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

The U.S. Navy, by action of the Congress is directed to comply with regulations set forth in the international agreement MARPOL Annex V (MARPOL 73/78). The Committee on Shipboard Pollution Control was convened by arrangement between the Navy and the National Research Council to evaluate technology options that are relevant to Navy compliance with Annex V for surface ships by 2000 and submarines by 2008. In addition, the committee was asked to consider technology implications of future regulations.

MARPOL Annex V places limits on ocean discharge of solid waste materials. Plastics may not be discharged into the sea at all. Paper (including cardboard), metal, and glass may not be discharged in Special Areas. Special Areas include the North Sea, the Mediterranean Sea, the Greater Caribbean (including the Gulf of Mexico), and other important areas. In this report, the committee focuses on technologies that will help and enable the Navy to comply with these restrictions.

The U.S. Navy has a highly diverse fleet of ships, consisting of a variety of ship classes spanning a broad range of sizes and missions. There are about 373 ships in 1995. The largest combat ships are the aircraft carriers and the amphibious assault ships. Crew sizes are quite large, 5,000 to 6,000, including air wing, for the carriers and about 3,000, including troops, for the amphibious assault ships.

A number of combat ship classes fall into the mid-size range with lengths of 400 to 600 ft. These classes include a number of cruisers, destroyers, frigates, and some of the smaller amphibious warfare ships. Crew sizes are on the order of several hundred, and the amphibious ships can carry about 900 troops. A number of these ships will also support limited helicopter air operations.

Combatant submarines fall into two major classes: attack submarines (SSNs) and ballistic missile submarines (SSBNs). The SSNs are smaller, with lengths of about 350 ft and crew sizes on the order of 130, and the SSBNs have lengths of about 560 ft and crew sizes of about 150. All combatant submarines are nuclear powered.

In addition, there is a wide range of support and special mission ships, including fleet replenishment, refueling and repair, minehunting, salvage, and surveillance. The size of these different classes can range from around 100 ft to over 500 ft, and the number of crew personnel varies from fewer than 100 to more than 500.

The various classes of ships share many characteristics. Combat ships are designed for maximum combat effectiveness, and supporting ships are designed to permit achievement of that goal. A variety of factors are important, including reliability, maintainability, and capability to operate under extreme adverse weather conditions. Ability to sustain battle damage and continue to operate effectively is a key criterion for warships.

Navy ships have a rather long life cycle. A new class of ship typically requires 2 to 8 years for concept and feasibility studies and design. Construction can then take another 5 to 8 years. Once delivered, the ship in-service lifetime extends for another 30 to 35 years, with periodic overhaul and backfitting of major new systems. Typically, only a few ships are added to the fleet each year.

The long life cycle and slow turnover have implications for waste treatment. Most of the ships in the current fleet will be in service well into the next century. Thus, installation of equipment for environmental compliance will to a large extent have to be accomplished by backfitting. The

environmental systems must be compatible with current ship space, weight, power, and other variables, which may limit the types of waste treatment facilities that can be used.

The operational environment of warships is quite different from that of commercial ships. Typical mission duration is 30 to 60 days for surface ships and several months for submarines. Passenger and cargo ships are rarely out of port for more than a few days at a time. Consequently, storage of wastes on Navy ships is much more of a problem than it is for commercial vessels. Storage of significant amounts of flammable waste material (paper and plastic) is a problem in any case but a particular problem in combat operations. Navy surface ships are resupplied at sea frequently (perhaps twice a week). There is a regular stream of foodstuffs, fuel, and other materials coming aboard with their accompanying packaging materials. Thus, the waste material continues to build up while the ships are at sea. The kinds of waste materials depend to some extent on class of ship. For example, amphibious support ships have extensive medical facilities to handle injured troops and therefore generate quantities of medical waste. Repair ships tend to generate wastes similar to those from industrial plants. In general, however, Annex V wastes will be similar from ship to ship and the quantities will scale with the ship's complement.

Submarines are quite different from surface ships. Typically, submarines deploy with all required supplies and do not have at-sea replenishment, often returning to the same port at the end of their tour. Because of their serious space limitations, submarine crews will generally eliminate all unnecessary packaging material as the ship is loaded. Other major differences between surface ships and submarines come from the very different environment in which they operate. Surface ships have access to the atmosphere, providing unlimited amounts of air to support incineration of wastes and providing a sink for the discharge of combustion gases. In submarines, air is limited and incineration of waste impractical. Space aboard submarines is especially tight, and acoustic silence is a fact of life. For these reasons, submarine management has carefully controlled the amount and kind of material brought on board.

