Wastewater Grade 4 Exam UPDATED
QUESTIONS AND CORRECT ANSWERS
Carbon Dioxide - CORRECT ANSWER -Lowers pH
-In anaerobic digestion ratio is Methane 70% / CO2 30%
Chlorine Gas - CORRECT ANSWER Cl2
Alum - CORRECT ANSWER -Coagulant
-Liquid alum has pH of 2
Bisulfide - CORRECT ANSWER HS
Calcium Carbonate - CORRECT ANSWER -Raises pH
-Active ingredient in lime
-Adding lime to build alkalinity
Ferrous Chloride - CORRECT ANSWER -Use over alum as coagulant
-Use for Struvite control in Anaerobic Digester
-Contact with metal
Gasoline - CORRECT ANSWER C8H
-LEL at 1.5%
-UEL is upper explosive limit
-LEL is lower explosive limit
Hydrogen Peroxide - CORRECT ANSWER -Use to treat toxicity
-Supersaturates wastewater with O2
, -Reduces odor / foaminess / COD
Hydrogen Sulfide - CORRECT ANSWER -Rotten egg smell in LOW concentrations
-Heavier than air
-LEL 4.0 / UEL 44.0
-Sewer gas / stink damp
-Also known as Hydrosulfuric Acid
Hydrogen Sulfite - CORRECT ANSWER -Caustics removes it
Hypochlorous Acid - CORRECT ANSWER Disinfection agent, pH 7.5
Lime - CORRECT ANSWER Raises pH, Conditions sludge, Builds Alkalinity
Methane - CORRECT ANSWER Anaerobic digester ratio 70% CH4 : 30% CO2
Mercaptans - CORRECT ANSWER Skunk smell, Treat with caustics
Nitrate (or Nitrate Nitrogen) - CORRECT ANSWER Present in anoxic zone where DO
< 0.2
Nitric Acid - CORRECT ANSWER Holds Phosphorus
Potassium Permanganate - CORRECT ANSWER Oxidizer in water treatment, Creates
purple solution
Sodium Carbonate - CORRECT ANSWER Also known as soda ash, Builds alkalinity
QUESTIONS AND CORRECT ANSWERS
Carbon Dioxide - CORRECT ANSWER -Lowers pH
-In anaerobic digestion ratio is Methane 70% / CO2 30%
Chlorine Gas - CORRECT ANSWER Cl2
Alum - CORRECT ANSWER -Coagulant
-Liquid alum has pH of 2
Bisulfide - CORRECT ANSWER HS
Calcium Carbonate - CORRECT ANSWER -Raises pH
-Active ingredient in lime
-Adding lime to build alkalinity
Ferrous Chloride - CORRECT ANSWER -Use over alum as coagulant
-Use for Struvite control in Anaerobic Digester
-Contact with metal
Gasoline - CORRECT ANSWER C8H
-LEL at 1.5%
-UEL is upper explosive limit
-LEL is lower explosive limit
Hydrogen Peroxide - CORRECT ANSWER -Use to treat toxicity
-Supersaturates wastewater with O2
, -Reduces odor / foaminess / COD
Hydrogen Sulfide - CORRECT ANSWER -Rotten egg smell in LOW concentrations
-Heavier than air
-LEL 4.0 / UEL 44.0
-Sewer gas / stink damp
-Also known as Hydrosulfuric Acid
Hydrogen Sulfite - CORRECT ANSWER -Caustics removes it
Hypochlorous Acid - CORRECT ANSWER Disinfection agent, pH 7.5
Lime - CORRECT ANSWER Raises pH, Conditions sludge, Builds Alkalinity
Methane - CORRECT ANSWER Anaerobic digester ratio 70% CH4 : 30% CO2
Mercaptans - CORRECT ANSWER Skunk smell, Treat with caustics
Nitrate (or Nitrate Nitrogen) - CORRECT ANSWER Present in anoxic zone where DO
< 0.2
Nitric Acid - CORRECT ANSWER Holds Phosphorus
Potassium Permanganate - CORRECT ANSWER Oxidizer in water treatment, Creates
purple solution
Sodium Carbonate - CORRECT ANSWER Also known as soda ash, Builds alkalinity
