This is a good presentation to better understand the rationale of using purified wastewater as a sustainable and saleable source of freshwater. It also describes the Business Case, two Case Studies and the treatment technologies involved.

1. Terry Keep
Florida DEP, September 2012
UV-Oxidation for Direct and Indirect
Potable Reuse

2. Learning Objectives
• IPR/DPR Drivers
• IPR/DPR economics, business case
• Public Perception/ the Language of IPR/DPR
• History of IPR in California
• Why UV Oxidation/Science of UV Oxidation
• Case Studies: Orange County, CA (IPR) & Big Spring,
TX (DPR)

3. • Water stress (CA, TX, NM, AZ, Australia, Israel,
Singapore)
• Environmental effects
• Beach closures, coral reef degradation,
• Water Body improvement:
• Coastal: Tourism/beaches, Shell Fish Industry
• Great Lakes: Algal Blooms, beaches, sport fishing
IDP/DPR Drivers

4. UN Definition:
Water stress occurs when the demand for water exceeds the available
amount during a certain period or when poor quality restricts its use. Water
stress causes deterioration of fresh water resources in terms of quantity
(aquifer over-exploitation, dry rivers, etc.) and quality (eutrophication,
organic matter pollution, saline intrusion, etc.)
Source: UNEP Freshwater in Europe; glossary
Some Stats:
Canada and the U.S. are the two OECD countries that use the most water.
• USA = 2000 m3/person/year
• CANADA = 1600 m3/person/year
• DENMARK = 200 m3/person/year (Least Consumptive OECD Country)
WATER STRESS

5. Only about 0.5% of global water is “available” for consumption - all other
water is sea-water or ice.
WATER STRESS

6. • Growing demand on use of 0.5% of world’s water
due to
– Population growth, 80 MM people per year globally
– Rapidly rising energy demands
• Year 2000*
– 30% of world’s total accessible fresh water was
being used
• Future (2025/2030)*
– 70% of world’s total accessible fresh water will be
used
– 47% of world population in areas of water stress
* Water, Energy and Security, EESI Congressional Briefing, Dr. Allan R.
Hoffman, U.S. Department of Energy, 13 September 2006
WATER STRESS

7. California
Some of the most populated regions
of the state including Los Angeles and
San Diego receive the bulk of their
water from the Colorado river in the
northern part of the state. Crosses St.
Andreas fault
• Extreme costs associated with
transportation
Texas
Extreme heat and drought conditions
causing strain on natural drinking
water sources such as water tables
and reservoirs
WATER STRESS IN THE U.S.

8. • Reduce Growth
• Conserve Existing Water Stores
• Develop New Water Sources
• Water Transfer
• Desalination
– Seawater
– Brackish Water
• Non-potable Reuse to Offset DW
• Indirect or Direct Potable Reuse (IPR/DPR)
WATER STRESS: WHAT ARE THE OPTIONS?

9. FINANCIALS
IPR is cheaper than desalination and recycled non-potable water reuse
• Desal: Higher energy costs
• Purple Pipe: Installing new distribution system
Fermian Business and Economic Institute, 2011

10. WATER SHORTAGE: WHAT ARE THE OPTIONS?
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
Desalination IPR Local
Surface
Water
Water
Transfer
kWh/m3
IPR/DPR = 75% Less
Energy than Desalination
IPR/DPR is also less energy
intensive than other water
shortage solutions
IPR is an Attractive Option Both
in Terms of:
1. Costs
2. Energy Use
3. Security (not imported)
City of San Diego report, 2011:
IPR cost includes 10 mile
pipeline to reservoir
ENERGY

11. Indirect/Direct Potable Reuse: The Business Case
The Business Cases:
• Existing wastewater plant is a
cost to municipality
• Adding more technology &
convert wastewater to a saleable
product and reduce, if not
eliminate, WWTPs operating
costs
11

12. Indirect/Direct Potable Reuse: The Business Case
The Business Cases:
• IPR: Water is returned to aquifer:
no new piping system needed =
low infrastructure cost
• DPR: Water is returned to
distribution system or WTP = no
cost pumping water into aquifer
and pumping it out again.
• Aquifer water quality lower
than treated water
12

13. Indirect/Direct Potable Reuse: The Business Case
• Drinking water quality
affords flexibility in its
usage (not just for golf
courses, lawn watering) i.e.
new building developments
= increase tax revenue
• Sustainable use of limited
resource (new source of
fresh water)
• Lower impact on receiving
waters and wildlife habitat
13

