ΕΘΝΙΚΟ ΜΕΤΣΟΒΙΟ ΠΟΛΥΤΕΧΝΕΙΟ

Conclusions
The pilot-scale GAC column system was found to effectively remove all of the
ECs examined already from the first batch experiment. In the second batch
experiment, despite the problems arisen, this removal started to be quantified (the
breakthrough limits for each EC were established and the first constants N0 and K, as
well as the first values of Lcritical were calculated, although these results are not
trustworthy).
The third and fourth batch experiments gave much more clear results
(especially the third batch experiment) about the breakthrough of each EC, compared
to the second batch experiment. However, probably because of the microbiological
activity observed (especially in the fourth batch experiment) the values of the
constants N0 and K do not change as usual versus the linear flow rate.
As for the ECs examined, in every batch experiment it seems that the EDCs
examined (and particularly Triclosan) were more effectively removed from the water
compared to the PPCPs (that’s why in the EDCs lower breakthrough limits were
established). Among the PPCPs no significant differences were observed in their
removal from the water.
In conclusion, for a proper design of a GAC column unit in a water treatment
plant a design diagram with the values of N0 and K versus the linear flow rate is
required. Therefore it is necessary additional batch experiments to be conducted in
different linear flow rates, so that this design diagram for each EC to be completed.
Furthermore, due to the fact that microbiological activity was observed in
every batch experiment it would be better during the design of the GAC column unit
to include that microbiological activity, as it seems to help in the removal of those
substances (particularly in the fourth batch experiment).
Finally, due to the fact that one of the main entrance route of EDCs and PPCPs
in the aquatic environment is through the effluents of wastewater treatment plants it is
necessary to also investigate the potential of the removal of those substances from the
effluents of wastewater treatment plants. In case of the effluents a much smaller GAC
column service time and a much faster breakthrough limit reach is expected,
compared to those found in the water samples of this thesis, because of the presence
of Natural Organic Matter (NOM) in the effluents.
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