Environmental Engineering Reference
In-Depth Information
activated sludge effluent
Flow = 8.34 mg/L
Suspended solids = 17 mg/L
BOD = 20 mg/L
anaerobic digester
Solids in = 6.6%
Solids out = 13.5%
Volatile matter in = 65.5%
Volatile matter out = 47.9%
Plant influent
Flow = 8.45 MGD
grit channel
Number of channels = 2
Channel length = 45 ft
Channel width = 3 ft
Water depth = 3.5 ft
12.40 What is the hydraulic detention time (in hours) for primary set-
tling when both tanks are in service?
12.41 What is the hydraulic detention time (in minutes) in the grit chan-
nel when both channels are in service?
12.42 What is the hydraulic detention time (in days) of the anaerobic
digester?
12.43 Appreciable quantities of septic sludge “burping” to the surface
of primary settling tanks could indicate
.
12.44 When a high organic waste load reaches an activated sludge plant,
the operator's first indicator is a decrease in
.
12.45 What is the purpose of the bar screen?
12.46 What two methods are available for cleaning a bar screen?
12.47 Name two ways to dispose of screenings.
12.48 Turbidity in wastewater is caused by
.
12.49 What must be done to the cutters in a comminutor to ensure
proper operation?
12.50 The comminutor jams frequently. A review of the maintenance
records indicates that the cutters were changed approximately
2 weeks ago and the cutter alignment was checked yesterday.
What are the possible causes for the continued jamming prob-
lem? What action should you recommend to identify the specific
cause?
12.51 The reaction of chlorine and ammonia in wastewater produces
what compound?
