CIM_6240_5.pdf

Commandant United States Coast Guard

2100 Second Street, S.W.

Washington, DC 20593-0001 Staff Symbol: G-WKS Phone: (202) 267-1883

COMDTINST M6240.5

10 October 1999

COMMANDANT INSTRUCTION M6240.5

Subj: WATER SUPPLY AND WASTEWATER DISPOSAL MANUAL

1. PURPOSE: To provide standards and public health information for Coast Guard personnel responsible for producing, storing, monitoring, and using potable water and wastewater systems at afloat and ashore units.

2. ACTION:

a. Area Commanders: Ensure units under their operational control carry out this Manual's provisions.

b. District Commanders: Ensure units under their operational control carry out this Manual's provisions.

c. Commanders of Maintenance and Logistics Commands: Ensure units under their operational control carry out this Manual's provisions and provide technical oversight and support to all units within their area of responsibility to ensure compliance with this Manual.

d. Commanding Officers of Headquarters Units: Ensure adherence to this Manual's contents.

e. Assistant Commandants for Directorates and Special Staff Offices at Headquarters: Perform all duties related to policy guidance and direction.

3. DIRECTIVES AFFECTED: COMDTINST M11300.2 is canceled.

4. FORMS AND REPORTS: Local reproduction is authorized of CG-5648 (6-98), Potable Water Quality Log, found in Appendix 1.A.

COMDTINST M6240.5

5. DISCUSSION: Few environmental factors affect an individual's well-being more than an adequate supply of potable (drinkable) water.

An impaired potable water system may adversely affect health, mission, and morale. Proper disposal of wastewater also is critical to CG members' and the environment's health and safety. Recent large-scale disease outbreaks involving drinking water systems and increased regulation are among the challenges inherent in water and wastewater systems and underscore the need for commands afloat and ashore to ensure compliance with this Manual.

6. SCOPE: This manual applies to all active and reserve afloat and ashore commands.

a. For afloat commands, water monitoring requirements found in Chapter 1 do not apply under the following condition: Vessel is moored and receives shore water from an approved municipal source which maintains a free available chlorine residual. In addition, shore water must bypass the ship's water storage tank(s).

b. Ashore commands with CG-owned water systems, ? see section 2-H, are required to comply state or EPA monitoring and reporting requirements. Ashore commands who receive water from approved municipal treatment facilities are exempt from monitoring and reporting requirements if the water has a reliable disinfectant, e.g., chlorine, residual and is not further treated or stored. In addition to this Instruction, units must coordinate with their servicing Maintenance and Logistics Command, state regulating authority, and the Environmental Protection Agency to determine applicable regulations.

/s/ JOYCE M. JOHNSON Chief, Office of Health and Safety

COAST GUARD WATER SUPPLY AND WASTEWATER DISPOSAL MANUAL

CONTENTS

CHAPTER 1: COAST GUARD WATER SUPPLY AFLOAT. 3

A. Introduction and Policy. 3 B. Receipt and Transfer. 5 C. Potable Water Storage Tanks. 7 D. Disinfecting Potable Water Supplies. 11 E. Ballast and Cargo Water. 19 F. Emergency Water Supplies. 21 G. Evaluating Taste or Odor Problems in Shipboard Potable Water. 23 H. Cross-Connections. 28 I. Manufacturing and Handling Ice. 33 J. Water Testing Requirements and Procedures. 34 K. Water Sanitation Bill. 40 Appendix 1.A. Potable Water Quality Log 41 Appendix 1.B. Sample Potable Water Discrepancy Report 42 Appendix 1.C. Sample Potable Water Sanitation Bill 43

CHAPTER 2: COAST GUARD WATER SUPPLY ASHORE. 3

A. Introduction and Policy. 3 B. Water Distribution Systems. 7 C. Water Main Flushing and Disinfection. 8 D. Potable Water Storage. 10 E. Water Treatment. 12 F. Water Quality Standards. 18 G. Water Quality Monitoring. 21 H. Coast Guard-Owned Water Systems. 23 I. Purchased Water, e.g., Public Water Systems. 23 J. Environmental Sampling Overseas. 24 K. Military-Unique Chemicals and Other Potentially Hazardous Materials. 24 L. Operational Environmental Monitoring. 24 M. Sampling and Preservation Procedures. 24 N. Reporting and Record-Keeping. 25 O. Remedial Action. 26 P. Contingency Planning. 26 Appendix 2.A. Water Sources 28 Appendix 2.B. Potable Water Monitoring Program for the Medical Department Representative 34 Appendix 2.C. NPDWR Surveillance Requirements 36 Appendix 2.D. Contingency Planning for Potable Water 37

CHAPTER 3. TESTING WATER. 2

A. Introduction. 2 B. How to Collect Bacteriological Water Samples. 2 C. Accepted U.S. Coast Guard Bacteriological Testing Protocol:

Colilert Test Technique 4 D. Accepted U.S. Coast Guard Bacteriological Testing Protocol:

Membrane Filter (MF) Technique. 5 Appendix 3.A. Remedial Actions for Contaminated Water Samples 16 Continued...

