Water Quality & Treatment Flashcards
6 cards from real ETC practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Water Quality & Treatment flashcards as text
What is the regulatory significance of Total Maximum Daily Load (TMDL) under the Clean Water Act?
Answer: It sets the maximum amount of a pollutant a water body can receive and still meet water quality standards
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.
Which treatment technology uses semi-permeable membranes under pressure to remove dissolved salts and contaminants from water?
Answer: Reverse Osmosis (RO)
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.
What is the primary mechanism by which activated carbon (GAC) removes contaminants from drinking water or groundwater treatment systems?
Answer: Physical adsorption of organic molecules and some inorganics onto the carbon surface
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.
Eutrophication of a lake or reservoir is primarily caused by excess loading of which two nutrients from agricultural and urban runoff?
Answer: Nitrogen and phosphorus
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.
What is the regulatory trigger for a Tier 1 public notification under the Safe Drinking Water Act?
Answer: An acute health risk violation such as a positive E. coli result or MCL exceedance for nitrate
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.
A stormwater technician observes turbid runoff from a construction site entering a storm drain. Which regulatory program is the construction site most likely violating?
Answer: NPDES Construction General Permit (CGP) stormwater requirements
Construction sites disturbing one or more acres must obtain coverage under the NPDES Construction General Permit, which requires implementation of BMPs (sediment traps, silt fence) to prevent turbid stormwater discharge.