CE 428 Wastewater Treatment Plant Visit
To be turned in on Monday, March 7 in class.
1.
Ask the chief operator, what is the sludge age or solids residence time (SRT) of the
wastewater treatment plant?
Based on the various operating and concentrations data (you need to ask the chief
operator), estimate the SRT of the wastewater treatment. State all assumptions clearly in
your calculations.
Compare and comment on your estimated SRT with the SRT provided by the chief
operator.
2.
For the secondary clarifiers, estimate the actual parameters that are typically used for
design of secondary clarifiers.
How are these values compared with values found in your book?
Comment on which design parameter controls the design/operation of the secondary
clarifier at Marshalltown WWTP.
3
The sequencing batch bioreactor operates in a batch mode where flow is sent to one tank
and then to the other tank.
How many cycles are there per day and how long is each cycle?
For each cycle, specify the sequences (feed, fill, decant, etc) and their times?
What is the HRT of the SBR?
4.
You will find that lime is used for the SBR to provide sufficient alkalinity since
nitrification occurs in the SBR? Estimate the amount of alkalinity (kg as Ca(OH)2 per
day) that is needed in the SBR and compare your result with the actual lime used on site.
Comment on any differences between theoretical and actual.
5.
UV is used for disinfection at Marshalltown.
What is the HRT or contact time for UV disinfection at the treatment plant?
What other parameters should be considered?