Table 13.6 clearly shows that the water coming out from the tested technology
complies with the requirements for drinking water from the microbiological point of
view. The disinfecting effect of ferrates has already been described in the literature.
Nevertheless, such results have been achieved owing to the combination of different
factors—disinfecting effect caused by ferrates reacting in water, sorption of microorganisms into the formed iron hydroxides microflakes, the impact of ultrafiltration
with the pore size of 0.45 μm, and disinfecting the line before the test. However, the
reliability of the disinfecting effect of the tested technology has yet to be confirmed
under operating conditions in the long run.
13.6.3 Economic Point of View
The price of commercial ferrates for industrial applications is currently (2018) about
EUR 80 per kilo. As the dose of ferrate ensuring the effectiveness of the arsenic
removal from the tested groundwaters is 10–15 mg/L, i.e., 10–15 g/m
3 , the price of
the amount sufficient to treat 1 m
3 of water could range between 1.0–1.1 EUR/m
3 .
In 2017 the following ferrate-based products were available on the market for the
purpose of laboratory tests (see Table 13.7).
Since the production of ferrates is demanding, batches from individual producers
may vary. Therefore, it is recommended that the quality of the particular batch
should be checked in the following steps:
1. Verify the presence of Fe in a ferrate aqueous solution by fundamental analysis.
Table 13.6 Results of the microbiological analysis of KLU water—input and output water from
the tested technology for each dose of the commercial ferrate (sampling point—after UF)
Bacterial
microflora
Unit
KLU
INPUT
KLU
ENVIFER
10 mg/L
without
flocculant
KLU
ENVIFER
10 mg/L
KLU
ENVIFER
15 mg/L
KLU
ENVIFER
20 mg/L
Clostridium
perfringens
CFU/
100 mL
0
0
0
0
0
Coliform
bacteria
CFU/
100 mL
100
0
0
0
0
Enterococci
CFU/
100 mL
5 7
0
0
0
0
Escherichia coli CFU/
100 mL
0
0
0
0
0
Microorganisms
cultivated at
22
C
CFU/
mL
3300
18
0
3
0
Microorganisms
cultivated at
36
C
CFU/
mL
2900
10
0
0
0
308
M. Heřmánková et al.
complies with the requirements for drinking water from the microbiological point of
view. The disinfecting effect of ferrates has already been described in the literature.
Nevertheless, such results have been achieved owing to the combination of different
factors—disinfecting effect caused by ferrates reacting in water, sorption of microorganisms into the formed iron hydroxides microflakes, the impact of ultrafiltration
with the pore size of 0.45 μm, and disinfecting the line before the test. However, the
reliability of the disinfecting effect of the tested technology has yet to be confirmed
under operating conditions in the long run.
13.6.3 Economic Point of View
The price of commercial ferrates for industrial applications is currently (2018) about
EUR 80 per kilo. As the dose of ferrate ensuring the effectiveness of the arsenic
removal from the tested groundwaters is 10–15 mg/L, i.e., 10–15 g/m
3 , the price of
the amount sufficient to treat 1 m
3 of water could range between 1.0–1.1 EUR/m
3 .
In 2017 the following ferrate-based products were available on the market for the
purpose of laboratory tests (see Table 13.7).
Since the production of ferrates is demanding, batches from individual producers
may vary. Therefore, it is recommended that the quality of the particular batch
should be checked in the following steps:
1. Verify the presence of Fe in a ferrate aqueous solution by fundamental analysis.
Table 13.6 Results of the microbiological analysis of KLU water—input and output water from
the tested technology for each dose of the commercial ferrate (sampling point—after UF)
Bacterial
microflora
Unit
KLU
INPUT
KLU
ENVIFER
10 mg/L
without
flocculant
KLU
ENVIFER
10 mg/L
KLU
ENVIFER
15 mg/L
KLU
ENVIFER
20 mg/L
Clostridium
perfringens
CFU/
100 mL
0
0
0
0
0
Coliform
bacteria
CFU/
100 mL
100
0
0
0
0
Enterococci
CFU/
100 mL
5 7
0
0
0
0
Escherichia coli CFU/
100 mL
0
0
0
0
0
Microorganisms
cultivated at
22
C
CFU/
mL
3300
18
0
3
0
Microorganisms
cultivated at
36
C
CFU/
mL
2900
10
0
0
0
308
M. Heřmánková et al.