Holly Lane
Land & Soil Remediation
Excavating, processing and re-engineering 250,000m³ of former landfill waste
Contamination & Knotweed Treatment
Bioremediation of hydrocarbons and eradication of Japanese knotweed
Groundwater & Compliance Management
Settlement lagoons, water re-use and full regulatory sign-off
Project Overview
Dunton worked with Persimmon Homes to remediate a complex former landfill in a densely populated area of Birmingham and enable the land for housing. Acting as Principal Contractor, we re-designed the original 2010 scheme using modern techniques and our experience in regenerating landfills.
Tight control of the earthworks specification and on-site geotechnical testing meant most of the new homes could be built on traditional foundations, while the gas venting and leachate removal systems were designed out altogether.
Project Cost
5 Million
Size
5 Hectares
Recycled Materials
85%
250,000m³ of landfill material
Completion Time
2 Years
The Problem
The site was a former landfill surrounded by houses, a local park, a school and a watercourse — a challenging setting that demanded careful control of dust, water and disruption. The existing 2010 design needed value engineering to make the scheme affordable and buildable.
Challenges Faced
- Value engineering the project to make it affordable
- Re-engineering landfill waste to the required earthworks specification
- Unacceptable TOC levels for gas mitigation
- Unexpected pockets of contamination, including asbestos, plus leachate
- Opening a live culvert and re-engineering the existing brook
- Working in a densely populated residential area
- Removing large mature areas of Japanese knotweed
- Protecting the watercourse and rare flora, including protected orchids
- A high water table affecting excavation and re-engineering
The Solution
Dunton mobilised to site as Principal Contractor in spring 2021. We hoarded the site to protect local residents, eradicated the Japanese knotweed with our Eradzion8 product, and temporarily translocated the rare orchids to a British Orchid Society facility.
After stripping vegetation, we excavated to design level (approx. 4m below ground), segregated the material and re-engineered it to the required levels — testing throughout to prove compliance with the specification.
Innovative Techniques
- Dunton Hammer compaction — a specialised 13t Rapid Dynamic Compactor to induce future settlement before filling
- Material processing — screening, lime/cement stabilisation and crushing, all tracked via a Materials Management Plan (MMP)
- Groundwater control — settlement lagoons captured water at the 4m dig depth and re-used it on site for dust suppression
- Bio-accelerator treatment — our patented product to treat hydrocarbon-impacted material on site
- Compliant clean import — naturally occurring fill imported under CL:AIRE and DoWCoP to reach finished levels
The Result
A final verification report demonstrated compliance with the specification and was accepted by all the regulators, including the EA, Local Authority, EHO and NHBC.
Key Results
- Former landfill fully remediated and enabled for housing development
- Most homes able to be built on traditional foundations thanks to tight earthworks control
- 250,000m³ of landfill waste re-engineered and re-used on site
- Gas venting and leachate removal systems designed out of the scheme
- Japanese knotweed eradicated and protected orchids safely conserved
- Full regulatory sign-off achieved across all bodies
What Our Partners Say
“Dunton’s expertise in land remediation transformed what seemed like an insurmountable challenge into an opportunity for success. Their innovative methods saved us time and money while delivering exceptional results. We couldn’t be happier with the outcome.”
