C R E A T I N G A N D D E L I V E R I N G B E T T E R S O L U T I O N S

E B A E N G I N E E R I N GC O N S U L T A N T S L T D .

Presented by

Gilles Wendling, Ph.D., P.Eng.

Water Microbiology

Outline

Why should we be concerned?- Brief history - What is the problem- Status in BC

Outbreaks and pathogenes Bacteria and viruses

- Definition- Characteristics

Other waterborne- Algae and fungi

Symptoms and illnesses What can we do about it?

- treatment

Treatment: started ~100 years ago

Began in early 1900’s in England (1908 in Chicago and Jersey City)

- Continuous application of chlorine Waterborne disease such as typhoid fever

was prevalent.- Major cities were suffering 100 or more typhoid

deaths a year per 100,000 persons. 1910 – 1920: thousands of drinking water

treatment plants initiated chlorine disinfection

- The typhoid death rate fell simultaneously.

Source: Chlorine Chemistry CouncilSource: Chlorine Chemistry Council

Treatment (cont’d)

The number of typhoid fever cases is now insignificant - In developed countries- However, >250 000 children died in

Bangladesh in 2000 due to waterborne diseases

Table 3. Waterborne Pathogens

Legionella

Vibrio (cholera)

Salmonella (typhoid)

Vibrio (noncholera)

Yersinia

ReovirusShigella

Entamoeba histolyticaHepatitis ASalmonella (nontyphoid)

Giarda lambliaEntero (poliomyelitis,coxsackie, echo, rotavirus)

Escherichia coli

Cryptosporidium parvumNorwalk-likeCampylobacter

ProtozoaVirusesBacteria

Etiology of Waterborne Outbreaks in USA, 1971-1992

Etiology Outbreaks Casses of Illness Hospitalized Cases Deaths

Undetermined 341 82,486 253 0

Protozoan 127 43,952 67 0

Bacterial* 98 19,351 720 6

Viral 58 14,167 85 0

Chemical** 60 4,202 45 6

TOTAL 684 164,158 1,170 12

Etiologic Agents Most Frequently Identified in Waterborne Outbreaks of Infectious Diseases in USA

1971-1992

Etiologic Agent Outbreaks Cases of Illness

Giardia lamblia 118 26,733

Shigella 57 9,967

Norwalk-like virus 24 10,908

Hepatitis A 29 807

Campylobacter 13 5,257

Salmonella 12 2,370

Cryptosporidium parvum 7 17,194

All others*23 4,243

TOTAL 283 77,479

*Toxigenic E. coli, Yersinia, rotavirus, S. typhi, V. cholera and others *Toxigenic E. coli, Yersinia, rotavirus, S. typhi, V. cholera and others

Causes of Waterborne Outbreaks in USA, 1971-92

Causes of Outbreak Percent of Outbreaks

Community Water Systems Non-Community Water Systems

Contamination of distribution system 29% 7%

Inadequate disinfection ofunfiltered surface water

24% 8%

Inadequate disinfection of groundwater

14% 30%

Untreated groundwater 11% 42%

Inadequate filtration of surface water 11% 1%

Miscellaneous; unknown causes 5% 6%

Inadequate chemical feed 3% 1%

Untreated surface water 2% 5%

Inadequate filtration of groundwater 1% 0%

TOTAL 100% 100%

Outline

Why should we be concerned? Outbreaks and pathogenes Bacteria and viruses

- Definition- Characteristics

How big are they?

http://micro.magnet.fsu.edu/cells/index.html

Silt

SandGravel

Pore Size

VirusVirus

FungiFungi

PorePore

Bacteria

Bacteria

Classification

Until 1800s, two classes of living organisms Plants or animals (many people still have

this perception)

In 1866, Ernst Haeckel proposed a third kingdom, Protista, which included all microorganisms, such as bacteria, protozoans, and certain fungi and algae.

Classification

Five-kingdom classification of living organisms H.R. Whittaker of Cornell University (1969)

Alternative seven- and eight-kingdom classifications Recently Due to many factors (electron microscopy and

gene sequencing, etc.)

Now, the five-kingdom system is commonly used

Living Organisms: 5 groups

Living Organisms

Procaryotae Eucaryotes

Fungi ProtozoaHigher PlantsAnimalsBacteria

Bacteria

A fundamental biological distinction is made between bacteria and all other organisms. genetic material (DNA and RNA) is NOT

contained in a membrane-enclosed nucleus.

