Remediating Complex Sites. East land Quality Forum. By Steve Edgar. VertaseFLI BRISTOL SHEFFIELD HERTFORD MANCHESTER

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1 Remediating Complex Sites East land Quality Forum By Steve Edgar VertaseFLI BRISTOL SHEFFIELD HERTFORD MANCHESTER

2 Complex Sites What do I mean by Complex? Truly complex sites need bespoke solutions from start to finish

3 The Familiar Process Desk Study Site Investigation Compile CSM Generic QRA DQRA Post Remediation DQRA Options Appraisal Remediation Validation/Verification

4 It all starts here..

5 Complex site-complex Site Investigation 5 phases of SI over 10 years Remediation estimates from 10m to unremediatable 1m spent on remediation Whole site contaminated Between 2 and 15m 60K Targeted SI Plume completely different Able to firm up and fix remediation cost

6 Delineation, Delineation, Delineation!

7 The Importance of Good and Full CSM s You might even need more than one per site!

8 DQRA and RE-QRA DQRA is important to generate targets and assess risks It is not the be all and end all.controversial maybe but true understanding is more valuable. Often on complex sites the data gap is large and targets unachievable as the conservatism is too high. Understand this and seek to improve the model. This doesn t mean you need a MODFlow Model! Rubbish in rubbish out Once you have remediated your site may have significantly changed so has your CSM. Is your DQRA valid. If not RE-QRA!!

9 Typical Complex Site Former Bayer Crop Science Site, Hauxton, Cambridgeshire Agrichemicals, herbicides, pesticides and associated compounds Designated as a Special Site under Part 2A of the Environmental Protection Act (1990) Primary use post remediation will be residential

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13 Rem ediati on Benton ite Wall Riddy Brook River Cam Flooding Groun dwater Impact s Reside ntial Develo pment Effluent Plant and water treatability Neighbour s land Soil Contam ination Part 2A Managing liability Getting register amended Odours Free produc t No EQS s Rare toxicology Health Effects complaints Planning permission for remediatio n! Unachieva ble targets Local Opposition Off site contaminat ion Ecology Former Owners Public Consultatio n Human Health Confidence Hard to understand Local Stakeholde rs footpaths Historic Buildings Expectatio ns

14 Contaminants Contaminant Types 1 23 Contaminants of Concern from initial list of 217 including: Organo-phosphates/nitrates Ethofumesate, Schradan, Simizine Acid Herbicides MCPA, Mecoprop Targets developed but understand them and their behaviour

15 Phenolics 2-Methyl-4,6-Dinitro-Phenol, Chlorinated Phenols Chlorinated Solvents and BTEX In addition, 30 CNPI identified during remediation.

16 Complex site but simple solutions Treatment Methodologies Ex-situ biopile 116,561m 3 material excavated 179 treatment beds Average volume: 617m 3 Average treatment bed turned 9 times 1,000,000m 3 passed through treatment process Average treatment time 18 weeks up to 30+ in some cases

17 Treatment Methodologies Ex-situ bio-pile with amendments Spent mushroom compost added to many beds to improve soil properties and aid treatment. Careful control not to affect geotechnical properties Added to 76 treatment beds (nearly 50% of total treatment material) Soils semi cohesive/cohesive and need significant processing.

18 Treatment Methodologies Force Ventilation Vapour Extraction Unit 13 treatment beds treated in FVE Kit 6.15% of total treatment materials Type A and Type B materials

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22 Average concentration in selected treatment beds (µg/kg) Figure 136. Contaminant concentration reduction curves for 12 selected Hauxton COCs in selected treatment beds Ethofumesate Phenoxy Acetic acid herbicide: MCPA Phenoxy Acetic acid herbicide: Mecoprop ,4,6-Trichlorophenol Chloro-2-methylphenol Bis (2-chloroethyl) ether Tetrachloroethylene Trichloroethylene 4000 Simizine 2000 Toluene Xylene Time (weeks) 1,2-Dichlorobenzene

23 Odours, Health and Nuisance Odour Issues Highly publicised site and development with a long history Close to local villages Hauxton and Harston Contaminants with low odour thresholds Ex-situ remediation required to address the problems Corby case coincidental with works

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26 Understanding the site and environs Prepare to Investigate hard! DQRA & RE-QRA Think wider than just the treatment Bespoke design to fit the Environment and the end users. Utilise new technology push the limits If you don t have data, get it or generate new standards Communication Helping others to understand Don t forget the Stakeholders Be innovative!

27 Recent Projects include: Ex-situ bioremediation In-situ Bio-remediation Anaerobic In-situ bio Dual phase extraction Pump and treat systems High Vacuum Extraction Hydraulic capture Free product recovery Air Sparging Steam Stripping Soil washing Stabilisation and re-use Stabilisation and disposal Excavation and disposal Chemical Oxidation In-situ Chemical Oxidation Ex-situ Selective Excavation Recovery of Landfill Waste Soil Vapour Extraction Abiotic Reduction (Zvi) General Contaminants Include General Hydrocarbons PAH s Naphthalene Chlorinated solvents Pesticides Insecticide Herbicides Chlorinated Phenols Radioactive Waste Phenols BTEX Metals Cyanide complex Ammonia Creosote Tar Tri-methyl benzene Japanese Knotweed and other invasive species Geotechnically difficult soil Landfill Waste

28 Thank you Contact details Steve Edgar VertaseFLI