CA Wastewater Grade 4 Exam UPDATED
QUESTIONS AND CORRECT ANSWERS
3 considerations, besides does, that impact the effectiveness of UV. - CORRECT
ANSWER Water Clarity
Water hardness (causes build up on lamps)
Frequency of lamp cleaning
Units on MCRT - CORRECT ANSWER S = lb MLSS in system (AB + Secondary
Clarifiers0
E(dot) = lb/d TSS unintentionally removed in effluent
W(dot) = lb/d TSS intentionally removed in WAS
Conventional Activated Sludge: MCRT, F:M, Organic Loading, MLSS mg/L, Aeration Basin
HRT (hours), Qras % of Q - CORRECT ANSWER MCRT = 5 - 15 Days
F:M = 0.2 - 0.4 lb BOD/d*lb MLVSS
OL = 20 - 40 lb BOD/d*1000 ft^3
MLSS = 1500 - 3000 mg/L
HRT = 4 - 8 hours
Qras% = 25 to 50% of Q
Extended Aeration Activated Sludge: MCRT, F:M, Organic Loading, MLSS mg/L, Aeration
Basin HRT (hours), Qras % of Q - CORRECT ANSWER MCRT = 20 - 30 Days
F:M = 0.05 - 0.15 lb BOD/d*lb MLVSS
OL = 10 - 25 lb BOD/d*1000 ft^3
MLSS = 3000 - 6000 mg/L
HRT = 18 - 16 hours
Qras% = 75 to 150% of Q
, Contact-Stabilization Activated Sludge: MCRT, F:M, Organic Loading, MLSS mg/L,
Aeration Basin HRT (hours), Qras % of Q - CORRECT ANSWER MCRT = 5 - 15
Days
F:M = 0.2 - 0.6 lb BOD/d*lb MLVSS
OL = 60 - 75 lb BOD/d*1000 ft^3
MLSS = Contact: 1000 - 3000 mg/L, Stabilisation: 4000 - 10,000
HRT = Contact: 0.5 - 1 hours, Stabilisation: 3 - 6 hours
Qras% = 25 to 100% of Q
Step Feed Activated Sludge: MCRT, F:M, Organic Loading, MLSS mg/L, Aeration Basin
HRT (hours), Qras % of Q - CORRECT ANSWER MCRT = 5 - 15 Days
F:M = 0.2 - 0.4 lb BOD/d*lb MLVSS
OL = 20 - 40 lb BOD/d*1000 ft^3
MLSS = 2000 - 3500 mg/L
HRT = 3 - 5 hours
Qras% = 25 to 75% of Q
Complete Mix Activated Sludge: MCRT, F:M, Organic Loading, MLSS mg/L, Aeration
Basin HRT (hours), Qras % of Q - CORRECT ANSWER MCRT = 5 - 15 Days
F:M = 0.2 - 0.6 lb BOD/d*lb MLVSS
OL = 50 - 120 lb BOD/d*1000 ft^3
MLSS = 3000 - 6000 mg/L
HRT = 3 - 5 hours
Qras% = 25 to 100% of Q
T/F: When measuring VA in an anaerobic digester, the final step is to titrate the sample with
sulfuric acid. - CORRECT ANSWER False: Titrate 0.1 N of Sodium hydroxide to the
phenolphthalein endpoint (pH =8.3)
In order for denitrification to occur, what must happen first? (3 items) - CORRECT
ANSWER Nitrate must be present
QUESTIONS AND CORRECT ANSWERS
3 considerations, besides does, that impact the effectiveness of UV. - CORRECT
ANSWER Water Clarity
Water hardness (causes build up on lamps)
Frequency of lamp cleaning
Units on MCRT - CORRECT ANSWER S = lb MLSS in system (AB + Secondary
Clarifiers0
E(dot) = lb/d TSS unintentionally removed in effluent
W(dot) = lb/d TSS intentionally removed in WAS
Conventional Activated Sludge: MCRT, F:M, Organic Loading, MLSS mg/L, Aeration Basin
HRT (hours), Qras % of Q - CORRECT ANSWER MCRT = 5 - 15 Days
F:M = 0.2 - 0.4 lb BOD/d*lb MLVSS
OL = 20 - 40 lb BOD/d*1000 ft^3
MLSS = 1500 - 3000 mg/L
HRT = 4 - 8 hours
Qras% = 25 to 50% of Q
Extended Aeration Activated Sludge: MCRT, F:M, Organic Loading, MLSS mg/L, Aeration
Basin HRT (hours), Qras % of Q - CORRECT ANSWER MCRT = 20 - 30 Days
F:M = 0.05 - 0.15 lb BOD/d*lb MLVSS
OL = 10 - 25 lb BOD/d*1000 ft^3
MLSS = 3000 - 6000 mg/L
HRT = 18 - 16 hours
Qras% = 75 to 150% of Q
, Contact-Stabilization Activated Sludge: MCRT, F:M, Organic Loading, MLSS mg/L,
Aeration Basin HRT (hours), Qras % of Q - CORRECT ANSWER MCRT = 5 - 15
Days
F:M = 0.2 - 0.6 lb BOD/d*lb MLVSS
OL = 60 - 75 lb BOD/d*1000 ft^3
MLSS = Contact: 1000 - 3000 mg/L, Stabilisation: 4000 - 10,000
HRT = Contact: 0.5 - 1 hours, Stabilisation: 3 - 6 hours
Qras% = 25 to 100% of Q
Step Feed Activated Sludge: MCRT, F:M, Organic Loading, MLSS mg/L, Aeration Basin
HRT (hours), Qras % of Q - CORRECT ANSWER MCRT = 5 - 15 Days
F:M = 0.2 - 0.4 lb BOD/d*lb MLVSS
OL = 20 - 40 lb BOD/d*1000 ft^3
MLSS = 2000 - 3500 mg/L
HRT = 3 - 5 hours
Qras% = 25 to 75% of Q
Complete Mix Activated Sludge: MCRT, F:M, Organic Loading, MLSS mg/L, Aeration
Basin HRT (hours), Qras % of Q - CORRECT ANSWER MCRT = 5 - 15 Days
F:M = 0.2 - 0.6 lb BOD/d*lb MLVSS
OL = 50 - 120 lb BOD/d*1000 ft^3
MLSS = 3000 - 6000 mg/L
HRT = 3 - 5 hours
Qras% = 25 to 100% of Q
T/F: When measuring VA in an anaerobic digester, the final step is to titrate the sample with
sulfuric acid. - CORRECT ANSWER False: Titrate 0.1 N of Sodium hydroxide to the
phenolphthalein endpoint (pH =8.3)
In order for denitrification to occur, what must happen first? (3 items) - CORRECT
ANSWER Nitrate must be present