Contents Page 1

COAST GUARD WATER SUPPLY AND WASTEWATER DISPOSAL MANUAL

CHAPTER 4: WASTEWATER TREATMENT AND DISPOSAL AFLOAT AND ASHORE. 2

A. Introduction and Policy. 2 B. Coast Guard Discharge Permit Requirements. 4 C. Wastewater Treatment and Disposal Afloat. 4 D. Wastewater Treatment and Disposal Systems Ashore. 15 Appendix 4.A. CHT Maintenance and Sewage Spill Clean-Up Kit 27

ENCLOSURE (1) TREATED WATER QUALITY STANDARDS

ENCLOSURE (2) CHLORINE SOLUTIONS AND CONCENTRATIONS

ENCLOSURE (3) REFERENCES AND RESOURCES

ENCLOSURE (4) DEFINITIONS

Contents Page 2

COAST GUARD WATER SUPPLY AND WASTEWATER DISPOSAL MANUAL Chapter 1

CHAPTER 1: COAST GUARD WATER SUPPLY AFLOAT. 3

A. Introduction and Policy. 3

1. Purpose. 3

2. Policy. 3

3. Responsibilities 3

4. Potable Water Sources for Coast Guard Vessels. 4

5. Water Use and Quality. 4

6. Potable Water Usage Requirements. 5

B. Receipt and Transfer. 5

1. Preventing Contamination. 5

2. Approved Sources. 6

3. Doubtful Sources. 6

4. Care of Shipboard Potable Water Hoses and Equipment. 6

5. Connection Procedures. 6

C. Potable Water Storage Tanks. 7

1. Design and Construction. 7

2. Introducing Non-Potable Water. 8

3. Interior Coating. 8

4. Vents and/or Overflow Lines. 8

5. Manholes. 8

6. Measuring the Water Level. 9

7. Filling Lines. 9

8. Potable Water Piping. 9

9. Repairs. 10

10. Potable Water Tank Coatings. 10

11. Labeling Potable Water Systems. 11

12. Potable Water Hose Lockers. 11

D. Disinfecting Potable Water Supplies. 11

1. Purpose. 11

2. Procedure. 12

3. Disinfectants (Halogens). 12

4. Mechanical Treatments. 13

5. Chlorinators. 13

6. Brominators. 13

7. Batch Chlorination. 14

8. Halogen Requirements. 15

9. Disinfecting Potable Water Tanks and Systems. 16

10. Disinfecting Potable Water Hoses and Appurtenances. 17

11. Disinfecting Water for Emergency Drinking and Cooking. 18

12. Chlorine Dosage Calculator. 18

13. Required Halogen Residuals. 19

Chapter 1 Page 1

E. Ballast and Cargo Water. 19

1. Policy. 19

2. Cargo Water. 20

3. Receiving Cargo or Transferred Water. 21

F. Emergency Water Supplies. 21

1. Battle Dressing Stations. 21

2. Emergency Potable Water, 5-Gallon Containers. 22

3. Boats, Rafts and Battle Stations. 23

G. Evaluating Taste or Odor Problems in Shipboard Potable Water. 23

1. General. 23

2. Causes of Taste or Odor in Potable Water. 23

3. Indicators of Taste or Odor Problems. 24

4. Initially Evaluating Taste or Odor Problems. 25

5. Controlling Taste or Odor Problems. 27

6. Request for Outside Assistance. 28

H. Cross-Connections. 28

1. Scope. 28

2. Definitions. 28

3. Selecting and Installing Backflow Prevention Devices. 29

4. Defective Piping Installation. 31

5. Potential Contamination Sites. 31

6. Monitoring and Inspecting Potable Water Supplies. 33

I. Manufacturing and Handling Ice. 33

1. Manufacture. 33

2. Special Precautions. 33

3. Cleaning and Disinfecting. 34

4. Bacteriological Quality. 34

J. Water Testing Requirements and Procedures. 34

1. Scope. 34

2. Temperature and pH. 34

3. Salinity. 35

4. Halogen Residual (Chlorine or Bromine) Testing. 35

5. Bacteriological Collecting and Testing. 37

6. Potable Water Quality Log (PWQL). 39

7. Potable Water Quality Discrepancy Report (PWQDR). 40

K. Water Sanitation Bill. 40 Appendix 1.A. Potable Water Quality Log 41 Appendix 1.B. Sample Potable Water Discrepancy Report 42 Appendix 1.C. Sample Potable Water Sanitation Bill 43

Chapter 1 Page 2

HAPTER 1: COAST GUARD WATER SUPPLY AFLOAT. C

. Introduction and Policy. A

1. Purpose. This Chapter explains how to handle potable water safely and properly aboard vessels to help prevent waterborne diseases.

Enclosure (1) describes the bacteriological, physical, and chemical characteristics of potable water. All personnel who fill, treat, store, distribute, and medically monitor potable water should be familiar with the current policies and regulations in this Manual.

2. Policy. Preventing waterborne disease transmission requires high-quality potable water. Potable water for shipboard use comes from the ship's distillation plant or reverse osmosis (RO) systems.

Present distillation plants aboard Coast Guard cutters, designed to make the ship as self-sufficient as possible, can produce potable water from bacteriologically contaminated water if the system operator follows the specific procedures set forth in the * Naval Ships' Technical Manual (NSTM), Chapter 531. The system operator must properly disinfect all distillate to be used as potable water and avoid distilling water from harbors or polluted sea water except in emergencies. Assume water is polluted when ships operate in close formation. While making potable water, do not empty bilges or sewage tanks forward of the water intakes. Operational checks of distillation plants afloat and inspecting and approving watering points ashore constitute only some of the precautions necessary to assure a safe water supply. Many points of possible contamination exist within the ship and may contribute to waterborne disease outbreaks. Therefore, regardless of the water's source, the Engineering and Medical Departments must effectively enforce standards and monitoring to assure adequate protection from subsequent contamination.

