Sizing of an equalization basin
Sizing of an equalization basin
(OP)
We are working on an equalization basin for a 0.35 MGD WWTP. I have come up with the theoretical value, (40,000 gal) but all the literature I have read says to increase that number by 10-40%. How does one decide on the appropriate factor? Additionally, at what point should aeration of the basin be considered?





RE: Sizing of an equalization basin
Wastewater goes septic in three to four hours. If your expected detention time in the basin is more than that consider adding aeration. By all means, design the basin so that aeration can be easily added later if needed.
Good luck
RE: Sizing of an equalization basin
RE: Sizing of an equalization basin
Depending on how long you hold the waste and it's source (I&I, surges from industrial users, etc.) you might or might not need to aerate it.
Tanks have been used for storage. What will the baffling do? If it is for aeration, mixing, or other primary treatment ok, if not, do you really need it? Make the bottom where the tank will drain. If it doesn't, you will have odors. Make sure your hydraulics work.
One of my main concerns would be the regulating authority. What will they allow?
RE: Sizing of an equalization basin
The WWTP currently operates with two headworks pumps which do not have vfds. Therefore they are pushing full flow or no flow into the facility. They also have very little storage upstream. Due to the configuration, the plant has been subject to washouts and will be under an agreed order with IDEM (Indiana EPA) shortly to correct the problems. We are proposing to install an equalization basin/tank upstream of the headworks pumps. Additionally, the headworks pumps would be reconfigured to operate off of vfds.
Since the equalization basin would be inline, it would always have wastewater in it but it would turn over frequently. The only purpose I would see for baffling would be for mixing and/or aeration.
RE: Sizing of an equalization basin
Need for aeration depends much more on the kind of process that you will use for the treatment.