Water Quality Testing Abridged

Samples to be tested for coliforms are collected in plastic bottles that must contain what?

Sodium Thiosulfate

The volume of a sample for coliform compliance is what?

100 mL

If a water sample is not analyzed immediately for chlorine residual, it is acceptable if it is analyzed within how long?

15 minutes

The best choice to collect a water sample from a customer’s faucet when responding to a complaint would be a what?

Faucet without threads

When measuring for a free chlorine residual, which method is the quickest and simplest?

DPD Colorimetric Method

A what is a single-volume sample collected at one time from one place.

Grab sample

Under the Ground Water Rule (GWR), what type of sampling is required for larger systems for chlorine residual?

Continuous

What are three broadly classified areas from which samples are generally collected?

Raw water supply, treatment plant, distribution system.

Consistency among laboratories in analytical results is overseen by state primacy programs and by what organization?

USEPA

If samples arrive at a laboratory past the specified holding time, following collection, the laboratory must do what?

Reject the samples

The radiation term corresponding to an energy absorption of 100 ergs per gram of any medium is called a(n) what?

Rad

In reference to the multiple-tube fermentation or membrane filter test, any sample that does not contain coliform bacteria is said to be what?

Negative

Which of the following is a technique used to measure the concentration of organic compounds in water?

Gas Chromatography

When receiving a customer complaint about water quality, which of the following is a good approach for customers who are in a highly emotional state?

Obtain the customer’s name and address at the beginning of the discussion.

What is the waiting period to receive a coliform test result?

24 hours is generally needed for incubation, but some tests may be completed in 18 hours

How can the chlorine residual decrease when more chlorine is added to a water sample?

If ammonia is present, chloramines form, increasing the residual.

As more is added, these chloramines are partially destroyed until the breakpoint is reached and the residual rises again.

Why can’t samples be preserved for delayed determination of pH?

The value changes, so field tests are needed for accurate results.

What is the third major step of the multiple-tube fermentation method?

Completed test

How long does the N, N-diethyl-p-phenylenediamine (DPD) test kit take to complete?

About 5 minutes.