3. Responsibilities.

a. COMDT (G-SEN). COMDT (G-SEN) designs, constructs, and maintains shipboard potable water supply and distribution systems, including treatment facilities and processes, to assure safe drinking water is available at all times.

b. COMDT (G-WKS). COMDT (G-WKS) establishes and promulgates standards and instructions for water quality afloat and publishes appropriate instructions, notices, or other publications to reflect water quality requirements.

c. Area Commanders. Area commanders or their designees issue necessary implementing directives to ensure each ship within the command has and enforces adequate water sanitation standards.

d. Commanders of Maintenance and Logistics Commands. Commanders of Maintenance and Logistics Commands (MLCs) provide technical support and medical oversight for all afloat potable water systems. MLC(k) particularly emphasizes identifying and abating class-wide health hazards. Additionally, each respective MLC(k) ensures unit-level potable water systems monitoring and periodically conducts sanitary surveys.

Chapter 1 Page 3

e. Commanding Officer, Engineering Logistics Center. The Commanding Officer, Engineering Logistics Center, reviews policy and provides assistance with shipalt/boatalts and Authorized Equipment Listings development.

f. Commanding Officer. Each ship's Commanding Officer (CO) promulgates a water sanitation bill to ensure engineering and medical personnel follow procedures to receive, transfer, treat, store, distribute, and monitor potable water. Appendix 1.C.

contains a Sample Potable Water Sanitation Bill.

g. Engineering Department. Reporting to the CO, the ship's Engineering Department implements the shipboard water supply system's operation and maintenance, produces an adequate amount of water, and ensures proper disinfection.

h. Medical Department Representative. The Medical Department Representative (MDR) comprehensively monitors the potable water system for health and safety, including adequacy of disinfecting procedures, collecting samples for bacteriological analysis, and monitoring required halogen residuals from the distribution system. The MDR shall notify the CO of any discrepancies he or she observes in the water distribution system. For units without assigned corpsmen, the Executive Officer/Executive Petty Officer, as the unit medical officer, must ensure these requirements are met.

4. Potable Water Sources for Coast Guard Vessels.

a. Distillation or other approved method, e.g., reverse osmosis.

b. Shore-to-ship delivery from an approved source.

c. Shore-to-ship delivery from an unapproved source if an approved source does not exist; see * Paragraph B.3.

d. Ship-to-ship.

5. Water Use and Quality.

a. Potable water, i.e., water of drinking quality, is used aboard ship for drinking, cooking, laundry, medicine, personal hygiene, and other purposes.

b. Water quality standards include physical, chemical, and bacteriological requirements. * Paragraph 1.J. discusses limited testing procedures to evaluate pertinent physical, chemical, and bacteriological quality of shipboard water.

c. Using non-potable water in any food service space, including sculleries, is prohibited at all times unless the commanding officer obtains specific written approval to do so from the area Maintenance and Logistics Command (k) before installation. The dangers in using water polluted through cross connection from overboard sources cannot be over-emphasized. Regardless of source, cross connections between potable water and non-potable water are not permitted. Non-potable water connections are prohibited on food service equipment.

Chapter 1 Page 4

d. Non-potable water is used aboard ships in the fire mains and for general sanitary purposes. Since constant potable water conservation is required, it is impractical to use potable water for all purposes. Therefore, a ship uses sea water under certain controlled circumstances, e.g., flushing weather decks, water closets, urinals, laundry, and decontamination showers.

Engineering personnel selecting a potable water source must consider water in harbors, off-shore from habitations, and when operating in fleet strength polluted and fit for use only in fire and flushing systems; do not use it for other purposes. If in an emergency a ship needs to produce water from contaminated sources, the Medical and Engineering Departments must monitor the system for halogen residual, pH, and bacteriological contamination more frequently.

6. Potable Water Usage Requirements.

a. Properly indoctrinating the crew in water conservation and reducing leaks and waste should limit potable water consumption to reasonable amounts. At times water hours may become necessary on some ships, limiting personal hygiene practices. Members may keep clean and live under sanitary conditions, even with a limited water supply, if their supervisor adequately indoctrinates and properly supervises them. If unusual conditions require drastically restricting potable water use, the minimum allowance should be two gallons per person per day for drinking and cooking.

b. Table 1.1. lists the quantities of potable water generally required aboard ship. Actual consumption varies widely, depending on vessel type, where it operates, and what work members do. If using potable water for all purposes, consumption may expend 12 to 35 gallons per person per day, though the higher figure might be considered wasteful.

Table 1.1. Recommended Amounts of Potable Water Aboard Ship Type of Use Gallons per Person per Day Drinking Water 0.5-1.0 Galley and Scullery 1.5-4.0 Personal and Hygiene 5.0-20.0 Laundry 5.0-10.0 Total 12.0-35.0

B. Receipt and Transfer.

1. Preventing Contamination. When receiving or transferring water from an external source, improper filling techniques and multiple handling can contaminate potable water. If water received aboard does not have the required disinfectant residual, the system operator must add enough chlorine or bromine to produce the proper residual. If the water contains the correct disinfectant residual, the receiving ship need not disinfect. The designated MDR or EDR must determine the chlorine or bromine residual immediately before the water is transferred.

Chapter 1 page 5

Authorized personnel must make or supervise all water connections between shore and ship. Potable water hoses must not be submerged in harbor water.

2. Approved Sources. Procure potable water from these approved shore facilities or other vessels:

a. Facilities owned and/or operated by the U.S. military.

b. Water points listed in the joint U.S. Public Health Service and Food and Drug Administration publication, Acceptable Vessel Watering Points Interstate Conveyance Official Classification List. The MDR should attempt to obtain this information before the ship departs from CONUS. U.S. Embassies and area MLC (kse)s also may have accurate information.

3. Doubtful Sources. The MDR and EDR should consider all water supplied by public or private unapproved systems of doubtful quality. If in doubt about water quality, he or she or a responsible officer must investigate the source and examine the water as thoroughly as possible with the means available. The MDR must then advise the CO about necessary procedures, safeguards, and disinfection. If the ship must receive suspect water, the MDR or EDR will disinfect it in accordance with * Paragraph 1.D.