In addition to the technological methods that can be used to enable compliance with Annex V, there are a number of significant issues that are essentially management matters. Although the committee was brought together for technical input, several members have management experience in environmental areas, both civilian and Navy. Therefore, in this section the committee makes observations that are not technological in character but are important in the successful management of the technologies chosen to achieve compliance.

A successful program for environmental compliance will be difficult to achieve unless clear-cut commitment and objectives are articulated from the top of the Navy command, supported by all levels of officers and implemented by orientation and training of officers and crew. The importance of the environmental mission must be reflected in visible aspects of the naval organization. In a sense, environmental responsibility has become the price of access to waters in which the Navy must provide a forward presence under peacetime conditions.

In view of the ship-specific nature of environmental compliance, captains should receive environmental orientation just before they assume command of a ship. The orientation should cover all aspects of the ship's environmental systems and include other officers, specifically the ship's engineering and supply officers. Noncommissioned officers should also be involved. The command staff should be made aware of Annex V regulations and of details and limitations of the ship's waste management system. This is akin to what chemical industry plant managers have to master before being given responsibility for a chemical plant's emissions. A formal orientation program allows the captain and the principal officers to issue appropriate directives to the crew and makes a statement about the captain's support for the program. At the same time, training and tracking programs should be initiated.

It is suggested that environmental commitment will require that the Navy establish a respected cadre of specifically trained officers. Concentrating responsibility in a single environmental officer and providing considerably more training and fundamental background for that individual should yield benefits. In chemical and manufacturing plants, companies have set up environmental protection groups and assigned specialists to assist plant managers. The Navy could make it attractive for technically oriented naval personnel to attend programs on environmental training. Subject matter could include:

• Law and regulations,

• International commitments and related issues,

• Equipment testing and maintenance,

• Environmental policy,

• Shipboard testing of water and air emissions,

• Waste stream characterization, and

• Advances in environmental technology.

The fleet has substantial installations of waste management equipment aboard today, and more are coming. Establishment of effective management teams and provision of training and instruction are key issues required for long-term compliance with Annex V and future regulations. The chemical and airline industries make good use of videotape courses for personnel, both for employees assigned to new systems and as reinforcement for continuing employees. Tapes could show details of proper operation of waste management systems as well as critical aspects of safe storage of flammable materials.

The Navy could also make good use of goals for source reduction for each ship. This will entail keeping records of waste generated in a standard format. As this database develops, it can be used for performance metrics, for benchmarking with other ships, and as an incentive for source reduction of waste materials.

As presented in this report, two principal approaches to Annex V compliance appear promising. First, compaction and storage of wastes for landfill disposal or ocean discharge outside Special Areas for paper, metal, and glass can be implemented rather quickly. The Navy is already implementing a program for compacting plastic by means of a Navy-developed processor. The resulting discs will be stored for shore disposal. Commercial equipment exists and space requirements are modest for many ships. Second, incineration can reduce the volume of Annex V waste by an order of magnitude and offers an option that can lead to compliance while minimizing storage and transfer. At this time, the Navy has 107 incinerators installed on ships; and with modernization and operational improvement, they can probably burn 70 percent of the total waste paper and plastic generated by the Navy at sea. In the longer term, advanced technologies (e.g., plasma arc or supercritical water oxidation) are being developed that could replace incineration.

Based on successful implementation in the cruise line industry, the committee has great enthusiasm for incinerator-based integrated systems that can manage Annex V wastes, food waste, black water, gray water, bilge water, and other waste streams. It is clear that the Navy problem is more complex than that of the cruise line industry, but the committee believes that some form of integrated system can be implemented in the intermediate term, say over the next 5 to 15 years. Existing technology for managing liquid wastes is well established, and a number of advanced technologies are being developed in this connection. Backfitting integrated systems will be a challenge of considerable dimension.

The U.S. Navy's most recent plan was put forward in 1993 (U.S. Navy, 1993). In regard to Annex V waste, the plan called for the following:

1. Metal and glass were to be shredded, using Navy-developed shredders, and placed in sinkable cloth bags which were to be discharged into the sea.

