ΕΘΝΙΚΟ ΜΕΤΣΟΒΙΟ ΠΟΛΥΤΕΧΝΕΙΟ

Service time {days}
12
10
8
6
4
2
0
Bohart-Adams Bisphenol-A
R² = 0,9779
0 0,05 0,1 0,15 0,2
GAC bed depth {m}
Figure 5 : Bohart-Adams lines of Bisphenol-A (left) and Ibuprofen (right).
Fourth batch experiment
The fourth batch experiment was conducted with the working parameters of
the third batch experiment, except from the linear flow rate of the solution, which was
increased to 3,65 m/h. The concentrations of the EC’s were 2 μg/L and the GAC bed
depth was 0,04 m at each column. The results from this batch experiment clearly
showed breakthrough of all EC’s at all columns of the system. After approximately
three days microbiological activity was also observed in column A.
From the results of this batch experiment breakthrough curves for each EC
were made (for example Figure 6 shows the breakthrough curves from the fourth
batch experiment of the EDC Bisphenol-A and the PPCP Ibuprofen) and the
breakthrough limits of the second batch experiment were applied. The Bohart-Adams
model was applied for each EC and the constants N0 and K were calculated (for
example Figure 7 shows the Bohart-Adams lines from the fourth batch experiment of
the EDC Bisphenol-A and the PPCP Ibuprofen). Finally, for each EC the Lcritical was
calculated from the constants N0 and K respectively.
The Bohart-Adams lines that were made in this batch experiment showed
some correlation of GAC bed depth and column service time. R-square values were
ranged from 0,9360 (Diclofenac) to 0,9931 (Naproxen). This was probably due to the
microbiological activity, as the columns A and B reached breakthrough limits earlier
compared to the third batch experiment (as expected), but not columns C and D.
~ ix ~
Service time {days}
10
8
6
4
2
0
Bohart-Adams Ibuprofen
R² = 0,9977
0 0,05 0,1 0,15 0,2
GAC bed depth {m}