4. Care of Shipboard Potable Water Hoses and Equipment.

a. Potable water hoses must not be used for any other purpose. The EDR must properly label, store, and protect them from sources of contamination at all times and routinely examine them and remove them from use if cracks develop in the lining or leaks occur. * Paragraph 1.D.10. describes how to disinfect potable water hoses.

b. Each hose connection must be fitted with a cap and keeper chain.

Ship risers must be properly labeled, color-coded, and disinfected before each use.

c. Sounding tubes for potable water tanks must have screw caps attached to keeper chains secured with a lock. On ships with sounding rods, when not in actual use the rod should remain in the tube at all times. On ships using steel tapes, the EDR must sanitize the tape before each use and use it to measure potable water only. EDRs shall store steel tapes in a clean, dry location.

5. Connection Procedures.

a. In transferring potable water shore-to-ship and ship-to-ship these connection procedures are general guidelines; the Engineering Officer may want or need to modify these procedures due to ship configuration or operating conditions.

Chapter 1 Page 6

b. Shore-to-Ship.

(1) Remove cap and flush pierside potable water outlet for 15 to 30 seconds. Immerse outlet and rinse fitting in a solution containing 100 ppm free available chlorine for at least 2 minutes. See * Paragraph 1.D.13. and Enclosure (2) on preparing chlorine solution. Flush to waste for 15 to 30 seconds.

(2) Just before connecting, deliver a clean, disinfected potable water hose to the outlet. Remove hose caps or uncouple hose ends and disinfect if necessary. Connect to pierside outlet and flush.

(3) Using the solution described in * Paragraph 1.D.13., disinfect shipboard riser connections. Connect hose to the potable water shipboard riser and deliver potable water.

(4) When the transfer is completed, secure the shore water source, remove the ship connection, and then remove the shore connection. Thoroughly flush the potable water outlet and recap. Drain the potable water hose thoroughly, replace caps or couple ends, and store in the potable water hose storage locker.

c. Ship-to-Ship Transfers.

(1) Personnel trained in handling potable water must transfer potable water ship-to-ship. Normally, the supplying ship provides potable water hoses.

(2) The leading potable water hose should have the cap in place during the high-line procedure.

(3) When the receiving ship secures the potable water hose, the EDR removes the cap and disinfects the hose coupling.

(4) Both ships disinfect their respective potable water riser connections.

(5) The supplying ship connects its end and flushes the hose.

(6) When the transfer is completed, the receiving ship removes the potable water hose and replaces the caps on the receiving connection and the potable water hose.

(7) The supplying ship then retrieves, couples or caps, and properly stores the potable water hose.

. Potable Water Storage Tanks. C

1. Design and Construction. Potable water tanks' construction and location should prevent contamination of the contents. To use space optimally, on most ships potable water is stored in inner bottom tanks, other skin tanks, and peak tanks. The ship's bottom, which serves as the outer shell of inner bottom tanks, is subjected to maximum external pressure from possibly heavily polluted water and is vulnerable to leakage. The plating over the inner bottom tanks often

Chapter 1 Page 7 serves as deck spaces. Inner bottom and other skin tanks may have common bulkheads with ballast tanks, fuel tanks, or other storage spaces. These potential sources of contamination require the EDR to carefully maintain the quality of water stored in skin tanks, particularly those located in inner bottoms.

2. Introducing Non-Potable Water. Do not fill potable water tanks with ballast water unless absolutely necessary for the ship's survival. If introducing non-potable water into potable water tanks, the EDR must disconnect all tanks, lines, fittings, and pumps from the potable water system, plug or cap them, and reconnect them only after adequate disinfection.

3. Interior Coating. Contractors and authorized maintenance personnel shall paint potable water tanks' interior with an epoxy coating system complying with the * Coast Guard Coatings and Color Manual, COMDTINST M10360.3A, Chapter 12, Table 19. Potable water tanks shall be coated in accordance with NSTM, Chapter 631, "Preservation of Ships In-Service (Surface Preparation and Painting)." All potable water tank coatings must be approved by and applied in accordance with National Sanitation Foundation (NSF) International Standards.

4. Vents and/or Overflow Lines.

a. Vents and/or overflow lines provided on potable water tanks will be located to reduce the possibility of contamination. The openings must be screened with mesh 18 or more non-corrosive metal wires.

b. Vents and/or overflow lines must not terminate in food service, medical, toilet, or other spaces that may transmit contamination or odors to the water, nor in any space where electrical or electronic equipment is located.

c. Potable water tanks shall not vent outside the ship. Exception:

Where such vents exist in the current fleet, an exception may be granted if vent location and ship design make shipalt impractical.

5. Manholes.

a. Manholes' construction and location should minimize the possibility of contamination. If a manhole is located on the side of the tank, flush-type construction is acceptable. If located on the top (including the deck, if the deck forms the top of the tank), a coaming or curb rising at least one-half () inch above the top of the tank must be provided and the manhole cover must extend to the outer edge of the curb or flange.

b. The cover must have an intact gasket and a device to secure it in place. Normally, manholes not exposed to the weather decks are fitted with a flush manhole cover or a raised, bolted-plate cover.

The latter is preferable for potable water tanks.

Chapter 1 Page 8

6. Measuring the Water Level.

a. There are several methods to measure water in tanks, including automatic level gauges, petcocks, and sounding tubes. Many ships have more than one system.

b. On ships with sounding rods, when not in actual use the rod should remain in the tube at all times.

c. On ships using steel tapes, the EDR must sanitize the tapes before each use; store them in a clean, dry location; and use them only to measure potable water.

d. Sanitize sounding tapes by soaking the entire tape apparatus in a solution of 100 ppm chlorine for two minutes.

