Model Procedures provide a framework for making decisions about land contamination risks and are a useful resource which offer a lot of detail leading up to, and after, remediation. The remediation stage is often a significant and complicated financial commitment for any project, however the design and delivery of a project gets minimal attention in CLR11. There is a wealth of guidance on specific remediation techniques, some of which is outdated. Therefore, the process can be fraught with uncertainty and a lack of evidence on how the remediation strategy was developed can lead to a lack of confidence in it. This process needs to be open and transparent and stakeholders need to be fully engaged throughout the entire process. During this webinar, Martin presents an overview and worked examples of the process when undertaken in accordance with best practice principals.

1. Model Procedures : Framework for decision making about land contamination risks (CLR11).
Despite the remediation stage of a project often being a significant and complicated financial
commitment, the design and delivery gets minimal attention in CLR11, albeit is a key process.
Discussion of how to comply with an navigate model procedures and undertake remediation
options and sustainable implementation.
Martin Westwood
Environmental Scientist BSc (Hons) CEnv
7th August 2018
“Remediation Action taken to prevent or minimise, or remedy or mitigate the
effects of any identified unacceptable risks” (Contaminated Land Report 11)

2. Safety Moment

3. Content
1. Model Procedures
2. Remediation Process
3. Remediation Options Appraisal
4. Pilot Trial
5. Remediation Strategy Development
6. Detailed Design/Implementation
7. Costing /Cost Benefit
8. Licences / Permits/ Material Management Plan
9. Verification of Remediation
10.Four Case Studies

4. Model Procedures for the Management of Land
Contamination, CLR11(2004)
1. Remediation Options Appraisal
2. Remediation Strategy Development
3. Implementation Plan
4. Design / Implementation / Verification of Works
How did you design the method?
How did you carry out the works?
How can you show the success of the works?

5. Remediation Process- The basics
There are three main ways to reduce or control unacceptable risks
Remove or treat the (source) of pollutant(s);
Remove or modify the pathway(s);
Remove or modify the behavior of receptor(s).
Ex-situ – where contaminated material is removed from the ground prior to above-ground treatment
or encapsulation and/or disposal on or off-site.
The main advantage of ex-situ techniques, compared with in situ, is that contaminants, being brought up to the surface, are made more
accessible to treatment processes
In-situ – where contaminated material is treated without prior excavation (of solids) or abstraction
(of liquids) from the ground.
The main advantages of in-situ methods are that they can often avoid excessive environmental impacts and costs associated with excavation and
abstraction and they can typically be implemented on operational sites.
Hybrid /combined options -one or more appropriate remediation options
Normally for different contamination phases or different receptors.
CIVIL ENGINEERING
BIOLOGICAL
CHEMICAL
PHYSICAL
STABILISATION AND SOLIDIFICATION
THERMAL METHODS

6. Remediation Options Appraisal
Document and Record Everything and set out clearly from first principals
The SuRF-UK framework draws on existing methods with the aim to develop a robust and streamlined framework for
assessing sustainable remediation that is compliant with legislative requirements

7. Remediation Options Appraisal

8. Pilot Trails
Encouraged for all remediation process except civil engineering methods
Can be expensive, but so is failure
Always best to measure than model
Laboratory tests
Field Trials
Specialist contractor should have a method to assist that they have adopted previously
Case studies (on line)
CL:AIRE case studies

9. Remediation Strategy Development

10. Detailed Design/Costing

11. Cost Benefit Analysis
Guidance allows for continual review of the process of
remediation
Consideration of costs and benefits of remediation with time
Is remediation sustainable?
How does the environmental benefit from continued operation
correlate with other factors as Timescales, financial, socio-
economic, energy use, noise etc
Get an economist and cost manager on board- this is formal
process not just cost cutting

12. Licences and Permits/Material Management Plan
https://www.gov.uk/guidance/check-if-you-need-an-
environmental-permit#what-you-need-a-permit-for
Waste operation
Mobile plant licence
Land and groundwater Deployment
Water discharge / activity/ abstraction
Work near controlled water
Foul sewer discharge consent
Other i.e. ecological, air, waste etc

