The Relationship Between Water and the CCR Rule

Transcription

1 The Relationship Between Water and the CCR Rule A Vital Issue for CCR Rule Compliance Teresa L. Entwistle, P.E., CFM AECOM St. Louis, MO MWCC Conference

2 Introduction With the strict regulations presented in the EPA s CCR Rule, has water become a liability? The objective of this presentation is to highlight some of the issues that must be addressed with continued water usage in the power industry and the regulations as they apply to Surface Impoundments.

3 CCR Unit Water Regulations for Consideration CCR Rule June 14, 2016 CCR Rule Surface Water CCR Rule Groundwater CCR Rule Uppermost Aquifer NPDES Discharge and Dewatering ELGs

4 June 14, 2016 The inactive impoundment closure, Section 100, has been accepted for vacatur. EPA will issue the Extension Rule Will address revision dates for compliance in regards to Surface Impoundments Very Soon

5 Surface Water Timeline (T-18, 10/17/2016) Section Certifications Included Type of Action Action That Has to Be Completed Closure Trigger (a) Yes Complete Hazard potential classification No (c) No Compile History of Construction No (d) Yes Complete Structural Stability Assessment If Not Submitted (c) Yes Prepare Initial inflow design and flood control system plan No

6 Surface Water Analysis Points to Consider Upstream Conditions Operating Conditions Erosion Potential Spillway Capacity (or no spillway) Changing Conditions during Remediation Activities Differing Hazard Category than State Hazard Potential Classification High Significant Low Initial Inflow Design and Flood Control System Plan Design Storm PMF 1000 year 100 year

7 Surface Water Certifications October 17, 2016 Relevant Sections (a)(2) Hazard Potential State vs CCR (c)(1) History of Construction Description of each spillway and diversion design features, capacities, and calculations used in their determination (d)(3) Structural Stability Slope protection to protect against surface erosion, wave action, and adverse affects of sudden drawdown Spillway configured as specified Adequately manage flow during and after peak discharge Hydraulic Structure Penetrations Structural integrity Free of significant deterioration, distortion, deformation Bedding deficiencies Sedimentation and debris

8 Groundwater Monitoring Timeline (T-30) Timeframe Due Date Section Certifications Included Type of Action Action That Has to Be Completed Closure Trigger T-30 mos 10/17/ (f) Install Groundwater monitoring system (f) (f)(6) Select Statistical Method for baseline monitoring to establish background levels (b) Initiation of and Collection of Detection monitoring program 8 independent samples (d) (d)(3) Demonstrate Optional - Alternative monitoring frequency Timeline starts when rule published in Federal Register Monitoring program must be in place within 30 months Characterization of groundwater system and identification of uppermost aquifer Installation of monitoring wells Development of Sampling and Analysis Plan 8 independent samples from wells to form background dataset Typically quarterly sampling for 2 years Language provides for flexibility and a shorter total time period

9 Groundwater Monitoring System Requirements Monitoring Wells Thorough hydrogeologic characterization to identify uppermost aquifer, groundwater flow characteristics, and seasonal/temporal variability Wells to be located at downgradient waste boundary (perimeter of waste unit) Minimum of 1 upgradient, 3 downgradient wells Presumption that more wells are needed - use of minimum has to be justified Facilities with large CCR units could have as many as thirty or more downgradient wells Sampling Cannot filter samples for metals analysis Consider spatial and seasonal variability Triggers One statistical failure in detection monitoring triggers assessment monitoring (unless alternative source or error can be demonstrated within 90 days) Exceedance of a GWPS at unlined surface impoundments triggers closure A multi-unit monitoring program is allowed However, triggers apply to all units being monitoring (e.g., forced closure of all units)

10 Groundwater Compliance Timeline Timeframe Due Date Section Certifications Included Groundwater - Date not dependant upon CCR Rule publication date T-90 days w/in 90 days of detection of constituents w/in App III (e) (e)(1); or (e)(2) Type of Action Establish; or Demonstrate Action That Has to Be Completed Assessment Monitoring Program; or Source other than CCR unit responsible for statistical increase Closure Trigger - T-90 days w/in 90 days of triggering Assessment Monitoring (b) Conduct Analyses for all parameters inappendix IV - T-90 days + T-90 days after results T-90 days + T-90 days after results w/in 90 days of obtaining results from (b) w/in 90 days of obtaining results from (b) (d) Conduct Analyses for all parameters in Appendix III and for those constituents in Appendix IV that are detected in response to paragraph (b) (g)(3)(i); or (g)(3)(ii) (g)(3)(ii) Initiate; or Demonstrate Assessment of Corrective Neasures Source other than the CCR unit caused the contamination, or that the statistically significant increase resulted from error - Yes (g)(5) if unlined As soon as feasible (a) Document Groundwater Corrective Remedy meets requirement - Upon Completion (e) Document Remedy has been completed in compliance -

