Viridor has invested £4.5m in a new leachate extraction system at its Dimmer Landfill site in Somerset in a ground-breaking project which combines multiple cutting-edge treatment technologies within a single leachate management system.
The initiative will not only meet Environment Agency discharge compliance requirements to the River Cary, but the move to an on-site treatment method will help to avoid approximately 2,000 articulated tanker movements to Dimmer Landfill site every year.
Project team members Mike Denman (Dimmer Leachate Treatment Plant Project Manager), Robin Shirley (Leachate Control and Treatment Manager) and Rob Hawkins (Landfill Operation Manager – South) said work on the plant began in April 2018 and the facility became operational in August 2019.
They said: “The new Dimmer Leachate Treatment Plant is the most advanced leachate treatment facility in the UK. Cutting edge technologies include a biological, chemical and physical treatment process incorporating nanofiltration and activated carbon filtration.”
Nanofiltration is an extremely sophisticated treatment process which sees liquid pass through pores the width close to that of a single strand of DNA. Material removed by the plant is fed through activated carbon filters, with the spent carbon returned to the manufacturer where it is reprocessed or reuse.
Cutting edge technologies include a biological, chemical and physical treatment process incorporating nanofiltration and activated carbon filtration
The Viridor project team said £1m of the £4.5m investment had funded an improved leachate extraction system which allows the efficient removal of leachate from the landfill site for subsequent treatment.
The investment on site has also catered for the design and build of a three-hectare willow bed. This bed can be irrigated with the clean, treated leachate over the summer months, recovering value from the original waste-stream.
An intelligent monitoring system links the treatment plant with the site’s willow beds and the River Cary, monitoring the moisture content of the soil and indicating whether the willow beds require irrigation and whether water levels in the River Cary are high enough to allow discharge.
Somerset Waste Partnership MD Mickey Green said: “By both cutting vehicle movements and improving environmental management, Viridor – as Somerset Waste Partnership’s residual waste treatment contractor – is investing in a sustainable future and ensuring innovative and responsible long-term care of a landfill site that has served Somerset’s needs for decades.”
Dimmer Landfill Site is due to close to active waste deliveries early in the new year in line with the commissioning of Avonmouth Resource Recovery Centre (where non-recyclable waste will be used to create low carbon electricity).
Restoration of the landfill site will be followed by a 60-year aftercare period during which the site will continue to produce leachate at an anticipated rate of close to 25 million litres per year and will be responsibly managed by Viridor.
The new treatment plant will operate 24/7 with a dedicated technician. Viridor has worked with engineering consultants Pell Frischmann to develop the new plant.