2. Paper was to be made into a pulp along with food waste, using Navy-developed pulpers, and it was proposed to discharge the pulp into the sea.

3. Plastic was to be converted into discs, using the Navy-developed plastics processor, and stored on board for later transfer to shore facilities.

The first two proposals, for paper, metal, and glass, violate the Annex V prohibition (as imposed on the Navy by the Congress) of solid discharge in Special Areas, and the plan was rejected by the U.S. Congress. The Navy is currently working on a new plan which is expected to be presented to the Congress in early 1997.

Naval ships are exempt from Annex V regulations, but some nations are moving toward compliance. The committee has not done a broad survey of international practice and plans, but some information is available for the United Kingdom and Germany.

The Royal Navy plans to meet Annex V regulations when operationally possible by mechanical means. Specifications were established for a system that would process all ships' mixed garbage in a timely way, be operable by untrained crew, demonstrate high reliability over a 25-year life, and be modular in construction to facilitate installation on all ships, new and existing. The processed garbage must be in units that will sink in sea water in 5 minutes, not exceed 15 kg in weight, not exceed 450 mm in any dimension, and be suitable for 7 days' storage.

A private firm anticipated the Royal Navy request and demonstrated, using private funding, a system that performed the required processing (Strachan & Henshaw, private communication, 1995). The basic unit consists of a combination shredder-compactor, with two stages of compaction. The waste is placed in a steel container, which is sealed. This system worked well for “dry” waste, that is, not food contaminated. The specifications handed down by the Royal Navy stated that plastic waste could contain food matter and the machine must seal the food waste without containerization to prevent the growth and spread of harmful bacteria for at least 45 days. To accomplish this, a special modification was made to melt the plastic surface while inside the compactor. On cooling, the plastic forms a thick skin (4 mm thick). Note that this heated chamber machine is very similar to the U.S. Navy-developed plastics processor. Each ship is to have two machines, one for dry waste and the other modified for plastic processing. A prototype unit was installed on a Royal Navy ship in 1994. The U.K. Ministry of Defense has placed orders for 12 installations on Royal Navy ships.

The committee does not have specific Royal Navy plans for storage and transfer to shore facilities and dates for compliance. Note that the approach does not involve Royal Navy investment in apparatus development beyond issuance of performance specifications.

The German Navy also has plans to comply with the Annex V regulations, and Germany operates under much stricter environmental laws than other nations. Storage of uncompacted and separated waste

is mandatory for German vessels to facilitate recycling. About 7 days' storage is contemplated. Solid waste will be off-loaded at port or onto logistical support ships. No technology is involved.

Incinerator technology is also being investigated for task group missions. This is apparently in the context of an integrated system, and only existing commercial technology is being studied.

As part of its effort to bring the Coast Guard fleet (about 228 ships 765 ft in length) into compliance with all existing and emerging regulations, laws, and international protocols, the U.S. Coast Guard has a plan and program (U.S. Coast Guard, 1994) relating to MARPOL Annex V. The current plan dated February 1, 1994, is broken down by ship type as follows:

1. The two existing icebreakers and the polar icebreaker under construction (crew size about 200) will have a waste-handling system to dispose of solid waste, plastics, and waste oil, consisting of an incinerator and trash compactor in one compartment and a pulper in another. A compact incinerator (Golar 500) (320 lb/h of 8,000 BTU/lb dry waste), continuous manual (sluice) feed now (to have automatic feeder later), has been under trial, and emissions measurements have been made by China Lake.

2. Large cutters (existing and new construction) will have a 2 ft × 2 ft × 6 ft commercial compactor (ship tested), a stand-alone unit, capable of serving a crew of about 200, and costing $5,000 to $10,000. Because these will be on weather decks, they are made of stainless steel. An incinerator will also be installed, probably only on larger cutters, if current trials are satisfactory and space is adequate, in addition to a small pulper if feasible. Pulpers (Navy-developed and commercial) will also be installed on large cutters to dispose of paper, dunnage, and food waste where allowed.

3. Small cutters will have small commercial compactors (< $1,000).

The costs, including tests, acquisition, and installation, of the MARPOL V-related program are summarized in Table 1.1.