WRF Webcast Hexavalent Chromium Treatment with Strong Base Anion Exchange (#4488)

Transcription

1 WRF Webcast Hexavalent Chromium Treatment with Strong Base Anion Exchange (#4488) November 13, 2014 No part of this presentation may be copied, reproduced, or otherwise utilized without permission.

2 Recent Cr6 Regulatory Developments

3 Project # Title (Bold = Completed; Italics = Ongoing) Topic 4488 Hexavalent Chromium Treatment with Strong Base Anion Exchange and Chemical Reductive Treatment, Residuals Media 4450 Impact of Water Quality on Hexavalent Chromium Removal Efficiency and Cost Treatment, Cost 4365 Feasibility of Microfiltration in the RCF Process for Hexavalent Chromium Removal Treatment 4404 Trace Level Chromium-6 Occurrence and Analysis Occurrence 4423 Assessment of Single-Pass IX and Adsorptive Media for Hexavalent Chromium Removal from Treatment Drinking Water WITAF 320/ National Implications of Community-Level Cost for a Theoretical Cr(VI) SDWA Standard Cost Total and Hexavalent Chromium Occurrence Analysis Occurrence 4418 Guidelines for Hexavalent Chromium Treatment Testing Treatment 4445/4516 Development of a Uniform Approach to Prepare Drinking Water Hex Chrome Compliance Plans Cost, Removal 4449 Sources, Fate & Treatment of Hexavalent Chromium Sources, Speciation, Treatment 4497 Chromium in Treatment Chemicals and Chromium Chemistry/Fate through WTPs and DSs Sources, Speciation 4556 Cost-Effective Residuals Management Strategies Residuals 4561 Bench-Scale Evaluation of Alternative Cr(VI) Removal Options for Small Systems Treatment 4562 Cr(VI) Contribution from Corrosion to Delivered Water Corrosion

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7 Hexavalent Chromium Treatment with Strong Base Anion Exchange and Chemical Reductive Media WRF Project 4488 Chad Seidel, PI Craig Gorman, Co-PI Amlan Ghosh, Co-PI

8 Project Participants Project Team Soquel Creek Water District Taj Dufour, Christine Mead, John Henderson, Kim Adamson Corona Environmental Consulting Chad Seidel, Craig Gorman, Amlan Ghosh University of California Davis Jeanne Darby, Peter Green, Xue Li Technical Advisors Laurie McNeill, Utah State University Dennis Clifford, University of Houston IonexSG Phil Chandler, Mike Waite, Rosa Daviu

9 Project Participants Water Research Foundation Mary Smith, Research Manager Project Advisory Committee Phil Brandhuber, HDR Stefan Cajina, California Dept. of Public Health Eugene Leung, California Dept. of Public Health Erin Mackey, Carollo Engineers (now West Yost) Francois Rodigari, San Jose Water

10 Soquel Creek Water District 38,000 population served 4,280 AF annual water production ~72 gpcd average water use 100% groundwater 15 active wells 5 wells with Cr(VI) Near or above 10 µg/l up to 40 µg/l ~600 1,100 gpm

11 How did we get here? Initial paper study assessed Cr(VI) treatment approaches Identified strong base anion exchange (SBA-IX) treatment Proposed and contracted WRF4488 Hexavalent Chromium Treatment with Strong Base Anion Exchange WRF4488 bench- and pilot-testing of SBA-IX treatment and residuals minimization strategies WRF4488 report published Implement 1,000 gpm SBA-IX treatment with brine treatment 2015 Comply with new California 10 µg/l Cr(VI) MCL

12 Initial Cr(VI) Treatment Technology Assessment Evaluate water quality data Evaluate site specific information Evaluate treatment alternatives viability Technical feasibility Performance of existing pilot or full scale demonstrations at other utilities Operational complexity Residual disposal Recommend viable treatment alternatives for pilot testing

13 Initial Cr(VI) Treatment Technology Assessment Technologies considered in detail: Reduction / coagulation / filtration (RCF) Strong base anion exchange (SBA-IX) Weak base anion exchange (WBA-IX) Chemical reductive media (CRM) Technologies not considered in detail: Reverse osmosis Biological reduction and filtration