7. Filling Lines.

a. Potable water lines must never cross-connect to any non-potable line or system. If a common line is used to load and distribute potable water to non-potable tanks, an air gap must deliver the non-potable water to non-potable tanks.

b. Filling lines that have a common piping arrangement to direct potable water from an approved source to non-potable water systems by means of valves or interchangeable pipe fittings are not acceptable.

c. Filling connections (hose valves) must be clearly labeled and color-coded to comply with * NSTM, Chapter 505, and the Coast Guard Coatings and Color Manual, COMDTINST M10360.3A. Screw caps attached with keeper chains must secure filling connections.

d. Filling connection hose valves must have the potable water receiving connection at least 18 inches above the deck and turned down to protect it from contamination.

8. Potable Water Piping.

a. Potable water tanks are usually installed low in the ship. The EDR must pay careful attention to the piping installed in the bilge area, particularly piping on the suction side of the potable water pumps where leakage could contaminate the potable water system.

b. When piping potable water through non-potable tanks and non-potable liquid through potable water tanks, a sloped, self-draining pipe tunnel must surround the pipe.

Chapter 1 Page 9

c. An adequate air gap must separate any potable water outlet and a non-potable water system, fixture, or machine; permanent direct connections must be installed only with approved back flow prevention devices; see * Paragraph 1.H.3.

d. All potable water pumps should be airtight and have no cross-connections. Never use non-potable water to prime pumps or maintain packing gland seals. The EDR must disinfect pumps dismantled for repair after reassembly and before returning them to service.

e. Do not connect charcoal-impregnated or other filters to potable water piping outlets. Some of these devices remove required trace halogen (chlorine or bromine) residual from the potable water and defeat the purpose of residual halogen protection. The EDR must remove any filtration equipment already installed.

f. Paint potable water piping, including valve bodies, to match the surrounding areas to comply with the * Coast Guard Coatings and Color Manual, COMDTINST M10360.3A (series), Chapters 10-A-23 and 12, Table 16.

g. If feasible, identify potable water piping to indicate contents, destination, and flow direction to comply with the * Coast Guard Coatings and Color Manual, Chapter 10-A-23.a. through h.

h. Paint potable water valve handles and levers dark blue (Fed. Std.

595, Color Number 15044) to comply with the * Coast Guard Coatings and Color Manual, Chapters 10-15-A-23.g. and 12, Table 17.

i. Do not paint potable water valve packing glands, valve stems, threads, and other similar working surfaces.

9. Repairs.

a. If any accidental or intentional break occurs in the potable water system, or a potable water tank is entered for any reason, the Engineering Department must disinfect all involved tanks, parts, and lines before returning the system to use. The EDR must notify the MDR of the break or entry and the Department's disinfection procedure.

b. The Engineering Department shall not repair potable water piping or butter up flanged joints with white lead or other lead-containing substances or putty because these are toxic.

Sealants for use in potable water piping systems must meet NSF International Standards. Confirm sealants by contacting the nearest MLC.

10. Potable Water Tank Coatings. To avoid difficulties with taste, odors, and the danger of contamination by toxic chemicals, use only those tank lining materials specified in * NSTM, Chapter 631, and NSF International Standards. Follow proper application methods, including the coat's thickness, touch-up material, ventilation, temperature, humidity, and curing time, etc., or taste and odors may result.

Chapter 1 Page 10

11. Labeling Potable Water Systems.

a. Clearly label potable water sounding tubes with an identification plate. Color-code the sounding tube cover dark blue to comply with the * Coast Guard Coatings and Color Manual. Ships using steel tapes to sound potable water tanks must color-code in dark blue, label, or otherwise identify the tape handle POTABLE WATER

USE ONLY.

b. Conspicuously designate valves that receive or supply potable water by a warning plate inscribed POTABLE WATER ONLY in 1-inch-high letters.

c. Hoses receiving and discharging potable water shall be constructed of material meeting NSF International Standards and approved for that purpose. Potable water hoses must be labeled POTABLE WATER ONLY approximately every 10 feet and the end couplings painted dark blue. An approved potable water hose (NSN: 4710-01-248-8828) is available through the Federal stock system.

d. Potable water hose storage lockers must be identified and labeled POTABLE WATER HOSE AND FITTINGS STORAGE ONLY in letters at least one-half ()-inch high.

e. Potable water lines passing through any given space must be appropriately labeled to indicate the type of service and an arrow to indicate flow direction.

12. Potable Water Hose Lockers.

a. When not in use, potable water hoses must be coupled or capped and stored in designated self-draining, smooth, non-toxic, corrosion-resistant, easily cleaned, vermin-proof, locked lockers used for no other purpose and elevated at least 18 inches off the deck when located on weather decks.

b. Printed instructions outlining step-by-step methods to disinfect potable water hoses and risers must be posted conspicuously inside the hose storage locker.

c. Where it is not practical to use designated lockers due to space limitations, the EO must ensure potable water hoses are stored separately from other hoses in a secure and sanitary location.

D. Disinfecting Potable Water Supplies.

1. Purpose. Disinfecting water destroys pathogenic organisms.

Maintaining a halogen residual (either chlorine or bromine) is the usual method of guarding against sanitary defects or accidents that may occur in producing, handling, storing, and distributing potable

Chapter 1 Page 11 water. The residual's presence provides a safety factor but does not correct unsanitary practices or conditions. The absence of a free available chlorine (FAC) or total bromine residual (TBR) in the ship's potable water may indicate contamination. In pure water, free halogen residual concentrations as high as 2.0 ppm usually do not cause objectionable tastes and odors, but if certain organic substances are present, very small concentrations combined with chlorine or bromine can produce undesirable tastes or odors, though these do not affect the safety of water if the halogen residual (FAC or TBR) is at least 0.2 ppm.

