ARMY TM 10-4610-309-14
MARINE CORPS TM 10802A-14/1
TACTICAL WATER PURIFICATION SYSTEM (TWPS)
0002 00
DESCRIPTION AND THEORY OF OPERATION
EQUIPMENT DESCRIPTION AND DATA
Reverse Osmosis (RO) System
The MF filtrate becomes the RO feed water. The RO feed water is pressurized in the RO system to flow
through the RO elements. A portion of the feed water passes through the RO membranes and is
collected as product water that contains only a small amount of dissolved salts (total dissolved solids,
TDS). Most of the salts do not pass through the membranes. The remaining water and the salts that do
not pass through the RO membranes are called "reject". The reject water is discharged through the
waste out hoses back to the raw water source. The reverse osmosis system includes the following major
components (listed in the general flow sequence through the system):
RO System: RO Feed Tank to High Pressure Pumps (see Figure 13)
RO Feed Tank T-2. Stores a sufficient supply of filtrate (for RO feed water) to allow the
production of product water to continue uninterrupted during the intervals when the MF modules
are being backwashed. Also used for cleaning solutions when cleaning the RO and MF
assemblies.
and, if needed, to provide added generator load to avoid wet stacking during normal operation.
(Wet stacking is the collection of condensation in the generator exhaust system that can occur
when operated at low loads. Wet stacking over a period of time can corrode the generator
exhaust system.)
Temperature Indicator TI-202. A dial thermometer that indicates the temperature of the fluid
inside the RO feed tank. Used primarily for certain cleaning procedures.
RO Feed Tank Main Drain Valve V-412 and Auxiliary Drain Valve V-210. Used to drain the
tank.
level in the RO feed tank.
RO Feed Tank Pump Inlet Strainer S-3. A removable, coarse strainer that is positioned inside
the RO feed tank over the tank outlet to the RO feed pump P-4 suction. This strainer prevents
coarse objects, which may fall into the tank, from entering the pump.
RO Feed Pump P-4. Draws RO feed water from the RO feed tank and provides the pressure
needed by the HP (high pressure) pumps. This pump also circulates the cleaning solutions used
when cleaning either of the MF or RO systems.
Antiscalant Injection Check Valve V-623. Injection point for an antiscalant chemical solution
that inhibits salt scale formation on the RO membranes.
RO Feed Temperature Transmitter TT-201. Provides a temperature measurement that is used
by the PLC to indicate when the feed water temperature exceeds 110 F and to indicate if the RO
feed tank heaters are turned off during cleaning.
High Pressure Pump Feed Valve V-212. Used for various cleaning and maintenance
procedures.
Inline Strainer S-4 and Drain Valve V-213. Protects the HP pumps. Catches sand and dirt that
may have entered the RO feed tank before it reached the HP pumps.
RO Feed Pressure Gauge PI-202. Indicates the pressure from the RO feed pump. Usual
pressure is 40 to 45 psig.
PLC to shut down the HP pumps when the pressure from the RO feed pump drops below 35 psig.
High Pressure Pump (HPP) Inlet Drain Valve V-214. Used to drain water from the HPP inlet
pipes and hoses.
0002 00-12
