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Vale Acton Refinery Closure
Shortlisted for Brownfield Awards Category 7: Best Project Closure/Verification
Overview
Our submission demonstrates the highly successful project closure and verification process associated with decommissioning, demolition and remediation activities at a former Platinum Metals Refinery based in Acton, London.
Arcadis was appointed by the Client (Vale Europe Limited (VEL)) to act as the project controller, in addition to providing technical services to support the verification of the site decommissioning, but also the design, implementation and verification of the subsequent demolition and remediation phases. The site had been operational since the 1920’s, and specialised in the recovery of rare earth metals or Platinum Group Metals (PGM – Pt, Pd, Rh, Rd, Ir, Os).
The refinery closed in 2018 and was sold later that same year to a commercial developer, incorporated into the wider Old Oak and Park Royal Development Corporation (OPDC) redevelopment project – the UK’s largest regeneration scheme. The sale included a commitment from VEL to the buyer to decontaminate, decommission and clear the site of all buildings and former plant, surrender the site’s Environmental Permit and complete the necessary remediation readying the site suitable for commercial redevelopment.
The project was challenged on programme from the outset, with only limited existing information associated with the condition of the site, the significant decontamination and decommissioning works needed to be undertaken prior to demolition, the unknown extent of remediation activities, and the need to surrender the site’s Environmental Permit. This submission provides detail on the verification process implemented to ensuring that closure activities were completed robustly, efficiently and ultimately on time – along with an astounding recovery of metals worth in excess of £30M.
The Project
Location: Former Vale Acton Refinery, Acton, London, NW10 6SN.
Description: The decommissioning, decontamination, demolition and remediation of a 95+ year old refinery, to render the site suitable for commercial redevelopment.
Programme: The refinery closed in June 2018 and immediately progressed into a period of decommissioning, undertaken by the VEL. The completion of the final decontamination, demolition and remediation activities was later completed by the appointed demolition contractor (AR Demolition). The project works were required to be completed, verified and signed off by the new owner at the start of 2021, and no later than June 2021, in accordance with the contractual sales agreement in place. The key project milestones achieved are highlighted on Image 1.
Image 1 – Project timeline and key milestones
Stakeholders: Key Project stakeholders involved included:
- Client: Vale Europe Limited
- Project Controls: Arcadis (UK) Limited
- Environmental, Technical and Design Services: Arcadis (UK) Limited
- Decommissioning Contractor: Vale Europe Limited
- Demolition and Remediation Contractor: AR Demolition Limited
- Regulator: Environment Agency
Challenge
The key challenge to the delivery of the project was the timeframe available in which to complete the closure activities. The decommissioning of the site was a complex process given the unique hazards involved, the opportunity for recovery of valuable but hazardous PGMs, and the long site history. The decommissioning phase of the project, involving the decontamination and removal of much of the former process equipment, lasted nearly two years hence leaving just over 6 months to complete the demolition and remediation activities - the start of which ended up coinciding with the global pandemic.
The site also held an Environmental Permit for the former refining operations which was required to be surrendered prior to handover of the site. The surrender process was highlighted a significant programme risk following engagement with the Environment Agency in 2019. It was identified the surrender process could potentially take up to 12 months to process, and could only be commenced following completion of all decommissioning activities (and remediation if required). This presented a real risk to achieving the contractual end date with the new buyer.
Understanding the Hazards Associated with PGMs
The site’s long history of refining PGM’s presented a unique potential for contamination at the site. The presence of PGM’s was not just limited to the potential for soil and groundwater contamination, but also the presence of former process residues, the potential for PGM to be absorbed within former below ground structures including drainage, pits, sumps as well as building fabric including flooring materials. With a history spanning over 90 years, the potential for spills of PGM rich liquors in process areas, and the potential for absorption into porous materials as well as general dust and dirt was considered significant.
Whilst most people consider PGMs (e.g. platinum) as generally harmless and inert, this same inertness means the extraction and refining of PGMs require aggressive chemical processes. This leads to a variety of intermediate PGM compounds being formed, with very different properties to the metal in its elemental form. The most common of which are chloroplatinates – intermediates in the refining of platinum – and very potent sensitisers that can cause respiratory allergy in some workers if exposed to them even at very low concentrations and below the EH40 workplace exposure limits.
Given these risks, the Client, Arcadis and appointed contractors developed bespoke decontamination and verification methods for equipment, as well as robust characterisation strategies for building fabric and soils. In addition, site specific assessment criteria for PGMs were developed for the site, considering the risk to potential future users and to guide any remediation works at the site.
Decommissioning, Site Characterisation and Regulatory Engagement
Decommissioning of the site was led by VEL, utilising the former refinery expertise to dismantle equipment taking into account the exposure risks from PGMs. Once the equipment had been dismantled and quarantined it could be tested to verify whether or not former process residues remained, and if so whether PGMs at recoverable levels were present.
Arcadis led the wider characterisation and verification of the building fabric throughout former process areas, as well as below ground soil characterisation studies. Given the short timescale available for remediation and time pressures associated with the submission of the Permit surrender application, the investigations were completed with the aim of providing detailed information to facilitate both the Site Condition Report (SCR) but also the remediation strategy, covering any remediation effort needed beyond the requirements of the permit surrender (i.e. historical remediation impacts).
The assessment works were undertaken in parallel to the ongoing decommissioning works. Any data gaps were highlighted as works (pre-demolition) progressed, with further characterisation including within a ‘discovery phase’ as part of the overall remediation strategy. Importantly, and in light of the risk associated with the permit surrender timeframes, VEL and Arcadis engaged early with the Environment Agency regarding the proposed PGM characterisation verification strategies, and also shared results in advance of submission of the Permit Surrender Application.