Nitrifying bacteria cross sectionPhoto credit: Mary Ann Bruns, Center for Microbial Ecology, Michigan State

Nitrifying bacteria cross sectionPhoto credit: Mary Ann Bruns, Center for Microbial Ecology, Michigan State

Bacteria

Single-celled, with each cell carrying out all of the cell functions.

Bacteria have three basic shapes: spherical, termed cocci (singular: coccus); rod shaped, termed bacilli (singular:bacillus); and spiral shaped.

Bacteria can group themselves in distinctive ways. For example, cocci that form grape-like clusters are termed staphylococci and those that form chains are called streptococci

Streptococcus pyogenes Streptococcus pyogenes

Waterborne Bacteria

Potential pathogens include Vibrio cholerae, Campylobacter jejuni, Salmonella species, and Escherichia coli (E. coli).

Why pathogenes? secrete toxins that cause inflammation of

the stomach and intestinal linings.

Color-enhanced scanning electron micrograph of Salmonella typhimurium (red) invading cultured human cells.

Photo Source: Photo by Rocky Mountain Laboratories, NIAID, NIH with information from The National Institute of Allergy and Infectious Diseases

E-coli

Universally used in standard tests as indicators of fecal contamination.

E. coli strains vary widely in their pathogenicity. People tend to have a degree of immunity to local strains brought about by exposure (not visitors...! - tourista)

More dangerous strains: i.e., E. coli 0157:H7, can cause hemorrhagic colitis that results in thousands of life-threatening illnesses and hundreds of deaths a year.

(Although most are associated with food contamination, not contaminated drinking water)

http://www.microscopyconsulting.com/

E. coli O157:H7

Living Organisms

Living Organisms

Procaryotae Eucaryotes

Fungi ProtozoaHigher PlantsAnimalsBacteria

Protozoans

Genetic material enclosed in a distinct membrane-covered nucleus.

Protozoans have a flexible outer covering, rather than a semi-rigid cell wall like bacteria.

Protozans

Play key roles in the environment: decay of organic matter to constituting a

large portion of plankton Protozoans become dessicated easily and

require damp or aquatic environments.

They are generally much larger than bacteria some overlap between the largest bacteria

and the smallest protozoans.

Protozoans – Important Feature

Capable of producing cysts under adverse conditions: lack of moisture, food, or oxygen, or in the presence of

toxic chemicals. In the case of parasitic protozoans, the cyst allows the

organism to survive outside a host (days to weeks), which is crucial for those protozoans whose life cycle requires multiple hosts.

Cysts present some challenges for water treatment

because they are resistant to disinfection.

Protozoans and Cyst cycle

giardia troph

Protozoa: Giardia

Giardia lamblia possibly the most common cause of

waterborne diarrheal disease in the north America

commonly endemic in day-care centers more than 5% of adults and children are

carriers who shed cysts in their feces, yet may have no symptoms.

Infection is usually through cyst-contaminated water.

Giardia Cyst in Stool

Photo Source: www-medlib.med.utah.edu/parasitology/glambim.html

Protozoa: Cryptosporidium

Cryptosporidium widespread in the natural environment probably of greater concern than Giardia

- because its smaller size makes it harder to filter- it is more resistant to disinfection.

Other Protozoae

Cyclospora and Microsporidia recently emerging protozoal pathogens. Cyclospora:

- cysts are bigger than those of Cryptosporidium, must be mature before they are infectious. So, if cysts are shed from the body before maturation, the host can avoid infections.

Microsporidia: - less known and it is likely that cases may be

underreported.

Viruses: Definition

Viruses fall into an entirely different category.

In fact, they may not qualify to be called organisms.

Living Organisms

Procaryotae Eucaryotes

Fungi Protozoa Higher Plants AnimalsBacteria

Viruses: Definition

All living organisms contain both DNA and RNA. Viruses may have DNA or RNA, but not both.

Unlike true living organisms, their nucleic acids are inactive outside of host cells.

- once they enter host cells, their nucleic acids become active, and they are able to replicate.

