Steve Reiber, Ph.D.

1
Water Treatment
Past History/Future Challenges
Legionella
Steve Reiber, Ph.D. HDR Engineering
Seattle, WA
2
Evolutionary Change in Water treatment
The History of a Developing Market
Early water treatment engineers describe the
first dirt molecule.
3
Take-Away Points

• Despite predictions to the contrary, the cost of
  new technology (especially membranes) will not
  increase the cost of water treatment.
• When quality is factored in, the cost of water
  treatment will actually decline.
• Conventional sand filtration will be phased out
  in favor of low-pressure membranes. (This
  represents a 10 BGD market.)

4
Disinfection The Most Important Treatment Step

• Gate Houses and Chlorination Plant at Boonton
  Reservoir (Jersey City),circa 1908

5
Evolution of Water Filtration Technology
Slow Sand Filtration (Germany 1820)
River Bed Filtration (Roman Times)
Rapid sand filters are no longer the most
cost-effective polishing step.
Rapid Sand Filtration (Chicago 1900)
Cellulosic Membranes (1980)
6
Market Drivers
Numerous factors are influencing these changes.

• New water supplies are inferior.
• Fear of waterborne disease.
• SDWA regulations
• Expensive infrastructure replacement

7
The Water-Consuming Public is Aware
(and Wary)

• Well-publicized events
• Bottled water sales increase dramatically

8
Waterborne Disease Outbreaks Cause Irreparable
Damage to Public to PWSs
Year State/Territory Cause of Disease No. of People Affected
1985 Massachusetts Giardia lamblia (protozoan) 703 illnesses
1987 Georgia Cryptosporidium parvum (protozoan) 13,000 illnesses
1987 Puerto Rico Shigella sonnei (bacterium) 1,800 illnesses
1989 Missouri E. coli 0157 (bacterium) 243 illnesses / 4 deaths
1991 Puerto Rico Unknown 9,847 illnesses
1993 Missouri Salmonella typhimurium (bacterium) 650 illnesses / 7 deaths
1993 Wisconsin Cryptosporidium parvum (protozoan) 400,000 illnesses 50 deaths
1998 Texas Cryptosporidium parvum (protozoan) 1,400 illnesses
1999 New York E. coli 0157 (bacterium) 150 illnesses / 1 death
2000 Ontario E. coli 0157 (bacterium) 1,000 illnesses / 7 deaths
Source HDRs Handbook of Public Water Systems
9
Public Health Issues
Pathogenic bacteria, viruses and protozoa in
water and wastewater represent potential risks to
public health.
Bacteria (E.coli)
Protozoa
Viruses (Hepatitis, Polio)
(Giardia)
(Cryptosporidium)

10
Historical mortality from waterborne diseases
exceeds the current mortality rates of all
diseases combined.
Typhoid Fever Mortality in Chicago (1860-1950)
U.S. Leading Causes of Death (1990)
11
Classes of Microorganisms The Microbial World
Viruses smallest (0.02-0.3 µm diameter)
simplest nucleic acid protein coat (
lipoprotein envelope) Bacteria 0.5-2.0 µm
diameter prokaryotes cellular simple
internal org. binary fission. Protozoa
most gt2 µm - 2 mm eucaryotic uni-cellular
non-photosynthetic flexible cell
memb. no cell wall wide range of
sizes and shapes hardy cysts and
oocysts flagellates (Giardia sp.),
amoebae, ciliates, sporozoans
(Cryptosporidium sp.) and microsporidia.
C. parvum oocyst 5 um
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What is a low-pressure membrane?
Membranes can remove anything that is smaller
than the pores.
13
Giardia
Cryptosporidium
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A Short History of Membrane Technologies
Membrane treatment is not new. Cellulosic
membranes have been in use for four decades.
What is new is that membrane systems are now
affordable!
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Membrane Treatment What is driving the technology?

• Competitive costs
• Complete microbial barrier
• Improved organics removal
• Small space requirements
• Reduced solids
• Automation

16
Improved materials are the key to cost-effective
performance. More recent polymeric materials are
more robust than cellulosic materials.
Chemical and Mechanical Resistance
They foul more easily, but can be regularly and
vigorously cleaned.
17
Growth in drinking water low-pressure systems is
exponential.
Combined
Microfilter
Ultrafilter
Nanofiltration
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Capital costs for membrane technology continues
to drop.

