7.9 Potable Water

Question 1

Flash Type Distiller

Answer 1

Relies on a combination of lowering the pressure within the distiller and introduction of preheated seater

Question 2

Reverse Osmosis (RO) Desalination

Answer 2

Seawater is forced through a membrane, which removes impurities

Question 3

Flash Type Distiller specs

Answer 3

Used on platforms with auxiliary steam production. (CVN 68-77, LCC 1-2, LHD 1-7)
High capacity
Multiple stages
Max temp: 170 +- 5F

Question 4

RO Filtration Process

Answer 4

Used on ships with limited or no steam production, no heat required
Relies on pressurized seawater to push through a membrane
High capacity and more efficient
Less maintenance required

Question 5

RO Components

Answer 5

Filter System
High Pressure Pump System
RO Module

Question 6

Factors that influence production amoutns

Answer 6

Bacteriological contamination
Salinity
Temperature

Question 7

Treatment methods onboard ships

Answer 7

Brominator Method (in-line & primary method)
Chlorine Disinfection Method (batch & secondary method)

Question 8

Shore Water Procedures

Answer 8

Medical representative must be at the location
All connections immersed in 100 ppm of chlorine
Connections must be free of rust, dirt, etc. by flushing
Do not connect Collect, Hold, Transfer (CHT) and potable water at the same time - Connect water FIRST to prevent contamination!

Question 9

Potable Water Hoses

Answer 9

Blue; POTABLE WATER USE ONLY
Must not contact seawater
Locker must be at least 18 in above the deck

Question 10

Medical Potable Water testing requirements

Answer 10

Prior to receipt (if from shore)
Daily from each potable water tank
From various locations throughout the ship

Question 11

Engineering Potable Water testing requirements

Answer 11

30 minutes after being treated in potable water tank
Prior to putting a potable water tank into service
Tank changed regularly according to supply, demand, and potable water production
Upon bromine cartridge change out

Question 12

Test Limits for Chlorine and Bromine

Answer 12

Free Available Chlorine (FAC) or Total Bromine Residual (TBR)

TBR and FAC limits:
-0.2 ppm = Distilled on board or taken on board.
-2.0 ppm = Water from area where amebiasis or hepatitis endemic exists or unapproved shore source water is used
-5.0 ppm = Emergency use only

Question 13

Bromine Safety

Answer 13

Must have warning plates at each chemical feeder and storage locker
Avoid contact with skin & eyes
Use a face shield and gloves
Do not reuse empty containers

Question 14

Chlorine Safety

Answer 14

Do not mix with anything but water
Do not let it come in contact with combustible materials
Dispense only in clean dry utensils & only in amounts required for immediate use
Avoid contact with skin or eyes
Do not reuse containers
Store ready use bottles in vented locked box mounted on the bulk head
Do not store in temperatures above 100o
Lockers should be labeled:
-HAZARDOUS MATERIAL
-CALCIUM HYPOCHLORITE
Dispose in water only

Question 15

Flash Type Plant Major Components

Answer 15

Seawater Feed Pump
Distiller Condenser
Seawater Heater
Feed Inlet Box
Flash Chamber
Demister Pads
Distillate Pump
Salinity Cells
Solenoid Dump Valve
Brine Pump
Air Ejectors
Air Ejector Condenser
Seawater Heater Drain Pump