San Diego s Advanced Water Purification Demonstration Project: Performance & Integrity

Transcription

1 Arizona Water Association Water Treatment Committee Seminar Series Next Horizons in Water Treatment Wednesday February 11 th, 2015 GateWay Community College San Diego s Advanced Water Purification Demonstration Project: Performance & Integrity James DeCarolis (Black&Veatch), Bill Pearce (City of San Diego) Outline of Discussion Project Background Testing and Monitoring Objectives Performance Monitoring Water Quality Monitoring Challenge Testing Integrity Monitoring Summary & Conclusions Acknowledgments Pure Water San Diego Update SBP style.pptx 1

2 PROJECT BACKGROUND Project Background 2004 the City Council approved a study to evaluate options to increase the use of recycled water Water Reuse Study identified six (6) potential options to maximize reuse with Reservoir Augmentation of the City s San Vicente Reservoir as the preferred reuse strategy City Council voted to proceed with a Demonstration Project to evaluate the feasibility of augmentation San Vicente with advanced treated purified water. SBP style.pptx 2

3 Demonstration Facility Located at the North City Water Reclamation Plant (North City) Construction period March to June MGD capacity consisting of microfiltration/ ultrafiltration, reverse osmosis, ultraviolet light/advanced oxidation Final product water (Purified water) used to supplement the North City recycled water system AWP Unit Processes Full scale alternative comparisons Low Pressure Membranes MF and UF side by side Pressurized hollow fiber, PVDF membranes Reverse Osmosis Membranes Two stage and three stage Energy recovery turbochargers Ultraviolet Light / Advanced Oxidation Trojan PHOX low pressure, high output lamps Single reactor, 72 lamp configuration SBP style.pptx 3

4 Demonstration Facility Processes ACE13 ANNUAL CONFERENCE AND EXPOSITION 6 TESTING AND MONITORING OBJECTIVES SBP style.pptx 4

5 Testing & Monitoring Objectives Verify that final product (purified water) water quality meets public health and reservoir augmentation criteria Demonstrate integrity monitoring techniques and performance reliability measures Monitor Constituents of Emerging Concern Collect operational performance data of the various AWP unit processes to assess O&M requirements of potential full scale facility 8 Testing and Monitoring Approach ACE13 ANNUAL CONFERENCE AND EXPOSITION Developed & Implemented Testing & Monitoring Plan 12 Month Testing Period Water Quality Monitoring Multiple Certified & Specialty Labs Challenge Testing Integrity Monitoring Operational Performance Monitoring INDEPENDENT ADVISORY PANEL (NWRI) 9 SBP style.pptx 5

6 PERFORMANCE MONITORING Performance Monitoring ACE13 ANNUAL CONFERENCE AND EXPOSITION Water Quality Monitoring Regulated Non Regulated Challenge Testing Nitrosdimethlyamine (NDMA) 1,4 Dioxane Integrity Testing Direct & Indirect Methods Critical Control Point Monitoring CEC Performance ADVANCED PURIFIED WATER AWP DEMONSTRATION FACILITY SCADA OVERVIEW SCREEN 11 SBP style.pptx 6

7 Water Quality Monitoring ACE13 ANNUAL CONFERENCE AND EXPOSITION Federal and State Primary and Secondary Drinking Water Maximum Contaminant Levels (MCLs) California Department of Public Health (CDPH) Notification Levels (NLs) CDPH Groundwater Replenishment Reuse DRAFT Regulation San Diego Regional Water Quality Control Board Basin Plan Objectives California Toxic Rule State Implementation Policy Constituents of Emerging Concern (State Water Resources Control Board Recycled Water Policy) 12 Quarterly Water Quality Monitoring Constituent Group Sampling Location Purpose Federal & State Regulated Drinking Water Standards Tertiary Effluent Purified Water Raw Water Public Health Regulatory USEPA s Priority Pollutant List Tertiary Effluent Purified Water Raw Water Public Health Regulatory / Reservoir Regulatory CDPH Notification Limits & UCMR3 Tertiary Effluent Purified Water Raw Water Public Health Regulatory CEC s Tertiary Effluent Purified Water Raw Water Public Health / AWP Performance 13 SBP style.pptx 7

8 Comparison of Water Quality Results to Demonstration Goals Note: Phosphorus was determined to be the limiting nutrient in the reservoir. Spiking tests showed RO removes 99.8 to 99.9% of the phosphorous present in the feedwater. 14 Water Quality Monitoring Results of Regulated Constituents Number of Regulation and Total Number Purified Water Constituents / Guideline Group of Tests Parameters Results Primary Drinking Water Meets all MCL Secondary Drinking Water Meets all MCL Microbial Non-Detect CDPH Notification Level Below all CDPH Groundwater Replenishment Meets all Reservoir Limits Meets all Total Number of Constituents / 231 7, Parameters 15 SBP style.pptx 8