Photo Caption: This is a slide of a type B viral Hepatitis as shown in its chronic stage.Photo Source: Transplant Pathology at the University of Pittsburgh, tpis.upmc.edu/Photo Caption: This is a slide of a type B viral Hepatitis as shown in its chronic stage.Photo Source: Transplant Pathology at the University of Pittsburgh, tpis.upmc.edu/

Viruses: Characteristics

Viruses in general are much smaller than bacteria.- can be viewed only by electron microcroscopes. - there is some overlap in size between the largest

viruses and the smallest bacteria.

Their small size and resistance to environmental stress creates water treatment challenges.

- viruses are less easily filtered by soil than bacteria, - viruses have been detected in groundwater that was

absent of fecal indicator bacteria.

Viruses: Types

Enteric viruses that have been associated with waterborne disease outbreaks - Hepatitis A virus, Hepatitis E virus,

Norwalk and Norwalk-type viruses, Rotaviruses, and Enteroviruses. ( large group that includes Polioviruses).

Viruses: Testing and Treatment

Difficult to test for the presence and concentration of viruses

Water systems that use surface water or groundwater that is directly under the influence of surface water are required to use a combination of treatment options and disinfection that will result in a four-log (99.99 percent) reduction or inactivation of viruses.

Outline

Why should we be concerned? Outbreaks and pathogenes Bacteria and viruses Other waterborne

- Algae and fungi

Fungi

have eucaryotic cells (genetic material in membrane-enclosed nucleus)

no chlorophyll obtain nutrition by absorbing soluble

substances across their cell walls

Fungi that are multi-cellular fall into the Fungi kindgom, which includes mushrooms and most molds.

Living Organisms

Living Organisms

Procaryotae Eucaryotes

Fungi ProtozoaHigher PlantsAnimalsBacteria

Algae

The term “algae” has no officially recognized biological meaning.

Referred to any simple aquatic plant. Most biologists now use algae (singular: alga) to refer to organisms that have no true roots, stems, or leaves

Have chlorophyll and are capable of photosynthesis.

Mixed bloom of Dinophysis acuta and D. norvegica co-occurring with a bloom of Ceratium furca

Living Organisms

Living Organisms

Procaryotae Eucaryotes

Fungi ProtozoaHigher PlantsAnimalsBacteria

Algae

Largely viewed mainly as the cause of taste, odor, and color problems

Some algae (cyanobacteria Microcystis, Cylindrospermopsis, and Anabaena) have recently come under more scrutiny in the U.S. for their health effects (linked to nerve and liver damage).

Algae

Algae and their toxins are currently unregulated by the Safe Drinking Water Act. However, they are included on EPA’s Drinking Water Candidate Contaminant List (CCL).

Australia has a regulatory program in place for cyanotoxins and the World Health Organization has a 1.0 microgram per liter guideline for microcystin.

Outline

Why should we be concerned? Outbreaks and pathogenes Bacteria and viruses Other waterborne

Symptoms and illnesses

Illnesses Associated with Waterborne Pathogens

Bacteria and protozoa generally induce gastrointestinal disorders with a wide range of severity. Bacteria also cause life-threatening diseases such as typhoid and cholera.

Viruses cause serious diseases such as aseptic meningitis, encephalitis, poliomyelitis, hepatitis, myocarditis and diabetes.

Illnesses Associated with Waterborne Pathogens

Severity of illness ranges from mild gastrointestinal upset, fever and vomiting, and intermittent diarrhea to chronic diarrhea, dehydration, liver damage, acute respiratory illness, adverse neurological effects, depressed immune systems and death.

Most healthy individuals in the general population usually experience only mild gastroenteritis that is easily controlled and of short duration.

Certain segments of the population are especially vulnerable to acute illness (morbidity) and can exhibit high death (mortality) rates. - pregnant women, infants, the elderly and those whose

immune systems are compromised by cancer, AIDS

Outline

Why should we be concerned? Outbreaks and pathogenes Bacteria and viruses Other waterborne Symptoms and illnesses What can we do about it?

