ABC Field Test and Inspection Procedures 2

Question 1

When collecting a water sample for bacteriological analysis, what is the minimum flush time before sample collection from a chlorinated distribution tap?

Accepted Answer

2–3 minutes

Answer

30 seconds

Answer

10 minutes

Answer

No flushing required

Question 2

A Hach DR spectrophotometer reads a chlorine residual of 0.00 mg/L in a distribution sample. The first troubleshooting step should be:

Accepted Answer

Replace the reagent powder pillow and re-test

Answer

Report a chlorine deficiency immediately

Answer

Collect a new sample from a different tap

Answer

Check the meter's wavelength setting

Question 3

What field parameter is used to estimate the carbonate-bicarbonate equilibrium and corrosivity of a water supply?

Accepted Answer

Langelier Saturation Index (LSI)

Answer

Turbidity (NTU)

Answer

Total dissolved solids (TDS)

Answer

Conductivity (µS/cm)

Question 4

Which instrument measures the dissolved oxygen concentration directly without the need for chemical titration?

Accepted Answer

Membrane electrode DO meter

Answer

Colorimeter

Answer

Winkler titration kit

Answer

Nephelometer

Question 5

During a wastewater effluent inspection, the inspector notices a persistent oily sheen on the receiving stream. The FIRST regulatory concern is:

Accepted Answer

Violation of oil and grease discharge limits

Answer

Elevated BOD loading

Answer

Excessive nutrient loading

Answer

High suspended solids concentration

Question 6

A composite sample for wastewater analysis is best described as:

Accepted Answer

Multiple grab samples combined proportionally over time or flow

Answer

A single grab collected at peak flow

Answer

A 24-hour average calculated from lab results

Answer

A sample filtered before collection

Question 7

What is the maximum holding time for a chlorine residual field measurement once the sample is collected?

Accepted Answer

Immediately — analyze on-site only

Answer

15 minutes

Answer

6 hours

Answer

24 hours