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

Water Microbiology

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

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

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 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 Bacteria

Campylobacter Escherichia coli Salmonella

(nontyphoid)

Shigella

Viruses

Norwalk-like Entero (poliomyelitis, coxsackie, echo, rotavirus) Hepatitis A Reovirus

Protozoa

Cryptosporidium

parvum Giarda lamblia Entamoeba histolytica Yersinia

Vibrio

(noncholera)

Salmonella

(typhoid)

Vibrio

(cholera)

Legionella

Etiology of Waterborne Outbreaks in USA, 1971-1992

Etiology Outbreaks Casses of Illness Hospitalized Cases Deaths Undetermined 341 Protozoan Bacterial * 127 98 58 Viral Chemical ** TOTAL 60 684 82,486 43,952 19,351 14,167 4,202 164,158 253 67 720 85 45 1,170 6 12 0 0 6 0

Etiologic Agents Most Frequently Identified in Waterborne Outbreaks of Infectious Diseases in USA 1971-1992 Etiologic Agent

Giardia

lamblia

Shigella

Norwalk-like virus Hepatitis A

Campylobacter Salmonella Cryptosporidium

parvum All others * TOTAL

Outbreaks

118 57 24 29 13 12 7 23 283

Cases of Illness

26,733 9,967 10,908 807 5,257 2,370 17,194 4,243 77,479 * Toxigenic

E. coli

, Yersinia, rotavirus, S. typhi, V. cholera and others

Causes of Waterborne Outbreaks in USA, 1971-92 Causes of Outbreak

Contamination of distribution system Inadequate disinfection of unfiltered surface water Inadequate disinfection of groundwater Untreated groundwater Inadequate filtration of surface water Miscellaneous; unknown causes Inadequate chemical feed Untreated surface water Inadequate filtration of groundwater TOTAL

Percent of Outbreaks Community Water Systems Non-Community Water Systems

29% 7% 24% 8% 14% 11% 11% 5% 3% 2% 1% 100% 30% 42% 1% 6% 1% 5% 0% 100%

Outline

  Why should we be concerned?

Outbreaks and pathogenes 

Bacteria and viruses - Definition - Characteristics

How big are they?

Pore Size Gravel Silt Sand

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

Virus Fungi

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

Procaryotae Bacteria Living Organisms Fungi Eucaryotes Protozoa Higher Plants Animals

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 section Photo 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

Waterborne Bacteria

Potential pathogens include

Vibrio cholerae

,

Campylobacter jejuni

,

Salmonella Escherichia coli

(

E. coli

). species, and 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)

E. coli O157:H7 http://www.microscopyconsulting.com/

Living Organisms

Procaryotae Bacteria Living Organisms Fungi Eucaryotes Protozoa Higher Plants Animals

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 infections. Cryptosporidium , must be mature before they are infectious. So, if cysts are shed from the body before maturation, the host can avoid  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.

Procaryotae Bacteria Living Organisms Fungi Protozoa Eucaryotes Higher Plants Animals

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/

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

Procaryotae Bacteria Living Organisms Fungi Eucaryotes Protozoa Higher Plants Animals

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

Procaryotae Bacteria Living Organisms Fungi Eucaryotes Protozoa Higher Plants Animals

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

Drinking Water Treatment

: Contact Time

CT values at 5ºC for 1 log removal: (mg*min/L) Free chlorine (0,5 mg/L, pH 6-7) Chlorine dioxide Monochloramines (pH 8-9) Ozone E. coli 0,02 – 0,03 0,4 – 0,8 Giardia Crypto.

32 - 47 8,7 424 95 - 180 0,02 735 0,63 21,2 Viruses 0,01 – 2,0 0,1 – 3,4 350 - 3500 0,003 – 0,3

Drinking Water Treatment: membrane filtration and UV

UV disinfection: Example of UV dose required: (mJ/cm²) UV dose (1 log) UV dose (3 log) E. coli 1,5 – 4,4 4,1 – 7,3 Giardia Crypto.

2,1 11 2,5 12 Viruses 4,1 - 30 14 - 90 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

Final note…Our knowledge is very relative

Number of generation since Christ: 100 The 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. 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. American Health Organization. Chain-Wen Wang and Craig Mains

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