Scaynes Hill Landfill measured approximately 2.4 hectares and was located within the north-west corner of an operational water treatments works. During the 1960s and 1970s the landfill was operational accepting general domestic refuse. Underlying the site was a sandstone aquifer. The boundary of the landfill was situated adjacent to The River Ouse, which was showing signs of pollution, causing concern for the Environment Agency.

The operators of the water treatments works were instructed by the Environment Agency to carry out a combined geotechnical and environmental investigation to check the integrity of the landfill. The site works were divided into two elements: intrusive investigation and follow-up monitoring. The main objectives of the investigation were: -

1. To determine the nature and geotechnical properties of the underlying strata, confirm or otherwise the presence of an engineered capping layer, to establish the properties of the capping layer and finally to assess the potential for structural instability and failure of the landfill boundary bund.
2. To determine the extent, volume and characterise the nature of the waste and leachate within the landfill facility.
3. To indentify pollutant linkages and to evaluate the risk to identified receptors.

The site works consisted of the following elements:-

• Drilling of cable percussive boreholes using clean method drilling to depths of 15m, with dual installations within the weathered sandstone aquifer and the landfill itself.
• Shallow window sampler boreholes were installed to assess near surface gas regimes.
• Trial pits were excavated by machine to visually examine and characterise the waste.
• Hand excavated trial pits were dug around the perimeter of the landfill to delineate its extent.
• Water quality of the adjacent River Ouse was conducted through sampling up and down stream of the landfill.

Harrison Group Environmental acted as principal contractor during the site works and compiled the pre-construction health and safety plan. Toolbox talks were issued to all site operates working on this Red/ Yellow classified site by our site engineer.

We were pleased to successfully complete the execution of the fieldworks and issue of reports within the allocated timeframe and budgets.