2017 NWC Spring Seminar Series

1. Menu B. Leddy
Principal Scientist
April 5, 2017
Groundwater Replenishment
System (GWRS)

2. Personal Background
Water Factory 21,
1998
•BS, Stony Brook University,
New York
•Thesis: Association of Reovirus
Proteins w/ Structural Matrix of
Infected Cells
•Graduate thesis: Instability of
Pseudomonas putida strain 54G
•Funded by: OCWD, Naval Civil
Engineering & NWRI
•Microbial communities
identification by 16s rRNA

3. • Formed in 1933 to
protect & manage OC
groundwater basin
• Encompasses 229,000
acres (925km2) in the
lower Santa Ana River
(SAR) watershed
• OC groundwater basin
serves over 2.5 million
people
Orange County Water District (OCWD)

4. Imported water
•From Colorado River &
Northern California
(Metropolitan Water District)
•31% of the source water used
in Northern & Central
Orange County
•Nearly 100% used in South
Orange County
Sources of Water for Orange County
State Water
Project
Central Valley
Project
California Aqueduct
(144 mi)

5. Groundwater
•OCWD provides 72% of the
water used in Northern &
Central OC
•Is pumped from wells to cities
& agencies
•Basin is recharged by SAR,
rain, imported & recycled
water (GWRS)
Sources of Water for Orange County
OCWD recharge facilities

6. •SAR is southern
California’s largest
watershed & river
•Watershed covers
~3,000 sq. miles;
encompass LA,
Riverside, San
Bernardino & Orange
counties
•SAR flows start at
mountains &
discharge into the
ocean at HB
Santa Ana River (SAR)
SAR Trail
SAR
SAR watershed

7. OCWD OCSD
A joint effort of the
Orange County Water District & Orange County Sanitation District
January 2008

8. •Advanced wastewater purification
facility with 100 MGD capacity
•30 MGD of water produced is used
for sea water intrusion barrier;
serves 250,000 people directly
•Takes treated wastewater that
would be wasted to the ocean and
purifies to near-distilled quality
water
•GWRS uses advanced purification
technology: Microfiltration (MF),
Reverse Osmosis (RO), Ultraviolet
light (UV) & hydrogen peroxide
What is GWRS?

9. secondary
effluent
OCSD
Anaheim
Recharge
Basins
(70 MGD)
UV w/ hydrogen peroxide
Brine treated
in OCSD Outfall
MF
RO
Seawater
intrusion
barrier
(30 MGD)
Backwash
sent to OCSD
GWRS Advanced Purification Process

10. • Tiny, straw-like hollow fiber
polypropylene membrane (Siemens)
• ~137 MGD of 2nd treated wastewater
through membranes
• Sodium hypochlorite (bleach) added
to prevent biological fouling of
membranes
• 0.2 micron pore size (1/300 diameter
of human hair)
• Removes bacteria, protozoa,
suspended solids & some viruses
(attached)
MF System
15,000 fibers

11. RO System •Produces 100 MGD RO water;
membranes under high
pressure (150 PSI;
Hydranautics; polyamide)
•Removes salts, dissolved
minerals, viruses & organic
compounds (pharmaceuticals)
& dissolved minerals
•Produces near-distilled quality
water; add minerals back
(lime) to prevent corrosion of
pipes

12. •113 MGD Trojan UVPhox System
•Low pressure-high output lamp
system (250 watt)
•Uses hydrogen peroxide to create an
advanced oxidation process (AOP)
•Destroys trace organics
•Effective advanced oxidation
process keeps compounds (NDMA;
1-4 Dioxane) from reaching
drinking water supplies
UV/AOP System

13. • ~30% of GWRS water
sent to seawater
intrusion barrier
•14 mile pipeline located
west SAR levee
• Majority of water sent
to recharge basins in
Anaheim (Miraloma)
Where does GWRS water go?
N

