ETC Water Quality & Treatment 2

Question 1

What is the regulatory significance of Total Maximum Daily Load (TMDL) under the Clean Water Act?

Accepted Answer

It sets the maximum amount of a pollutant a water body can receive and still meet water quality standards

Answer

A TMDL is a calculation of the maximum daily pollutant load a water body can receive from all sources while still attaining its water quality standards, serving as the basis for allocating loads among point and nonpoint sources.

Question 2

Which treatment technology uses semi-permeable membranes under pressure to remove dissolved salts and contaminants from water?

Accepted Answer

Reverse Osmosis (RO)

Answer

Reverse osmosis forces water through semi-permeable membranes under high pressure, rejecting dissolved salts, heavy metals, nitrates, and other contaminants while allowing water molecules to pass through.

Question 3

What is the primary mechanism by which activated carbon (GAC) removes contaminants from drinking water or groundwater treatment systems?

Accepted Answer

Physical adsorption of organic molecules and some inorganics onto the carbon surface

Answer

Granular activated carbon (GAC) removes contaminants primarily through physical adsorption, where organic molecules and some inorganic compounds are attracted to and held on the highly porous carbon surface.

Question 4

Eutrophication of a lake or reservoir is primarily caused by excess loading of which two nutrients from agricultural and urban runoff?

Accepted Answer

Nitrogen and phosphorus

Answer

Excess nitrogen and phosphorus stimulate explosive algal growth (algal blooms) that depletes oxygen when the algae die and decompose, causing eutrophication that harms aquatic life and impairs water uses.

Question 5

What is the regulatory trigger for a Tier 1 public notification under the Safe Drinking Water Act?

Accepted Answer

An acute health risk violation such as a positive E. coli result or MCL exceedance for nitrate

Answer

Tier 1 (24-hour) notification is required when violations or situations pose an acute risk to public health, such as a positive total coliform/E. coli result, nitrate MCL exceedance, or system going off-line without backup.

ETC - Environmental Technician Certification Practice Test

ETC - Environmental Technician Certification Practice Test

ETC Water Quality & Treatment 2