14 Initial Cr(VI) Treatment Technology Assessment Conclusions WBA-IX No full-scale potable experience Most expensive; simplest operation SBA-IX Proven full-scale potable experience No vendor costs provided, concern over potential diminishing exchange capacity Potentially lowest cost; more intensive operation RCF Full-scale industrial experience; demonstration-scale potable experience Potentially lowest cost; likely most intensive operation Chemical Reductive Media No full-scale potable experience Potentially lowest cost; uncertain operational requirements

15 WRF4488 Proposed Objectives Demonstrate Cr(VI) treatment performance of highest ranked technologies Strong-Base Anion Exchange (SBA-IX) Chemical Reductive Media (CRM) Investigate treatment residuals minimization strategies for SBA-IX Inform design and permitting of full-scale treatment installation and answer operational questions that impact capital and lifecycle costs

16 WRF4488 Approach SBA-IX Bench-scale resin screening Evaluate EBCT conditions Multiple loading and regeneration cycles Pilot-scale testing CRM Confirm bench-scale performance Investigate direct brine recycling Generate brine for advanced brine treatment Pilot-scale testing

17 Bench Scale Objectives Identify the best performing SBA-IX resin to be used in pilot scale testing Assess potential treatment capacity loss due to repeated loading and regeneration

18 San Andreas Well Water Quality Parameter Units Historic Raw Water Bench Testing Pilot Testing Chromium (Total) µg/l ph SU Sulfate mg/l Iron mg/l <0.025 Manganese mg/l < Nitrate mg/l as NO Arsenic µg/l 0.6 <1 <1 Bicarbonate mg/l as HCO Bicarbonate Alkalinity mg/l as CaCO Carbonate Alkalinity mg/l as CaCO3 <1 Uranium* pci/l <1 <1 Total Dissolved Solids (TDS) mg/l Total Organic Carbon (TOC) mg/l Turbidity NTU

19 SBA-IX Resin Screening Conducted in two phases at UC Davis Lab Phase 1: EBCT screening Phase 2: Resin screening 19

20 SBA-IX Resin Screening Co-current regeneration

21 SBA-IX Resin Screening Resins and column design Manufacturer Resin Type Loading/Regen Cycles A600E 9149 Type I Gel 10 Purolite Type I Macroporous A520E 6 Nitrate selective ResinTech SBG1 Type I Gel 5 DOW DOWEX SAR Type II Gel 6 Lanxess/ Sybron LEWATIT GW66 Type I Gel 5 Bench-scale Column Design Parameters Values Column diameter (cm) 1.5 Length of resin bed (cm) 6.1 Approximate volume of resin (cm 3 ) 10.8 EBCT (sec) 45 HLR (gpm/ft 2 ) 2.0 Flow rate (ml/min) 14.4

22 EBCT Screening Proposed plan assumed 5,000 bed volumes (BVs) to breakthrough Recent WaterRF research showed >10,000 BVs to breakthrough Resin Empty Bed Contact Time, EBCT (sec) Purolite A600E X X X Purolite A520E X X

23 Resin Screening: EBCT Resin, EBCT (sec) Total Chromium ( g/l) A600E, 90 A600E, 90 (raw) A600E, 45 A600E, 45 (raw) A600E, 30 A600E, 30 (raw) 30 sec 90 sec Approaching 30,000 BVs to breakthrough at 8 µg/l Minimal performance impact at 45 sec EBCT 0 5,000 10,000 15,000 20,000 25,000 30,000 35,000 40,000 45,000 Bed Volumes Treated sec

24 Resin Screening: First Loading Resin, EBCT (sec)

25 Bench-scale Multiple Cycles: Best Resin

26 Bench-scale Multiple Cycles: All Resins BVs to 8 µg/l

27 Regeneration Collected periodic and composite brine samples throughout regeneration Total chromium recovery calculated Regeneration conditions: 2 N NaCl 5 BV regenerant; 2 BV rinse solution

28 Regeneration

29 Regeneration: Chromium Recovery Chromium ( g) 4,500 4,000 3,500 3,000 2,500 2,000 1,500 1, Total Cr Removed (µg) Total Cr Eluted (µg) 0 Loading Cycle % Recovered

