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Landfill and Ground-Gases - VOCs and Vapour Intrusion - The Assessment and Management of Gas Contamination in Australia
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Landfill and Ground-Gases - VOCs and Vapour Intrusion - The Assessment and Management of Gas Contamination in Australia


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Reviews guidance (and the lack thereof) on LFG, Ground Gas and Soil Vapour Intrusion and postulates the need for such guidelines to be developed for Australia.

Reviews guidance (and the lack thereof) on LFG, Ground Gas and Soil Vapour Intrusion and postulates the need for such guidelines to be developed for Australia.

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  • 1. Landfill and Ground-Gases – VOCs and Vapour Intrusion –The Assessment and Managementof Gas Contamination in Australia Peter Gringinger & Anthony Lane EcoForum 2010, 23-24 February 2010, Sydney
  • 2. Contents• Why bother about Landfill Gas (LFG), Ground Gas (GG), VOCs and Soil Vapour Intrusion (SVI)?• Sources, pathways, receptors & risks of GG & SVI• Current guidance on GG and SVI in Australia (?)• Development and status of guidance in UK and North America• GG and SVI assessment as part of the LCM cycle• Australian GG and SVI Guidance Framework• Conclusions
  • 3. Why bother about LFG?• Cranbourne landfill case, in context of urban sprawl, demand for housing, brownfields development
  • 4. Why bother about LFG?• Cranbourne Landfill LFG CSM
  • 5. Why bother about GG?• Loscoe, Derbyshire, 1986• Abbeystead, Lancashire, UK 1984
  • 6. Why bother about VOCs and SVI?• Barkley Street Case, Brunswick• Redfield, Colorado
  • 7. Why bother about VOCs and SVI?• Endicott, Upstate New York
  • 8. “Hypothetical” Case GG Former Landfill 1960s-1970sProposedResidentialDevelopment
  • 9. “Hypothetical” Case SVI Possible Sources for SVI Primary School Car Dealership Service Station
  • 10. Sources, pathways, receptors & risks of GG and SVI (CSM)
  • 11. Sources and Risks of GG• Landfills • 1990s and 2000s: Moderate to very high (but mostly lined and controlled) • 1960s to 1990s: Moderate to very high risk • <1960s: Low to moderate• Fill (with high organic content), foundry sands, sewage sludge: Low to moderate• Coal mine workings: Low to high• Peat and coal measures: Low
  • 12. Sources and Risks of SVI• Service Stations and Drycleaners: High• Workshops and small factories: Moderate to high (incl. bakeries, engineering shops etc)• Petro-chemical industry: Very High• Landfills: Low to High• NOTE: Organic sources and plumes can emit methane due to biodegradation (i.e. 1mg/L of CH4 in GW could result in up to 4% in soil vapour but flow rates likely low)
  • 13. Current guidance on GG and SVI in Australia• EPA Vic Pub 722 – Reduction of GHG from Landfills (?)• EPA Vic Pub 788 – Siting, Design, Operation and Rehabilitation of Landfills• EPA SA – Env Mgmt of landfill facilities• EPA NSW Technical Note on VI• Revised NEPM? (noting that VI criteria for Petroleum Hydrocarbons will be included)
  • 14. Overseas Guidance on GG – UK• Developed over last 25 years after incidents in 1980s• Mature guidance, regularly updated, extensive practical experience• GG assessments are required and integral part of LCM cycle and development policies (planning, building, environmental regulations)• Main Guidance documents • Construction and Industry Research and Information Association – CIRIA C665, 2008 and C682 (SVI), 2009 • British Standard BS8485: 2007 • National House-Building Council NHBC 2007 • (Ground Gas Handbook, 2009)
  • 15. GG Assessment Approach (UK)• Initial Desk Study (Phase 1) with CSM on sources, potential pathways, receptors critical (including good knowledge of Geology & Hydrogeology) & initial screening• Intrusive assessments (Phase 2) • Detailed soil (organic material) descriptions • TOC/DOC & gas generation tests • Gas monitoring wells • Spacing depends on gas risk and sensitivity of end use • Bore installation determined by CSM (i.e. permeable strata) • Periods and frequency of monitoring determined by gas risk and sensitivity of end use (range from 4x1 to 24x24)
