In a closed system with no TOC generation, a skimmer will only remove 30% and bigger skimmers will remove it faster, however, in the manner in which we run them (ie. continuously) the bigger skimmer WILL WORK BETTER because it will remove the labile TOC faster than the others. For example, if the rate of removal of the labile TOC is greater than the rate of labile TOC generation there will be no accumulation; however, if your skimmer is undersized you won't be removing the labile TOC as fast as they are generated and you will have TOC build up.
The rate of removal becomes even more important if you are running carbon dosing systems, such as vodka dosing, where you are converting the refractory TOC (that is otherwise not removed by a skimmer) to biomass in the form of bacteria. Since you would then be able to remove all of the TOC, not just the labile TOC, the equations they use become skewed. In this situation you will need an oversized skimmer to keep up with removal demands as removable products increase from 30% to anywhere from 65% to 80% (not all TOC is converted to biomass since the bacteria produce CO2 during metabolism, assuming all TOC is consumed by bacterial metabolism).
I wouldn't say that this article says spending a ton on a high end skimmer is a waste but (break issues described above aside) it makes the case for oversizing your skimmer. They didn't show suspended solid removal (ie. bacteria removal) in these tests at all. The high end skimmers that produce smaller bubbles in high quantities will remove organic suspended solids much faster than a POS skimmer will. So again, since we are running in a continuous manner, rate and size become important.
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