5

Integrated Systems Approach

In Chapter 2, Chapter 3 through Chapter 4, the committee focuses on technologies that can be usefully applied to Annex V regulated waste materials. The terms of reference also include a less restrictive question: “Accepting answers to Questions 1-4 as the study's number one priority, but recognizing that environmental restrictions on Navy ships and submarines may increase with time, what additional technologies and practices hold promise of ultimately permitting Navy ships to be discharge-free during the course of an average cruise.” 1

In this chapter, the committee discusses integrated waste management systems that can handle Annex V materials as well as other important shipboard waste streams. The committee believes that the breadth of coverage, operating convenience, and demonstration of environmental responsibility justify the considerable cost in terms of money and space. Intuitively, this option seems best suited for large ships with long missions, but its candidacy deserves study for a wide range of Navy vessels.

The committee has considerable enthusiasm for an integrated waste treatment system, as opposed to a piecemeal approach whereby a variety of separate methods are employed to treat the waste streams individually. The committee is impressed with the integrated systems installed on many ships in the cruise line industry. The Navy Annex V compliance problem is different from that of the cruise line industry, but there are shared elements and it is probable that some Navy ships are good candidates for systems similar to those in use on cruise ships. These ships have elaborate systems that include the following components:

  • Large incinerators with automatic feed, combustion control, and automatic ash-handling equipment;

  • Shredders that reduce the particle size of waste material for easier transport and processing;

  • Compactors to minimize storage volume for materials that must be stored;

  • Pulpers to facilitate transport and discharge of food waste;

  • Dewatering equipment to remove excess water from food pulp, black water sludge, gray water residues, and so on;

  • Holding tanks for biological treatment of black water and destruction of pathogens; and

  • Oil-water separators for bilge water (most Navy ships already have these).

Shredders, compactors, pulpers, and dewatering units are “desk-sized” pieces of equipment. They weigh from one-half to 3 tons. Installation usually does not require significant rearrangements of shipboard facilities. Incinerators are large, heavy, and expensive installations, some with lengths of 20 to 30 ft, costing upwards of $250,000, and weighing from 10 to 60 tons. Installation on existing ships is a major alteration. Holding tanks need to be very large if the ship carries many people because of the long holding times required for biological treatment. Clearly there are important choices to be made in connection with any integrated system suite of apparatus.

Shipboard waste streams can be categorized in terms of the following materials classes: (1) paper and cardboard, (2) metal and glass, (3) plastic, (4) food waste, (5) black water, (6) gray water, (7) bilge oil,

1  

The term “discharge-free” is somewhat unfortunate in that it is likely that ships will continue to emit stack gases, water separated from solid and liquid waste, and metal and glass. The important issue is environmental responsibility in regard to the residual discharges.



The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement



Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.

OCR for page 31
SHIPBOARD POLLUTION CONTROL: U.S. Navy Compliance With MARPOL Annex V 5 Integrated Systems Approach In Chapter 2, Chapter 3 through Chapter 4, the committee focuses on technologies that can be usefully applied to Annex V regulated waste materials. The terms of reference also include a less restrictive question: “Accepting answers to Questions 1-4 as the study's number one priority, but recognizing that environmental restrictions on Navy ships and submarines may increase with time, what additional technologies and practices hold promise of ultimately permitting Navy ships to be discharge-free during the course of an average cruise.” 1 In this chapter, the committee discusses integrated waste management systems that can handle Annex V materials as well as other important shipboard waste streams. The committee believes that the breadth of coverage, operating convenience, and demonstration of environmental responsibility justify the considerable cost in terms of money and space. Intuitively, this option seems best suited for large ships with long missions, but its candidacy deserves study for a wide range of Navy vessels. The committee has considerable enthusiasm for an integrated waste treatment system, as opposed to a piecemeal approach whereby a variety of separate methods are employed to treat the waste streams individually. The committee is impressed with the integrated systems installed on many ships in the cruise line industry. The Navy Annex V compliance problem is different from that of the cruise line industry, but there are shared elements and it is probable that some Navy ships are good candidates for systems similar to those in use on cruise ships. These ships have elaborate systems that include the following components: Large incinerators with automatic feed, combustion control, and automatic ash-handling equipment; Shredders that reduce the particle size of waste material for easier transport and processing; Compactors to minimize storage volume for materials that must be stored; Pulpers to facilitate transport and discharge of food waste; Dewatering equipment to remove excess water from food pulp, black water sludge, gray water residues, and so on; Holding tanks for biological treatment of black water and destruction of pathogens; and Oil-water separators for bilge water (most Navy ships already have these). Shredders, compactors, pulpers, and dewatering units are “desk-sized” pieces of equipment. They weigh from one-half to 3 tons. Installation usually does not require significant rearrangements of shipboard facilities. Incinerators are large, heavy, and expensive installations, some with lengths of 20 to 30 ft, costing upwards of $250,000, and weighing from 10 to 60 tons. Installation on existing ships is a major alteration. Holding tanks need to be very large if the ship carries many people because of the long holding times required for biological treatment. Clearly there are important choices to be made in connection with any integrated system suite of apparatus. Shipboard waste streams can be categorized in terms of the following materials classes: (1) paper and cardboard, (2) metal and glass, (3) plastic, (4) food waste, (5) black water, (6) gray water, (7) bilge oil, 1   The term “discharge-free” is somewhat unfortunate in that it is likely that ships will continue to emit stack gases, water separated from solid and liquid waste, and metal and glass. The important issue is environmental responsibility in regard to the residual discharges.

