Shipboard Pollution Control: U.S. Navy Compliance with MARPOL Annex V (1996)

The Committee on Shipboard Pollution Control was formed under the auspices of the Naval Studies Board, based on discussions between U.S. Navy and National Research Council representatives. The issues involved in shipboard pollution control are a complex mixture of Navy management, congressional mandate, international agreements, environmental community concerns, and technology. The committee as a whole was chosen for its expertise in technology.

The first term of reference for the study poses the following question: “What is the technical feasibility of eliminating, by 2000 for surface ships and 2008 for submarines, nonfood solid waste discharge from Navy ships operating in Special Areas?” ¹

The Special Areas referred to are defined in the international agreement on Marine Pollution, MARPOL, with specific reference to Annex V, which covers nonfood marine pollution solid waste. Naval ships are exempt from MARPOL, but the U.S. Congress required compliance by the U.S. Navy in the Marine Plastic Pollution Research and Control Act of 1987 as modified by the National Defense Authorization Act for Fiscal Year 1994. Various deadlines and extensions have been applied, with the latest deadlines those given in the above question. Special Areas already designated include the Baltic Sea, the North Sea, and the Antarctic Ocean. Special Areas expected to be designated in the future include the Mediterranean Sea, the Persian Gulf, the Gulf of Mexico, and the Caribbean Sea.

Under Annex V, the nonfood solid waste materials that are controlled are as follows:

• Paper and cardboard (hereinafter referred to as paper),

• Metal,

• Glass (including crockery and similar materials), and

• Plastics.

None of these materials may be discharged overboard in Special Areas. Plastics may not be discharged in the ocean anywhere.

The quantities of these materials generated on Navy ships are given in Table ES.1. These numbers are very approximate and can be expected to vary significantly from ship to ship. An “intrinsic volume” was estimated from densities (i.e., densities as recorded in handbooks of physical properties of materials) of the various material classes and the weights. Generally waste materials are received admixed with air to a considerable extent, and the volume occupied may be larger than the “intrinsic volume” by a factor of 10 to 30. By crushing, shredding, and compacting, the volume of nonfood solid waste can be brought down to about twice the “intrinsic volume. ” The committee refers to this volume as the compacted volume, and it is an important factor in consideration of shipboard space needed for storage of waste materials. Note that the compacted volume is 78 percent paper and 14 percent plastic, figures that identify these materials as good targets for source reduction and destruction when storage space is tight.

In its 1993 program plan (U.S. Navy, 1993), the Navy considered the use of compactors as an interim solution, and the committee views this technology as one that should be reexamined to help achieve compliance before 2000. A study of the effect of systematic, fleetwide use of compaction, similar to the recent Center for Naval Analyses study (Speer, 1995), would be valuable in this connection.

A good strategy for minimizing the amount of waste that must be stored is to leave as much packaging as possible on the dock. Submariners have achieved a significant reduction in this area, and the USS Kamehameha has reported (U.S. Navy, 1995) waste generation of only 0.56 lb/person/day or about 0.028 ft³ of compacted volume, a reduction of about 60 percent relative to quantities generated on surface ships. This approach is a good first step in any waste reduction program, and it has been used to some extent on Navy surface ships.

The problem assigned to the committee was to identify and evaluate the technologies that will make Navy management of nonfood solid waste under Annex V as effective as possible. Analysis was carried out in terms of mechanical, incineration, and long-range options, and these approaches are discussed in detail in Chapter 2, Chapter 3, Chapter 4, and Chapter 6. Mechanical methods are intended to minimize the volume of waste that must be stored until it can be off-loaded to other ships for shore disposal or recycling or can be discharged outside Special Areas. Incineration is intended to destroy the organic waste, and long-range options include advanced techniques that may eventually supercede incineration.

It must be decided at the outset whether the waste streams will be separated or processed mixed. Paper can be incinerated with little ash. Metal and glass waste, on the other hand, are not burnable. Plastic burns readily and can be burned with quite acceptable emissions, notwithstanding environmental objections to incineration of plastics at sea (NRC, 1995). These waste streams may be kept separate to enable recycling of one or more types of material. In some ports, separated waste may be more acceptable for shore disposal. If the Annex V waste materials are contaminated with food, the problem is particularly difficult. Although ground-up food waste can be put into the water even in Special Areas (outside the 3-mile limit), food-contaminated solids are subject to Annex V restrictions. Food-contaminated solids are a problem to store because of odors and sanitation factors. This fact could influence the waste management technologies chosen by the Navy.

Currently available compactors, shredders, crushers, pulpers, and other processors enable the conversion of voluminous waste to compacted waste. These machines are available in robust models, and they do not require large amounts of space. For example, a station capable of compressing and crushing the waste for a large ship could be accommodated in a room 10 ft × 20 ft × 8 ft. Additional space to accommodate crew access and temporary storage of incoming waste materials would more than double the floor area required. The cost of commercial apparatus to equip the station could range from $100,000 to more than $200,000. Storage volume of the order of 0.1 ft³/person/day between off-loading would be required. If the waste is contaminated with food, the waste would need some form of odorproof packaging (of high integrity). Only the Navy can decide whether this space is available for this purpose. Whether the waste is to be stored for the duration of a mission (as long as 60 days for surface ships) or could be

periodically off-loaded to combat logistics force ships is another matter that only the Navy can answer. Issues of flammability must also be addressed. Officer and crew training issues must be addressed as well. Even so, the committee believes that diligent pursuit of waste management by mechanical means could provide a route to compliance with Annex V for many or all Navy surface ships by the year 2000.

