ΕΘΝΙΚΟ ΜΕΤΣΟΒΙΟ ΠΟΛΥΤΕΧΝΕΙΟ

However, from the results of the batch experiments conducted this does not
seem to happen in any of the ECs examined. This was probably due to the
microbiological activity, particularly in the fourth batch experiment, where the
columns A and B reached breakthrough limits earlier compared to the third batch
experiment, but not columns C and D. Microbiological activity was also observed
earlier in the fourth batch experiment, compared to the second and third batch
experiment. This also seems to have affected the results from the fourth batch
experiment, resulting in decreased correlation of GAC bed depth and column service
time compared to the third batch experiment.
Furthermore, the difference of the linear flow rate between the forth batch
experiment and the second and third batch experiments is probably not statistically
significant and so the changes of the values of the constants N0 and K are not
statistically significant either. So, for the reasons aforementioned the results were
assumed to be of a single linear flow rate (the average value of 3,39 m/h) and the
values of the constants N0 and K were extracted from all batch experiments for each
EC examined. Table 1 shows the final values of the constants N0 and K for each EC
examined. Those constants are referred to a single linear flow rate (3,39 m/h).
Table 1 : Final values of the constants N0 and K at 3,39 m/h for each EC examined.
Emerging contaminant N0 {g/m 3 } K {m 3 /(g·h)} Breakthrough limit
Bisphenol-A 12,82 7,48 10%
Triclosan 8,41 19,69 7,5%
Ibuprofen 8,89 15,99 20%
Naproxen 9,14 25,88 20%
Ketoprofen 9,46 15,18 20%
Diclofenac 10,85 12,86 20%
In the design of a GAC column unit in a typical water treatment plant in order
to remove from water one of the ECs examined (Diclofenac) it seems that the surface
needed is relatively large (551 m 2 ) probably due to the fact that the flow rate of the
unit is very small compared to the flow rate of the plant. So, it is suggested the
redesign of the unit with bigger flow rates and new constants N0 and K respectively.
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