13. Verification
As specified by CLR11, prepare a Remediation Implementation Plan that sets out in detail the
methodology for the design, preparation, implementation, verification, monitoring and
maintenance of the remediation.
The Implementation Plan should include a Verification Plan which sets out what information
should be obtained during the development of the site (and when) so that a permanent record
exists of the remediation actions completed to address the identified RPLs.
The Implementation Plan should be agreed prior to undertaking any works on site.
Typical verification criteria for in-situ remediation:
Reduction in contaminant concentrations to below assessment criteria
Reduction in contaminant distribution
Asymptotic conditions for remediation system
Stable contaminant concentrations in verification monitoring wells
Typical verification criteria for ex-situ remediation:
Contaminant concentrations laboratory analysis

14. Case Studies Under Model Procedures

15. In-situ Vacuum Enhanced Free Product Recovery- Gas Oil (1)

16. EA policy is remediation was required to remove the free phase gas oil.
24m3 of free-product in the ground to be removed
Remediation options evaluation undertaken
Chosen method: In-situ Vacuum Enhanced Free Product Recovery (Venturi effect)
under licence
Delineation During Contract
Free phase product and soil vapour are extracted simultaneously from a network
of wells using a vacuum pump
Free-product is separated for storage and disposal off-site at an appropriate
licensed facility (waste management)
Waters and condensate pass through a treatment system prior to discharge to the
sewer (discharge consent)
200 extraction wells over 3000m2
Recharge rate very slow (80% yield)
4 week recharge
Near Asymptotic Conditions
300 days operation
18m3 of gas oil
In-situ Vacuum Enhanced Free Product Recovery- Gas Oil (2)

17. Reed bed- Free phase Relict Creosote (PAHs)
• Perched groundwater management/ exploitation of existing ground conditions
• Free phase (DNPAL) management and collection system
• Wetland / reed bed (biological water treatment (3 month capacity)
• Representative TPH CWG concentration: 12 mg/L.
• 70 % COC removal /35m3 per day
• Treatability Trial)
• Piped water outfall to River under SWDC
• Facility to construct further treatment steps (if required)
• Temporary water management and treatment was significant cost
• Verification- testing groundwater into and out of reed bed and compliance at discharge point
• Post Completion Environmental Management System / maintenance plan

18. Permeable Reactive Barrier (PRB) Chlorinated Solvents
• PRB in aquifer
• In-situ: Activated carbon /hydrogen release compound /in situ anaerobic bioremediation or
• Ex-situ: Additional treatment step (Groundwater pump and treat)

19. Avenue Coking Works- Tar sediment, Soils and Dry Wastes (1)
Technique Designs
Volume
Final /
Forecast
Treatment (m3)
Thermal desorption 270,300 257,266
Soil screening /sorting 237,600 203,485
Bioremediation 74,000 181,206
Total 581,900 641,497
Off-Site Disposal (Tonnes)
Asbestos 2352 913
Metal 3000 550
Other waste 4600 2470
Recovered Timber 1450 10,000
Tar 0 19,000
Total 11, 402 32,020
Groundwater and Surface Water Treated 650,000
All Earthworks (m3)
Total Material volume (cut) 1,883,377 2,244,989
Total Material volume (Fill) 1,934,896 2,178,20
Total 3,818,273 4,423,189
Material Import to Create Landform 0 80,000
Groundwater and Surface Water Treated ?? 650,000

20. Information Sources

21. Conclusions
Follow Model Procedure Framework
Adapt the methodology (but be clear if there is a deviation or amalgamation)
The remediation and model procedures should be proportional to the scheme complexity
Each step is iterative (but try to think holistically)
Design sustainably and to minimise resource (cost benefit)
Document everything /all decision (undertaken in tabular format)
Consult with client, regulators and contractors at all stages
Get contractor on board at earliest opportunity
Undertake a remediation plot trial
Expect the unexpected and try to accommodate it
When you prepare the contract documents make sure the relevant technical uncertainties are
covered in case of unforeseen conditions (the contractor wont look at your technical report)
Make sure that the verification requirements are documented in contract
Update the risk assessment based on changes in contaminant mass/distribution
Thank You. Any Questions