Incinerators are available now that could play a central role in compliance with Annex V. These incinerators have automatic feed, combustion control, and ash-handling equipment. They have proven to be important elements in the cruise line industry's success in complying with Annex V requirements. These units cost about $300,000 for one providing large-ship capability, and they occupy significant space, perhaps 10 ft × 24 ft × 8 ft. Incinerators sized for smaller ships are smaller and less expensive. Incinerators require duct access to stacks. Waste may be shredded or otherwise mechanically processed before being put into the incinerator. The Navy has many ships equipped with incinerators but has no experience with the modern class of incinerator discussed in this report. The committee recommends that the Navy investigate modernization of its existing incinerators. The committee urges the Navy to gain experience and begin naval architecture studies in connection with the installation and operation of modern incineration systems. All classes of ship for which compliance with Annex V is expected to be a problem should be included in these considerations.

The committee doubts that the Navy can acquire sufficient experience with modern incineration equipment to achieve complete Annex V compliance by this route by the year 2000. Equipment in various sizes and formats is available commercially, but gaining experience, arranging procurement, and getting the ships in and out of refitting centers would require more than the available time. It is likely that important naval architecture studies can be completed and some number of ships fitted for incinerator operation before the deadline. The high cost and potentially significant space accommodation imply considerable redesign and backfitting. Even so, the appeal of incineration as a keystone technology for all shipboard pollution control is so strong for surface ships that the committee recommends that a substantial program be initiated.

The incinerator is particularly valuable in dealing with food-contaminated waste. Food-contaminated paper and plastic can be readily burned. Food-contaminated metal and glass would emerge from the incinerator little changed but cleansed of the food. This treatment would ease storage and could make the waste more acceptable for landfill disposal. Some commercial incinerators are designed to accept unsorted waste streams, including paper, metal, glass and plastic, and food. It is necessary to provide for handling much larger “ash” loads in this mode of operation. The option to separate plastic waste is open.

Beyond the Annex V materials, a further major advantage of incineration is the ability to destroy food waste, bilge oil, gray water and black water solids, oily rags, medical waste, classified documents, and so on. With careful management of air emissions and solid residues (ash, metal, and glass), the ship can become entirely friendly, from an environmental point of view. The committee strongly recommends that the Navy pursue an integrated system for the management of all waste streams rather than seek piecemeal solutions for the individual waste classes. This will enable the Navy to install cost-effective equipment and procedures to comply with present requirements and prepare a smooth transition to compliance with future restrictions as they develop.

Incineration has been subjected to criticism by the environmental community, and future regulation of air emissions can be expected to be increasingly strict. The class of modern incinerator recommended in this report for shipboard use is well adapted to provide acceptable emissions by present standards and will meet or can be adapted to meet reasonable future standards. Air emissions will require continued attention, but the technology is available for compliance.

Among potential pollutants that should be considered for control, the following are important already:

• Nitrogen and sulfur oxides, carbon monoxide, and hydrogen chloride;

• Metals such as lead, chromium, copper, manganese, cadmium, and mercury;

• Smoke, particulates, and dust;

• Environmental estrogens such as polychlorinated dibenzodioxins; and

• Pathogens.

It would be a false economy to adopt incineration technology that could not control emissions of these and other pollutants. However, the technology is available and with continued research and development will continue to improve.

In the fullness of time, advanced destruction technologies may replace incineration of the treated waste stream. There are so many candidates here that the committee was forced to limit discussion to specific examples that give a flavor of what is possible. Potential advantages of the newer technologies include smaller and lighter units, reduced hazardous emissions, production of a favorable “ash” form, and ultimately lower cost and greater convenience. There are considerable technical challenges in achieving these advantages over incineration for wastes of diverse solid composition. Note also that none of these methods has been demonstrated in the marine environment. Time scales for implementation in the Navy environment should be measured in terms of several years to decades, and it is too early to estimate costs.

The advanced technologies under consideration as substitutes for incineration include plasma arc, supercritical water oxidation, molten metal reduction, molten salt processing, and vitrification. A number of these processes are already receiving Navy support, including plasma arc and supercritical water oxidation (supported by the Advanced Research Projects Agency [ARPA]). The committee urges the Navy to maintain support of research as appropriate and to encourage commercialization when results are sufficiently favorable. At this time, the committee cannot discern advantages over incineration, but this could change. Additional advanced technologies relevant to integrated systems in connection with treatment of liquid waste include semiconductor photocatalysis, electrohydraulic cavitation, pulsed-power cold-plasma reactors, membrane separations, and biological treatments.

