At Cognition Land and Water, we pride ourselves on being an environmentally friendly and conscious company with a deep focus on the sustainability of our work.Read more
Apart from being a requirement for regulatory compliance and environmental protection, the treatment of groundwater is very often an integral part of the remediation and regeneration of brownfield land. Cognition Land and Water has many years of experience and innovation in this area and we have developed our in-house capability, resources and expertise to include a wide range of techniques and technologies for the treatment and discharge or disposal of groundwater, surface water and tank contents. These include:
A Permeable Reactive Barrier (PRB) is a treatment zone of reactive material that is built below ground to clean up polluted groundwater. The reactive zone may be installed as a below-ground wall to intercept a migrating plume of contaminated groundwater. Alternatively, the contamination can be funnelled by low permeability barriers (e.g., slurry walls) to a gate or vessel containing the reactive media - the funnel and gate method. The reactive media is selected to absorb or adsorb the pollutants from the groundwater or to convert harmful chemicals to harmless by-products.
Cleaning groundwater with a PRB may take many years as the time taken depends on the amount of pollution present in the groundwater and how fast the groundwater moves through the PRB. Despite this, there are several advantages of using a PRB to remediate contaminated groundwater:
Cognition Land and Water has successfully installed PRBs at more than 100 sites.
PFAS (Perfluorinated alkylated substances) are a group of man-made substances used in many industrial and consumer products such as carpeting, clothing, fire-fighting foams, cooking pans, coatings, etc. because of their resistant to water, oil and heat. These chemicals are highly persistent, very mobile in soil and groundwater, and resist degradation in the environment. They bioaccumulate and PFOA - one of the primary compounds within the PFAS group - is believed to be in the blood of virtually every living creature on the planet… including 99% of humans. These ‘forever chemicals’ have been linked to adverse health effects such as low birth weight, delayed puberty onset, elevated cholesterol levels and reduced immunologic responses to vaccination. At Cognition Land and Water, we have been closely monitoring the progress of knowledge around these new and emerging chemicals and have been actively involved in the design and implementation of remediation strategies for a number of key sites including former airfields and fire fighting facilities. We are also partnering with the Australian developer of a novel and innovative water treatment process that removes all detectable traces of PFAS from treated water at high throughput rates, at low cost and without the need for costly and limited capacity reagents, catalysts or filters. In our aim to be at the forefront of our industry, Cognition is actively funding the production of CIRIA best practice guidance on the assessment and remediation of PFAS impacts as well as being a member of the Project Steering Group.
Asbestos in soils has been a contentious and problematic issue on development sites throughout the UK for many years. Without correct management of the demolition of previous buildings or the placement of fill or made ground that contains asbestos fragments, cleaning up the problem can be costly, time consuming and fraught with risk. But this doesn’t have to be the case…
At Cognition Land and Water, we have a longstanding track record of managing and remediating issues associated with asbestos in soils. Careful materials management, selective screening, hand picking, processing and treatment of soils can remove the bulk of the asbestos. Once this much smaller volume of highly concentrated asbestos has been removed from site and disposed at a suitably licensed facility, the residual soils can be reused within the works. If placed in a distinct and recorded location, beneath a clean cover system, there is no risk to future site users or the local environment and the development can progress without undue cost, programme of regulatory compliance issues.
From bench and field trials in the challenging conditions and climate of Kuwait to scores of successful bioremediation projects in the UK, Cognition Land and Water has an enviable track record in the successful and cost-effective remediation of hydrocarbon impacted sites using bioremediation technologies. We have funded and undertaken academic research and trials to ensure that the additives we use and the temperature and moisture condition we maintain in our works result in the most aggressive conditions for the breakdown of hydrocarbons in the least time possible.
On our projects, we regularly treat excavated and processed hydrocarbon-impacted soils ex-situ using bio additives. The soils are treated using a number of additives including HCR, Bio SRO2, PGA, Bio nutrient, cultured indigenous bacteria and Skyhawk Hydroeater. Cultivated indigenous bacteria and ligninolytic fungi may also be used to supplement treatment processes and Oxygen Release Compound (ORC) Granules may be used for extended aerobic bioremediation of the hydrocarbons.
Where it is uneconomical or not possible to remove material for bioremediation, we have also carried out in-situ bioremediation. These methods are implemented through boreholes, forming trenches or in-situ bio piles and can prove very effective in the right circumstances.