- treatment

Drinking Water Treatment: Goals

99% removal of Cryptosporidium oocysts (2 log) 99,9% removal of Giardia cysts (3 log) 99,99% removal of viruses (4 log)

But these goals are intimately related to the credit given to conventional treatments (otherwise an economical crisis would be created)

The log removal credits are: Specific to a technology or process Specific to each organism

Drinking Water Treatment: Methods

Two major types of treatments: Filtration Disinfection

Filtration and UV disinfection are more efficient for protozoa

Chemical disinfections are more efficient for viruses

Drinking Water Treatment: Filtration

Turbidity is an indicator of the overall water quality Turbidity is use to make sure disinfection will be

efficient Turbidity may also be used to follow treatment

performances:- Chemically-assisted filtration (conventional treatment or direct

filtration), slow sand filtration and diatomaceous earth filtration are given general process log removal credits based on the turbidity of the filtered water

Variation of treated water turbidity is more important than its actual value

Drinking Water Treatment: Disinfection

Many disinfectant can be used and their efficiency varies a lot depending on the target organism

The most commonly used are:- Free chlorine- Chlorine dioxide- Ozone- Chloramines (monochloramines)

Depends on residual concentration, contact time, temperature and pH

CT values at 5ºC for 1 log removal:

Drinking Water Treatment: Contact Time

(mg*min/L) E. coli Giardia Crypto. VirusesFree chlorine(0,5 mg/L, pH 6-7)

0,02 – 0,03

32 - 47 - 0,01 – 2,0

Chlorine dioxide 0,4 – 0,8 8,7 424 0,1 – 3,4Monochloramines(pH 8-9)

95 - 180 735 -350 - 3500

Ozone 0,02 0,63 21,20,003 –

0,3

Drinking Water Treatment: membrane filtration and UV

UV disinfection: Example of UV dose required:

No residual after the reactor: another disinfectant must be used for distribution

If an alarm triggers, water must be stopped because there is no residual

(mJ/cm²) E. coli Giardia Crypto. VirusesUV dose (1 log) 1,5 – 4,4 2,1 2,5 4,1 - 30UV dose (3 log) 4,1 – 7,3 11 12 14 - 90

Final note…Our knowledge is very relative

Number of generation since Christ: 100The earth is flat…till Galileo: only 25

generations ago!First dissections on cadavres ~ Da Vinci

(1452-1519) ..25 generations ago Discovery of bacteria:

Related to discovery of microscope Recent big step with use of electronic

microscope

Final note…Our knowledge is very relative

……..We still have a lot to discover

Nov 2004: discovery of bacteria 100x larger that bacteria known to date!!!

Recommendations

Groundwater can be a very safe resource

Proper installation and sealing of well High wellhead standard Source protection

Credits

http://c3.org/chlorine_knowledge_center/whitepapercl.html#Water

http://www.whoi.edu/redtide/rtphotos/rtphotos.html

http://micro.magnet.fsu.edu/cells/index.html

Hughes, J.M. 1993. Infectious Diseases Transmitted by Drinking Water in the United States: Perspectives of the Centers for Disease Control and Prevention. Pp. 11-16. Safety of Water Disinfection: Balancing Chemical & Microbial Risks. ILSI.

Craun, G.F., Ed. and multiple contributors. 1993. Safety of Water Disinfection: Balancing Chemical & Microbial Risks. ILSI.

Craun, G.F., and multiple contributors. 1996. Water Quality in Latin America: Balancing the Microbial and Chemical Risks in Drinking Water Disinfection. Proceedings of the Regional Symposium on Water Quality, sponsored by International Life Sciences Institute, Argentina.

Craun, G.F., Bull, R.J., Clark, R.M., Doull, J., Grabow, W., Marsh, G.M., Okun, D.A., Regli, S., Sobsey, M.D., and Symons, J.M. 1994. Balancing Chemical and Microbial Risks of Drinking Water Disinfection, Part I. Benefits and Potential Risks. Pp. 192-199. J Water SRTÑAgua. 43:4.

Craun, G.F., Bull, R.J., Clark, R.M., Doull, J., Grabow, W., Marsh, G.M., Okun, D.A., Regli, S., Sobsey, M.D., and Symons, J.M. 1994. Balancing Chemical and Microbial Risks of Drinking Water Disinfection, Part II. Managing the Risks. Pp. 207-218. J Water SRTÑAgua. 43:5.

Craun, G.F. 1994. Waterborne Disease in the United States. 1996. Pp. 55-77. Water Quality in Latin America. Pan American Health Organization.

Chain-Wen Wang and Craig Mains

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E B A E N G I N E E R I N GC O N S U L T A N T S L T D .

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