Microbiology in water and waste management — A/L Biology

How do I practise Microbiology in water and waste management?

1 question with a worked solution

1. Why is Escherichia coli widely adopted as the universal indicator organism for assessing the biological safety and sanitary quality of potable water supplies?
   1. A) It reproduces and multiplies rapidly in pure nutrient-free deep well water
   2. B) It is the direct causative agent of all waterborne outbreaks of cholera and typhoid
   3. C) Its presence indicates recent fecal contamination and the potential presence of enteric waterborne pathogens
   4. D) It survives chlorine disinfection at doses that destroy all other viruses and bacteria
   Check my answer

   Correct answer: C) Its presence indicates recent fecal contamination and the potential presence of enteric waterborne pathogens

   E. coli resides exclusively as a normal inhabitant of the intestinal tract of warm-blooded animals and humans. Finding E. coli in treated water provides definitive evidence of recent fecal contamination, signaling that dangerous pathogens sharing the same fecal origin (e.g., Salmonella, Shigella, hepatitis A) may be present.

   Show worked solution

   Step 1: Define indicator criteria: High abundance in feces, absent in unpolluted water, survives slightly longer than pathogens, easy and safe to culture. Step 2: E. coli presence definitively flags fecal pollution. Answer: Its presence indicates recent fecal contamination and the potential presence of enteric waterborne pathogens.
   Modelled on: the A/L Biology examination pattern

Get this auto-marked

Next in the syllabus

Where does Microbiology in water and waste management fit in the syllabus?

Year 2 · Term 3