2. Procedure. Disinfect shipboard water by adding sufficient chlorine or bromine compound to produce at least 0.2 ppm FAC or TBR after 30 minutes' contact time. The amount of chlorine or bromine required to do so can vary widely because of halogen demand, the amount of chlorine or bromine used in reactions with substances present in the water. All water-even distilled water produced by the evaporators-has some halogen demand.

3. Disinfectants (Halogens).

a. Chlorine is available for shipboard use as granular solid calcium hypochlorite (HTH-65 to 70% available chlorine) or liquid sodium hypochlorite in varying strengths (common household bleach is a 5.25% sodium hypochlorite solution). Calcium hypochlorite (HTH) is used most frequently because of its relatively long shelf life and smaller space requirements. However, calcium hypochlorite presents a potential hazard because it is corrosive and chemically active in nature. This material is dangerous and requires special storage precautions. Handle and stow it to comply with * NSTM, Chapter 670. Contact between calcium hypochlorite and oxidizable material may result in spontaneous combustion. Because calcium and sodium hypochlorite lose strength gradually with age and more rapidly when opened and stored in hot spaces, procure in 6-ounce plastic containers.

b. The Engineering Department must stow its issued stock of ready-to-use, 6-ounce bottles in a locked box, preferably metal, such as a first-aid locker, mounted on a bulkhead, preferably in Department office space. Never install the box in a machinery space, flammable liquids storeroom, berthing space, storeroom, or the oil and water test laboratory areas. Department personnel shall drill vent holes, e.g., three -inch holes, in the bottom of the box to allow the release of any chlorine products. The Department shall maintain a maximum of a seven-day supply of ready-to-use stock at any time.

c. Engineering Department personnel must store calcium hypochlorite stocks in labeled, ventilated lockers or bins located where they are not subject to condensation or water accumulation. The maximum temperature must not exceed 100 F (37.8 C) under normal operating conditions and the lockers and bins must be located at least five (5) feet distant from any heat source or surface that may exceed 140 F (60 C). The bins must not be located adjacent to a magazine or in a storage area for paints, oils, grease, or other combustible organic materials. An individual locker or bin may contain a maximum of 48 6-ounce bottles. Supervisors will issue bottles only to personnel designated by the MDR or Engineering Officer.

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d. Label all lockers, bins, and enclosures containing calcium hypochlorite with red letters on a white background, HAZARDOUS

MATERIAL: CALCIUM HYPOCHLORITE.

e. Bromine comes in a slightly corrosive bromine-impregnated resin cartridge requiring proper handling and storage procedures. Store bromine cartridges in a clean, dry, ventilated storeroom. Bromine storage lockers require a hazardous warning plate described in NSTM, Chapter 533, Figure 6. Bromine cartridges have a shelf life of two years from the manufacturing date; Engineering personnel can use cartridges exceeding that shelf life, but the cartridges may not be as effective.

4. Mechanical Treatments. At present, two halogen compounds, chlorine and bromine, are the only approved methods to disinfect shipboard potable water. Mechanical treatment methods are preferable to batch treatment procedures, which are less reliable, require more time and effort, and are generally less effective; a batch treatment with bromine does not exist.

5. Chlorinators. Coast Guard vessels use several types of chlorinators, which may be installed in the distilling plant, distillate line, the shore fill line, or jointly on the distillate and shore fill lines.

a. The distillate line generally has an electric motor-driven chlorinator with controls that activate the chlorinator in conjunction with the distillate pump motor and water flow past the chlorinator.

b. The shore fill line generally has either a hydraulically actuated or electric motor-driven chlorinator. Both units inject hypochlorite solution into the water system proportionally to the flow of water through a meter.

c. A fill line chlorinator may serve the distillate line and the fill line if the distilling plant is large enough to permit sufficient flow through the unit. This type of installation generally has either a hydraulically actuated or electric motor-driven chlorinator.

6. Brominators. Brominator treatment installations are of two types, one used on the distillate discharge line and the other used to recirculate water in the potable water tanks during treatment.

a. Distillate discharge line brominators-called automatic proportioning brominators-are capable of feeding bromine at two feed rates. Dual-feed rate automatic proportioning brominators feed a fixed rate of either 0.7 ppm total bromine residual (TBR) or 2.7 TBR at the high feed rate, the latter used if the ship is distilling water from a contaminated source.

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b. The recirculation brominator system treats water in potable water tanks by recirculating it from a potable water tank through the brominator and back to the same tank. This treatment offers flexibility in recirculating and brominating shipboard water from external sources or increasing bromine levels if necessary. As the selected tank's water recirculates, a portion of the recirculated water is automatically diverted to flow through the bromine cartridge. A timing device limits flow through the cartridge to achieve the required bromine feed into the selected tank. After a pre-set period of time based on individual tank volume and water temperature, the timing device terminates the bromine feed into the water. Water continues to recirculate for an additional pre-calculated duration to completely, evenly disperse bromine through the tank. The system operator also can pre-set this recirculation unit to deliver 0.7 ppm bromine to recirculating water. A sampling tap is present to test the bromine residual after recirculation. If the first process does not achieve the desired bromine level, the system operator can reset the timer and recirculate the water until it reaches the desired TBR level; however, efforts to achieve 2.0 or more ppm bromine levels may not be practical due to the length of time required. It may be more convenient to use batch chlorination procedures to rapidly chlorinate the water supply, particularly if the water is contaminated or requires superhalogenation.