Per gal/d of Installed Capacity
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Membrane Architecture is Evolving
Encased systems trap solids, are difficult to
backwash and cannot be used with high
concentrations of coagulants or adsorbants, but
offer high flux rates!
Open systems are easier to backwash, but
generally have lower flux rates!
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Hollow Fiber Encased Membranes
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Submerged Membranes
Zenons ZeeWeed Process
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Integration with Other Processes

• TOC DBPs (Coagulant/PAC/GAC)
• Taste Odor (Aeration/PAC/GAC/ClO2)
• Soluble Fe Mn (Oxidants)
• Arsenic (Ferric coagulants)

23
Particle Removal vs. Dissolved Organics Removal
Solids Contact Separation System
Treated water
Immersed membrane
Evolution
Residuals
PVDF and Fluoropolymer systems
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Membrane processes are not trouble free!
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Cellulose acetate (CA)
Hydrophilic Fouling Resistant
Poly(m-phenylene isophtalamide) (Normex)
Polyacrylonitrile (PAN)
Hydrophobicity
Polysulphone (PSf)
Polyethersulphone (PES)
Hydrophobic Fouling Susceptible
Polyvinylidenefluoride (PVDF)
Teflon
Polycarbonate (PC)
Polypropylene (PP)
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Membrane
Support Substrate
27
Fouling by organic material is the most serious
threat to membrane operations.
The dense NOM gel-like layer reduces capacity and
fouls an unprotected membrane.
Fouling at 20 hours 79 flux reduction
28
Membranes do fail. However, failure is never
catastrophic less serious than microbial
penetration of rapid sand filter beds.

• Membranes fail incrementally one fiber at a
  time.
• Statistically, individual fiber breaks are
  insignificant to the overall microbial water
  quality.

29
What Will Not Change!
Water Industry/Distribution System Issues
Non-Commodity Pricing of Water!!

• Urban-Industrial society depends on a safe and
  abundant supply of water. It is the most
  important public health function - bar none!!!
• Water Wars are not imminent.

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The American Water Industry is Not Being
Privatized!
Municipal advocacy supplants privatization
efforts Merchant water will be limited to
speculative markets.
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What is Changing?
Sanity is returning to the regulatory process.
The emphasis on extremely speculative health
threats has diminished.

• Proposed As MCL ltlt 10 ppb
• Perchlorate, Boron, Chromium Regulation to be
  Limited
• Radon Rule Still in Limbo
• Mandated cost/benefit analyses
• Local dollars required for implementation

Why?
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Distribution Water Quality is Improving
Almost 100 of national samples tested met
health-based and aesthetic standards for drinking
water
Compliance Percent
The number of tests failing water quality
standards has fallen by 60 since 1992
33
The Cost Efficiency of Public Water Purveyors is
Increasing
Cost as a of Household Income
Inflation-Adjusted Homeowner Costs
/ 1000 Gal.
1990
2000

• Public drinking water is a remarkable bargain
• Efficiencies derive primarily from manpower and
  technology
• It is still inexpensive despite more stringent
  regulations and dwindling supplies

34
The Cost of Technology is Diminishing
Plant Capital Costs for Membrane Water Treatment

• Despite predictions to the contrary, the cost of
  new technology (especially membranes) will not
  increase the cost of water treatment.
• When quality is factored in, the cost of water
  treatment will actually decline.
• Membrane processes (UF,NF) will become
  competitive with conventional treatment.

/ Gallon
Plant Size (MGD)
35
Waterborne Disease Outbreaks are Decreasing.
Distribution System Contribution is Increasing
Source Lee and Blackburn, 2004
1971 1974
1975 1978
1979 1982
1983 1986
1987 1990
1991 1994
1995 1998
1999 2000
2001 2002

• Most distribution failures are related to
  cross-connection and back siphonage.
• Magnitude of outbreaks 180 illnesses per event.

36
Disease and Distribution System

• Evidence shows that current endemic levels of
  gastrointestinal diseases are associated with
  the consumption of tap water
• The typical disease symptoms are generally mild,
  short term, and clear spontaneously
• The organisms causingthese diseases arecultured
  in the distributionsystem (not the raw water)

37
Challenge Many 20th century iron distribution
mains are approaching the end of their service
lives.
Projected annual replacement needs for
transmission lines and distribution mains.
Source EPA 2002)

• Average post-WWII pipe service life 75 years.
• 19th century cast iron pipe service life 120
  years
• Drinking water infrastructure spending to reach
  6 billion per year by 2010.

38
Challenge - The Bottled Water Industry Continues
to Grow
Bottled Water Market U.S. Per Capita Consumption
Why People Drink Bottled Water
Year GPC Annual Change
2000 17.3
2001 18.8 9.7
2002 20.9 10.7
2003 22.4 7.3
2004 24.0 7.4
2005 25.7 7.1
Fairly, or not, the continued success of bottled
water creates the perception of a growing
deficiency (lack of purity) in our public water
system.