9 Water quality monitoring results of nonregulated constituents Majority were below quantifiable concentrations in the purified water Quantifiable concentrations were below public health concerns (i.e. at least 18 times lower than DWELS and / or other health reference levels.) Bromochloromethane, hexavalent chromium, acesulfame potassium, iohexal, triclosan, and strontium 111 Constituents < Reporting Limit > Reporting Limit 16 UV/AOP Challenge Testing Purpose: Demonstrate removal of target constituents Gather information related to the impact of UV/peroxide dose on removal efficiency Limited feedwater concentrations of target constituents Required spiking of concentrated solutions To Main PLC LAB PREPARED SPIKING SOLUTION SPIKING SOLUTION INJECTION PUMP 17 SBP style.pptx 9

10 UV/AOP Challenge Testing Results ACE13 ANNUAL CONFERENCE AND EXPOSITION Challenge Constituent 1 Target Log Removal 2 Measured Removal (n=3) EE/O Calculated (kwh/1000 gallons/log removal) NDMA 1.2 (93.7%) 1.5 (98.6%) ,4 Dioxane 0.5 (68.4%) 0.6 (74.9%) Notes: 1 Target removal based on 2008 DRAFT Groundwater Recharge Regulations, subsequently revised in 2011 and Operating under design conditions: 1 MGD, 97% UVT, 3 mg/l hydrogen peroxide dose 18 Impact of UV Dose on Removal Efficiency 18 SBP style.pptx 10

11 1.00 Impact of Peroxide Dose on 1,4 Dioxane Removal Log removal = *peroxide dose (mg/l) R² = ,4 Dioxane Log Removal Target 1,4 Dioxane Removal Average EED = 0.31 kwh/1000 gallons Target Peroxide Dose (mg/l) 20 Integrity Monitoring Objectives ACE13 ANNUAL CONFERENCE AND EXPOSITION Demonstrate the reliability of the AWP unit processes Establish baseline performance of each unit process under intact conditions Maintain routine / continuous verification of integrity throughout the testing period Demonstrate integrity monitoring methods Develop measureable performance criteria and action plan response RO MEMBRANE VESSEL PROBING MF MEMBRANE FIBERS 21 SBP style.pptx 11

12 Membrane Integrity Monitoring Results ACE13 ANNUAL CONFERENCE AND EXPOSITION Unit Process Method Frequency Result MF/UF Pressure Decay Testing 1 per 24 hours Pressure decay <0.08 psi/5 min. RO Vessel Probing Post membrane Conductivity increased by stage in installation direction. No leaks detected. RO RO RO Pressure / vacuum decay testing Continuous on-line RO permeate conductivity monitoring RO permeate TOC monitoring Pre membrane installation Continuous Continuous Vacuum decay <= 0.37 inches Hg/min.. Permeate conductivity < 30 µs/cm Permeate TOC between ug/l 22 Critical Control Point Monitoring Critical Control Points Main unit processes (MF,UF, RO, UV/AOP) Critical Limit Parameters (CLPs) Membrane pressure decay rate to assess the integrity of the MF/UF membranes Online TOC to assess the performance of the RO membranes On line power consumption to assess electrical energy applied to the UV/AOP system Establish performance limits for each CLP Develop corrective actions in the event performance limits are exceeded. 23 SBP style.pptx 12

13 Critical Control Point Monitoring ACE13 ANNUAL CONFERENCE AND EXPOSITION Critical Critical Limit Monitoring Control Point Parameter Frequency Alert Limit MF/UF Pressure Decay 1 per day Value above baseline that approaches Critical limit. RO UV/AOP UV/AOP TOC, Conductivity Reactor Power Level Hydrogen peroxide dose rate Continuous (flow confirmation) Continuous Continuous 1 per day by draw down Continuous flow confirmation % change of measured concentration in combined RO permeate. 100% (2 to 7 lamp failures or 1 to 3 ballast failures). minimum dose (~22 ml/min.) to provide 3 mg/l peroxide Critical Limit 0.4 psi / 5 min. based on the maximum decay predicted to achieve 4 log removal Cryptosporidium. Online permeate conductivity = 150 µs/cm. Online permeate TOC = 100 ppb or greater for five consecutive measurements. 0% (8 or more lamp failures or 4 ballast failures ). 0 ml/min. indicating pump failure or loss of flow confirmation, Example Corrective Actions Confirm Results. Assess fiber breakage. Isolate/ repair/replace damaged membrane. Automatic shutdown (conductivity). Monitor individual RO trains. Verify analyzer accuracy. Conduct vessel probing. System alarm. Automatic increase of reactor power to 100% or system shutdown. Check / replace lamps and/or ballasts. Check dosing system. Recalibrate pump. Auto switch to standby pump. 24 ACE13 ANNUAL CONFERENCE AND EXPOSITION Critical Control Point RO Critical Control Point Monitoring Critical Limit Parameter Monitoring Frequency TOC, Continuous Conductivity Alert Limit % change of measured concentrati on in combined RO permeate. Critical Limit Online permeate conductivity = 150 µs/cm. Online permeate TOC = 100 ppb or greater for five consecutive measurements. Example Corrective Actions Automatic shutdown (conductivity). Monitor individual RO trains. Verify analyzer accuracy. Conduct vessel probing. 24 SBP style.pptx 13

