term1 Definition1term2 Definition2term3 Definition3
Please sign in to your Google account to access your documents:
What are the six key monitoring points within the activated sludge process?
Plant influent, primary clarifier effluent, aeration tank, secondary clarifier, internal plant recycles and plant effluent.
For each of the monitoring points listed above, explain what key characteristics a TPO should look for.
Plant influent – check for flow increase and influent solids increase
primary clarifier effluent – check BOD/COD, TSS and nutrients
aeration tank – check MLSS/MLVSS, residual DO, pH and total alkalinity, SOUR, color and the biomass
secondary clarifier – check sludge blanket level, sludge return rate and floating solids on clarifier surface
internal plant recycles – check digester or sludge holding tank supernatant and sludge dewatering or thickening process recycle
plant effluent – check turbidity and NPDES permit requirements
Calculate the pounds of solids under aeration for a plant with the following information:
Plant Flow: 400,000 gallons per day
MLSS: 2,000 mg/L
Pounds of solids under aeration = (MLSS, mg/L) x (aeration tank volume, Mgal) x 8.34
= (2,000 mg/L) x (0.4 Mgal) x 8.34
= 6672 lbs of solids
Calculate the MCRT assuming the following:
• Total system flow is 5 MGD
• Aeration Tank Volume is 4 million gallons
• MLSS = 3,000 mg/l
• Effluent suspended solids concentration: 3.5 mg/L
• Sludge wasting rate (WAS flow) = 0.1 MGD
• Waste activated sludge suspended solids (WASSS) = 8,000 mg/L
MCRT = 3,000 mg/l x 4 MG x 8.34
3.5 mg/l x 5 MGD x 8.34 + 8,000 mg/l x 0.1 mgd x 8.34
MCRT = 100,080 lbs
145.95 lbs/day + 6672 lbs/day
MCRT = 14.68 days
Calculate the F/M ratio given the following:
Aeration tank volume is 500,000 gal
Aeration tank influent BOD = 200 mg/L
Influent flow = 1.0 MGD
MLVSS = 2,000 mg/l
F/M = Influent BOD (or COD) lbs/day
MLVSS in aeration, lbs-day
= 200 mg/L x 1.0 mgd x 8.34
0.5 mg x 2,000 mg/l x 8.34
= 1,668 lbs/day BOD
8,340 lbs MLVSS-day
F/M = 0.2
Calculate the SVI for an activated sludge sample given the following:
30-minute settleable solids volume = 200 mL
MLSS = 2,000 mg/L
% settleable solids = (200/1000) x 100 = 20
SVI = 20 x 10,000 = 100 mL/g
2,000
Calculate the required WAS rate given the following:
Volume of aeration tank = 1.7 Million gallons
MLSS = 1,600 mg/L
Plant flow = 10 MGD
Effluent suspended solids = 10 mg/L
WAS suspended solids = 8,000 mg/L
Target MCRT = 5 days
5 days = (1600mg/L x 1.7 mgal x 8.34) (10 mg/L x 10.0 mgd x 8.34) + (8000 mg/L x WAS x 8.34)
(10 mg/L x 4.0 mgd x 8.34) + (8000 mg/L x WAS x 8.34) = 22,684.4 lbs
5 days
834 lbs + (8000 mg/L x WAS x 8.34) = 22,684.4 lbs
day 5 days
(8000 mg/L x WAS x 8.34) = 4536.88 lbs - 834 lbs
day day
8000 mg/L x WAS x 8.34 = 3702.88 lbs
day
WAS = 3702.88 lbs
8000 mg/L x 8.34
WAS = 0.06 mgd
If there is a large increase in influent plant solids, you may need to increase the ___________ in the aeration tank.
a. MLVSS
b. BOD
c. Total suspended solids
d. Phosphorus
Typical wastewater parameters that are used to characterize influent loadings include (select all that apply):
a. Flow
c. TSS
d. Ammonia
e. Phosphorus
T/F: Biochemical oxygen demand (BOD) can be used as a measure of the organic compounds in water or the “food” for microorganisms.
T
Need help typing ? See our FAQ (opens in new window)
Please sign in to create this set. We'll bring you back here when you are done.
Discard Changes Sign in
Please sign in to add to folders.
Sign in
Don't have an account? Sign Up »
You have created 2 folders. Please upgrade to Cram Premium to create hundreds of folders!