Environmental Engineering Reference
In-Depth Information
8.15 aCTivaTed sludge ProCess
reCordKeePing reQuireMenTs
Wastewater operators soon learn that recordkeeping is a major
requirement and responsibility of their jobs. Records are important
(essential) for process control, providing information on the cause of
problems, providing information for making seasonal changes, and
compliance with regulatory agencies. Records should include sampling
and testing data, process control calculations, meter readings, process
adjustments, operational problems and corrective action taken, and pro-
cess observations.
8.16 ChaPTer revieW QuesTions
8.1
Increasing the wasting rate will
the MLSS concen-
tration,
the return concentration,
the MCRT and F/M ratio, and
the SVI.
8.2
What two purposes does the air supplied to the aeration basin
serve?
Use the following data for Questions 8.3 through 8.7:
Plant influent
SSv test
Flow = 2.10 MGD
Sample = 2000 mL
BOD = 230 mg/L
30-min settleability test = 1750 mL
TSS = 270 mg/L
60-min settleability test = 1050 mL
Primary effluent
Waste activated sludge
Flow = 2.10 MGD
Flow = 0.090 MGD
aeration tank influent
Solids = 6125 mg/L
BOD = 175 mg/L
Volatile solids = 4105 mg/L
TSS = 133 mg/L
return activated sludge
aeration tank
Flow = 0.50 MGD
Volume = 1,265,000 gal
Solids = 5785 mg/L
MLSS = 2780 mg/L
Volatile solids = 4165 mg/L
MLVSS = 1860 mg/L
Settling tank volume = 882,000 gal
Desired F/M ratio = 0.25 lb/lb
Desired MCRT = 6.5 days
8.3
What is the mean cell residence time (MCRT) in days?
8.4
What is the food-to-microorganism (F/M) ratio?
8.5
What is the SSV
60
in mL/L?
8.6
Using the SSV
60
in mL/L, what is the sludge volume index?