7. Batch Chlorination.

a. Engineering personnel can use "batch chlorination" disinfection methods if mechanical treatment methods are not available.

However, this is the least desirable method to disinfect potable water because it may result in over-chlorination due to an inability to properly mix the water and hypochlorite solution.

Engineering personnel must determine the proper chemical dosage for the volume of water to be disinfected; see the * Chlorine Dosage Calculator, Enclosure (2). If using 65 to 70% calcium hypochlorite, dissolve the calculated amount in a non-glass container of warm water (80 to 100 F) and allow the suspended matter to settle out, discarding the remaining sediment. When the tank is about one-quarter full, add one gallon of potable water to flush the sounding tube and introduce the clear fluid (supernatant) into the sounding tube or fill connection. Never attempt to chlorinate by adding the solution to the brominator cartridge container. The stirring action of the incoming water as the tank fills generally mixes the water and chlorine solution sufficiently; the ship's motion and recirculation also mix the water slightly. If introducing the chlorine solution into a full tank, recirculating through a pump is the only way to mix adequately. If using pumps that are not an integral part of the potable water system, disinfect them first.

b. The system operator should sample the water and test it for an FAC residual 30 minutes or more after the tank is filled or mixing is completed. If the tank has no sampling petcocks, for sampling purposes the system operator may use a potable water outlet in the distribution system nearest the tank. If the FAC residual is less than required, the system operator must add more chlorine, mix it into the water and, after 30 minutes, determine the FAC residual again. One ounce of full-strength calcium hypochlorite added to 5,000 gallons of water is the approximate dose to achieve a 1.0

Chapter 1 Page 14 ppm initial chlorine concentration. Exposure to air rapidly reduces the amount of active chlorine in 65 to 70% calcium hypochlorite, so use all the contents as soon as possible after opening the container. This "rule of thumb"-one ounce per 5,000 gallons-is helpful in calculating dosages for batch chlorination and is a suggested starting point only; the actual required amount depends on temperature, pH, and the water's chlorine demand. NEVER remove the manhole cover to batch-chlorinate a tank; introduce the chlorine into the tank through sounding tubes or air vents or by other methods.

c. Chlorination or bromination procedures are not adequate until the water contains the required FAC or TBR after 30 minutes. * Paragraph 1.D.13. lists required residuals.

d. Ships with bromine systems may add bromine to previously chlorinated water with no harmful effect.

8. Halogen Requirements.

a. To assure safe potable water throughout the ship's distribution system, all parts of that system must contain a measurable trace halogen residual. Sometimes this standard is difficult to achieve in certain sections of the ship, particularly in the O level with its reduced usage of potable water. In the absence of bacteriological contaminants, a lack of measurable residual in less-used outlets should not be a matter of concern, but requires close bacteriological monitoring.

b. All water delivered to the tanks, whether from approved sources or produced on board, must be chlorinated or brominated to provide at least 0.2 ppm halogen residual (FAC or TBR) after 30 minutes' contact time.

c. If obtaining potable water from approved sources that use chloramines to disinfect, the Engineering Officer shall contact the area MLC (kse) about required testing, treatment, and monitoring. As is FAC, chloramines are a chlorine residual, albeit slower and less effective than FAC. Produced by combining chlorine and ammonia, chloramines are bactericides but their disinfection rate is 60 to 100 times slower than FAC. To measure chloramine levels, follow the procedures for testing combined residual chlorine using the DPD test kit.

d. The system operator must chlorinate or brominate water received from an unapproved source, one of doubtful quality, or an area where amoebiasis or infectious hepatitis is endemic to achieve between 2.0 to 5.0 ppm halogen residual (FAC or TBR) in the tanks after 30 minutes. In these instances, if the ship's brominator cannot achieve a TBR of 2.0 ppm, the system operator must chlorinate the water by the batch method to at least 2.0 ppm FAC after 30 minutes' contact time. Once the water in the tank meets this criterion, it is safe to use.

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9. Disinfecting Potable Water Tanks and Systems.

a. The two types of disinfection procedures are mechanical cleaning combined with chemical disinfection and chemical disinfection alone.

b. Mechanically cleaning tanks includes all measures necessary to remove existing foreign materials, rust, and other substances from the tanks.

c. Contractors or authorized maintenance personnel will mechanically clean and chemically disinfect the tanks when their condition has deteriorated to the point at which chlorine demand has increased significantly and bacteriological evidence indicates the tank has become grossly polluted. After mechanically cleaning any tank, workers will chemically disinfect it. Perform mechanical cleaning and chemical disinfection under these conditions:

(1) New tanks, including those on new vessels;

(2) Rehabilitated or repaired tanks;

(3) Sludge or rust accumulation seriously impairs the quality of water delivered.

(4) Tanks have been loaded with non-potable ballast water.

(5) Voids or tanks converted from non-potable water to potable water tanks.

CAUTION: Tanks are confined spaces and entry could immediately endanger life or health. Always ensure a gas-free engineer or competent person has evaluated and approved entry and work procedures before workers enter.

d. Butter-worthing-mechanical cleaning at sea with sea water-is permitted, but always follow it with chemical disinfection.

Mechanical cleaning, especially if using sea water, promotes rust in the tanks and is laborious and time-consuming.

e. Chemical disinfection is required under these conditions:

(1) Tanks show evidence of continued bacteriological contamination after normal disinfecting procedures;

(2) Pipelines, valves, pumps, etc., have been dismantled, repaired, or replaced.

(3) Tanks have been entered.

