MINNESOTA CLASS D WATER
COMPREHENSIVE STUDY GUIDE 2026
DRINKING WATER SYSTEMS SOLUTIONS
VERIFIED A+
◉ What happens to iron and manganese when exposed to air?
Answer: They change from a dissolved form to a colored solid form.
◉ What is required for safe chemical handling?
Answer: All operations specialists should be trained in proper
methods of handling chemicals, detecting leaks, and emergency
procedures.
◉ What personal protective equipment should operations
specialists have?
Answer: Rubber gloves, goggles or facemask, a dust respirator,
protective clothing, and clean running water.
◉ What is the purpose of Self-Contained Breathing Apparatus
(SCBA) in chemical handling?
Answer: To provide respiratory protection for trained personnel,
with at least 30 minutes of capacity.
,◉ What role do phosphate compounds play in water treatment?
Answer: They inhibit pipe corrosion and sequester iron and
manganese.
◉ How do phosphate compounds prevent scale formation?
Answer: By chemically tying up scale-forming ions of calcium and
magnesium.
◉ What is the effect of phosphate addition on customer complaints?
Answer: It reduces complaints of discolored water.
◉ What is orthophosphate used for in water treatment?
Answer: It inhibits corrosion and is most effective in low hardness
water with a pH of 7.1 - 7.8.
◉ What is the function of polyphosphate in water treatment?
Answer: It sequesters iron and manganese and prevents scale
buildup.
◉ What is blended ortho-polyphosphate also known as?
Answer: Zinc phosphate.
, ◉ What is sodium silicate used for in water treatment?
Answer: It inhibits corrosion and sequesters iron and manganese
without being a nutrient for bacteria.
◉ What is sequestration in the context of water treatment?
Answer: A process that keeps scale-causing ions in dissolved form to
prevent precipitation.
◉ What are the storage requirements for sequestration chemicals?
Answer: They must be stored in corrosion-resistant tanks and
approved for potable water use.
◉ What is the typical dosage range for corrosion control chemicals?
Answer: Between 0.5 and 3 mg/L, potentially up to 10 mg/L.
◉ Why must chlorine be fed downstream from the phosphate feed
point?
Answer: To prevent chlorine from oxidizing iron and manganese
before phosphate can sequester them.
◉ What is the minimum chlorine residual required when using
phosphate?
Answer: At least 10 mg/L in the storage tank.
COMPREHENSIVE STUDY GUIDE 2026
DRINKING WATER SYSTEMS SOLUTIONS
VERIFIED A+
◉ What happens to iron and manganese when exposed to air?
Answer: They change from a dissolved form to a colored solid form.
◉ What is required for safe chemical handling?
Answer: All operations specialists should be trained in proper
methods of handling chemicals, detecting leaks, and emergency
procedures.
◉ What personal protective equipment should operations
specialists have?
Answer: Rubber gloves, goggles or facemask, a dust respirator,
protective clothing, and clean running water.
◉ What is the purpose of Self-Contained Breathing Apparatus
(SCBA) in chemical handling?
Answer: To provide respiratory protection for trained personnel,
with at least 30 minutes of capacity.
,◉ What role do phosphate compounds play in water treatment?
Answer: They inhibit pipe corrosion and sequester iron and
manganese.
◉ How do phosphate compounds prevent scale formation?
Answer: By chemically tying up scale-forming ions of calcium and
magnesium.
◉ What is the effect of phosphate addition on customer complaints?
Answer: It reduces complaints of discolored water.
◉ What is orthophosphate used for in water treatment?
Answer: It inhibits corrosion and is most effective in low hardness
water with a pH of 7.1 - 7.8.
◉ What is the function of polyphosphate in water treatment?
Answer: It sequesters iron and manganese and prevents scale
buildup.
◉ What is blended ortho-polyphosphate also known as?
Answer: Zinc phosphate.
, ◉ What is sodium silicate used for in water treatment?
Answer: It inhibits corrosion and sequesters iron and manganese
without being a nutrient for bacteria.
◉ What is sequestration in the context of water treatment?
Answer: A process that keeps scale-causing ions in dissolved form to
prevent precipitation.
◉ What are the storage requirements for sequestration chemicals?
Answer: They must be stored in corrosion-resistant tanks and
approved for potable water use.
◉ What is the typical dosage range for corrosion control chemicals?
Answer: Between 0.5 and 3 mg/L, potentially up to 10 mg/L.
◉ Why must chlorine be fed downstream from the phosphate feed
point?
Answer: To prevent chlorine from oxidizing iron and manganese
before phosphate can sequester them.
◉ What is the minimum chlorine residual required when using
phosphate?
Answer: At least 10 mg/L in the storage tank.
