than those of 2 μm. For both raw water and ozonated water, two filters had different
performance; Filter 1 achieved slightly better performance than Filter 2. However,
after dosing the coagulants, such differences were not shown.
The field trials were carried out at the pilot plant where the operating conditions
followed the main plants. Therefore, the ferrate(VI) dose used was very low, 0.1 mg
Fe/L, in order to equally compare with the performance of ferric chloride (0.1 mg
Fe/L) and ozonation (4 mg O 3 /L) running at the main plant. Table 12.3 shows the
comparative performance of ferrate(VI) and FeCl 3 at 0.1 mg/L dosage in pilot-scale
experiments. Both performed similarly in the removal of particles, UV absorbers,
and dissolved organic carbon (DOC) under the given conditions. However, ferrate
(VI) can achieve 10% reduction of metformin, benzotriazole, and acesulfame, but
FeCl 3 with ozonation cannot remove any of these compounds. Moreover, the ferrate
(VI)-treated water did not generate bromate, but the ozonated water did although the
resulting bromate concentration was 11 μg/L.
12.3.2 Crude Sewage Treatment Performance in the Pilot
Plant
During the pilot-plant study, properties of the crude sewage were tested. Concentrations of the target quality parameters varied from 242 to 730 mg/L for the SS, 523 to
1125 mg/L for the COD, 235 to 441 mg/L for the BOD, and 11.3 to 18.5 mg/L for
the phosphate as total P.
The comparative performance of ferrate(VI) and ferric sulfate can be seen in
Table 12.4. With a low dose (0.03 mg Fe/L), ferrate(VI) can achieve similar or better
performance than a high dose of ferric sulfate (37 mg Fe/L).
Table 12.3 Comparative performance of ferrate(VI) and FeCl 3
Unit
Raw water
Ozone water
Ferrate(VI)
FeCl 3
Ferrate(VI)
FeCl 3
Fe dosage
Mg/L
0.1
Turbidity
%
~80
~80
~90
~90
UV-254
No change
DOC
No change
Residual Fe
μg/L
~16
~9
~15
~12
Particle removal
%
~93
~94
~98
~98
Bromate formation
μg/L
0
0
~11
~11
Benzotriazole removal
%
10
0
10
0
Acesulfame removal
%
10
0
10
0
Metformin removal
%
10
0
10
0
X-ray contrast medium removal
%
100
100
100
100
12 Field Study III: Evidence Gained from Site Studies for the. . .
293
performance; Filter 1 achieved slightly better performance than Filter 2. However,
after dosing the coagulants, such differences were not shown.
The field trials were carried out at the pilot plant where the operating conditions
followed the main plants. Therefore, the ferrate(VI) dose used was very low, 0.1 mg
Fe/L, in order to equally compare with the performance of ferric chloride (0.1 mg
Fe/L) and ozonation (4 mg O 3 /L) running at the main plant. Table 12.3 shows the
comparative performance of ferrate(VI) and FeCl 3 at 0.1 mg/L dosage in pilot-scale
experiments. Both performed similarly in the removal of particles, UV absorbers,
and dissolved organic carbon (DOC) under the given conditions. However, ferrate
(VI) can achieve 10% reduction of metformin, benzotriazole, and acesulfame, but
FeCl 3 with ozonation cannot remove any of these compounds. Moreover, the ferrate
(VI)-treated water did not generate bromate, but the ozonated water did although the
resulting bromate concentration was 11 μg/L.
12.3.2 Crude Sewage Treatment Performance in the Pilot
Plant
During the pilot-plant study, properties of the crude sewage were tested. Concentrations of the target quality parameters varied from 242 to 730 mg/L for the SS, 523 to
1125 mg/L for the COD, 235 to 441 mg/L for the BOD, and 11.3 to 18.5 mg/L for
the phosphate as total P.
The comparative performance of ferrate(VI) and ferric sulfate can be seen in
Table 12.4. With a low dose (0.03 mg Fe/L), ferrate(VI) can achieve similar or better
performance than a high dose of ferric sulfate (37 mg Fe/L).
Table 12.3 Comparative performance of ferrate(VI) and FeCl 3
Unit
Raw water
Ozone water
Ferrate(VI)
FeCl 3
Ferrate(VI)
FeCl 3
Fe dosage
Mg/L
0.1
Turbidity
%
~80
~80
~90
~90
UV-254
No change
DOC
No change
Residual Fe
μg/L
~16
~9
~15
~12
Particle removal
%
~93
~94
~98
~98
Bromate formation
μg/L
0
0
~11
~11
Benzotriazole removal
%
10
0
10
0
Acesulfame removal
%
10
0
10
0
Metformin removal
%
10
0
10
0
X-ray contrast medium removal
%
100
100
100
100
12 Field Study III: Evidence Gained from Site Studies for the. . .
293