Biological Treatment of Groundwater Containing Perchlorate Using Fluidized Bed Reactors

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1 Biological Treatment of Groundwater Containing Perchlorate Using Fluidized Bed Reactors Bill Guarini August 23-24, 2000

2 ACKNOWLEDGMENTS AEROJET CORPORATION: US FILTER: ENVIROGEN: Craig Fegan Gerry Swanick Mike Girard Casey Whittier Gene Mazewski Bob Hines Paul Hatzinger Sam Frisch Scott Drew Dave Enegess

3 Presentation Outline 1. Envirogen/USFilter Partnership 2. Perchlorate Biological Degradation 3. Selection of Reactor Type 4. Fluidized Bed Reactor 5. Case Histories - Pilot - Full-Scale 6. Summary

4 Envirogen-USFilter Relationship Joint Marketing for Perchlorate and MTBE applications Envirogen focus - microbiology and biocatalysts USFilter focus - systems and hardware Strong synergy between the two organizations

5 Bacterial Metabolism Requirements: Energy Source (organic or inorganic) Electron Acceptor (O 2, NO 3, SO 4, CO 2 ) Carbon Source (organic or CO 2 ) Macronutrients (N,P,S) Mineral Ions (Ca, K, Mg, Fe, Cu, Zn, Co, et al.) Vitamins and/or Amino Acids

6 Biological Perchlorate Reduction Terminal Electron Acceptor: ClO 4 - ClO 3 - ClO 2 - O 2 + Cl - (perchlorate) (chlorate) (chlorite) H 2 O

7 Organic Pollutants Biomass + CO 2 Benzene (substrate) Nutrients (N,P) e - H 2 O O 2

8 Perchlorate Biomass + CO 2 Substrate Nutrients (N,P) e - Cl - + H 2 O ClO 4 -

9 Utilization of Electron Acceptors CO 2 CH 4 Methanogenesis SO 4 - S - Redox (mv) ClO 4 - Cl - NO 3 - N 2 Denitrification Groundwater + Substrate O 2 H 2 O

10 Bioreactor System Options for Treatment of Organic Chemicals FLOWRATE, GPM CONTAMINATED WATER OR WASTEWATER FEED ph CONTROL NUTRIENTS OXYGEN FLUIDIZED BED REACTOR SYSTEM OXYGENATOR STATIC BED REACTOR SYSTEM TREATED EFFLUENT CONTAMINATED WATER OR WASTEWATER FEED OXYGEN ph CONTROL NUTRIENT(S) MEMBRANE BIOLOGICAL REACTOR SYSTEM TREATED EFFLUENT ,000 2,000 10,000 50, ,000 CONCENTRATION, mg/l

11 FBR Flow Schematic EFFLUENT FEED (i.e., CONTAMINATED GROUNDWATER) NUTRIENT(S) ELECTRON DONOR RECYCLE BED HEIGHT CONTROL SYSTEM FLUIDIZED BED REACTOR INFLUENT

12 FBR Advantages High biomass concentration means long SRT and short HRT High volumetric efficiency translates to compact system Simplicity of operation minimizes need for operator attention Small impact from changing feed conditions, as feed is combined with recycle before entering the reactor

13 Key Mechanical Components Device and method used to distribute influent flow to the reactor Device and method used to control the expansion of the fluidized bed due to biofilm growth Method to control electron donor dosage rate

14 Pilot-Scale Laboratory Testing for Perchlorate

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16 Laboratory-Pilot FBR Treatability - Application: Groundwater treatment - Feed: 6-10 ppm C1O 4, 1-2 ppm NO 3 -N - Effluent: < 4 ppb C1O 4 (NO 3 -N not measured) Treatability - Application: Groundwater / Process water - Feed: 400 ppm C1O 4, 480 ppm C1O 3, 20 ppm NO 3 -N - Effluent: < 0.02 ppm C1O 4, < 1 ppm C1O 3 < 1 ppm NO 3 -N

17 Study Laboratory-Pilot FBR Application: Media Comparison, sand vs. GAC Feed: ppm ClO 4 Effluent: < 4 ppb ClO 4 Study Application: Electron Donor Comparison (Ethanol, Methanol, Acetate) Feed: ppm ClO 4 Effluent: < 4 ppb ClO 4 (EtOH), < 20 ppb (HAc), ~1 ppm (MeOH), < 4 ppb (EtOH/MeOH)

18 FBR Media Performance Comparison 30 with ethanol Perchlorate Removal (mg/l) Sand Media Synthetic Feed Water Actual Groudwater Diagonal Perchlorate Removal (mg/l) GAC media

19 Electron Donor Performance Comparison with silica sand FBR media Perchlorate Removal (mg/l) with methanol Diagonal Perchlorate Removal (mg/l) with ethanol

20 Treatment of High Concentration Perchlorate Waters using Pilot FBRs 700 Perchlorate Concentration (m g/l) FEED FBR #1 EFFLUENT (2.1 hr HRT) FBR #2 EFFLUENT (3.1 hr HRT) < PQL Day of Operation HRT = Hydraulic Retention Time

21 Treatment of Chlorate and Nitrate in Pilot FBRs Chlorate Concentration (mg/l) Chlorate 700 FEED FBR #2 EFFLUENT (3.1 hr HRT) 200 FBR #1 EFFLUENT (2.1 hr HRT) 100 < PQL(1mg/L) Day of Operation 25 Nitrate-Nitrogen FEED Nitrate-N Concentration (mg/l) FBR #1 EFFLUENT (2.1 hr HRT) FBR #2 EFFLUENT (3.1 hr HRT) < PQL (1-4 mg/l) Day of Operation

22 Full-Scale FBR Treatment of Perchlorate

23 Full-Scale FBR Installation (Perchlorate Reduction) Design Basis 4,000 gpm Four reactors Ethanol as electron donor GAC media Volumetric ClO 4 loading = 44 lb/day/kcf

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26 Full-Scale FBR Performance Nitrate Perchlorate 2 1 a a Operation Time (weeks) a Insufficient ethanol dose during system tests.

27 Summary GAC media yielded quicker startup and showed more resiliency than sand. Ethanol is a more effective electron donor than methanol. Biological treatment to below quantitation limits has been demonstrated for high and low concentration waters. Consistent treatment of perchlorate to below quantitation limits has been demonstrated in a full-scale FBR system for more than 1 year.