14. Benefits of GWRS
• Protects against seawater intrusion
• Provides reliable supply of water
• Reduces ocean discharges
• GWRS water meets federal & state drinking water
standards
• Improves groundwater quality (TDS)

15. Prado Dam
•OCWD facilities capture SAR water for
groundwater recharge
•Prado Dam is an army core of engineer
flood control structure
•OCWD maintains water rights to the
SAR downstream of Prado Dam
•OCWD operates constructed wetlands
to remove nitrogen from a portion of
flows feeding Prado Dam
Recharge facilities
OCWD recharge facilities

16. Groundwater recharge by surface spreading
Indirect potable reuse (IPR) practiced by OCWD
Recharge
Basin

17. Surface Water Recharge System for GWRS
•25 recharge facilities; 1,100 acres of recharge basins
•Basin depth varies from 5 to 150 feet
•3 Orange County flood control basins
•26,000 acre-feet of combined storage capacity
•230 acre-feet/yr of water into the basin
•Primarily gravity flow systems
 6 pumping stations
 For dewatering basins & transferring water
•Water sources
 SAR flows (base & storm flow)
 GWRS
 imported water

18. Recharge Facilities Map
•Miraloma basin
designated to
recharge GWRS
water
•Online since
2012
•GWRS water
recharged at
Kraemer, Miller
& Miraloma
basins
•Future La
Palma basin

19. Miraloma Basin for GWRS water recharge
Miraloma
Basin
•Max. recharge capacity
30 MGD
•Provides reliable basin
to recharge GWRS
water that is not
impacted by storm flow

20. OCWD basin recharge sources (2010-2015)
Natural incidental
recharge 17%
Storm flow 14%
Imported water 13%
Recycled water 26%
Base flow 30%

21. Advanced Water Quality Assurance Laboratory
•Conducts WQ testing required by
state, regulatory agencies,
independent advisory panels &
voluntary monitoring
•Runs ~400,000 analyses on 20,000
water samples/yr
•Required to test for 129
constituents for compliance
monitoring & additional 430
constituents of emerging
contaminants to support GWRS &
groundwater recharge programs

22. Monitor for GWRS: MF/RO/UV-AOP
•Permit requirements & “voluntary” monitoring for process control
•Quarterly testing for >400 chemicals
•Routine coliform/E.coli testing
•Phage testing of RO product
•On-line monitoring
MF Integrity & Performance: Turbidity, TMP & PDT
RO: Conductivity & TOC reduction
UV-AOP: UVT, temp, flow, energy use & dose
•WQ higher purity than most other recharge alternatives

23. • Acute microbial risk
– virus
– protozoa
– pathogenic bacteria
– CDPH 12/10/10 requirement
• Acute chemicals risk
– NO3, NO2, Perchlorate (ClO4)
• Chronic chemical risk
– Inorganic chemicals (e.g., metals)
– Organic chemicals (e.g., DBPs, NDMA,
solvents)
Norovirus
CDC, Leonard Williams, NC A&T University
What are we trying to protect against?

24. R&D at OCWD
•R&D Department formed in early 1980s;
study the problem of biofouling layer
(slime) on RO membranes
•Focused on:
 membrane biofouling (biological)
 percolation enhancement in recharge
basins (bacteria-related)
 biological treatment of groundwater
contaminants
 Dr. Harry Ridgway Clark Water Prize
recipient (2002)
SEM image of fouled RO ESPA2 membrane

25. Current Research Activities
• Current research focus area includes:
 membrane studies: MF/UF and RO
(piloting new tech; optimization)
 UV/AOP (contaminant destruction; 1-4
Dioxane )
 recharge enhancement (i.e., basin
monitoring, silt removal)
 Prado Wetlands
 microbial methods (water quality)

