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Contaminated soils can affect safety, programme, waste costs, compliance and the viability of redevelopment. On constrained or higher-value projects, poor remediation decisions can create delays, increase disposal costs and add risk to the wider construction programme.
As a soil remediation specialist, we combine early technical input, practical treatment strategies, materials management and disciplined delivery to help clients move from strategy through to completion and final verification.
Soilfix delivered remediation and enabling works at a decommissioned crude oil terminal, treating hydrocarbon-impacted soils and groundwater to stringent standards in support of permit surrender. The project demonstrated our ability to manage complex contamination, integrate unforeseen issues into the programme and deliver to high Quality, Health, Safety & Environmental standards.
Understanding the latest remedial technology is not enough for successful delivery of a remediation project. Health & safety, logistics, construction programs, waste management, changing legislation and the clients’ objectives are all essential components. Soilfix prides itself on having well-trained collaborative personnel with the necessary skills and experience to deliver a complete remediation service.
We have in-house capability and experience to implement a wide variety of soil treatment techniques including bioremediation, stabilisation/solidification, complex sorting (including landfill materials), encapsulation systems and dealing with asbestos in soils. Depending upon site specific requirements / constraints, soil remediation can be applied either ex-situ, in-situ or a combination of techniques.
Soilfix are renowned for our expertise in soil remediation. Contact us today and let’s work together.
An increasingly common legacy of former industrial sites is the presence of asbestos containing materials (ACM’s) deposited or dispersed within made ground, resulting in asbestos contaminated soils (ACS) present in the ground.
This problem is often exacerbated by poorly controlled demolition practices, resulting in ACM fragments becoming spread across the site surface and/or throughout crushed materials. The presence of ACM’s and ACS can result in significant potential liabilities, programme delays and escalating costs for landowners and developers.
Soilfix has significant experience in adopting pragmatic, robust yet cost-effective solutions for asbestos contaminated sites, fully in compliance with the Control of Asbestos Regulations (CAR) 2012 and relevant waste management legislation. Through careful planning of pre-treatment and materials management requirements, the volumes of hazardous and non-hazardous wastes removed off-site can be minimised.
Works are either carried out by Soilfix appropriately trained staff under a Notifiable Non-Licensable Works (NNLW) Notification, or, where higher risk ACM’s are encountered, carried out using a licensed Asbestos Contractor. The following sustainable and cost-effective remedial measures are routinely carried out by Soilfix:
All Soilfix staff working with asbestos are Non-licensed/Notifiable non-licensed work trained and have regular medicals and respirator face-fitting to ensure compliance with CAR2012.
Bioremediation is a highly sustainable and cost-effective treatment technique that can significantly reduce carbon emissions on a remediation project. Soilfix offers a range of bioremediation solutions for contaminated soils, either as a stand-alone treatment or part of a multi-disciplinary project.
Bioremediation is the process of using endogenous or specially cultured biological microorganisms, to breakdown hazardous materials and substances in soils and groundwater into less toxic, non-toxic and/or more stable compounds.
Many organic contaminants provide an energy source for naturally occurring micro-organisms (e.g. bacteria) present within the soil. These processes can be enhanced by manipulating the conditions within the soils that enable the relevant micro-organisms to both thrive and interact with the contaminants.
The presence of nutrients and available carbon within the soil will provide the basic building blocks for the organisms and can be artificially increased with the application of various bio-nutrient products or fertilisers. Optimising pH, temperature, moisture and oxygen conditions can boost populations and enable maximum interaction with the contaminant.
Achieve maximum rates of bioremediation at your site
Biorememediation can be accelerated within ex-situ soils using vented biopiles or managed windrows. Oxygen release, oxygen infusion, bio-venting, sparging or permeable reactive barriers (PRBs) can be used to accelerate biological breakdown processes in-situ.
Soilfix can design and build the systems that will enable you to achieve maximum rates of bioremediation at your site.
Where more complex contaminant situations or ‘biomass limited’ situations arise, Soilfix has experience in bio-augmentation using both specially cultured and indigenous biomass (or combination of the two) to enhance the treatment process. Bench-scale and field-scale treatability trials can be carried out in advance of the main project for optimisation of the bioremediation design.
Screening, sorting and segregation of deleterious (waste) materials and asbestos fragments from made ground, demolition and landfill using mobile plant is commonly termed ‘Complex Sorting’. Significant economic benefits can result by reducing hazardous / active waste disposal volumes and the premium costs these incur. Moreover, environmental and circular economy benefits are achieved by optimising re-use of materials (soils & aggregates), reducing material import and export during the regeneration of brownfield land.
Complex Sorting is often implemented as a ‘treatment-train’ approach involving the following stages to segregate deleterious materials from soils and hardcore that can be beneficial re-used on site:
Our solution
Soilfix utilises its extensive in-house experience of processing a wide variety of made ground and landfilled materials to determine the most effective treatment methodology on a site-specific basis. Treatment is carried out under our Environmental (Mobile Plant) Permit and most commonly re-used under a materials management plan (MMP) drafted in accordance with CL:AIRE Code of Practice (DoWCoP). In certain circumstances, such as re-use of certain landfilled materials or imported stockpiles, re-use of materials subjected to Complex Sorting treatment require a Deposit for Recovery permit.
