Project Description: Hydrogeological Risk Assessment and Landfill Permit Application

Client: Waste Recycling Group plc

Introduction

All development companies are now required to submit an IPPC application in order to comply with new Pollution Prevention and Control Regulations. A crucial part of this application is the hydrogeological risk assessment.

Project Brief

Egniol were commissioned by WRG to prepare a hydrogeological risk assessment as part of an application for a Landfill Permit under Tranche 2B.

The location was an existing landfill site in a sand and gravel quarry in southern England and the assessment was undertaken in line with current Agency guidance.

The site is located on the Carstone Formation, which is reported to be a major aquifer under the Policy and Practice for the Protection of Groundwater. The site will accept non-hazardous waste streams, but due to the sensitivity of the setting, a detailed risk assessment was also equired. The site had a limited unsaturated zone of 2 m beneath the site

Project delivery

In order to properly assess the risks posed to the groundwater environment from listed substances contained within the leachate, the numerical modelling package LandSim v2.5 was used to create a model of the site. This demonstrated that leachate could be maintained at 1m for the duration of the operational control period.

The assessment also reviewed the sensitivity of the site to leachate heads maintained within each engineered cell. As part of the requirements, the environmental monitoring processes were reviewed and recommendations for changes made based on the findings of the risk assessment. Trigger and control values were proposed for the down gradient monitoring boreholes.

The outcome of the assessment indicated that the site would be compliant with the requirements of the landfill directive.