14. THE PRICE OF UV-OXIDATION
When compared to microfiltration and RO, incorporating UV-oxidation can
be considered a negligible additional expense both in terms of costs and
energy use.
0%
20%
40%
60%
80%
100%
IPR Energy Use
EnergyUse(%ofTotal)
UV-Oxidation
Microfiltration
Other Energy Use
Reverse Osmosis
6.8%

15. WHAT’S INHIBITING ACCEPTANCE OF IPR/DPR?
Negative public
perception

16. Many people do not like the idea of their drinking water coming from treated
wastewater even though in many parts of North America it is happening
unintentionally
• Great Lakes
• Major Rivers (Mississippi, Ohio)
The words used to describe IPR are often perceived as “unclean” and
unattractive leading to negative opinions.
• “Waste”water
• “Re”cyled water and “Re”used water
Greater acceptance for “purified” water
DOES WORDING AFFECT OPINION?
“purified”

17. PUBLIC SUPPORT FOR IPR INCREASES WITH EDUCATION
San Diego County Water Authority: 2011 Public Opinion Poll Report, Rea & Parker 2011

18. WATER REUSE: WORLD PROGRESS
• Israel reuses over 70% of its WW
• Singapore reuses 15% with
plans to double that by end of
2011
• Australia reuses 8%, has a
national goal of 30% by 2015
• USA reuses 5-6% of WW for
non-potable and potable
purposed and this number
continues to grow.
Source: Guy Carpenter. WateReuse Association 2010

19. CALIFORNIA WATER REUSE REGULATIONS
• The state of California is currently
drafting the only law abiding
regulations related to the
application of non-potable reuse
for drinking water augmentation in
North America.
• These regulations primarily
monitor treated wastewater used
for groundwater replenishment.

20. CALIFORNIA WATER REUSE REGULATIONS
These regulations are part of the California Code of Regulations (CCR):
Title 22
Division 4 – Environmental Health
Chapter 3 – Recycling Criteria
Article 5.1 – IPR for Groundwater Replenishment-Surface Applications
Article 5.2 – IPR for Groundwater Replenishment – Subsurface Applications

21. U.S. WATER REUSE REGULATIONS - HISTORY
1978 • First groundwater replenishment regulations introduced
to Title 22 in California
• Regulations have been evolving for over 30 years
• First groundwater regulations dealt with surface water
spread
1989 • Regulations were re-done to incorporate direct
groundwater injection

22. U.S. WATER REUSE REGULATIONS - HISTORY
2001-2002 • Regulations to total organic carbon (TOC) levels and
organic treatment modified due to the emergence of
NDMA and 1,4 Dioxane as contaminants of concern
2002-Present • Regulations continually being updated to reflect
contaminants of emerging concern
Present • Ground water recharge projects must incorporate
advanced oxidation treatment after secondary
wastewater treatment for direct groundwater injection
projects

23. CCR TITLE 22 – KEY POINTS
Advanced Oxidation (AO)
Definition: Taking secondary treated wastewater and applying reverse
osmosis (RO) and oxidative treatment processes for the further removal or
microorganisms, total organic carbon (TOC), salts and other contaminant
molecules
This is a mandatory treatment step for groundwater replenishment projects
which use direct groundwater injection.
It is also highly recommended for groundwater replenishment projects
through surface water spreading.

24. CCR TITLE 22 – KEY POINTS
The Treatment Goals of Advanced Oxidation Include but are not Limited to:
• < 10 ng/L NDMA
• 0.5 log reduction of 1,4-Dioxane
• <0.5 mg/L Total Organic Carbon
• 99.5% rejection of salts
Pathogen Removal (Groundwater Injection and Surface Water Spread)
• 12 log enteric virus reduction
• 10 log Giardia cyst reduction
• 10 log Cryptosporidium oocyte reduction

25. REAL WORLD ADVANCED OXIDATION
AO requires at least three different treatment processes (in addition to
secondary wastewater treatment).
Example: The Orange County Water District uses the following three
treatment steps for groundwater injection.
1. Microfiltration
2. Reverse Osmosis
3. UV-Oxidation
Microfiltration
Removes 50% or organic material and effectively removes bacteria,
protozoa, parasites and viruses
Prevents downstream fouling of reverse osmosis membranes improving
their functional lifetime

26. REAL WORLD ADVANCED OXIDATION
Reverse Osmosis
Removes molecules as small as 100 atomic mass units and 95% of organic
contaminants.
Required for advanced treatment according to Title 22
Removal portion of treatment train
UV-Oxidation
Provides an additional barrier for disinfection
Removes molecular contaminants that escape microfiltration and RO
through a combination of UV energy and oxidation.
Destruction portion of treatment

