Detailed Remediation Method Statement Land at Five Oaks Lane Chigwell Essex Countryside Properties PLC 514 R02: Issue 1 July 2015 Green Earth Management Co Ltd Title Detailed Remediation Method Statement Land at Five Oaks Lane, Chigwell, Essex Prepared for Countryside Properties Plc Countryside house The Drive Brentwood Essex CM13 3AT Confidentiality, Commercially Confidential copyright and reproduction This document has been prepared by Green Earth Management Company Limited in connection with a contract to supply goods and/or services and is submitted only on the basis of strict confidentiality. The contents must not be disclosed to third parties other than in accordance with the terms of the contract. File reference 514 Report number 514 R02: Issue 1 Date 8th July 2015 Prepared by Green Earth Management Co Ltd East Gores Farm East Gores Road Coggeshall Essex CO6 1RZ Name Signature Date D. Robson 08/07/2015 Author: Reviewed by: P. Taylor 08/07/2015 Authorised by: L. Jackson 08/07/2015 Issue Record Project No 514 Project Name Five Oaks Lane, Chigwell, Essex Client Jackson Civil Engineering on behalf of Countryside Properties Plc Report Title Detailed Remediation Method Statement Report Date of Issue Author Reviewer Details of Changes Distribution No. Issue No. Countryside Properties Plc Jackson Civil Engineering R02 DR PT 08/07/15 Issue 1 Issue 1 EC Harris Arcadis London Borough of Redbridge CONTENTS CONTENTS ............................................................................................................................................I TABLES ............................................................................................................................................ IV FIGURES AND APPENDICES ................................................................................................................ IV REPORT STRUCTURE ........................................................................................................................... V 1 INTRODUCTION ...................................................................................................................... 1 1.1. Project Details .................................................................................................................................... 1 1.2. Objectives .......................................................................................................................................... 1 1.3. Scope of Work ................................................................................................................................... 1 1.4. Previous Investigations ...................................................................................................................... 2 1.5. Project Stakeholders .......................................................................................................................... 2 1.6. Terms of Reference ........................................................................................................................... 3 2 SITE DETAILS ........................................................................................................................... 4 2.1. Site Setting ......................................................................................................................................... 4 2.1.1. Site Location ................................................................................................................................... 4 2.1.2. Site Description ............................................................................................................................... 4 2.1.3. Surrounding Area ........................................................................................................................... 9 2.1.4. Topography .................................................................................................................................... 9 2.2. Geology, Hydrogeology and Hydrology ............................................................................................. 9 2.3. Ground Conditions ........................................................................................................................... 10 2.3.1. Made Ground ............................................................................................................................... 10 2.3.2. Clay ............................................................................................................................................... 11 2.4. Groundwater ................................................................................................................................... 11 2.5. Contamination Conditions ............................................................................................................... 11 2.5.1. Conceptual Site Model – Summary of Linkages of Concern ......................................................... 11 2.6. Pre-Remediation Risk Assessment .................................................................................................. 12 3 DETAILED REMEDIATION STRATEGY....................................................................................... 14 3.1. General ............................................................................................................................................ 14 3.2. Construction Considerations ........................................................................................................... 14 3.2.1. Cut and Fill .................................................................................................................................... 14 3.2.2. Piling Works for Foundations ....................................................................................................... 15 3.3. Key Elements of Remediation Strategy ........................................................................................... 15 3.4. Removal of Visible ACM (Bulk Products) ......................................................................................... 16 3.5. Tree and Vegetation Clearance ....................................................................................................... 17 3.6. Clearance of Fly-Tipped Waste ........................................................................................................ 17 3.6.1. Disposal / Removal of Skip Waste ................................................................................................ 17 3.6.2. Construction / Demolition Wastes ............................................................................................... 18 3.6.3. Wood Waste ................................................................................................................................. 19 3.6.4. LPG (Propane and Butane) Bottles ............................................................................................... 19 3.6.5. ‘Mulch’ - shredded wood waste. .................................................................................................. 19 3.7. Removal of Hotspots of Asbestos Contaminated Soils .................................................................... 20 3.7.1. Plot 58 / 59 Fly-Tipped Soils ......................................................................................................... 21 3.7.2. Plot 42 Haul Road Materials ........................................................................................................ 21 3.8. Demolition ....................................................................................................................................... 29 514 R02: Issue 1 - Detailed Remediation Method Statement, Five Oaks Lane, Chigwell, Essex July 2015 Page i of vii 3.8.1. Demolition of Above Ground Structures ....................................................................................... 29 3.8.2. Breakout of concrete hard standing, excavation of underground obstructions and crushing of site won hard materials ............................................................................................................................. 29 3.8.3. Emptying and Removal of Above Ground Oil Storage Tanks ....................................................... 29 3.8.4. Emptying of Septic Tanks and Cesspits......................................................................................... 30 3.8.5. Perched Water Management ....................................................................................................... 30 3.9. Off-Site Disposal / Treatment of Japanese Knotweed (JK) .............................................................. 30 3.9.1. Off-Site Disposal of Japanese Knotweed ...................................................................................... 30 3.9.2. Cell Burial Method ........................................................................................................................ 32 3.10. Recycling of Site Won Topsoil .......................................................................................................... 33 3.11. Excavation and Treatment of Potentially Contaminated Made Ground ......................................... 33 3.11.1. Complex Sorting Operations ......................................................................................................... 34 3.11.2. Ex-Situ Bioremediation ................................................................................................................. 34 3.11.3. Validation of Treated Soils for Re-Use