& ANSWERS | A+ GRADED 100% VERIFIED
• What minerals can cause water hardness . Answer: Calcium and
magnesium
• A public water system must at all times provide . Answer: Adequate
quantity of water, pressure, and disinfection
• A source groundwater would be . Answer: aquifer
• Fecal coliform organisms sometimes found in water supplies are an
indication that . Answer: Water supply is contaminated, harmful bacteria
may be present, possible pathogenic organisms in the water, water is
unsuitable for drinking
• A disease that may be spread by inadequately disinfected water .
Answer: Dysentery
• A common chemical used in disinfection of small water supply is .
Answer: Calcium hypochlorite
• A physical connection between a potable water supply and house well
would be . Answer: A cross connection
• The amount of chlorine in mg/L that is used up by reacting with iron
organics of bacteria is called . Answer: Demand
• Which of the following is a physical characteristic of chlorine gas .
Answer: Greenish-Yellow Color, heavier than air, pungent penetrating
odor, corrosive
,• Which of the following would be considered a part of a hypo-
chlorinator system . Answer: Solution feed pump
• According to state requirements, all public water Supply wells should
be provided with a raised concrete sealing block, screened vents, and- .
Answer: A flow measuring device
• Drawdown of a water well is determined by . Answer: Difference in
static and pumping levels
• pH of water indicates . Answer: If it's acidic or basic
• The pH of water is expressed on a pH scale of . Answer: 0-14
• Water that is considered neutral is expressed on the pH scale at .
Answer: 7.0
• Which of the following is a required Step in collecting a routine
distribution sample for bacteriological testing? . Answer: Use of an
approved, sterile sample container
• Sand filtration will remove which of the following from surface water .
Answer: Turbidity
• Activated carbon is used in a surface water plant primarily for .
Answer: Taste and odor control
• Which or the following chemicals are commonly used as coagulants in
surface water treatment . Answer: Alum and ferric chloride
• Ground storage tanks are required to provided with which of the
following . Answer: Screened vents, an approved locking roof hatch, an
overflow pipe with hinged flap device, annual inspection and
maintenance as needed
, • An elevated storage tank should be protected against corrosion by .
Answer: Painting, cathodic protection, water stabilization, and only
using galvanized and lead based primed components
• A public water supply system should maintain residual pressure of 20
psi and a minimum of normal operating pressure of . Answer: 35 psi
• Before a new or repaired water line is placed into service, it must be
properly disinfected by providing a chlorine dosage of _________ and
proper detention time . Answer: 50 mg/L
• Water bearing formations beneath the earths surface that are used as a
source of water for public water supplies are . Answer: Aquifers
• The purpose of an air line on a well is . Answer: Determine Water
leves in the well
• The mesh size is an important feature of a well screen because properly
sized openings should . Answer: Reduce the amount of Sand pumped
• When treating surface Water, the process of coagularon will be most
affected by the . Answer: pH, alkalinity, temperature, and chemical
Dosage
• A rapid sand filter should be backwashed When . Answer: The loss of
head gauge indicated between 6 and 10 feet
• Which of the following is an acceptable disinfection residual at the far
reaches of the distribution System . Answer: 0.2 mg/L free chlorine
residual, 0.8 mg/L chloramine residual when using chloramine
treatment, 0.5 mg/L chloramine for surface water supply, 0.5 mg/L free
chlorine residual for ground water Supply
• What is the approximate total volume of a circular tank in gallons, if it
is 30 feet in diameter, and 15 feet deep . Answer: 79,300 gallons