(4) New or contaminated hoses.

f. To chemically disinfect a system, engineering or maintenance personnel must take these steps:

(1) Introduce enough chemical into the tanks to produce at least 100 ppm FAC; see the Chlorine Dosage Calculator in * Enclosure (2).

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(2) Fill tank with potable water.

(3) Using the ship's pumps, drain chlorinated water from each outlet to ensure this treatment reaches all contaminated system components (pumps, valves, lines and hoses).

(4) After four hours' contact time in the tanks and system, the FAC residual must be at least 50 ppm; test the water once an hour to ensure it maintains the proper FAC. If ever during the four hours the FAC residual falls below 50 ppm, add chlorine to bring the residual to 100 ppm and start the four-hour contact time again.

(5) Pump potable water from the lowest opening in the tanks through the contaminated lines, pumps, and valves, and return it to the tank or dispose.

g. If chemically disinfecting two or more tanks, re-use the highly chlorinated water from the first tank to disinfect other polluted tanks; the system operator may need to add more chlorine to maintain desired residual until all have been treated.

h. If it is impractical to disinfect a potable water tank as described above, follow this procedure:

(1) Thoroughly clean and rinse the tank.

(2) Swab all tank surfaces with a solution of 100 ppm chlorine or pump the solution through hoses so it reaches all tank surfaces. Use adequate personal protective measures, including appropriate respirators as recommended by the gas-free engineer; see * caution below.

(3) Flush all water used for super-chlorination from the tank.

(4) Rinse with potable water, and the tank is ready for use.

Engineering personnel must maintain an FAC residual of at least 2.0 ppm in water transported and stored in these tanks.

CAUTION: Chlorine at 100 ppm may generate vapors dangerous to persons working in these tanks. The gas-free engineer must authorize entry into these tanks. See * NSTM, Volume 3, Chapter 74.

10. Disinfecting Potable Water Hoses and Appurtenances

a. Disinfect potable water hoses by filling with a solution containing at least 100 ppm FAC. The solution must contact the entire internal surface of the hose for at least two minutes.

Flush the hose with potable water 30 to 60 seconds; then use.

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b. Before connecting the potable water to either the ship riser or shore source, disinfect the fittings' interior by at least two minutes' contact with a solution of 100 ppm FAC. Flush the shore water source to waste 15 to 30 seconds before hooking up the ship's water hose.

c. Disinfect both sounding tapes and rods by wiping with a 100 ppm chlorine solution.

11. Disinfecting Water for Emergency Drinking and Cooking.

a. If potable water is not available during an emergency, it may be necessary to treat poor-quality water for drinking and cooking.

Such water should be clean and as free of turbidity as possible.

Before using this water, chlorinate initially to at least 5.0 ppm FAC with a final residual of at least 2.0 ppm FAC after a 30-minute contact time to make sure the water is safe. Another way to make safe water is to boil it at a rolling boil for two minutes; however, it is impractical to boil adequate quantities of water.

b. If the water is excessively contaminated or turbid, consider using canned or other emergency drinking water sources or water purification tablets (NSN: 6850-00-985-7166).

12. Chlorine Dosage Calculator.

a. Theory of Operation. This chart, Enclosure (2), contains the chlorination "dosage rate." The water quality, e.g., the organic and inorganic materials present, will affect the final chlorine residual. "Chlorine demand" is the amount of chlorine required to react with and be absorbed by these materials. The absorbed or neutralized chlorine has no disinfectant value, so it is necessary to add enough chlorine (adequate dosage rate) to satisfy the chlorine demand and still provide FAC, the active disinfecting agent, to produce the chlorine reading, determined with the colorimetric test kit. A dosage rate of roughly 1 ounce of 65 to 70% calcium hypochlorite per 5,000 gallons yields 1.0 ppm. Due to chlorine demand, this dosage rate probably will produce a FAC residual of about 0.2 ppm after a 30-minute contact period.

b. Instructions for Use.

(1) Select desired parts per million. Determine the strength of sodium or calcium hypochlorite to be used. Compute number of gallons to be chlorinated. Read across to obtain quantity of material to be used.

(2) The 5% and 10% listings are liquid sodium hypochlorite; thus, the measurements are expressed as volume.

(3) The 65 to 70% listings are granular calcium hypochlorite;

thus, the measurements are expressed as weight.

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c. In determining the volume of a hose for disinfecting purposes, a standard 2" water hose has a volume of 0.25 gallons per foot. * "Water Supply Ashore," Chapter 2, Table 2.1, lists volumes for other hose sizes.

13. Required Halogen Residuals. This chart lists the required halogen residuals for various disinfection needs:

Dosage and Time Requirements Chlorination (FAC) Bromination (TBR) Treatment Required Dose and Time Dose and Time

1. Minimum residual required 0.2 ppm after 30 minutes in tanks for potable water produced on board or obtained from an approved source

2. Water from unapproved source 2.0 ppm after 30 minutes in tanks or area where amebiasis or hepatitis is endemic.

3. Water in potable water Trace readings throughout. Measurable trace distribution system. halogen residuals-detectable color changes noted when using a DPD comparator-are acceptable provided bacteriological test results are consistently negative.

4. Disinfecting tanks and 100 ppm initially; Not applicable system. 50 ppm after 4 hours

5. Disinfecting hoses, 100 ppm for 2 Not applicable couplings, and water minutes connections before connecting to potable water system.

6. Scrubbing interior of 100 ppm Not applicable contaminated tanks when potable water is scarce.

7. Emergency water supply 5.0 ppm after 30 Not applicable for drinking and cooking. minutes

8. Fuel cargo tanks converted 2.0 ppm at Not applicable to carry potable cargo destination water.

E. Ballast and Cargo…