Current State and Future Direction of Water Treatment

1
Current State and Future Direction of Water
Treatment

• Dr. Hans Peterson
• Safe Drinking Water Foundation

2
Canadian Water Quality Guidelines

• 53 Health-based
• 17 Aesthetic
• 8 Health and aesthetic
• Cities address most of these parameters. In Rural
  areas lt10 are addressed.

3
What are theThree Key Issues?

• Particles (natural)
• Dissolved organics (natural)
• Some inorganic components (natural)

4
Treatment Needs

• Removal of
• Particles (including microbes)
• Inorganic ions (Fe, Mn, As, NH4, SO4)
• Dissolved organics

5
Treatment Benefits

• Safe drinking water
• High quality water for industrial uses
• Water with low fouling and scaling potential

6
Water Treatment Which Technologies Can Produce
Safe Water?

• Conventional
• Advanced
• Emerging

7
City Source Water
8
Rural Source Water
9
Rural Water Characteristics

• Small drainage basins in close contact with
  vegetation, livestock, and human waste products
• Small water storage vessels (dugouts, small
  aquifers)
• Poor quality source water that frequently
  deteriorates during storage

Source water for a rural community (left) and
Saskatoon city (right).
10
Rural vs. CityWater Treatment

• Rural - Rapid processes lasting a few minutes,
  starting with poor quality raw water
• City - Slower processes lasting one or several
  hours, with good quality source water

11
Rural Water Treatment
12
The Dilemma

• Rural source waters are of poorer quality than
  city sources, yet receive less treatment

13
City vs. Rural Water

• Quality
• Treatment
• Research
• Trained personnel
• Cost

14
The Three Key Issues

• Particles
• Dissolved organics
• Inorganic components

15
Particles

• Bacteria
• Colloids
• Viruses

• Sand
• Clay
• Algae
• Parasites

16
Particle Size and SettlingThrough 1 m of Water

• Gravel 10 mm - 1 second
• Sand 1 mm - 10 seconds
• Fine Sand 0.1 mm - 2 minutes
• Clay, algae, parasites 10 µm - 2 hours
• Bacteria, algae 1 µm - 8 days
• Colloids, viruses 0.1 µm - 2 years
• 10 µm - 20 years, 1 nm - 200 years

17
Rural Water

• High particle loads (gt 10 000 particles/ml
  treated water lt 100/ml)

18
High Particle Levels Inhibit Treatment Efficiency
19
Particle sizes of Saskatoon City and Yellow Quill
First Nations water
10
5
10
5
Saskatoon City Water
Yellow Quill Raw Water
4
4
10
10
10
3
3
10
2
2
10
10
1
1
10
10
0
10
0
10
2-5
5-10
10-15
15-20
20-40
gt40
2-5
5-10
10-15
15-20
20-40
gt40
Particles counted / ml
10
5
10
5
Yellow Quill Treated Water
Yellow Quill Treated Water
Distribution System
4
4
10
10
at Plant
10
3
3
10
2
2
10
10
1
1
10
10
10
0
0
10
2-5
5-10
10-15
15-20
20-40
gt40
2-5
5-10
10-15
15-20
20-40
gt40
Particle Size (µm)
20
Particle Removals
21
Removal of Total Viruses and Total Bacteria
22
Microbes

• May cause human illness

bacteria
protozoa
viruses
Blue-green algae
23
Size of Different Particles
Human Cell
Cryptosporidium
E. coli
. Calicivirus
24
Viruses in Groundwater

• Enterovirus (30 positive)
• Hepatitis A virus (7 positive)
• Rotavirus (13 positive)
• Viral contamination not predicted by coliforms

25
Coliforms as Indicators

• 2/3 of waterborne disease outbreaks in the U.S.
  during the past decade have tested negative for
  coliforms
• Viral contamination and parasites in chlorinated
  water will frequently test negative for coliforms

26
Failures of the Total Coliform Rule

• Communities gt 10,000 people - 4
• Communities lt 10,000 people - 96

27
Bacterial Indicators
28
Detecting Waterborne Illness A large multiplier
game

• gt 1 of population may have to become infected
  before disease outbreak is detected (USEPA, 1998)
• Cryptosporidium detection is frequently lt 1
• Other microbes can have better rates of
  detection, but all need large multipliers to
  determine actual cases

29
Use of disease surveillance systems that only
detect large outbreaks is equivalent to basing
the science of meteorology only on the studies of
hurricanes
Frost et al., 1996
30
Microbial Contaminants
31
Enteric viruses are estimated to account for more
than 50 of waterborne diseases (USEPA, 2000)
32
Top 3 ProvincesReported Illnesses (1993-1997)

• Campylobacteriosis - BC (0.83), ON (0.62), PEI
  (0.52)
• Giardiasis - BC (0.42), SK (0.37), ON (0.27)
• Hepatitis A - MB (0.28), SK (0.20), BC (0.12)
• Shigellosis - SK (0.15), MB (0.13), BC/AB (0.07)
• Infant Mortality - SK (8.7), MB (7.2), NFLD (7.1)

33
Waterborne Pathogens and Sensitive Groups(Infant
Mortality)

• 40 higher infant mortality in rural Canada
  compared to urban Canada
• Potential link to poor water quality
• Highest in Saskatchewan and Manitoba

34
Rural Water

• High levels of DOC (gt 10 mg/L treated water lt 5
  mg/L)

35
Dissolved Organics

• Breakdown of plant and soil material
• causes water to be coloured,
• consumes chlorine,
• inhibits disinfection, and
• forms disinfection by-products

36
Dissolved Organic Carbon and Colour
37
Chlorine Consumption
38
THM Formation
39

• Disinfection is only effective when applied to
  good quality water.
• Degremont 1991

40
Inorganic Components

• Typically resulting from natural formations
  (iron, manganese, ammonium, arsenic, fluoride,
  sulphate)
• Can result from surface contamination (nitrate)
• Difficult to remove by conventional treatment

41
The Real IssueWater Treatment

• Conventional
• Advanced
• Emerging

42
Combined Treatment to Produce

• Water with lt 2 mg DOC/L
• gt 1 000-fold barriers to viruses, bacteria, and
  protozoan parasites

43
Membrane Treatment

• Other treatment technologies act as pre- and
  post-treatment methods

44
Operation Water Drop
45
Operation Water Dropis a unique program

• Focuses on water quality from a human drinking
  water perspective
• Promotes awareness of water quality issues
• Promotes protection and stewardship

46
Operation Water DropKey Points

• Where does your drinking water come from?
• How is your drinking water treated?
• What tests are routinely done on your water
  supply?
• How do your test results compare to Guidelines?
• Is your water safe?

47
Operation Water DropTest Kit

• Alkalinity
• pH
• Colour
• Nitrate
• Sulphate
• Residual Chlorine
• Heterotrophic Plate Count

48
Safe Drinking Water Foundation

• R D to make rural water safe
• Increasing awareness of health concerns with
  water
• Working with scientists and governments in native
  and non-native communities

49
Public Awareness

• Website www.safewater.org
• Conferences, workshops, and user groups
• Interviews with media
• Articles and opinions in newspapers and magazines
• Operation Water Drop

50
Financial Support

• George Weston Limited
• RBC Financial Group
• Anonymous Donors
• Alberta Ecotrust
• NSERC
• Our Ladies of the Prairies
• Individual Members