Scum Pumping
Scum Pumping
(OP)
Hello,
I am trying to size a scum pump but I am unable to find much information on scum generation per overflow rate, or any other similar standards. Most existing thread discuss pump selection and disposal.
Thank you in advance
I am trying to size a scum pump but I am unable to find much information on scum generation per overflow rate, or any other similar standards. Most existing thread discuss pump selection and disposal.
Thank you in advance





RE: Scum Pumping
Can we assume that you are pumping scum off the top of a settling tank given that you mention overflow rates?
If this is linked to an activated sludge plant the quantity of scum is not linked to overflow rates but more to the population of norcardia or other types of scum forming bacteria. In turn the rate of scum formation is then linked to things like aeration intensity , and plant configuration as well as the presence of or absence of a number of substances in the wastewater.
The reason there are no references to scum formation and overflow rates is because there is little direct relationship.
Regards
Ashtree
"Any water can be made potable if you filter it through enough money"
RE: Scum Pumping
Many times the scum pumping operation is a batch process.
RE: Scum Pumping
Scum to be skimmed off the top of clarifier
Secondary Treatment Parameters:
Facility influent 0.25 (mgd)
BOD 190 (mg/L)
SRT 20 (days)
Temp 60 (F)
MLSS 2526 (mg/L)
WAS 247 (lb/day)
NH3 0.37 (mg/L)
NO3+NO2 28.42 (mg/L)
DO 2.19 (mg/L)
Brush Aerators 20 (HP)
RE: Scum Pumping
Just to get a bit of understanding about your plant and how it is operating do you know what your SVI is? What is your design flow?
Have you tried shortening your SRT a little to see if you can reduce your scum?
Regards
Ashtree
"Any water can be made potable if you filter it through enough money"
RE: Scum Pumping
The I/I associated with seasonal changes ranges considerably, 0.25 mgd during the summer, historical peaks of 2.7 mgd during the winter.
For the proposed design SVI would be about 400 (ml/gm) during low flows, and 225 for historical high flows.
RE: Scum Pumping
Regards
Ashtree
"Any water can be made potable if you filter it through enough money"
RE: Scum Pumping
RE: Scum Pumping
Regards
Ashtree
"Any water can be made potable if you filter it through enough money"
RE: Scum Pumping
RE: Scum Pumping
Without knowing all your circumstances i would suggest that you dont have enough aeration capacity which in turn causes problems with the scum formation which is what you are trying to pump away.
You may well need some more settling capacity but maybe you should duplicate what you have already to give you some back up capacity and redundancy and allow one tank off line during the low season.
Then perhaps spend the rest of the money dealing with the infiltration issue and getting more aeration capacity
Regards
Ashtree
"Any water can be made potable if you filter it through enough money"
RE: Scum Pumping