Technology options for waste management on surface ships are outlined in Table ES.2. Options for managing non-Annex V waste in an integrated system are given in Table ES.3.

The committee strongly recommends long-range planning based on an integrated system for handling all of a ship's waste streams. Such planning will require a significant commitment on the part of the Navy, including space accommodation aboard, crew training, and enhancement of the status of the assignment. Incineration is the keystone technology of this approach in the near and intermediate term. The committee is convinced that an integrated system is the approach that will result in the most environmentally favorable form of pollution control at reasonable cost.

The terms of reference for the study raise the issue of backfitting existing ships for pollution control and designing waste management systems into new design ships. For the next few years, the Annex V compliance problem is overwhelmingly one of backfitting because only a small fraction of the fleet will be of new construction. In either case, however, the basic issue is the same: how much warfighting equipment can be sacrificed in order to accommodate waste management facilities? This question can be answered only by the Navy. The waste-handling equipment is available, but it is costly, will take up space, and will require the attention of trained personnel. The compromises implied are not easy.

Submarines were seen as a particularly difficult problem by the legislators, indicated by the more extended deadline 2008. However, the submariners have made great strides toward compliance with Annex V by employing outstanding management and attention to detail, and it may be possible for submarines to achieve compliance before 2008 without resorting to high-technology methods. As noted above, waste has been minimized by leaving much of the packaging on the dock and carefully selecting the form of supplies. A 60 percent reduction has been demonstrated. Submarine missions can last for months, but in that time no new supplies are brought on board. Therefore, it is feasible to store waste materials in sealed containers in areas occupied by the supplies at the outset. The committee sees no better

alternative to this approach, given that incineration and the more advanced technologies are not viewed as suitable for submarine application.

The additional development and testing of the equipment recommended in this report pose another question that requires Navy input. Both the mechanical compaction apparatus and the modern incinerators have been in commercial production for some years, and extensive marine experience has been demonstrated with positive results. The committee is conscious of the unusual demands placed on Navy ships, and additional testing would be prudent. Both classes of equipment are available as catalog items. In addition to installation of the equipment, a vigorous and continuing program to train officers and crew in the operation and maintenance of the apparatus and in related handling logistics is required. A change in culture, attitude, and sensitivity is implied.

The cost estimates given earlier do not include testing and installation costs. The committee has been told informally that the final cost of installed equipment on ships is typically seven times the supplier price. As it is envisioned that the entire fleet is to be equipped, although not all classes by the same technology, it is suggested that there should be economies of scale that could moderate the usual installation markup.

1. Source Reduction: Source reduction of waste materials, already practiced by the Navy, is endorsed as an important step toward Annex V compliance. It is recommended that the Navy set specific, demanding goals for source reduction for surface ships and submarines covering the periods up to 2000 and to 2008, respectively.

2. Integrated Systems Approach: It is recommended that the Navy adopt an integrated systems approach to manage all shipboard waste streams. It is now technically feasible to install and operate systems that will comply with Annex V restrictions and handle other waste streams as well. Avoidance of a piecemeal approach should offer economies of space and investment. The systems chosen may differ from one class of ship to another, but key elements will be common:

   • On-board reduction of the volume of waste streams by mechanical compaction, incineration, and other destructive technologies; and

   • On-board storage of waste for later transfer to shore facilities (either directly or by transfer to other ships) for landfill disposal or recycling or for legal ocean discharge outside Special Areas.

3. Mechanical Compaction: It is recommended that the Navy initiate a high-priority program to implement compaction and storage of Annex V waste streams to achieve compliance for surface ships by the year 2000. Commercial equipment exists in a variety of forms suited to the various Annex V waste streams. The Navy has developed its own equipment in this connection. Appropriate steps must be taken to eliminate any potential fire hazards.

4. Incineration: It is recommended that the Navy obtain experience with modern incinerator technology as a partial solution to waste management for Annex V compliance for surface ships by the year 2000

and as a keystone technology for waste management systems to serve the Navy for decades to come. This implies acquisition, testing, installation, and operation under conditions typical of Navy missions. Both installation of new incinerators and modernization of existing incinerators are recommended. To be meaningful in the year 2000 time frame, these matters must be considered in parallel rather than sequentially. Commercial equipment exists in a range of sizes, and use in the marine environment has been demonstrated. Incineration research and development should be encouraged and supported.

4. Advanced Systems: It is recommended that the Navy continue its program of research into advanced waste destruction technologies that may eventually augment or supercede incineration as the principal shipboard reduction technology. At this time, there is no single candidate recommended for development. Encouragement and support of commercial technology development are recommended. Further development of technologies for liquid waste management is recommended in connection with an integrated system to handle all waste streams.

5. Shipboard Discharge and Emission Characterization: It is recommended that the Navy continue and enhance investigations (including measurement, monitoring, and modeling) of the human health and environmental effects of materials discharged and emitted from ships in connection with waste management.

6. Submarines: Existing source reduction programs are endorsed and recommended for the entire submarine fleet. Development of sealed storage containers for compacted trash, especially food-contaminated trash, should be carried through. Installation of garbage disposals (i.e., devices used to grind up food) fleetwide is recommended.