Image 2 - Site Characterisation Locations
Demolition and Remediation
Whilst no remediation requirements were immediately identified as part of the site characterisation studies, or based on a deterioration in site conditions associated with the Environmental Permit baseline, data gaps remained associated with historical practices which could only be assessed on removal of former and buried site infrastructure.
To manage this, Arcadis incorporated a robust discovery and verification process into the site remediation strategy, including defined screening and sampling intervals within and beneath substructures, along with former drainage runs and in other areas inaccessible during the site investigations. This approach, building on the existing site investigations, supported a detailed verification plan ensuring that where concentrations of contaminants of concern above the defined site specific assessment criteria were established, they could then be excavated and removed for either recovery or disposal.
Image 3 - Remediation – Soil and Sub-Structure Remediation Verification Zones
Verification Screening Methods
Throughout all project phases, a constant pressure remaining in determining a method in which data could be collected to rapidly support and validate decision making. In support of the site characterisation and remediation verification processes, Arcadis introduced a hand-held X-Ray Fluorescence (XRF) device. The device was calibrated to detect low contractions of PGM and used to semi-qualitatively assess the presence of PGM in soils, building materials and process waste residues. This proved highly successful both in reducing sample numbers needing to be sent to the laboratory, with 1000’s of samples screened, but also as a screening tool to immediately identify where material was potentially contaminated with PGMs to aid real time risk based decision making. Where material was identified to contain significant detections of PGMs, it was immediately removed and quarantined for confirmatory laboratory testing. Materials containing PGMs were then removed to an off-site waste recovery facility specialising in the recovery of precious metals.
The use of the XRF supported a robust and high density grid based approach to the decommissioning, demolition and remediation waste verification activities, much more than would have been possible with traditional sampling and testing. It also significant reduced timeframes to get results (with results in as little as 30 seconds), most importantly mitigating delays seen during the pandemic with laboratories operating with reduced staff numbers.
Across all phases of the project the XRF supported with the identification and recovery of PGM from a variety of materials, including: former process waste residues; general dust and dirt that had built up over times in the facility; building fabric materials (e.g., tiles and grout); and, former refinery equipment such as process vessels, ducting and pipework.
Through the same screening and verification process, PGM levels in soils and groundwater beneath the site were not identified to either present a risk associated with the future use of the site, or be present a significant enough concentrations to be viable for recovery, hence they were left in-situ.
All materials were initially screened with the XRF, prior to then washing (where feasible) to recover the PGM washings. This reduced waste volumes, concentrated the PGM and decontaminated the materials. The materials were subsequently re-screened with the XRF to validate cleanliness and where possible recycled. Material containing high levels of PGM that could not be washed were segregated and transported to the recovery facility.
Image 4 – Example use of the XRF
Data Management
Given the volume of data collected, there was both a need to access and communicate data efficiently but also ensure a robust QA process was consistently applied. Arcadis used our 100% digital data collection program (FieldNowTM platform), Arcadis’ method of standardising, automating and integrating data at the point of collection.
Utilising the software solutions from our externally supplied platforms for data collection, FieldNowTM eliminates the need for manual data entry and provides rapid, real-time accessibility to field and other data which can then be analysed or transformed into visuals. By utilising the FieldNowTM platform through each stage of the verification process the final project verification report was able to be produced to a high quality immediately on completion of the works. The project included the following processes, amongst others:
• Data collection was completed via a tablet-based application developed by Arcadis for recording sample locations, field observations and screening results. The app constantly synced with the project databases to allow real-time data assessment and scheduling.
• Digital reports, including field screening (XRF data) were generated and accessible by project stakeholders. This negated the need for manual data transcription, consequently eliminating transfer errors and significantly reduced reporting time frames.
• Confirmatory laboratory data was provided by the lab in a compatible format for upload into Arcadis’ internal database (EsDAT). Data was uploaded directly from the laboratory reports, eliminating the need for manual data entry.
• Automatic comparison to the remediation assessment criteria was completed determining whether residual risks remained and if further remediation was required.
• Data visualisation using a GIS platform was undertaken to aid planning of sample locations using historical and current site plan layers highlight known potential areas of concern.
• The software was then used to visually represent the data collected, comparing XRF and laboratory data, to aid the assessment of the site condition.
This included the presence of PGM both within the building fabric but also soils. These visualisations were largely used to facilitate meetings between different project stakeholders to communicate findings in more user friendly manner.
Image 5 – Floor Tile and Concrete PGM Results (XRF and Lab Data)
Verification Outcome
The overall success of what was a time challenged project hinged on the design and implementation of a robust verification strategy throughout the decommissioning, demolition and remediation phases. In addition, the strategy needed to provide confidence to VEL, the future owner and the Environment Agency that the site had been de-risked and was ready for redevelopment, in a relatively short period of time. By incorporating innovative PGM screening methods and efficient and robust digital data management and assessment methods, Arcadis was able to reduce project timeframes, costs and risk whilst enhancing the opportunity for the recovery of PGMs within the time constraints imposed on the project.
Two of the key successes on the project, highlighting the effectiveness of the verification process employed include:
• This process ultimately supported the surrender of the site’s Environmental Permit before the end of 2020. This was 6 months ahead of the initial predicted response date suggested by the Environment Agency. Hence transfer of the asset to the new owner was timely, and in a condition ready for immediate redevelopment.
• Through robust screening and testing, in excess of 400 kilograms of PGM, with a value in excess of £30,000,000 was recovered. A truly sustainable outcome for the recovery and re-use of these rare earth elements.