  • 16. GG Risk Assessment Approach (UK)• Tier 1: CSM & S-P-R approach and likelihood and consequences (i.e. similar to AS on Env RA) and can include generic screening criteria• Tier 2: Qualitative Assessment for CH4 and CO2 • Gas screening value (GSV) = Borehole flow rate x gas concentration (%) • GSV determined risk classification (NHBC or CIRIA) • GSV determines scope of protection measures (types, design, construction & validation)• Tier 3: Quantitative Risk Assessment for high risk cases using fault tree analysis, models, continuous gas monitoring (e.g. Gasclam – )
  • 17. GG Risk classification & Mitigation
  • 18. SVI Guidance Approach (US/UK)• Can largely be based on ASTM, ITRC, USEPA & CIRIA guidance (and few others) and include phased and tiered risk based approach (see GG) • Sources, transport and pathways of VOCs may differ to GG (VOCs are complex from a process perspective) • Hence CSM’s account for this and in detailed investigations (e.g. bore locations, screen depths, screen lengths, use of multilevel installations etc)• Mitigation measures largely similar to GG (with differences in detailed design; e.g. resistance of barriers against VOCs)
  • 19. SVI Guidance Approach (US/UK)• Preliminary Risk Assessments (Tier 1) use Soil Guidance Values for Groundwater and/or Soil Vapour data (few jurisdictions)• Generic Risk Assessments (Tier 2) for SVI rely either on Attenuation Factors (AF between sub- surface and indoor air vapour concentrations) to determine risk levels or generic vapour transport models (i.e. most commonly the Johnson & Ettinger (1991) model)• Detailed Risk Assessments (Tier 3) use site specific models, numerical models, indoor air data etc
  • 20. Australian Framework Guidance to GG and SVI Assessment and Mgmt• Integrate with existing guidance (i.e. NEPM) and consideration from start of assessment process• Use phased and tiered risk based approach• Emphasise use of CSM and S-P-R approach• Use of GSV and AF plus models*• Reference to best available UK/US guidance for assessment to provide technical details• Has to be an iterative multiple lines of evidence approach• Include comprehensive coverage of mitigation and management measures (including design, construction and validation)• Who to develop? – e.g. CRC CARE, CSIRO
  • 21. Australian Framework Guidance toGG and SVI Assessment and Mgmt Figure 1. The Process of Managing Risks Related to Hazardous Ground Gases• Staged Assessment Site Characterisation Define the context & set the objectives Assessment of Risk Review data Determination / Validation of Remediation Identify remedial • Site Assessment objectives to mitigate unacceptable risks Carry out Phase One Desk Study Is data reliable? Identify feasible remedial options (e.g. appropriate No response zones, • Desk Study (Screening) variable/ unrepresentative Undertake Develop initial conceptual site model groundwater levels) & undertake preliminary risk assessment additional intrusive investigations Yes • Intrusive Investigation No Has monitoring been carried out Has development of model under varying Undertake included site specific factors No conditions likely additional Has sufficient that may influence to influence the gas intrusive data been • Monitoring & Sampling gas/vapour regime vapour regime? investigations obtained to allow No and/ or the selection/ design ITRC, 2007 Yes monitoring of appropriate & sampling remedial solutions? Yes Results sufficiently No • Data Assessment consistent/ reliable? No Have these factors identified the potential presence of gas/vapour? ASTM E2600 SVI CIRIA C682 Yes Source(s) of gas(es)/ vapour(s) No Yes Detailed evaluation of remedial options • CSM CIRIA C665 identified? SVI Develop a remedial strategy Yes Yes SVI Extent of source(s) established? No Design, implementation & verification of remedial measures • Risk Assessment GG No Are there potential Yes unacceptable risks? Refine conceptual site model Review/ No Is post installation/ amend construction Consider odour & toxicity and remedial • Tier 1, 2 and 3 monitoring required? incorporate strategy Yes into risk assessment as appropriate Yes Identify further actions to clarify potential unacceptable risks Undertake appropriate risk Undertake post installation/ • Mitigation Design & assessment modelling. Define gas regime construction monitoring Establish objectives of any further investigations Green Amber Red Is the monitoring No Implemention Carry out further investigation data acceptable? [desk based/intrusive/ Monitoring] Does risk No assessment demonstrate Yes corrective action required? Completion/Validation Report • Verification Yes NO FURTHER NO FURTHER NO FURTHER ACTION REQUIRED ACTION REQUIRED ACTION REQUIRED
