139
H.-J. Ceccaldi et al. (eds.), Marine Productivity: Perturbations and Resilience of Socio-ecosystems,
DOI 10.1007/978-3-319-13878-7_15, © Springer International Publishing Switzerland 2015
1
Introduction
Power plants that use seawater for their cooling
water usually suffer from biofouling. Chlorine is
often used to lessen biofouling and the associated
damage to the plant. When chlorine is added to
seawater, it oxidizes bromide ions, the product
being hypobromous acid (HBrO). Hypobromous
acid reacts with ammonia, and a variety of oxidants (mainly bromamines) are subsequently
generated. The sum of concentrations of these
substances is referred to as the total oxidant residue (or just “chlorine residue”) in seawater
(Fig. 1 ). In many cases, Japanese power plants
are required by local governments to keep the
Abstract
The concentration of chlorine residue was monitored near the outlet of a
large thermal power plant in Japan. The plant is required by the local government to ensure that the concentration of chlorine residue remains below
0.05 mg/L at the outlet. Background levels of chlorine residue were relatively high, though lower than 0.05 mg/L. There was a signifi cant positive
correlation between the concentrations of phytoplankton and the background concentrations of chlorine residue. About 0.3 mmol/L of H 2 O 2 was
required to produce a color reaction equivalent to the background signal
in the N-N -diethyl- p -phenylenediamine assay for chlorine residue.
However, reported concentrations of H 2 O 2 in the Sargasso Sea are only
0.0002 mmol/L. H 2 O 2 , which is produced by phytoplankton, oxidizes Br
−
and I
− to produce HBrO and HIO. We hypothesize that these oxidants react
with reagents in the N-N -diethyl- p -phenylenediamine assay and are naturally produced chlorine residuals.
T. Iibuchi (*) • M. Kiyono
Marine Ecology Research Institute ,
Towa- Edogawabashi Bldg., 347 Yamabuki-cho ,
Shinjyuku-ku , Tokyo 162-0801 , Japan
e-mail: iibuchi@kaiseiken.or.jp
S. Kobayashi
JAPAN NUS Co., Ltd. , Nishi-Shinjuku Kimuraya
Bldg., 7-5-25 Nishi-Shinjuku , Shinjuku-ku , Tokyo
160-0023 , Japan
S. Nanjou • K. Satou
Soma Kyodo Power Co., Ltd. , Shinchi Power Station,
1-1 Imagami, Komagamine, Shinchi-Town , Soma
County , Fukushima 979-2611 , Japan
T. Hara
Marine Ecology Research Institute, Central
Laboratory , Onjukumachi , Isumigun , Chiba
299-5105 , Japan
A Subject of the Chlorine
Management at a Thermal Power
Plant on the Northwest Pacifi c
Ocean in Japan
Toshio Iibuchi , Seiji Kobayashi , Sigenori Nanjou ,
Kanako Satou , Takeya Hara , and Michiyasu Kiyono
H.-J. Ceccaldi et al. (eds.), Marine Productivity: Perturbations and Resilience of Socio-ecosystems,
DOI 10.1007/978-3-319-13878-7_15, © Springer International Publishing Switzerland 2015
1
Introduction
Power plants that use seawater for their cooling
water usually suffer from biofouling. Chlorine is
often used to lessen biofouling and the associated
damage to the plant. When chlorine is added to
seawater, it oxidizes bromide ions, the product
being hypobromous acid (HBrO). Hypobromous
acid reacts with ammonia, and a variety of oxidants (mainly bromamines) are subsequently
generated. The sum of concentrations of these
substances is referred to as the total oxidant residue (or just “chlorine residue”) in seawater
(Fig. 1 ). In many cases, Japanese power plants
are required by local governments to keep the
Abstract
The concentration of chlorine residue was monitored near the outlet of a
large thermal power plant in Japan. The plant is required by the local government to ensure that the concentration of chlorine residue remains below
0.05 mg/L at the outlet. Background levels of chlorine residue were relatively high, though lower than 0.05 mg/L. There was a signifi cant positive
correlation between the concentrations of phytoplankton and the background concentrations of chlorine residue. About 0.3 mmol/L of H 2 O 2 was
required to produce a color reaction equivalent to the background signal
in the N-N -diethyl- p -phenylenediamine assay for chlorine residue.
However, reported concentrations of H 2 O 2 in the Sargasso Sea are only
0.0002 mmol/L. H 2 O 2 , which is produced by phytoplankton, oxidizes Br
−
and I
− to produce HBrO and HIO. We hypothesize that these oxidants react
with reagents in the N-N -diethyl- p -phenylenediamine assay and are naturally produced chlorine residuals.
T. Iibuchi (*) • M. Kiyono
Marine Ecology Research Institute ,
Towa- Edogawabashi Bldg., 347 Yamabuki-cho ,
Shinjyuku-ku , Tokyo 162-0801 , Japan
e-mail: iibuchi@kaiseiken.or.jp
S. Kobayashi
JAPAN NUS Co., Ltd. , Nishi-Shinjuku Kimuraya
Bldg., 7-5-25 Nishi-Shinjuku , Shinjuku-ku , Tokyo
160-0023 , Japan
S. Nanjou • K. Satou
Soma Kyodo Power Co., Ltd. , Shinchi Power Station,
1-1 Imagami, Komagamine, Shinchi-Town , Soma
County , Fukushima 979-2611 , Japan
T. Hara
Marine Ecology Research Institute, Central
Laboratory , Onjukumachi , Isumigun , Chiba
299-5105 , Japan
A Subject of the Chlorine
Management at a Thermal Power
Plant on the Northwest Pacifi c
Ocean in Japan
Toshio Iibuchi , Seiji Kobayashi , Sigenori Nanjou ,
Kanako Satou , Takeya Hara , and Michiyasu Kiyono