Water Quality Guidelines And Standards Flashcards
What makes risk different from hazard?
Risk is the likelihood of a hazard
Enumerate the 2 characteristics of water quality guidelines
- Represents the concentration of constituent that does not pose any significant health risk over a lifetime of consumption
- Based on human & usual domestic consumption
Which is true?
A.Water quality guidelines values are the basis of water quality standards.
B.The Philippine Standards for Drinking Water of 2007 are based on the Philippine Environmental Protection Agency (EPA) guideline values.
C.The Philippine Standards for Drinking Water of 2007 only applies to people working in water supply system; general public not included.
A
Most conmonly used indicator bacteria in water testing
Coliforms
Enumerate two types of coliforms for which water is tested.
- total coliform
2. fecal/thermotolerant coliform
What does it mean when coliforms are present?
Water sample is Contaminated with excreta; other organisms may also be present
What does it mean when coliforms are present in chlorinated water?
Failure in chlorination system
Residual chlorine - what is its purpose?
Needed to make sure that there are no more possible pathogens/disease-causing microbes in the water supply
Which is false?
A. Fecal bacteria is the only bacteria indicative of a health hazard.
B. It is more practical to test total coliform rather than residual chlorine.
C. Both are false
D. NOTA
B
Baliktad
Which is false? A. Fecal bacteria die off with time. B. Fecal bacteria die in low temperature. C. BOTA D. NOTA
B
Heat dapat
Nutrient medium used in Multiple Tube Method
MacConkey agar
In multiple tube method, presence of coliform bacteria is confirmed with what color change? What does the color change indicate?
Purple to yellow.
Acid production
Identify the method
A number of tubes are incubated containing diff volumes of water sample & by observing the number of positive reactions it is possible to derive the MPN of coliform bacteria
Multiple Tube method
Why is multiple tube method not very accurate?
You are only estimating the most probable number of coliform present
In Membrane Filtration Technique, what kind of membrane is used?
Cellulose membrane
In which method can you count all the colonies present? A. Multiple Tube method B. Membrane Filtration technique C. BOTA D. NOTA
B
Main disadvantage of PNSDW 2007 microbio standard
less than 1 colony is hard to interpret
Minimum frequency of sampling for Level I point source
Once in 3 months
Minimum frequency of sampling for Level II communal faucet
Once in two months
Minimum frequency of sampling for Level III (household faucet) is once a month, regardless of population size served. T/F?
F
Sa less than 5000 lang ito
Minimum frequency of sampling for Level III (household faucet), pop size- 5000 to 100,000
1 sample per 5000 population, monthly
Minimum frequency of sampling for Level III (household faucet), pop size- more than 100,000
20 samples + 1 additional sample per 10,000 population
Answer the ff:
A.Minimum frequency of sampling for emergency supplies of drinking water.
B.Purpose for testing
A.before delivery to users
B.check residual chlorine
Minimum frequency of sampling for water refilling stations, and water vending machines
One sample monthly
