- Jan 23, 2005
ceg4048;24970 said:I realize the test was performed within the context of possible large scale industrial application of sewage treatment and not in terms of aquariums but I noted that the comparison was between some floating plants, which I imagine have better access to CO2 at the surface, with our E. densa and Hydrocotle submerged in which I guess was a non-CO2 supplemented tank, possibly in bright sunlight.
The other thing I felt was "unfair" was that both SAMs were left alone without a substrate, but I understand that he wanted to eliminate any sediment effects.
The baffling thing though is how to explain the wildly different Summer curves of the two SAMs. I'm not sure how to interpret that at all. If most of the NH4 reduction was being done by bacteria in both cases shouldn't their NH4 curves be the same? How does this show that E. densa was better at NH4 uptake than Hydrocotyle at summer temperatures? If a plant removes NH4 doesn't that leave less for the bacteria to nitrify? Shouldn't that be reflected in an NO3 curve as shown by the hydrocotyle?
On page 3 paragraph 2 he concludes that E. densa is good at NH4 removal but poor at overall N removal - but I can't see how he reached that conclusion; if the rise in NO3 was so high doesn't that mean it was the bacteria consuming the NH4, not so much the E. densa?
Wouldn't it have been standard practice to do a "control" where no plants were in a tank to see the curves of that tank to determine the effect of the bacteria alone?
Of course, if he says E. densa is good at NH4 removal then I have to accept it but I'm having trouble believing it, because the data seems very conflicting. Could you help clarify?
Hi Tom,Tom Barr;25110 said:When you add very low levels of NH4, that's another matter and you can see from the bacterial actions, that 0.2ppm of NH4 will be gone in a matter of a couple of hours in an aquarium.