30 SBA-IX Bench Scale Summary 45 sec EBCT identified as most appropriate for subsequent bench and pilot testing Purolite A600E 9149 showed best performance of resins screened Some reduced treatment performance after initial regenerations, steady state thereafter Regeneration effectively recovers chromium

31 Pilot-scale Testing IonexSG IXL50 pilot unit Three columns Purolite A600E 9149 at 45 sec EBCT Operated April - August,

32 SBA-IX Pilot-scale: Objectives Confirm bench scale performance of best performing resin through 5 loading and regeneration cycles Investigate impacts of direct brine recycling Generate brine for bench-scale advanced brine treatment study

33 SBA-IX Pilot-scale Testing Pilot-scale Column Design Parameters Values Number of columns 3 Column diameter (cm / in) 21 / 8.3 Length of resin bed (cm / in) 17.3 / 6.8 Approximate volume of resin (L / ft 3 ) 6 / 0.21 EBCT (sec) 45 HLR (gpm/ft 2 ) 5.5 Flow rate (L/hr / gpm) 470 / 2.1

34 SBA-IX Pilot-scale Testing: Results Column 1 always regenerated with fresh brine Column 2 and 3 utilized recycled brine after first run 5 loading and regeneration cycles completed

35 SBA-IX Pilot-scale Testing: Fresh brine Total Chromium ( g/l) No indication of performance loss after 5 cycles using fresh brine Column, Run Pilot1_R1 Pilot1_R2 Pilot1_R3 Pilot1_R4 Pilot1_R5 0 5,000 10,000 15,000 20,000 25,000 30,000 35,000 40,000 45,000 Bed Volumes Treated

36 SBA-IX Pilot Testing: Brine reuse After first regeneration, brine from Column 2 was collected and reused to regenerate Column 3 Make up salt was added Brine was used a total of 8 times

37 SBA-IX Pilot Testing: Brine reuse Total Chromium ( g/l) st Use 2nd Use 3rd Use 4th Use 5th Use 6th Use 0 5,000 10,000 15,000 20,000 25,000 30,000 35,000 40,000 45,000 Bed Volumes Treated 37

38 SBA-IX Testing: Exceptionally promising results 15,000 30,000 BVs to breakthrough Higher water efficiency, lower brine waste disposal and cost than originally anticipated 5,000 BVs estimate: 99.85% efficient 15,000 30,000 BVs estimate: >99.97% efficient 38

39 Brine Testing Three technologies investigated Ferrous reduction/coagulation Weak Base Anion Exchange Chemical Reductive Media 39

40 Pilot-scale: Brine Treatment Tested approaches to remove chromium from waste brine to yield non-hazardous liquid waste Reduction/Coagulation WBA-IX Effective Ineffective CRM Effective, but costly

41 WRF4488 Conclusions SBA-IX was much more effective than anticipated >20,000 BVs of treatment before regeneration Over 10 loading and regeneration cycles Brine recycling feasible Brine treatment feasible

42 Approach moving forward Demonstrate SBA-IX at San Andreas well as quickly as possible Assess other impacted well sites and then proceed with design and construction

43 Demonstration Facility IX-C from Ionex SG, LLC 1,000 gpm SBA-IX at San Andreas Well Raw water pipeline from Bonita Well Can treat water from either well 43

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53 California DDW Permitting Developed Engineering Report and Operations Plan Obtained permit in September 2014 Includes operational and monitoring requirements for demonstration Intended to serve as a template for future SBA-IX Cr(VI) treatment permits

54 Next Steps Demonstration testing at San Andreas: Started producing water to system in October! Prove and optimize treatment performance Test and optimize brine treatment and disposal Site-specific testing of SBA-IX at other impacted wells Full-scale treatment system equipment procurement, design, permitting, construction, and startup Begin quarterly Cr(VI) MCL compliance sampling

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56 Thanks to all who collaborated to make this happen!

57 Q&A Chad Seidel, Ph.D., P.E. Corona Environmental Consulting, LLC (O) (C) Craig Gorman, P.E. Corona Environmental Consulting, LLC (O) (C)