27. WHY UV-OXIDATION
It has been documented that molecules less than 100 atomic mass units in
size and those with high hydrophobicity can pass through microfiltration and
RO without being treated
Contaminants with these characteristics include:
NDMA 1,4-Dioxane
Bisphenol-A Carbamazepine
DEET Estradiol
Ibuprofen Acetaminophen
Clofibric acid Diclofenac
Meprobamate
Triclosan
Oxybenzone

28. * Poussade, Y; A. Roux, T. Walker and V. Zavlanos. Advanced Oxidation for
Indirect Potable Reuse – A Practical Application in Australia. Presented at
OzWater 2009.
NDMA – MEASURED POST RO AT BUNDAMBA*

29. THE ROLE OF UV-OXIDATION
Molecules which elude filtration are eliminated by UV-oxidation through
the combined action of two (2) independent degrading processes.
1. Direct UV-Photolysis
2. UV-Oxidation

30. O2
UV light is absorbed by the pollutant P:
Degradation rate depends on:
• Quantum yield of P, Φλ
• Molar absorption coefficients of P in the UV range, ελ
• Intensity and spectral distribution of the light source
• Absorption of water background
ProductsP
hn (energy)
[radical species]
1. DIRECT UV-PHOTOLYSIS

31. 1. DIRECT UV-PHOTOLYSIS
Chemical bonds are
broken by UV light

32. UV light is absorbed by hydrogen peroxide:
Degradation rate depends on:
• OH radical rate constant kOH,P
• H2O2 concentration
• Intensity and spectral distribution of the light source
• Absorption of water background
• OH radical water background demand
Products
H2O2
hn (energy)
2 •OH
P + •OH
kOH,P
[radical species]
O2
2. UV-OXIDATION

33. 2. UV-OXIDATION
Hydrogen
peroxide
Hydroxyl
radical
Chemical bonds are
broken by hydroxyl
radicals

34. THE ROLE OF UV-OXIDATION
Some contaminants that escape RO cannot be removed through oxidation
and can only be eliminated through UV-light (photo-chemically labile)
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
1,4-Dioxane NDMA Atrazine Geosmin
UV-Photolysis/UV-OxidationContributiontoTotal
ContaminantReduction(RelativetoAtrazine)
UV + 10 ppm H2O2
Photolysis

35. THE ROLE OF UV-OXIDATION – FOCUS ON NDMA
The EPA Integrated Risk Information System (IRIS) classifies NDMA as a
class B2 (probable) human carcinogen
• One in a million cancer risk = 0.7 ppt
NDMA was one of the monitored contaminants from the Unregulated
Contaminant Monitoring Rule 2 (EPA, 2006)
• See Below
EPA’s Third Regulatory Determination (expected in 2013) considering NDMA
regulations.
• Compliance would be expected 2015-1016
TOXOCOLOGY DATA

36. THE ROLE OF UV-OXIDATION – FOCUS ON NDMA
NDMA PREVALENCE
EPA evaluated nationwide NDMA between 2008-2010
25% of tested facilities had NDMA concentrations over 2 ppt
• 1 in 1,000,000 cancer risk = 0.7 ppt
• California Reporting Concentration = 10 ppt
In Texas, 56% of 81 systems had NDMA concentrations above 2 ppt
In California, 46% of 145 systems had NDMA concentrations above 2 ppt

37. THE ROLE OF UV-OXIDATION – FOCUS ON NDMA
Due to NDMA’s resistance to chemical oxidation, alternate oxidation based
treatment technologies are not as effective as UV-Oxidation (photo-chemically
labile).
Pisarenko, A.N., et al., 2011. In Press

38. NDMA – TREATED AT BUNDAMBA (RO Effluent)
* Poussade, Y; A. Roux, T. Walker and V. Zavlanos. Advanced Oxidation for
Indirect Potable Reuse – A Practical Application in Australia. Presented at
OzWater 2009.

39. CASE STUDIES

40. GWR INSTALLATION - ORANGE COUNTY, CALIFORNIA
• 70 MGD (100 MGD peak)
California facility treating
wastewater to drinking water
standards for groundwater
replenishment
• Water is injected (to protect
from seawater) and percolated
(to replenish) into the aquifer
• MF/RO/UV-Oxidation treatment
train (UV system uses
monochromatic amalgam
lamps)
• System Expansion in progress
Orange County’s Water Factory 21
pioneered the use of UV-oxidation.

