Developing Appropriate Remedial Life-Cycle Costs through Effective Feasibility Testing

Transcription

1 Developing Appropriate Remedial Life-Cycle Costs through Effective Feasibility Testing Kevin Michael Lienau, P.E. Regional Engineering Manager GES Midwest Region

2 Introduction Feasibility test steps Feasibility test strategies conventional vs. enhanced Types of real-time data collected Using feasibility test results to select the right technology Life-cycle cost development Benefits of enhanced feasibility testing (case study) 2

3 Purpose of Feasibility Testing Enhance site conceptual model with field data on applicability and efficacy of site remediation Select most appropriate remedial technology > Sustainability/Green > Client Objectives > Life-Cycle Costs Provide data to design full-scale remediation system Feasibility testing usually leads to making remediation decisions that will cost > $100,000 (or likely even more)!! 3

4 Effective Feasibility Testing Four Steps to Performing an Effective Feasibility Test: > Step 1: Understand site conceptual model > Step 2: Plan the test > Step 3: Perform/assess the test with the appropriate equipment and personnel > Step 4: Summarize and evaluate test results 4

5 Step 1: Understand the Site Conceptual Model Determine horizontal & vertical impact Estimate mass in each phase (soil, groundwater, NAPL) Identify site-specific geology and hydrogeology Evaluate existing well construction Recognize site constraints and conditions Evaluate available historical slug test, pilot test, or previous remediation system data Identify data gaps Determine applicable clean-up goals 5

6 Step 2: Plan the Test Determine appropriate technologies to test Develop a strategy for obtaining data > Extraction equipment > Monitoring locations > Data collection methodologies and frequencies Select extraction/observation/injection wells 6

7 Step 2: Plan the Test (continued) Identify permit requirements > Discharge location > Treatment requirements/equipment > Waste collection and disposal > Chemical injection and storage Prepare a detailed feasibility test scope of work > Goals/objectives of testing > Decision points 7

8 Step 2: Plan the Test (continued) Determine Applicable Strategy Conventional... Enhanced... 8

9 Step 2: Plan the Test (continued) Conventional Strategy > Test one technology > Test one or two wells > Use available equipment > Collect data manually > Results reviewed following the test > Spend bulk of time setting up/tearing down 9

10 Step 2: Plan the Test (continued) Enhanced Strategy > Test multiple technologies > Test multiple wells > Use equipment that can handle different/unexpected site conditions > Log real-time continuous data > Review data in the field immediately > Minimize visits to site for additional tests or data collection 10

11 Step 2: Plan the Test (continued) Enhanced Strategy Testing Options > Soil Vapor Extraction (SVE) > Vacuum-Enhanced Groundwater Extraction (VEGE) > Groundwater Extraction (GWE) > Total Phase Extraction (TPE) > Air Sparging (with or without SVE) > Biosparging > In situ Chemical Injection (chemical oxidation, chemical reduction) > Bioremediation > Groundwater Reinjection 11

12 Step 2: Plan the Test (continued) Data Acquisition & Processing Laboratory (DAPL) > Self-powered (on-board generator) > Multiple blowers (two regenerative and one rotary claw) > Large air compressor > Electric and pneumatic submersible pumps > Oil/water separator > Chemical injection equipment > Programmable logic controller (PLC) system > Wireless monitoring of wells > Inline photoionization detector (PID) > On-board computer to view real-time data 12

13 Step 2: Plan the Test (continued) Vapor Flow Rate (scfm) Vapor Flow Rate (scfm) MW-8: Flow vs. Vacuum Vacuum (i.w.) MW-9: Flow vs. Vacuum Vacuum (i.w.) Why test at numerous wells? Example: Vacuum versus flow rate data often varies from well to well MW-8: iw vac MW-9: iw vac MW-1: iw vac Vapor Flow Rate (scfm) MW-1: Flow vs. Vacuum Vacuum (i.w.) Let the site s subsurface dictate the flows not the equipment brought to the site! 13

14 Step 2: Plan the Test (continued) Native Formation (Interbedded Seams) (Lower Permeability) Former Remedial System Interceptor Trenches (Higher Permeability) Current UST Basin (Higher Permeability) 14

15 Step 3: Perform the Test Install and develop new wells (observation and remedial test wells) Test conducted by trained personnel Obtain field data > Flow rate > Vacuum (applied and influence) > Liquid levels > PID readings Collect laboratory analytical data during test steps to compare mass recovery rates Typical of both conventional and enhanced testing 15

16 Step 3: Perform the Test (continued) Enhanced Feasibility Test Continuous review of real-time data > Groundwater elevations at extraction/observation wells > Pressure/vacuum levels at extraction/observation wells > Groundwater and vapor flow rates > Vacuum, pressure, flow data throughout system Field adjustments based on real-time data 16

17 Step 3: Perform the Test (continued) Data logging system stores real-time information, allowing the engineer to focus on analyzing data instead of manually collecting data Data Output VEGE Testing 17

18 Step 3: Perform the Test (continued) Real-Time Data (graphically) Extraction Well Vacuum / Flow Response 3 Vacuum Step Test 18