The technology is tailored to meet both the remedial and construction objectives of a project, often forming a robust development platform layer. Geotechnical modification of the host material is often required, either to optimise the Complex Sorting process
Soilfix provides a wide variety of stabilisation / solidification (S/S) treatment techniques for both remediation of leachable contaminants and geotechnical improvement (e.g. for engineered development platforms). By continually advancing this technology both ex-situ and in-situ, more complex contaminants can be immobilised, including PFAS compounds, coal-tar residues, crude oils, soluble metals and persistent organic compounds (POP’s).
Stabilisation / Solidification of soils is increasingly a cost-effective technology for the rapid treatment and / or immobilisation of hazardous wastes and contaminated soils or sludge’s. The terms “solidification” and “stabilisation” describe two distinct mechanisms.
Our solution
Prior to commencing, samples of the contaminated material are taken and laboratory-scale trials conducted to calculate the most cost-effective reagent or combination of reagents to achieve site-specific objectives. Binding agents are then applied and the soils rotavated either in-situ (e.g. auger, injection, rotavator) or ex-situ (e.g. batching plant, blending equipment). Traditional binding agents including Ordinary Portland cement (OPC) and quicklime can be combined with admixtures for enhanced sorption, including fly-ash, blast-furnace slag, powdered activated carbon and biochar.
Soilfix has effectively combined S/S treatment with chemical oxidation on NAPL-saturated soils, reducing the more mobile contaminant loading, whilst immobilising residual contamination.
Performance testing of the treated materials is usually completed throughout the works. Depending on requirements this can include tests on hydraulic conductivity, unconfined compressive strength, CBR and leachate characteristics.
Stabilisation/solidification can be tailored to meet both the remediation and construction objectives of a project (e.g. using contaminated soils to form a piling mat, capping layer or engineered sub-capping fill). Achieving a target (post-treatment permeability) can form an integral part of a remediation strategy through construction of an in-ground barrier or capping systems to manage groundwater flows and infiltration respectively.
Talk to our team
Peter Howland
Managing Director
Soil remediation is the process of removing, neutralising or immobilising contaminants in soil to restore it to a suitable and usable condition. It is necessary to protect human health, prevent environmental damage, and comply with regulatory standards, surrendering environmental permits and/or discharging relevant planning conditions.
A wide range of contaminants can be treated using a variety of techniques, including petroleum hydrocarbons, heavy metals (e.g. chromium-6, lead, arsenic), chlorinated / non-chlorinated solvents, and other more persistent compounds such as pesticides, herbicides and per/polyfluoroalkyl substances (PFAS). Each contaminant requires a tailored approach to ensure effective remediation.
Our treatment methods include bioremediation (using a combination of microbes, nutrients and organic substrates to break down organic pollutants), stabilisation/solidification (often with enhanced sorption agents), soil flushing, soil washing, vapour extraction, thermal desorption, and excavation with off-site disposal to a suitable permitted treatment facility or landfill. The choice depends on contamination type, site conditions, programme/logistical constraints and regulatory requirements, and is often based upon a Remedial Options Appraisal supported by Sustainability Assessments.
Project duration varies based on contamination severity, site size, and chosen method. Small-scale projects may take weeks, while complex sites can require several months (or more). Soilfix provide detailed works programmes and sequencing plans after reviewing available site information and seeking to understand a client’s priorities.
Yes. We manage all aspects of regulatory compliance, including permits, environmental standards, management plans and reporting to various stakeholders including regulatory authorities. Our team, including multiple WAMITAB Certificate of Technical Competence (CoTC) holders, ensure your project meets all legal and safety requirements. Ground improvement approaches such as dynamic compaction (DC) or high-energy impact compaction (HEIC) is carried out on multi-disciplinary projects using specialist sub-contractors. Piled foundations or vibro-stone columns are typically carried out by our clients own sub-contractors once the development platform has been constructed and handed over by Soilfix.
In short, soil remediation almost always impacts a build programme to varying degrees. The extent depends on the contamination type, remediation method, and regulatory approvals required. We always strive to understand the customers key project drivers and the overall delivery programme is often a key aspect of this. Phased handover of remediation areas can be achieved through advanced, proactive discussion. Selection of treatment technique can also significantly influence the remediation programme, and a cost vs benefit analysis is required to determine the optimal approach.
When a remediation project results in less soil than needed (deficit), this can result in reduced disposal volumes, provide an opportunity for import of clean fill for capping, design flexibility (e.g. reshaping the topography) and sourcing of more sustainable import materials.
Conversely, when a remediation project generates more soil than is needed (surplus), off-site disposal costs on the projects foreseeably increase. However, with advanced project planning and carrying out an options appraisal with a cost – benefit analysis, surplus balance scenarios present an opportunity to provide a more sustainable remediation project in line with UK circular economy objectives. This includes consideration of on-site soil treatment and re-use on sites, generating site-won aggregates through soil processing and re-purposing soils to form an integral part of development platform layers or site restoration.