“Industrial experiences in the use of S/S technology to remediate &

reuse dredged sediment”

By Emma Yates & Bill Gush

Land and Water Remediation Ltd

STARNET Conference 12th-13th April 2005

Introduction • Setting the scene

– UK Dredging Industry

• Incentives for remediation

• Remediation Challenges

• Overcoming challenges – 2 Case Studies

• Future Issues

UK Dredging Industry

• 470 million tonnes controlled waste produced between 1998-99– 57 million dredgings

• Inland waterways, coastal areas, lagoons, wastewater treatment & chemical industries

• Historical disposal routes: sea & landfill “Dig & Dump”

Backhoe Dredging using Floating Plant

Why Remediate?• Limitations on the number of disposal routes

– Classified as waste (EPA 1990 & WFD 1991) enforcing tighter controls (WML 1994)

• Liquid waste banned from Landfill disposal– “any waste that near instantaneously flows into an indentation void

made in the surface of the waste”– Hazardous liquid banned July 2002– Non-hazardous liquid to be banned October 2007

• Legislation enforcing more sustainable waste management – Compliance with EU Legislation e.g. Landfill Directive*

• Increased pressures on land resources for housing development– 300,000 ha contaminated land available for regeneration

Challenges & Incentives (1) • European Landfill Directive (EC/93/31)

– Implemented August 2002 (Landfill Regulations 2002)– Requirement for reduction in waste disposal– Classification requirements of waste – Prohibition of certain waste types – Pre-treatment requirements– Increased landfill costs / tax increase – although waterway dredgings are

exempt Finance Act 2003– Reduction in hazardous landfill sites (200 10)

• Benefits– Increased incentive to recycle, remediate and reuse waste – More control on disposal & pre-treatment requirements

• To improve physical stability / convert waste to non reactive – More control over waste classification– Remediation technologies more competitive with dig & dump

Challenges & Incentives (2)• Environmental Protection Act (1990)

– Waste Management Licensing Regulations (1994)• 2 licence types: “site licence” & “mobile plant licence”• License application procedure costly and timely

– Exemptions of licensing for reuse• Not always permitted • Regional difference in interpretation of waste• Abuse of exemptions currently under review

– Risk of Activity Vs Control not always proportional • Change in licensing system to Single Remediation Permit – under review

• Benefits– Controls treatment to disposal of waste - Duty of Care Regulations – Ensures technical competence & company competence– Exemption possibilities enable reuse / disposal of waste without a license

Other Challenges• Classification of waste for landfill disposal

– More responsibility for waste producers to classify waste – WAC compliance testing not yet enforced

• July 2005 for basic compliance – Landfill Regulations (2005)• No WAC for non hazardous waste to non hazardous landfill

• Classification of waste for reuse– Removal of ICRCL guidelines– Soil Guideline Values are limited – only 7 available – Risk based modelling required limited resources / costly

• Require approval of treatment technologies for reuse – Long term durability guarantees required – PASSIFY and other R&D groups vital for researching longevity of S/S waste for reuse

• One project may require a number of licenses / permits

• Timescale for tenders & lack of early contractor involvement

• Dig & dump still the preferred option even after pre-treatment

Case Study 1: Forth and Clyde Project

• British-Waterways Millennium Link Project to restore the Union and Forth and Clyde Canals

Contamination• Chromium, Lead, Zinc and TPH

Treatment– Ex-Situ S/S– Addition of Trojan Cement (PFA & OPC

blend) to 4,000m3 sediment– 7 days: UCS 223kN/m2, permeability

3.55x10-8m/s, density 1.40g/cm3

– Reused as engineering backfill to create a towpath and mooring facility

Compliance – Treatability testing & SSWP– SEPA mobile plant license

Case Study 2: Wigg IslandProject

• Excavation and disposal of waste from the former Runcorn and Latchford canal spur & development of a water treatment system

Contamination• High acidity, arsenic, lead, zinc and sulphate

• Treatment– Ex-Situ S/S– OPC & Andricite to treat 7500m3 sediment

for disposal.– Reuse of approx: 500m3 for development

of a hydraulic barrier

Compliance– Treatability testing– SSWP, Risk assessments, Method

statements– EA WML - mobile plant license – Reuse under WML exemption 9– QC procedures – Water discharge consent (WRA 1991)

Wigg Island Before & After

WML Exemption 9:-The spreading of waste consisting of soil, rock, ash or sludge, or of waste from dredging any inland

waters or arising from construction or demolition work, on any land in connection with the reclamation or improvement of that land if-(b) the spreading is carried out in accordance with a planning permission for the reclamation or improvement of the land and results in benefit to agriculture or ecological improvement;

Future Issues– Remediation incentives are in place but some legislation prevents the reuse

• Definition of waste & exemptions for reuse

– Exemptions of WML Reg’s for reuse are being reviewed• No exemption will be available for reuse of stabilised hazardous dredgings• Reuse should be related to risk

– Single Remediation Permit / Environment License under review• Result of the Kirby Report• Seeks to improve the current WML system

– Waste classification will become simpler • Landfill Regulation Amendments• Improved risk assessment models

– Landfill costs will continue to rise• £15 per tonne for active waste from April 2004 (now £18/tonne from April 2005) • Set to increase at a rate of £3/yr until it reaches £35

– Education of stakeholders• Need longer timescale / early involvement with Regulatory Authorities during tender stages • Need time to undertake treatability testing• Understanding of longevity / approval of technologies

– CASSST & PASSIFY projects (Greenwich University)– STARNET

Acknowledgements & Contacts

Acknowledgements• British Waterways - Client for Forth and Clyde

Canal Project

• Halton Borough Council - Client for Wigg Island Restoration Project

Contacts• Land and Water Remediation Ltd

– Tel: +44 (0) 1483 205647– www.land-water.co.uk