sorting, whereas metal contaminants can be treated by soil washing. Relatively simple and effective, these methods have been used for many years with great success.

However, these methods do require a considerable amount of plant to be available and can be labour intensive; soil washing requires ample water and sludge storage which can be a problem.

Using strong reactive chemicals ‘in-situ’ to convert contaminants into non-hazardous or less hazardous compounds. This can be a fast and effective method, but care must be taken in its use due to the potential to cause existing pollutants to become more mobile; and also the risks associated with the oxidants themselves.

This is a soil remediation process by which contaminants are rendered immobile through adding a binding agent such as cement, lime fly ash and organic binders. During this process contaminants are chemically bound or encapsulated into a matrix. This physically breaks contaminant pathways and prevents exposure of receptors.

This is a quick and effective method of remediating contaminated soils. An additional benefit is that it can also improve the structural quality of the soil to enable its reuse on site, thus reducing the amount of clean/structurally suitable materials imported and the associated costs.

While cost effective and proven in the field, stabilised material must be tested post-treatment to confirm its performance as a suitably stable material for re-use.

It is important to recognise that any contamination originally present in the soil remains in place; although this is chemically/physically bound-up, the remaining presence of contamination can lead to long-term warranty/liability issues.

Asbestos containing materials (ACM’s) are commonly found on industrial legacy sites. Fragments fall to the ground and become mixed within the soil leading to asbestos containing soils (ACS) – this becomes a complex contamination issue that must be managed extremely carefully.

Poor management of ACS/ACM contamination can result in complex regulatory problems, reputational damage, programme delays and escalating costs.

Works must be completed in compliance with the Control of Asbestos Regulations (2012) using “appropriately trained staff” under a Notifiable Non-Licensable Works (NNLW) Notification. In some cases, works must be carried out using a Licensed Asbestos Contractor.

Our significant experience of working on industrial legacy sites has allowed us to develop a legally compliant, safe but pragmatic system to manage ACM’s and asbestos containing soils.

Through selective excavation and careful sorting with subsequent stabilisation/encapsulation, we can minimise the volume of ACM taken off site. This minimises regulatory risk and reduces disposal costs; it is also preferable environmentally.

Extreme care is taken to negate any risk of asbestos fibre release using fully compliant abatement techniques. These controls are backed up through reassurance testing by trained staff using HSE-approved techniques and independent UKAS accredited testing laboratories.

We have full in-house capability to manage asbestos contamination – remediation, removal, reassurance testing, air monitoring, laboratory testing.