1. WATER SERVICES FORUM WATER QUALITY
Title of Presentation: The significance of microbiology in the drinking water industry Presenter: Monique Grundlingh, Senior Scientist, Rand Water Analytical Services
Date: 17 April 2019

2. Presentation overview
What are micro-organisms?
Waterborne diseases
Legislation
What are process indicators?
Purpose of testing water
Concluding remarks

3. WHAT ARE MICROORGANISMS? Microorganisms can be defined as:
Small living organisms that is not visible to the naked eye but can be seen under a microscope.
Viruses: Acellular organism that can only replicate (multiply) within the living cells of a host.
Bacteria: A single celled organism that has no nucleus.
Protozoa: A single celled organism that has a nucleus containing the genetic material. The sizes can vary from microscopic to macroscopic

4. WHAT ARE MICROORGANISMS?

5. Waterborne diseases
Waterborne diseases are caused by enteric pathogens
Excreted in faeces of infected individuals
Transmitted by faecal-oral route
Water source contaminated or not treated properly
Ingested by contaminated water or food
Waterborne infection affects the intestinal tract
Pathogenic bacteria transmitted by water causes gastroenteritis (an acute inflammation of the gastrointestinal tract)

6. Waterborne diseases
Cryptosporidium parvum/ hominis causes severe self-limiting gasstroenteritis in healthy individuals
Immunocompromised individuals will not recover from illness
Giardia lamblia causes severe gastroenteritis

7. Waterborne diseases ENTERIC PATHOGENS TRANSMITTED BY WATER Bacterium
Infectious dose
Vibrio cholerae
Cholera
Salmonella typhi
Thyphoid fever
High dose
Salmonella parathyphi
Salmonellosis
Campylobacter jejenum
Gastroenteritis
Shigella species
Bacillary dysentery
Moderate dose
Pathogenic E. coli
Diarrhoea
Cryptosporidium/ Giardia
Cryptosporidiosis/ Giardiasis
Low dose

8. Legislation

9. Legislation SANS 241-1:2015 definitions:
HPC- as count of the total number of visible colonies produced by micro-organisms in a water sample that grow on agar containing a complex organic carbon source under conditions of incubation specified for various purposes
E coli- faecal (thermotolerant) coliform bacteria that ferment lactose or mannitol with the production of both acid and gas, that produce indole from tryptophan, and that hydrolyse 4-methylumbelliferyl-b-Dglucuronide (MUG), all at 44 °C.

10. Legislation SANS 241-1:2015 definitions:
TC- a group of aerobic and facultatively anaerobic Gram-negative, non-spore-forming oxidase-negative bacteria that ferment lactose by β-galactosidase activity and that typically inhabit the large intestine of man and animals.
Protozoan parasites-(Cryptosporidium and Giardia) species: Unicellular eukaryotic animal that infects specific hosts including humans as part of its life cycle.

11. Legislation SANS 241-1:2015 definitions:
Somatic Coliphages-a bacterial virus that is capable of infecting selected E. coli and related host strains by attachment to the bacterial cell wall as the first step of the infection process. Somatic coliphages produce visible plaques (clearance zones) in a confluent lawn of host bacteria grown under appropriate culture conditions.

12. What are process indicators?
Process/Operational indicators: Give an indication how good the system is functioning (Efficacy of the process), for example the drinking water treatment process
Faecal indicators: Give an indication if faecal contamination (waste) is present for example in surface water or treated drinking water.

13. Purpose of testing Indicator organism Purpose of testing Risk
Standard limits
Heterotrophic plate count
Process indicator
Operational
≤ 1000
Total Coliform
≤10
Somatic coliphages
Indicator of faecal contamination
Not detected
Escherichia coli
Acute Health
Protozoan parasites (Cryptosporidium and Giardia species)
Indicator of faecal contamination. Provides information on treatment efficiency

14. Conclusion Good quality drinking water should be:
Free of potentially harmful organisms.
No enteric pathogens present.

15. Thank you