  • 22. Australian Framework Guidance to GG and SVI Assessment and Mgmt (Potentially) Contaminated Site • Site History (on- & offsite) • COPC’s (Gases and VOCs) Preliminary (GG/SVI) Site Assessment • Initial CSM & preliminary RA (Desk Study & Walkover) • Work Plan based on CSM • Intrusive Investigation Site Investigation • Monitoring Program • Collate Data Data Analysis • Analyse & Review (incl QA/AC) • Refine CSM • Include odour and toxicity issues Risk Assessment • Tier1: Generic guideline levels • Tier 2: GSV or AF & generic models • Tier 3: Site specific DQRA Risk Mitigation and Remediation •Remedial Objectives • Options Screening & evaluation • Remedial Strategy Site Close Out • Design, implement & verification • Monitoring and Validation
  • 23. Conclusions• Not only landfills produce ground gases• Not only servos and drycleaners have SVI issues• GG and SVI issues are common• It’s the Geology (pathway) stupid• Hence know your CSM and S-P-R (stupid)• Phased and tiered Risk based Assessment• Integration of GG and SVI from start of Land Contamination (just like soil and GW) Assessment• Mitigation and Mgmt details are part of the deal• National guidelines needed (to avoid another Cranbourne) & minimise litigation potential
  • 24. References and Links• CIRIA, 2007: Assessing risks posed by hazardous ground gases to buildings, C665.• CIRIA, 2009: The VOCs Handbook, Investigating, assessing and managing risks from inhalation of VOCs at land affected by contamination. C682.• Wilson, S.; G. Card & S. Haines, 2009: Ground Gas Handbook. Whittles Publishing, UK.• ASTM, 2008: E2600-08 Standard Practice of Vapor Intrusion into Structures on Property Involved in Real Estate Transactions.• British Standard, 2007: BS8485:2007 Code of practice for the characterization and remediation from ground gas in affected developments.• NHBC, 2007: Guidance on Evaluation of Development Proposals on Sites where Methane and Carbon Dioxide are Present. Report Edition No. 04, March 2007.
  • 25. References and Links• API, 2005. Collecting and Interpreting Soil Gas Samples from the Vadose Zone, A Practical Strategy for Assessing the Subsurface Vapor- to-Indoor Air Migration Pathway at Petroleum Hydrocarbon Sites. Publication No. 4741.• EPRI, 2005. Reference Handbook for Site Specific Assessment of Subsurface Vapor Intrusion to Indoor Air. March 2005.• ITRC, 2007: Vapor Intrusion Pathway: A Practical Guide. Technical and Regulatory Guidance, January 2007.• CALEPA/DTSC, 2004. Guidance for the Evaluation and Mitigation of Subsurface Vapor to Indoor Air, Interim Final, December 2004.• CALEPA/DTSC, 2009. Vapor Intrusion Mitigation Advisory. April 2009.• USEPA, 2008: Brownfields Technology Primer: Vapor Intrusion Considerations for Redevelopment. EPA/542/R-08-001, March 2008.• USEPA, 2008. Engineering Issue: Indoor Air Vapor Intrusion Mitigation Approaches. EPA/600/R-08-115, October 2008.• USDOD, 2009. DoD Vapor Intrusion Handbook. January 2009.
  • 26. References and Links• NYSDOH, 2006. Guidance for Evaluating Soil Vapor Intrusion in the State of New York. October 2006.• USEPA, 2002. OSWER Draft Guidance for Evaluating the Vapor Intrusion to Indoor Air Pathway from Groundwater and Soils (Subsurface Vapor Intrusion Guidance). EPA/530/D02-004, November 2002.• USEPA, 2005. Guidance for Evaluating Landfill Gas Emissions from Closed or Abandoned Facilities. EPA/600/R05-123a, September 2005.
  • 27. References and Links• Clu-In Vapor Intrusion Focus Area www.clu-• EnviroGroup Vapor Intrusion Links• Indoor Air Vapor Intrusion Database• ITRC Vapor Intrusion Site• The Landfill Gas Expert
  • 28. GG Training• ACLCA Vic is planning a 4-day short course on “Landfill Gas investigation, risk assessment and remediation” some time between July to September 2010• Watch for details on