TM 55-1930-209-14&P-4
CHAPTER 2 DESCRIPTION OF OPERATION
2-1 General. The chlorination system generates and automatically maintains chlorine in the form of a sodium
hypochlorite solution with a strength of 5000 to 6000 ppm expressed as total available chlorine equivalent. This strength
is maintained by constantly recirculating the solution from the holding tank through a series of nine electrolytic cells and
back to the holding tank for a predetermined period of time. A metering pump draws chlorine from the holding tank and
injects it into product water flowing from the ROWPU's. This combination of product and chlorine flows through a mixer
just before the water enters the drinking water storage tanks. The mixer evenly distributes the chlorine throughout the
product water. A sensor measures the amount of chlorine in the treated water downstream of the mixer and causes the
metering pump to inject either more or less chlorine to maintain the amount of chlorine in the drinking water at 5 to 7
ppm. As chlorine is withdrawn from the holding tank and the chlorine solution level drops, a float switch activates the
brine pump, which pumps brine solution from the brine tank to the holding tank. In the holding tank, the brine solution is
mixed and circulated with the chlorine solution from the electrolytic cells. When the level of chlorine solution in the
holding tanks reaches the proper level, the float switch turns the brine pump and circulating pump off. This process of
recirculating and replenishing continues as long as the chlorination unit and brine pump are activated and the metering
pump withdraws chlorine solution from the holding tank. On/Off operation of the metering pump is controlled by a flow
switch located in the ROWPU product water line. When the metering pump motor controller is in the AUTO mode, this
flow switch automatically starts the pump when ROWPU product water is flowing and stops the pump when product water
stops flowing.
2-2 Preparation for operation. Both the holding tank and the brine tank have to be primed before the system can
prepare the chlorine solution. Either seawater or fresh water may be used to prime both tanks. If seawater is used, it
may be supplied from either the seawater pumps in void 2 starboard or from the cooling pump in void 2 port. Fresh
water, if available, is obtained from the drinking water pressure set. Paragraph 3-5 gives details on priming the system.
After priming, this system takes about 4 hours to produce a chlorine solution of the proper strength in the holding tank.
The system can be placed in operation before this 4-hour period, but the metering pump will inject a larger amount of
solution into the product water to raise the chlorine level to the proper concentration. If the system must start injecting
chlorine into the product water as soon as the seawater and ROWPU systems are placed in operation, a commercial
hypochlorite solution (household bleach) can be added to the holding tank to create a usable solution.
2-3 Non-operating chlorination system . ROWPU barges have only one chlorination system. If this system cannot be
operated, arrangements must be made for an onshore water processing facility to add chlorine to the ROWPU barge
product water when the water comes ashore. To provide safe onboard drinking water during such a situation, water in
the reserve tank must be manually treated with chlorine according to instructions in TM 55-1930209-14&P-5 Drinking
Water System.
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