LAND AND WATER Remediation has dredged, treated and disposed of about 20,000m 3of contaminated sediments from Beverley Beck in Beverley, east Yorkshire.
The contamination is a legacy of industrial activity in the area, including tannery discharges and highway runoff. The resulting high levels of heavy metals and hydrocarbons mean the material is considered special waste that would normally have to be disposed of at a hazardous landfill site.
Land and Water was working under a £1M contract for main contractor Mowlem.The client is the East Riding of Yorkshire County Council.
The company performed sampling, testing and treatment studies to develop a waste separation strategy for the site. Excavated soil was split into clean coarse material and contaminated fine material, with the former reused on site.
The fine fraction was further separated into low and high contamination material, with the low contamination silts and clays also being reused.This approach meant the lowest possible quantity of only the most contaminated material had to be sent to landfill.
Land and Water designed an integrated system incorporating screening, sand separation and mechanical dewatering of the sediments using mobile plant. The resulting dry material could be accepted at landfills or restoration sites where liquid wastes are banned under new EU legislation.
Following post-treatment testing, the sand and gravels were accepted as being sufficiently clean to be used as engineering fill. A large proportion of the dewatered silt and clays has been reused in restoration of a closed colliery and a disused landfill.