14 Performance Based CEC Monitoring Indicators: Individual chemical occurring at quantifiable level which represents certain physiochemical and biological characteristics of a family of trace organics that are relevant to the fate and transport during treatment and provide a conservative assessment of removal. Surrogates: quantifiable change of a bulk parameter that can serve as a measure in quantifying the performance of individual unit processes or operation regarding their removal of trace compounds. Reference: Monitoring Strategies for Chemicals of Emerging Concern (CECs) in Recycled Water, Recommendations of a Science Advisory Panel, Panel Members: Paul Anderson, Jorg E. Drewes (Chair), Adam Olivieri, Daniel Schlenk, and Shane Snyder. State Water Resources Control Board, June 25, Performance Based CEC Monitoring Results Out of 92 CECs, 37 were identified as possible performance based indicator compounds based on occurrence and relevance in first 4 sampling events. 37 reduced to 16 based on consistent presence in RO feed in 4 weekly sampling events. Typically >90% removal across RO None are consistently above detection limit in RO permeate, so they are not adequately present to determine removal across AOP. presented. 26 SBP style.pptx 14

15 Differential Removal of Indicator Compounds Indicator 1 Avg. RO Feed (ng/l) 1 Avg. RO Permeate (ng/l) 1 Avg. UV/AOP Product (ng/l) RO Δ Removal (%) UV/AOP Δ Removal (%) Acesulfame K <27 <22 >99.9 >16.5 Sucraloase <100 <42 >99.9 NDMA 3 <2 <0.96 >65.5 Carbamezapine 190 <5 <1.2 >99 1 N=5 27 Differential removal of Surrogate Compounds Surrogate RO UV/AOP Δ Removal (%) Δ Removal (%) TOC 99.6% NA UV % 68.7% Monochloramines 72.8% Conductivity 99.0% NA 28 SBP style.pptx 15

16 SUMMARY AND CONCLUSIONS Summary & Conclusions Regulated Constituents water quality monitoring of regulated constituents has shown the Purified Water meets or exceeds all water quality goals established from anticipated regulatory requirements for IPR via surface water augmentation. Non Regulated Constituents water quality monitoring of 111 non regulated constituents showed only 6 were reported above the RL at least one time at concentrations order of magnitude lower than Drinking Water Equivalent Levels or other health based reference levels. Integrity Monitoring results showed the AWP unit processes to be reliable and allowed for the identification and quick response to the few exceedances of alert limits. 30 SBP style.pptx 16

17 Summary & Conclusions (Cont.) UV/AOP Challenge Testing demonstrated the target log removal of NDMA & 1,4 Dioxane was achieved and provided information required to assess the electrical efficiency of the UV/AOP system. CEC Indicator Compounds were identified which could be useful to monitor RO & UV/AOP performance. CEC Surrogates surrogates for verifying RO and UV performance have been identified. Further research is needed to identify surrogates for the oxidation aspect of AOP. 31 Acknowledgments City Demonstration Project Team AWP Operations and Data Management Team North City Water Reclamation Plant Operations Regulatory Agencies: California Division of Drinking Water California Regional Water Quality Control Board San Diego Region National Water Research Institute: Independent Advisory Panel (IAP) Members Funding Partners: United States Bureau of Reclamation California Department of Water Resources 32 SBP style.pptx 17

18 Pure Water San Diego Program Update 2013 Present City Council adopted the Water Purification Project Report and Directed by City Council to explore all potable reuse options including DPR. On going operation & testing at the Demonstration Facility supported by CA Proposition 50, CA Proposition 84 and the WateReuse Research Foundation (WRRF) funding to demonstrate DPR. Completion of Siting and Planning Studies for full scale potable reuse facilities. The City is working on a 20 year Pure Water Program consisting of a 15 mgd water purification facility to be operational by 2023 and an additional 83 mgd by Q&A DOWNLOAD FULL PROJECT REPORTS: Statements of fact and opinion expressed are those of the author(s) and presenter(s). AZ Water Association, AZAWWA and AZWEA assume no responsibility for the content, nor do they represent official policy of the Association. SBP style.pptx 18