Egg Beater Style Aerated Lagoon, Conversion.

[Michael Mills]

Hey Folks,
Question I have is, I am converting a older style Egg-Beater Style lagoon to surface aerated style and I am wondering if anyone has a possible formula to determine the current amount of Oxygen created by the Physical Egg Beater style Aeration, I have the original design calculations and I know what was originally calculated for the Oxygen input required but I want to reverse engineer as well from the current system to ensure I am capturing all the proper information.

 

[ashtree]

I am not sure what style of aerators are "Egg beaters" but many surface aerator designs work on very empirical data rather than complex oxygen transfer calculations. Typically its something along the lines of: You need x amount of oxygen. Our unit will supply y/hp therefore you need an aerator with Z horsepower. This sort of approach normally provides a fair margin in performance.

Unless you have very good information on the current lagoons and aeration system, as in how much waste in terms of BOD/COD has been treated, and how the aerators have been working (hours run, power used, operating DO etc) then any meaningful reverse engineering will be difficult and will rely on lots of assumptions.

Regards
Ashtree
"Any water can be made potable if you filter it through enough money"

 

[bimr]

When aerators are selected, there are 2 factors to be considered, a) mixing energy, b) aeration energy. One should select the larger of the 2 factors. Mixing energy is generally larger than the aeration energy but frequently ignored.

Suggest you contact an aeration supplier such as EDI and review your project with them.

 

[ashtree]

Whilst bimr's comments are correct the actual amount of energy required will depend on the style of lagoon you are operating and whether its complete mixed or only partially mixed. Complete mixed either require a lot more horsepower(some for mixing) or are smaller with much shorter hydraulic detention times than partially mixed lagoons. Partially mixed lagoons don't attempt to keep everything in suspension and thus have areas of the lagoon that could be classed as faculative rather than aerobic.




Regards
Ashtree
"Any water can be made potable if you filter it through enough money"

 

[geesamand]

I don't know what an egg-beater lagoon is, but many lagoons suffer from inadequate mixing that result in massive silt deposition. Something to consider when running your calcs.