26. Research activities related to microbial
methods & WQ
 qPCR detection & id. of human-
specific markers in GWRS & surface
waters (MSAR) by 16s rRNA genes
 Detection & id. of pathogens &
indicator organisms in GWRS &
surface waters (e.g., SAR, basins) by 16s
rRNA genes
 Development of rapid bioluminescent
Assimilable Organic Carbon (AOC) assay
 Next Generation Sequencing (NGS)
analysis of GWRS microbial
communities & related biofilms
B.t.
Biofilm scraping from MF
membrane for DNA extraction
DNA sequencer for 16s rRNA
V. harveyi

27. Start EndThe 16s rRNA Gene
PCR/qPCR amplify 35 cycles
RFU
Time
Unique PCR Fragment Size (bp)
Detection & id. of pathogens & indicator
organisms by 16s rRNA

28. Next generation sequencing (NGS) at GWRS
•In a given water or biofilm sample, NGS
allows shotgun DNA sequencing of whole
genomes or 16s rRNA genes present
•Identify parasites, fungi, bacteria,
viruses, ARG’s and virulence genes -
from family to strain level id.
•DNA sequences identified by advanced
metagenomics by mining sequence
databases such as CosmosID, GenBank
etc
Diagram of shotgun DNA sequencing

29. NGS Analysis of GWRS Biofilm Microbial Communities
Study to demonstrate the application of NGS to characterize
microbial communities in GWRS influent (Q1) & in biofilms from
MF & RO membranes. Collaboration w/ CosmosID & Dr. Rita
Colwell
Q1-water
sample
MF fiber biofilm for
DNA analysis
Scraping of RO membrane
biofilm for DNA analysis
GWRS Final
Product Water
(FPW)
MF
Break
Tank
UV Irradiation system
Sodium
Hypochlorite
OCSD
Secondary
Effluent Filter
Screens
Microfiltration
(MF)
Reverse Osmosis
(RO)
Clean MF fibers

30. Fungal species identified

31. Parasites species identified
•Identified 3 different parasite species
in Q1-water
•Identified Paramecium DNA in both
Q1-water & MF-biofilm
• Cryptosporidium/Giardia not
detected
• Further analyses planned to
confirm whether DNA extraction
failed or protozoa were removed
earlier in treatment
Parasite heat map

32. Bacterial species results
*Relative abundance threshold of ≥ 95% = confidence interval for the number of species present
• Greater number of species
were id. in Q1-water
compared to MF & RO
biofilms
•~30% of the species id. Q1-
water were above the 95%
threshold
•RO-biofilm had the lowest
number of species & ~48%
were above the threshold

33. Bacterial diversity
•Based on relative
abundance, greater
bacterial diversity was
observed in Q1-water
compared to MF & RO-
biofilm
•Bacterial diversity
lowest in RO-biofilm

34. Bacteriophage diversity
 Animal/human virus
DNA was not id. in the
RO biofilm
 Based on relative
abundance, lower viral
diversity was id. in MF-
biofilm
 Phage DNA id.
 ~ 4 different viral DNA
id. in Q1-water & MF-
biofilm

35. Fewer antibiotic resistance genes (ARGs) were
identified in the RO-biofilm
•Resulting in ~6% of the
ARGs in RO-biofilm
compared to Q1-water
• Five shared ARG
sequences were identified
in the MF & RO-biofilm
Leddy et. al., 2017. Characterization of microbial signatures from
advanced treated wastewater biofilms. JAWWA under review

36. • Characterize microbial
communities & their diversity
at GWRS treatment stages
• Relate to operational
parameters, season, biofilm
formation, log-reduction
credits, etc.
• Current study funded by
USBR: Characterization of the
Microbiome of a State-of-the-
Art Water Reuse System to
Enhance Treatment
Performance
Applications of
NGS at GWRS

37. Thank you
Questions?

38. NDMA Related Studies
• OCWD targets < 10 ng/L NDMA in finished product
water (disinfection byproduct)
• Portfolio of current studies includes:
– Extraction and non-targeted mass spectrometry analysis
of precursors (Arizona State University)
– WE&RF grant: evaluate conditions that promote NDMA
formation during advanced treatment (e.g., membrane
age, chemistry)