The main invasive species found on marginal land include Japanese Knotweed, Giant Hogweed, Himalayan Balsam and Rhododendron Ponticum. They are all highly regulated and allowing them to spread off your land can be a criminal offence. Although there is no obligation to remove from land you own, these species spread quickly, out-compete native plants, and can cause serious damage to structures, pavements and drainage infrastructure.
Working with specialist ecologists in the identification and survey of invasive species, Cognition Land and Water generally uses one or a number of the following methods to eradicate invasive species on our projects:
Soil Stabilisation involves the introduction of specially formulated cementitious or liquid solutions directly into or onto the ground through the use of purpose built injection augers or dosing at the surface followed by rotavation and compaction. The system is designed to achieve reduced permeability and/or increased strength within the soil mass to improve the physical properties of soils. However, it also has the added benefit of ‘locking in’ leachable contaminants, thereby providing a very effective remediation solution.
This technique is a cost effective alternative to importing aggregates for both temporary and permanent works. Cognition Land and Water was one of the first ground engineering contractors to introduce to the UK the notion of cement stabilisation of site arisings to create pile mats in the early 2000s. We now use this approach on over 90% of our sites resulting in a far more sustainable, cost-effective and quicker working platform than the disposal of site arisings and the import of aggregates.
In-ground soil stabilisation can be used to form highly efficient cut off walls within or around contaminated sites without needing to dispose of large volumes of contaminated spoil. Cognition has used this technique on many sites to great effect.
Scrupulous record-keeping and collating site verification/ validation/ completion report data from the start of the project (rather than upon completion as is oftentimes done by others) is a distinct approach taken by Cognition Land and Water. We have learnt through experience that the alternative approach (collating the required information at the completion of the project) is stressful, fraught with difficulties, and less likely to achieve a high quality Verification Report required for discharge of planning conditions, surrender of an environmental permit, confirmation of the completion of the works, and settlement of final payments.
This is why we have put in place comprehensive systems and procedures to ensure we maintain accurate and up-to-date records of site works from project commencement and collate those records in one location in our project folders from the outset to make the compiling of the final verification/ validation/ completion report a straightforward and painless process.
Cognition Land and Water is not a site investigation contractor and we do not regularly carry out site investigations as a single service on a project. However, through the vast experience and track record of our professional team, including several who have worked within ground investigation contractors and consultants for many years, we are adept at planning, specifying and managing site investigations for projects where we have been commissioned to carry out our ground engineering and/or remediation contracting services. This may include additional desk study research, supplementary ground investigation following gap analysis, ground investigation to finalise detailed design, additional investigation to refine our approach or solution to a project, installation of additional gas/ groundwater monitoring wells, or investigations into unforeseen ground conditions during a project.
Our in-house staff and plant resources makes the execution of ground investigations cost effective and rapid for our clients. Strong relationships with our network of specialist ground investigation contractors means that we can bring in these specialist services on larger investigations using a wide variety of techniques and technologies.
Cognition Land and Water offers an innovative solution for the remediation of free phase oil contamination of groundwater. Having already achieved great success in dealing with contaminated sites across much the USA, Cognition is unique in offering the system to the UK market.
Traditional remedial techniques, such as pump and treat, are often costly and inefficient in recovering free product. Based on extensive experience addressing petroleum and chemical spills, we can deploy the FabEx system to recover both light and dense non aqueous phase contaminants (LNAPL and DNAPL), also known as free-phase product.
The simple but highly effective NAPL Fabric Extraction Technique - FabEx - utilises an oleophilic/ hydrophobic fabric capable of adsorbing the product with a 99% recovery efficiency. The fabric is conveyed in a continuous loop into the well to intercept the oil-water interface. As the fabric travels through the interface, product is adsorbed. The adsorbed product is then removed in a specially designed desorption unit and the recovered oil collected in a storage drum or tank for disposal or recycling.
There are many advantages of the system over conventional groundwater treatment or product removal systems but the key benefits include:
For us at Cognition Land and Water, the key driver in establishing a pragmatic and cost-effective remediation strategy for a brownfield site is most often the minimisation of off-site disposal and onsite reuse of site won soils. On our Royal Wharf development in East London, we achieved 99.5% soil reuse on the project with massive sustainability, environmental, cost and programme benefits. High quality material management and effective processing, treatment and remediation of impacted soils is fundamental in achieving this enviable outcome.