41. GWR INSTALLATION - ORANGE COUNTY, CALIFORNIA

42. NDMA FULL SCALE TESTING - ORANGE COUNTY, CA
0
10
20
30
40
50
60
70
80
1 2 3 4 5 6 7
Run #
[NDMA],ppt
[NDMA], Inf
[NDMA], Eff
6 Reactors On
Flow: >8.5 MGD
4 Reactors On

43. DISINFECTION TESTING - ORANGE COUNTY, CA
Influent MS2
Effluent MS2
0.000
1.000
2.000
3.000
4.000
5.000
6.000
Log(pfu/mL)MS2

44. • 12.5 MGD California facility
also treating wastewater to
drinking water standards for
groundwater replenishment
• MF/RO/UV-Oxidation
treatment train (UV system
uses monochromatic
amalgam lamps)
• 1.3-log reduction of NDMA,
disinfection
GWR INSTALLATION – WEST BASIN MUNICIPAL WATER
DISTRICT, CA
West Basin Municipal Water District

45. NDMA FULL SCALE TESTING – WEST BASIN, CA
0
20
40
60
80
100
120
140
Influent NDMA Effluent NDMA
NDMAConcentration
(ng/L)

46. UV-Oxidation for Potable Reuse
Case Study - Big Spring, Texas
• Located approximately 300 miles west
of Dallas
• Population: 27,000
• Traditional Raw Water Sources:
– E.V. Spence Reservoir (Surface
Water)
• Surrounding Cities/Towns:
– Odessa
– Stanton
– Midland
Big Spring

47. UV-Oxidation for Potable Reuse
• Drinking water supply is managed by the Colorado River
Municipal Water District (CRMWD)
• In 2004, the CRMWD evaluated methods of augmenting or increasing
drinking water availability to support growth and provide protection
against the potential of supply shortages due to drought conditions.
• Three approaches were considered:
1. Obtaining Raw Water from Other Groundwater and Surface Water
Sources
2. Reusing Water for Non Potable Uses
– Golf Course Irrigation, Agriculture
3. Reusing Water as Potable Water

48. UV-Oxidation for Potable Reuse
Obtaining Raw Water from Alternative Sources:
• Local groundwater supplies are limited and aquifers are
not readily recharged
• Other surface water sources were too far and would
require extensive transportation
• Other surface waters could suffer decreased availability
due to drought conditions

49. UV-Oxidation for Potable Reuse
SOLUTION – Potable Reuse (Direct Raw Water Blending)
• CRMWD decided to build a single treatment plant that would treat
secondary wastewater from surrounding communities to an “advanced”
level
• Known as the “Raw Water Production Facility” (RWPF)
• The RWPF will generate “synthesized” raw water that will be added to
the “natural” surface raw water of the E.V. Spence Reservoir
• The synthesized raw water adds to the capacity of the reservoir and
preserves its supply of source water to the drinking water treatment
plants of Big Spring as well as the surrounding communities

50. UV-Oxidation for Potable Reuse
Reusing Waste Water for Non Potable Reuse:
• This approach would offset drinking water demand
• Water users were widely dispersed which would require
construction of an extensive distribution system
• Demand was also very seasonal and did not provide a
“year-round” solution

51. UV-Oxidation for Potable Reuse
Big Spring Reclamation Project
Source: Freese and Nicholls

52. UV-Oxidation for Potable Reuse
RWPF Details
• Advanced Treatment:
MF/RO/UV-oxidation
• UV-oxidation :
– Treatment of NDMA and
1,4-Dioxane
– Pharmaceuticals and
endocrine-disrupting
chemicals not removed
by MF or RO
– Additional disinfection
barrier
Raw Water Production
Facility Design Parameters
Design Flow: 1.8 MGD
Target Contaminants:
NDMA
1,4-Dioxane
Design NDMA Reduction: 1.2 - Log
Design 1,4-Dioxane: 0.5 - Log
Oxidant: H2O2
Disinfection Method: UV Light

53. UV-Oxidation for Potable Reuse
The Trojan Solution
• Trojan Supplied two (2)
TrojanUVPhox™ UV
chambers along with an H2O2
dosing system for the new
RWPF in Big Spring
• Construction is currently in
progress with commissioning
expected in Spring 2013
Testimonial
“The Trojan system offered a cost-effective additional layer of protection against a
number of water quality concerns, with removal/inactivation mechanisms distinct from
the membrane separation processes upstream”
David Sloan – Senior Water Engineer

54. SUMMARY
• State of California has been regulating IPR and groundwater
recharge installations for over 30 years.
• New regulations state that advanced treatment of wastewater
required both RO and an oxidation treatment step.
• Oxidation step removes molecules that are able to pass through RO
membranes

55. SUMMARY
• UV-Oxidation treats contaminants through both chemical oxidation and
direct photolysis
• UV-Oxidation (UV-photolysis) the only effective treatment against
emerging contaminants of concern such as NDMA
• After incorporating the required RO treatment and the highly
recommended upstream microfiltration treatment, the additional costs
associated with UV-Oxidation are minimal