Pilot-Scale Evaluation of MF-Ozone-BAC Process Train for Removal of Emerging Contaminants Vijay Sundaram Robert W. Emerick, Ph.D., P.E. John P. Enloe, P.E. Stan Shumaker, P.E. Michael Drinkwater, P.E. Stephen Long City of Reno

Study Motivation  Indirect Potable Reuse  Aquifer storage and recovery  Effluent Dominated Surface Water Discharge  Narrative toxicity

Wastewater Treatment Options Implemented  MF-Ozone  Las Vegas, NV (Lake Discharge)  Ozone-BAC  El Paso, TX (Groundwater Recharge)  MF-RO  West Basin, CA (Groundwater Recharge)  NEWater Project, Singapore (Potable Water Augmentation)  Scottsdale, AZ (Groundwater Recharge)  MF-RO-UV-Peroxide  Orange County, CA (Groundwater Recharge)

Process Train Comparisons CategoryMF-Ozone-BACMF-RO-UV-Peroxide EDCs and PPCPsDegradedConcentrated (side stream) Net TOC Rem.Slight Advantage EnergySubstantial Advantage SustainabilitySubstantial Advantage Reject/Side StreamsNoneSome SalinityUnchangedDecreased CorrosivityUnchangedIncreased

RSWRF Pilot-Scale Project

Membrane Pilot Unit WesTech Membrane Unit (0.01  M)

Ozone Pilot Unit Feed and Off-gas Ozone Analyzers Applied Process Tech. HiPOx Ozone Unit Liquid Oxygen Supply In-line Injection

BAC Unit ±11 gpm 30 min Empty Bed Contact Time Calgon Filtrasorb 400 Medium WesTech BAC Unit

Results and Discussion  Ozone Dosage Optimization / Peroxide Testing  EDC and PPCP Removal  Bromate Formation  GAC to BAC Conversion  Biomass  Population Fingerprint

Constituents below Detection Limits  Acetaminophen (< 10 ng/L)  Androstendione (< 10 ng/L)  Caffeine (< 50 ng/L)  Diethylstilbestrol ( < 2 ng/L)  Estradiol (< 2 ng/L)  Estriol (< 1 ng/L)  Ethinyl Estradiol (< 2 ng/L)  Ibuprofen (< 10 ng/L)  Iopromide (< 100 ng/L)  Pentoxifyline (< 1 ng/L)  Progesterone (< 10 ng/L)  Testosterone (< 10 ng/L)  alpha-Estradiol ( < 1 ng/L)

Constituents Removed at Ozone Dose of 3 mg/L or more  Oxybenzone  Estrone  Carbamazepine  Diclofenac  Gemfibrozil  Hydrocodone  Methadone  Naproxen  Trimethoprim  4-Nonylphenol monoethoxylates  4-Nonylphenol diethoxylates  Octylphenol

Constituents with Inconsistent Results  4-Methylphenol  Phenol  TDCPP  Triphenylphosphate  TCEP  Bisphenol A  Salicylic Acid  Atrazine  Diazepam

Removal of EDCs and PPCPs

Byproduct Formation

Bromate Mitigation: Experimental Design Factors Levels IIIIIIIVVVI O 3 Dose (mg/L)357 H 2 O 2 -O 3 Molar Ratio O 3 Injection Points13 Injection SequenceH 2 O 2 FirstH 2 O 2 Last Ozone Influent: Alkalinity = 92 mg/L pH = 6.9

Effect of Peroxide on Bromate Formation

Key Points Learned  Ozone Dose >= 5 is recommended for EDC and PPCP removal, but may produce excess bromate  Bromate control possible with peroxide addition, particularly peroxide first with multiple O 3 injection points  Ammonia also plays a major role in preventing bromate formation

Steady-State Process Monitoring Constituents RSWRF Pilot - Effluent Type SecondaryMembraneOzoneBAC TOC (mg/L) BDOC (mg/L) Plate Count (cfu/mL) 1.5E+022.8E+05 Bromate (  g/L) <1 3.9<1

GAC to BAC Conversion

Next Steps: Pilot-Scale Project Monitoring  Sampling and quantification of contaminants after each treatment process  300+ contaminants of concern  Biodegradable organic carbon (BDOC)  Estrogenic activity (E-Screen)  30+ samples  ±12 gallons/sample  $300,000 (approx. lab cost)

Acknowledgements  City of Reno  Southern Nevada Water Authority  Shane Snyder, Ph.D. (Technical Advisor)  University of Nevada, Reno  Edward Kolodziej, Ph.D. (Technical Advisor)  WesTech  Applied Process Technology  Microbial Insights Robert Emerick, Ph.D., P.E Vijay Sundaram Contacts: