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

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

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

WHAT ARE MICROORGANISMS?

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)

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

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

Legislation

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.

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.

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.

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.

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

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

Thank you