Source Water Characteristics Flashcards

Which parameter best indicates the presence of fecal contamination in a surface water source?

Answer: Fecal coliform count

Fecal coliform bacteria, particularly E. coli, are the primary indicators of fecal contamination in source water.

What is the primary cause of seasonal taste and odor problems in reservoir source water?

Answer: Algal blooms producing geosmin and MIB

Algae produce geosmin and 2-methylisoborneol (MIB) as metabolic byproducts, causing earthy or musty taste and odor complaints.

A source water with a pH of 9.5 is best described as:

Answer: Strongly alkaline

A pH of 9.5 is well above the neutral point of 7.0, placing it firmly in the alkaline (basic) range.

What does a high total organic carbon (TOC) level in source water indicate to a water treatment operator?

Answer: Greater potential for DBP formation during chlorination

High TOC provides more precursor material that reacts with chlorine to form disinfection byproducts such as trihalomethanes and haloacetic acids.

Which source water type is most susceptible to rapid quality changes following a heavy rainfall event?

Answer: Surface water reservoir

Surface water reservoirs are directly exposed to watershed runoff, causing rapid increases in turbidity, pathogens, and contaminants after rain events.

The ratio of bicarbonate, carbonate, and hydroxide ions in source water determines its:

Answer: Alkalinity

Alkalinity is defined by the buffering capacity of water, primarily contributed by bicarbonate, carbonate, and hydroxide ions.

Which natural process is primarily responsible for elevated iron and manganese concentrations in groundwater sources?

Answer: Dissolution from geological formations under anaerobic conditions

Iron and manganese dissolve from mineral-bearing geological formations when oxygen is depleted in groundwater, creating reducing (anaerobic) conditions.