OVERVIEW OF THE EREF POST-CLOSURE CARE APPROACH

1. OVERVIEW OF THE EREF POST-CLOSURE CARE APPROACH Post-Closure Maintenance Workshop California Integrated Waste Management Board 10 March 2008 Mike Houlihan, P.E., DEE Geosyntec Consultants

2. ITRC Member State Introduction to EREF and ITRC • EREF • Network • Industry • Academia • Consultants • Documents • Research and Development • Technical Guidance • Case Studies • Outreach • ITRC • Network • State & Fed regulators • Industry • Consultants • Academia • Community stakeholders • Documents • Technical and regulatory guidance documents • Technology overviews • Case studies • Training • Internet-based • Classroom

3. EREF and ITRC Efforts Today • EREF - Performance-Based System for PCC, Sept. 2006 • Leachate Characterization Study, Sept. 2007 • Multi-site Pre-requisites module data evaluation project (on-going) • ITRC – Evaluating, Optimizing, or Ending PCC, Sept. 2006 • Performing Web-based training • Over 300 regulators have been trained via the ITRC web-based training program and are beginning developing rules and/or guidance.

4. PCC Evaluation Elements

5. Underlying Problem Statement • At what point is post-closure care no longer needed? • To answer this question, the long-term trend in landfill performance must be predicted, and therefore predictable. • Are long-term leachate and LFG quality trends predictable for closed MSW landfill cells?

6. Progression of Leachate and LFG Quality Reference: Kjeldsen et. Al. 2003

7. EREF Leachate Study Data Set • 1402 Leachate Sample Events • 101 MSW Landfills • Mean age of waste at the time of capping: 14.6 years • Mean length of time post-capping: 7.1 years

8. EREF Leachate Study Conclusions • Time after capping has the greatest effect on leachate quality over time relative to age of waste and gas collection • Indicates annual decrease in concentration over time for all constituents and compound classes included in the study • Decrease in concentrations generally consistent with the decay curve of BOD • Preliminary confirmation of EREF study that BOD can be used as a surrogate for multiple compounds in leachate • Post-capping leachate quality trends appear to be predictable • If trends are predictable, existing data can be used to represent the potential for threats to receptors under a certain set of conditions

9. Advantages of Performance Evaluation of PCC • Structured approach (uniform process) to objectively evaluate the progress of PCC • Defining expectations through uniform process • Identify and demonstrate how a site has reduced or eliminated potential threats to human health and the environment • Tied to specific future use • Consistent with federal regulations • Focuses on four PCC components identified by EPA • Helps build consistency among regulators • Provides a forum for community input regarding long-term care • Provides an opportunity to reach concurrence between the regulator and owner/operator

10. PCC Evaluation Flowchart Step 1: Prerequisites Step 2: Evaluate Change Step 3: Make Change Step 4: Monitor for Effects Step 5: Outcome

11. PCC Module Evaluation Process

12. 1. Module-specific Requirements Purpose: Evaluate whether module-specific requirements are met • Leachate • Downward or steady trend in leachate quality and quantity • Landfill gas (LFG) • No impacts • Groundwater • Detection monitoring • Cap • All other modules are completed • Dependence of other outcomes on the cap are defined

13. 4. Monitor Impacts • Monitor the change made during Step 3 and confirm that it works as predicted • Confirmation monitoring • Monitoring during PCC to confirm that a change resulted in the predicted outcome • Surveillance monitoring • Monitoring after PCC for an extended period to further validate the decision to end PCC for a module

14. Evaluating Performance of Change: Confirmation Monitoring • “Demonstrating that data on which the evaluation was performed is complete and documents the existence of the trends that the evaluation was based on” • Performed for duration and at frequencies established during “Step 2 – Evaluation” • Monitoring data comply with performance criteria established during “Step 2 – Evaluation” • If the change “performs as planned” proceed to surveillance monitoring

15. Outcomes of Surveillance Monitoring 2 Possible Outcomes: • Monitoring Results as Expected: Develop Custodial Care Program and Proceed to Custodial Care • Monitoring Not as Expected: Re-evaluate the decision to terminate or change PCC Note that: • Completion represents the end of Post Closure Care • At end of Surveillance Monitoring, establish Custodial Care Program

16. Outcomes of Module Evaluations

17. Requirements for Ending PCC • Leachate management system • Concentrations do not pose a threat • Build-up of leachate head addressed (e.g., bathtub effects) • Landfill gas system • Gas migration in the future does not represent a threat • Groundwater monitoring • Currently in detection monitoring • Monitoring has been performed long enough to have detected a release • Final cover • Cap predicated on other modules’ requirements • Containment of waste addressed • Only provide de minimus care needed to maintain cap and the outcomes of other modules

18. What Happens after Surveillance Monitoring? • Regulatory PCC ends • Financial assurance ends • Custodial Care begins

19. Custodial Care • Continuing obligations to care for the closed landfill • Ensure that it does not pose a threat to human health and the environment • Outside of the direct jurisdiction of solid waste regulatory authority • Institutional controls or covenants to ensure the protective conditions • Deed restriction • Covenants • Alternate land use control mechanisms

20. Example: Minnesota Closed Landfill Program • Established in 1994 • The Minnesota CLP is the first program of its kind. • Increased local interest in using bioreactor and ACAP technology including their associated costs and environmental benefits and how they may apply to closed and operating sites.  • The information collected through mid-2006: • cumulative dollars for O&M and Remedial Construction and Design is pretty low over 12 years (i.e., has only spent $31M for O&M). • Number of landfills in the program about 110. • Landfill type (i.e., pre-Subtitle D – no liners or leachate collection), and variable geologic setting of some sites include potentially high “threat sites” like those located in sand and gravel mines, karst, etc.   • The State of Minnesota ranks sites annually based on threat to best allocate the spending of dollars.

21. In Summary • Post Closure Care can be shorten or lengthened • Defining the end-use of PCC for a successfully closed landfill site is an important first step in permitting a landfill operation • Four components of PCC for landfills • Leachate • Gas • The end of PCC occurs when a landfill no longer threatens human health and the environment base on a performance evaluation of the four components of PCC • Ending Post Closure Care is possible as well as practical • Custodial Care • After PCC ends Custodial Care occurs that involves de minimus amounts of care • Groundwater • Cap