Water Quality Impacted by External Events in the Demonstration-Scale Under-Ocean Floor Seawater Intake System

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Eustace Foster
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1 Water Quality Impacted by External Events in the Demonstration-Scale Under-Ocean Floor Seawater Intake System Yan Zhang, Tai J. Tseng, Robert C. Cheng, and Kevin L. Wattier Nov 15th, Water Quality Technology Conference Phoenix, AZ 1

2 Presentation Outline Project Overview and Approach Demonstration Scale Research and Findings Flow Data Water Quality Conclusion Findings Future Work 2

3 Presentation Outline Project Overview and Approach Demonstration Scale Research and Findings Flow Data Water Quality Conclusion Findings Future Work 3

4 Seawater Desalination Program A $20 M, 10-year investment Leverage various partnerships for technical input and other support Federal/State/Local Funds, 50% funding by Reclamation Pretreatment Intake/Discharge NF 2 or RO Post treatment / Distribution $5 M Project ($2 M DWR) Prototype UV/ClO 2 Mitigation of WQ impacts due to integration of new source 4

5 Types of Intake Systems Open Ocean Intake Subsurface Intake Horizontal/Directional Drilling Vertical Beach Well Infiltration Gallery (LBWD method)

6 Demonstration Site Layout Discharge Area Infiltration Area ~2000 ft 2 ~3100 ft 2

7 Cross Section of Intake Gallery

8 View at Low Tide

9 Construction

10 System Layout Filter Effluent delivered to Wet-well Raw Seawater To Discharge Gallery Cartridge Filtration and Membrane

11 Cartridge Filtration

Research Objectives Technical Can we sustain

Determine the maximum sustainable intake

Determine the additional treatment benefits

12 Research Objectives Technical Can we sustain water quantity? Determine the maximum sustainable intake filtration and discharge rate What is the water quality and how does it compare to Microfiltration? Determine the additional treatment benefits provided by the intake system Environmental Impingement/entrainment Federal Clean Water Act, Section 316 (b) Discharge Brine dispersion

Water Quality Monitoring Continuous online filtrate monitoring

13 Research Approach Yield Investigation Investigate Infiltration Rates of 0.05, 0.10, and 0.15 gpm/ft 2. Water Quality Monitoring Continuous online filtrate monitoring Weekly/Bi-weekly raw, filtrate and post CF microbial, general physical grab monitoring Intensive 30 day monitoring for external events impacts

14 Presentation Outline Project Overview and Approach Demonstration Scale Research and Findings Flow Data Water Quality Conclusion Findings Future Work 14

15 Flow through system (Jun '08- Oct '08, 155 gpm-0.05 gpm/ft 2 )

16 Flow through system (Oct '08- Mar '09, 310 gpm-0.1 gpm/ft 2 )

17 Flow through system (Apr '09- Jun 10, 233 gpm-0.15 gpm/ft 2 )

18 Flow through system (Sep 10- Oct 11, 465 gpm-0.15 gpm/ft 2 )

19 What s Causing the Shut Downs? System design Filter Gallery Size Engineered sand permeability Tidal conditions Low tide levels? Shut downs not consistently occuring at low tide levels Temperature-changing water permeability Raw Water Quality? Very frequent shut downs occurred in Nov/Dec heavy rain season, caused by deteriorated water clogging filter bed?

20 Water Production Summary

21 Presentation Outline Project Overview and Approach Demonstration Scale Research and Findings Flow Data Water Quality Conclusion Findings Future Work 21

22 WQ Improved with Time

23 WQ Improved with Time

24 WQ Impacted by External Events Rain Sewer Spill Red Tide Tidal Levels

25 Impacts of Rain on Total Coliform 25

26 Impacts of Sewer Spill 26

27 Impacts of Red Tide 27

28 Impacts of Tide Levels 28

29 Impacts on Turbidity 29

30 Impacts on TOC 30

31 Impacts on Conductivity 31

effective in removing raw water microbial levels spikes during rain and sewer spill events Heavy rain, red tide and

32 Water Quality Summary Water quality improves with time Heavy rain and sewer spill increased microbial levels in raw seawater, but no clear impacts observed with red tide events and different tide levels The filtration system was effective in removing raw water microbial levels spikes during rain and sewer spill events Heavy rain, red tide and sewer spill all increased raw seawater turbidity Red tide increased raw seawater TOC levels Heavy rain decreased raw seawater conductivity

33 Presentation Outline Project Overview and Approach Demonstration Scale Research and Findings Flow Data Water Quality Conclusion Findings Future Work 33

34 Findings Water Quantity: The system can produce a sustained capacity up to a flow rate of 465 gpm (infiltration rate of 0.15 gpm/ft 2 ) Water Quality: System product water quality improves with time External events can impact raw seawater quality, however, this impact was removed by the system

35 Future Work Continue testing on current and higher infiltration rates and investigate hydraulic profile to improve system capacity Membrane Testing

36 Acknowledgement Long Beach Water Department s staff, Cynthia Andrews-Tate, Ana Flores, and Eric Mintz for conducting the laboratory work CA Department of Water Resources and the US Bureau of Reclamation for partial funding of this project Technical Advisory Committee: Dr. Steve Duranceau, Steven Hubbs, and Gary Logsdon

37 Questions 37

Evaluating Membrane Fouling Conditions from Demonstration-Scale Under-Ocean Floor Seawater Intake System

Evaluating Membrane Fouling Conditions from Demonstration-Scale Under-Ocean Floor Seawater Intake System Tai J. Tseng, Jason B. Allen, Yan Zhang, Robert C. Cheng, and Kevin L. Wattier March 30th, 2011