Experimental site and flow system
Experiments were carried out during the 43rd cruise of
the research vessel “Akademik Alexander Sidorenko” using
a seawater flow-through system. The experimental system
was composed ofstainless steel plate heat exchangers
(Alfa Laval A45-FG) containing ten plates. These plates
were separated using CFC gaskets and the plates are equidistantly
spaced (3:7 mm). The heat exchanger was connected
to two seawater pumps using 5.08-cm diameter carbon steel
piping. One pump fed the odd numbered plates whereas and
the other fed seawater to the even numbered plates. The
seawater line feeding the even numbered plates was chlorinated
before it entered the plate heat exchangers using a
variable stroke chemical dosing pump connected to a programmable
timer device. This arrangement ensured that every
alternate plate was receiving chlorinated water. Thus one
set of plates ofthe plate heat exchanger was left untreated
and served as a control, and other set was chlorinated using
sodium hypochlorite (NaOCl). A chlorine residual of
1:2 mg l−1 applied for 2 h with 2-h intervals between applications,
determined from experiments conducted near the
shore, was tested. Subsequently, the effectiveness of this