11 Indeterminate Timelines If Groundwater Protection Standards (GWPSs) exceeded at an existing unlined impoundment, stop placing waste and initiate closure (or retrofit) within 6 mos. of determination Additional deadlines for many actions once monitoring program is in place, such as: Complete statistical determinations Annual reporting Conduct certain assessment activities Initiate and complete Corrective Measures evaluation Select a remedy Initiate Corrective Action

12 CCR Groundwater Compliance 01 Detection Monitoring Statistically Significant Increase (SSI) in Appendix III Constituent 02 Assessment Monitoring SSI of Appendix IV Constituent 03 Assessment of Corrective Action (leading to Corrective Action) or 04 Closure for Unlined Surface Impoundments 05 Alternate Source Demonstration Allowed Appendix III Boron Calcium Chloride Fluoride ph Sulfate TDS Appendix IV Antimony Arsenic Barium Beryllium Cadmium Chromium Cobalt Fluoride Lead Lithium Mercury Molybdenum Selenium Thallium Radium

13 Typical Structure of Groundwater Compliance Programs Detection Monitoring Purpose: to identify a release from the unit Based on comparison to background Statistically-based trigger Assessment monitoring Assessment monitoring (= Compliance monitoring) Purpose: Confirm release from unit as well as nature and extent of contamination Comparison of groundwater concentrations to GWPSs Default is background or drinking water standard, maximum contaminant level (MCLs) Flexibility for site-specific, risk-based Alternate Concentration Limits (ACLs) allowed at discretion of regulatory authority Exceedance of GWPSs Corrective Action Corrective Action to return to compliance with GWPSs

14 When Compliance Monitoring Programs Go Bad Regulations are based on simplistic assumptions Groundwater is uncontaminated prior to waste unit Representative background can be characterized Units have simple hydrogeology and geochemistry Releases are easily identified and then fixed Basic statistics are appropriate to identify release from unit Reality Many units are built over pre-existing groundwater contamination Many units pre-exist regulations, so groundwater is contaminated at the start of the monitoring program Large units can expect variable hydrogeology/ geochemistry conditions, such that simple upgradient/ downgradient comparison not appropriate Large units can create their own geochemical conditions not related to releases from the unit Ground disturbance/construction activities can change chemistry

15 When Complying with the Regulations Goes Awry Regulations are based on simplistic assumptions Water being discharged is uncontaminated prior to waste unit Representative background can be characterized Units have simple construction, hydrogeology and geochemistry Releases are easily identified and then fixed Basic statistics are appropriate to identify release from unit Reality Many units are built over pre-existing facilities or contamination Many units pre-exist regulations, so many units pre-date current regulations exclusive of CCR Large units can expect variable hydrogeology/ geochemistry conditions, such that surface water / groundwater is connected Large units can create their own geochemical conditions not related to releases from the unit Ground disturbance / remediation / construction activities can change discharge quantities, locations and chemistry

16 CCR Units in the Floodplain Why does it matter? Who decides regulatory obligations? Differing state requirements No-Rise, Floodplain Storage, Washout How to counteract opposition? Can a unit be removed from the regulatory floodplain? LOMR / LOMA and the important difference between them Presentation Title September 22, 2016 Page 16

17 Location Restrictions (Uppermost Aquifer) Applies to new and existing impoundments Minimum 5-ft separation between high groundwater and base of unit Groundwater in uppermost aquifer Geologic separation allowed Low yield/clay formations may not be included in this uppermost aquifer Definition of useable groundwater Alternative if less than 5 in arid conditions, may demonstrate no hydraulic connection between unit and groundwater If cannot demonstrate separation at existing unlined impoundment: Stop accepting waste Close or retrofit unit

18 Hydrogeology Identifying the Uppermost Aquifer Perched groundwater in residuum dominated by downward flow Uppermost aquifer may be in the underlying bedrock secondary porosity (caves and other karst conduits) Open channels = Rapid infiltration of rainfall Rapid flow-through to the river Similar to flow in an intermittent stream

19 Discharge and Dewatering Dewatering Questions Why How When Where to Discharge

20 Dewatering Points to Consider Composition of Stored Ash Percent of Saturation Location of Site Continued Operation Disposal of Water / Ash Final Configuration of Impoundment Pilot Study

21 Dewatering Why How Trenches Excavation, Stockpiling and Seepage Pumping Geomembrane, tube vs surface layer VCD When Where to Discharge How the NPDES Permit can work in your favor?

22 BRIEF Overview about ELGs Rule CCR ELG Applicability Set to manage the structures that contain the CCR and transport waters and any unanticipated releases. Set to measure the managed release of the water that comes out of the structure. Until rule is applicable for each individual unit, all legacy units can continue to discharge all streams produced under current NPDES permit. ELG regulation will likely lead to tighter management of water, conversion to dry handling methods, or reuse water collectively

23 Questions Discussion and Questions

24 Thank You Please contact us for more information Teresa L. Entwistle, P.E., CFM Senior Project Manager, AECOM