Integrated plant follows recipe for success
The solution deployed to regenerate Beverley Beck, involving integrated plant is reported as a 'first' in inland waterway application and is designed to meet the objectives of the Landfill DirectiveLand and Water Remediation Ltd is undertaking the dredging, treatment and disposal of approximately 20,000m3 of contaminated sediments from Beverley Beck, Beverley, as part of the overall Regeneration project as a an approximately £1 million sub-contract to Mowlem Civil Engineering for the client, East Riding of Yorkshire County Council.
The contamination in the sediments within Beverley Beck is a legacy of industrial activity in the area including tannery discharges and highway runoff. This industrial activity has led to elevated levels of heavy metals and hydrocarbons with the result that the material was considered a Special Waste that had to be disposed of to Hazardous Landfill.
Land and Water Remediation Ltd undertook extensive sampling, testing and treatability studies to develop a strategy of waste separation and minimisation where the "clean" coarse fraction could be separated from the contaminated fine fraction and beneficially reused. The investigation went further in zoning the contamination such that the fine fraction could be separated into low and high contamination with the low contamination silts and clays also being beneficially reused. This strategy results in the lowest possible quantity of only the highly contaminated fraction being landfilled.Integrated system
In order to execute this strategy on site, the company has designed an integrated system incorporating screening, sand separation and mechanical dewatering of the sediments using mobile plant, all covered by an Environment Agency Mobile Plant licence.
The use of this equipment not only facilitates the separation of the materials into high and low contamination but also reduces the volume and weight of material that has to be transported and reused or landfilled by removing excess water. The sand and pressed cake that is produced is in a condition that can be accepted by landfills or restoration sites under the terms of the new legislation where liquid wastes are banned.
Following post treatment testing and ongoing Quality Control Sampling and Analysis, the sand and gravels have been accepted as being sufficiently clean to be used as engineering fill behind piles whilst a large proportion of the dewatered silt and clays have been beneficially reused as soils for the restoration of a closed colliery and a disused landfill.
This strategy was fully aligned with the East Riding of Yorkshire Council's objective of waste minimisation and recycling for the projects it promotes. The use of this configuration of plant is the first for an inland waterway and provides a treatment technique that would enable clients with problems of remediation contaminated sediments and sludges to overcome the constraints of the new landfill legislation.
A leading waterway contractor, Land and Water Services Ltd, within a group of associated businesses, has developed a broad spectrum of expertise. Land & Water Remediation Ltd was launched at the beginning of last year to expand its remediation business and offer innovative technologies. The company specialises in the recovery and treatment of contaminated dredgings, sludges and settlement lagoon arisings.
The company entered a two-year TCS research programme with the Centre for Contaminated Land Remediation at the University of Greenwich.