A perfect example of this approach is when the developer of a proposed residential development at Worcester Park came to us with a problem! They had significant stockpiles of asbestos contaminated soil on site that was destined for landfill, archaeological remains that needed protection, a large excavation that needed filling and a requirement for import of 3,500m3 of pile mat material.
Cognition completely rationalised the groundworks design to arrive at a far cheaper, quicker and more practical solution:
1) Hand picking visible asbestos fragments from the stockpiled materials;
2) Processing, screening and mechanical segregation of stockpiled and excavated soils;
3) Placement of an archaeological protection system using sustainably sourced sand imported under the CL:AIRE DoWCoP;
4) Engineered filling of the existing voids using site won soils; and
5) Cement stabilisation of site soils and placement as pile mat.
Our approach on this and many other sites lead to significant cost and programme savings for our clients.
The former sewage treatment works was demolished and, together with a former landfill on the site, remediated to make way for 325 residential dwellings, a community hall and new roads and infrastructure. Since closure in 2005, the...Read More
The former Veolia Water Central Ltd offices and water treatment works at Three Valleys Way was to be redeveloped for housing. The site covers an area of approximately 4.2 hectares and required excavation, remediation and soil improvement...Read More
The former Ascham Street works were originally identified by The London Borough of Camden under its duty under Part 2A of the Environmental Protection Act 1990 for investigation as potentially contaminated land...Read More
The former industrial site was remediated so that it could be further developed for mixed commercial and residential development. Cannon Wharf had a long history of industrial development since 1834, leaving the site contaminated with heavy tar...Read More
The 1.2 hectare site in Rhodaus Town, Canterbury, comprised a former car dealership with showroom and workshops and a decommissioned Total petrol filling station (PFS). The site was known to have supported various garages, alongside a previous...Read More
The 1.5 hectare site was previously occupied by railway sidings and was redeveloped with the construction of eight student accommodation blocks each between six and eight storeys. The buildings were to be constructed using piled foundation but...Read More
Cognition carried out extensive remediation works at a former brickworks to treat and process soil contaminated with asbestos. The 24.2 hectare site, located on the outskirts of the town of Cranleigh, Surrey, comprised woodland to the south and...Read More
Cognition remediated an agricultural machinery yard in Crowmarsh, Oxfordshire which is to be redeveloped for residential housing. Large areas of the yard was built over foundry sand and clinker deposited on the site to raise the land and...Read More
Barratt Homes redeveloped the site with the construction of eight apartment blocks. Originally four of the blocks were to be located over a large basement to be used for car parking constructed within a secant pile wall. The north west area of...Read More
The former gasworks was remediated and excavated in order to make way for a new residential development. The site was formerly occupied by a gas works between 1871 and 1970, which resulted in the contamination of the site soils and groundwater....Read More
Dealing with a very large mixed residential and commercial use building development in the UK, Cognition had to ensure their remediation strategy was both cost-effective and sustainable. Cognition’s site Investigations identified...Read More
Cognition was contracted by a housing developer to propose a remediation strategy for the contaminated groundwater at a former cement works and petroleum supply depot in Great Blakenham, Suffolk. The site was operational between the...Read More
Croudace Homes contracted Cognition to carry out remediation works on three sites in close proximity to each other in Great Shelford, the sites originally occupied by a petrol station, car parking and a transport/haulage company. The sites were...Read More
The Liquid Effluent Treatment Plant (LETP) served 14 nuclear reactors from the main Harwell site. All reactors are no longer in service with all but three successfully decommissioned. The site is contaminated with a mix of low and very low...Read More
A former landfill dating from the 1930s-1960s covered the northern third of the site, occupying former clay pits mined in the early 20th century. The made ground within the landfill contained extraneous waste items such as ceramic, glass,...Read More
Hinkley Point ‘A’ Site is currently being decommissioned by Magnox. Diesel contamination was discovered in soil and groundwater during site investigations in an area known as an Area of Potential Concern, APC-9. The pollution was...Read More
Cognition was contracted by Wates to remediate a former industrial site in Whitmore Way Horley for a residential development. The site was occupied by the sewage treatment works and garages. Landfilling of pulverised waste had also taken place...Read More