19 Step 3: Perform the Test (continued) Real-Time Data (graphically) Observation Well Vacuum Response 0.25 Vacuum Response at Observation Wells During Testing at VP-3 VP-4 VP-2 MW-7 MW Vacuum Response (inches of water) Elapsed Time (seconds) 19

20 Step 3: Perform the Test (continued) Reacting to the Observed Results: > Increase/reduce groundwater pumping rate > Increase/reduce applied vacuum > Increase/reduce sparge flow rate > Change submersible pumps Lower/higher flow Top-load versus bottom-load > Change extraction wells > Extend/shorten test > Try another technology (TPE instead of VEGE) 20

21 Step 4: Summarize Test Results Provide raw data in a reader-friendly format: > Data logger results > Field data, calculated data, charts, visuals > Analytical results Determine from the data: > Mass recovery rates (dissolved, vapor, NAPL) > Hydraulic conductivity/transmissivity > Other pertinent system design information 21

22 Step 4: Summarize Test Results (continued) Table of Technologies Tested and Key Design Indicators Well Test Vac. ("Hg) Vap. Flow Rate scfm GW Flow Rate (gpm) SPH Recov. Rate (gph) Diff Water table elev (ft) PID Conc. (ppmv) BTEX Conc. (mg/m^3) C5-C9 HC Conc. (mg/m^3) BTEX Recov. (lb/day) C5-C9 Hydro. Recov. (lb/day) VP-1 GWE VEGE VEGE VEGE VEGE , VP-3 GWE < VEGE VEGE ND MW-16 GWE VEGE NM VEGE , MW-20 GWE < VEGE < VEGE <

23 Step 4: Summarize Test Results (continued) Graphically depict results: > Vacuum versus distance > Drawdown versus distance > Vacuum/pressure, DO, ORP influences 10 Distance vs. Observed Vacuum VEGE Pilot MW-5 (38 i.w. 79 scfm) Vacuum Influence (i.w.) Distance From Extraction Well (feet) 23

24 Step 4: Summarize Test Results (continued) Water Table Rise During 3-step SVE Test at OW-2 Rise in Water Table Elevation (ft) Step 1-21 iw, 32 scfm Step 2-40 iw, 42 scfm Elapsed Time (minutes) Step 3-69 iw, 46 scfm >C4-C10 Removal: 36.1 lb/day SVE Testing Analysis Water Table Drawdown During VEGE Test at OW-2 Water Table Drawdown (feet) GE only 3.5 gpm VEGE, 51 iw, 90 scf m 3.5 gpm >C4-C10 Recovery: lb/day VEGE, 51 iw, 95 scf m 4.9 gpm >C4-C10 Recovery: lb/day VEGE Testing Analysis Elapsed Time (minutes) 24

25 Step 4: Summarize Test Results (continued) Evaluate Tests to Determine... > Technology applicability > Relative magnitude of remedial system / option How many wells? Size of excavation? Amount of chemical? > Duration of potential technologies > Site specific issues that may limit implementation > Site revelations! Use the Data to Determine Life-Cycle Costs for the Site. 25

26 Developing Comparative Life-Cycle Costs Life-Cycle Costs > Capital Costs > Operation and Maintenance Costs > Monitoring Costs > Decommissioning Costs > Duration of Remedy > Efficiency of Remedy > Can Be Today s Dollars or Adjusted for Inflation > Typically Does Not Take Into Account Green and/or Sustainable 26

27 Developing Comparative Life-Cycle Costs (continued) Life Cycle Cost of Viable Remediation Technologies Remediation Cost Options Over Time (Feasibility Testing, Design, Construction, Equipment, O&M, Closure) $1,200,000 $1,000,000 Cost $800,000 $600,000 $400,000 $200,000 Chemical Oxidation GWE & SVE AS/SVE SVE Excavation & MNA $ Time (years) 27

28 Sustainability Implications of Life Cycle Costs Life-Cycle Costs are only one piece of the Sustainability Puzzle! 28

29 Conclusion Understand the site conceptual model Plan a test strategy enhanced feasibility testing is the most effective Use enhanced/flexible test equipment Use properly-installed/developed wells Collect real-time data Use experienced personnel to assess and respond to data Collect and summarize enhanced data Develop life-cycle costs and green/sustainability criteria 29

30 Result Follow all steps Likely Result: > Successful feasibility test completed > Right technology or technologies selected to remediate the site 30

31 Developing Appropriate Remedial Life- Cycle Costs through Effective Feasibility Testing Kevin Michael Lienau, P.E. Regional Engineering Manager GES Midwest Region (800) x 3175 klienau@gesonline.com

32 Case Study of Enhanced Pilot Tests (Presentation Bonus)

33 Benefits of Enhanced Feasibility Tests Case Study of Enhanced Tests Review of 27 DAPL pilot tests: > Eastern PA, > Full-scale systems installed following test Most sites >3,000 lbs of contaminant mass Most common technologies: TPE, VEGE, AS/SVE Goal: Determine if any measurable benefit to enhanced feasibility testing 33

34 Benefits of Enhanced Feasibility Tests (continued) Results: > Average time, system start-up to shut-down: 2.4 years > Achieved regulatory closure: 10 of 27 sites (many in post-remediation monitoring) > Needed another technology: 2 of 27 (both short-term chemical oxidation polishing) 34