An historic leaking active effluent drain on the site resulted in a sub-surface plume of radiological contamination. Also running through the area was a network of land drains that essentially acted as a pathway for mobilising Caesium137...Read More
The former gasworks was remediated to prepare the site for residential redevelopment. Three large gas holders, together with associated infrastructure and small buildings, were present on site at the outset of the works. A number of...Read More
A former landfill dating from the 1930s-1960s covered the northern third of the site. Landfill contained extraneous waste items such as ceramic, glass, brick, wood, metal and fabric. The soil was also contaminated with hydrocarbons which were...Read More
The 8 hectare former gasworks site at Willoughby Lane had been operational for over 100 years resulting in several distinct sources of contamination, notably; arsenic, cyanide, hydrocarbons, VOC’s and PAH’s in the soils and Dense...Read More
The site was formally occupied by the National Institute of Medical Research and previously by laboratories and research buildings dating back to the 1920s. A number of chemical stores, plant rooms and waste pits have been identified from plans...Read More
Newbury Gasworks site, within the Sterling Industrial Estate, has had a long history of industrial use leaving a heavily contaminated site within a built up area of Newbury surrounded by residential and commercial properties. Stringent...Read More
Newbury Gasworks site, within the Sterling Industrial Estate, had a long history of industrial use leaving a heavily contaminated site within a built up area of Newbury surrounded by residential and commercial properties. Cognition Land and...Read More
The former gas works was remediated in order to make it suitable for future redevelopment. The site in Nine Elms, London borough of Wandsworth, is approximately 60m south of the Thames and covers about 5.4ha. It is bounded to the north by Nine...Read More
The 5.3-hectare New South Quarter site in Croydon housed a former gasworks and required remediation prior to redevelopment for housing. Soils were contaminated with light aromatic organics, specifically BTEX compounds (Benzene, Toluene,...Read More
The construction of the rotation chamber for the Silvertown Tunnel and the consequential diversion of Millennium Way will result in the loss of car parking space for the O2 Arena. This will be replaced by the construction of a...Read More
The purpose of the works carried out by Cognition was to facilitate regeneration of the area and the residential led development. We completed additional ground investigation and finalised the remediation strategy and detailed...Read More
Dealing with one of the largest mixed residential and commercial use building developments in the UK, Cognition had to ensure that their remediation strategy was both cost-effective and sustainable. Extensive Site Investigations identified...Read More
The site was located on the periphery of an industrial estate and encompassed former sludge lagoons used by Guildford sewage treatment works. Gravel abstraction had been carried out on the site since the 1960s and was subsequently used as a...Read More
The Sony warehouse was destroyed by fire and the client wished to rebuild the warehouse on the same footprint. The site is located on a secondary aquifer (Kempton Park Gravel) overlaying London Clay. Groundwater was encountered between 1.78m...Read More
Cognition Land and Water was contracted by FM Conway Limited to undertake remediation and earthworks for the redevelopment of the former Southall Gasworks. The site was surrounded by watercourses with a central tip area containing...Read More
This site has been utilised for industrial activities for over 150 years, which have included brickworks, oil works, coal and oil gas manufacture, chemical works, benzole and tar manufacturing, docks and natural gas storage resulting in several...Read More
The 85 hectare site was previously occupied by a refractory brick works, quarry, colliery, various small industries and a 25,000m3 waste tip. This was remediated so that the site would be suitable for future redevelopment. The principle...Read More
The 1.7 hectare former PD Fuels Depot at Tipner formed part of the 44 hectare Tipner Regeneration Project that would transform the geographical area and provide a new gateway to Portsmouth. The site was located in a sensitive busy residential...Read More
The site was occupied by a former gasworks from as early as 1868. The gasworks developed with additional infrastructure including tanks, cranes, retort house and chemical works added over the years to the 1950s until its eventual closure in the...Read More
Cognition was contracted by Fenland District Council to remediate the Wisbech site in order to reduce environmental and human health risk as to enable redevelopment to facilitate the regeneration of this area. The remediation was partly funded...Read More
Cognition was appointed to carry out the remediation works at the former Kodak Factory in Harrow. The site is to be redeveloped by Barratt Homes with the construction of a number of residential blocks and associated landscaping and roads. ...Read More