OCR for page 31
SHIPBOARD POLLUTION CONTROL: U.S. Navy Compliance With MARPOL Annex V (8) oily rags, (9) medical waste, (10) chlorofluorocarbons (CFCs), (11) halons, (12) hazardous waste, and (13) antifoulants. Items 1 through 3 are the main focus of this report, and their management is discussed in Chapter 2 and Chapter 3. Items 4 through 9 are not regulated under Annex V, but they could be managed with an integrated system that would destroy paper and cardboard, food waste, black water sludge, gray water residue, bilge oil, oily rags, and medical waste. Metal, glass, and ash, a small fraction of the total waste volume, would be stored for transfer to shore facilities, other ships, or ocean discharge outside Special Areas. Items 10 through 13 do not fit into the systems discussed in this report. CFCs are being phased out worldwide in favor of chemicals that do not destroy ozone in the stratosphere. Halons are being retained in essential applications, as no substitutes are known, but their release to the atmosphere is being tightly controlled. Hazardous waste materials, containing radioactive waste, mercury, cadmium, and other noxious substances, are held on board and transferred to shore facilities for recycling or disposal. Advanced technologies could prove effective in dealing with hazardous waste and antifoulants. A sound strategy is to eliminate as much waste as possible during the loading phase. This method is practiced in an exemplary manner by the submarine service and may be adaptable to surface ships to some degree. The practice can be adopted without installation of complex machinery, and the importance of minimizing and husbanding packaging materials should be impressed on the crew. The committee has considered modification of packaging materials, i.e., arranging for suppliers to favor one packaging material over others. This approach is probably difficult and possibly expensive, since the Navy must acquire supplies at many far-flung ports. In addition, which material class to favor is not obvious. However, there are choices that are clearly correct, for example, the elimination of chlorine-containing plastics, which the Navy has already initiated. The keystone technology of an integrated system at this time is incineration. As noted, incinerators are large, heavy, and expensive. In addition, there are issues of safety and crew training and indoctrination that would attend installation of this equipment. Older models of incinerators exhibited problems that have turned many Navy people against the process. The committee believes that these problems have been successfully addressed in the design of modern incinerators, and their installation should be analyzed without prejudice. Further, modernization of existing shipboard incinerators should be pursued in the context of the integrated system concept. It is likely that air pollution standards will be tightened as time goes by, but compliance by modern incinerators will be maintained through the evolution of incineration practice. In the fullness of time, new technologies may emerge that will allow the incinerator to be replaced with equipment that is smaller, lighter, less expensive, functionally superior, and characterized by more benign by-products. There are many such technologies under investigation today, referred to herein as long-range options, and the committee is unable to distinguish any one of these that has a clear inside track for displacement of incineration. The Navy has a demonstration project in place for plasma arc treatment, and in that sense this technology might be considered ahead of other candidates. Even so, the committee regards plasma arc processing as at least a decade away from marine application to the shipboard waste considered in this report. A demonstration of supercritical water oxidation is being carried out (funded by ARPA) for the destruction of Navy hazardous waste. Other technologies could win, in the long run. Storage space is a factor in any scheme to manage shipboard waste streams, and it is particularly important in the Navy context. Navy ships are plainly crowded, and any excess space as may be found can immediately be assigned to some mission-related purpose. Bulk alone is not the only problem. Storage of combustible materials constitutes a dangerous situation on any ship; but when combat is considered, the danger is greatly enhanced. Food-contaminated materials in storage can cause odors and the development of dangerous organisms. Thus, there are good reasons for minimizing waste volume and avoiding the presence of food contamination in the waste. Incineration, or one of the long-range options for waste destruction, achieves the maximum reduction of volume and leaves the ash sanitized, which may simplify storage and disposal problems. This is an area that is not clear-cut, however. Metal and glass residues

OCR for page 31
SHIPBOARD POLLUTION CONTROL: U.S. Navy Compliance With MARPOL Annex V removed from an incinerator with the ash may be classified as toxic and lead to higher fees at landfill areas. The committee has used the term “destruction” where the actual process is conversion of waste to ash and air emissions by chemical means. The recommendation for adoption of an integrated system implies environmentally responsible disposal of the ash and air emissions. Navy ships already have holding tanks of considerable size that are employed for storage of waste liquids. It will require analysis beyond the scope of this report to decide whether these tanks are available and are large enough to support biological treatment of black water. The committee proposes that the integrated systems approach based on incineration is an attractive option for Navy ships, particularly for new construction, and offers good prospects for keeping pace with regulations as they evolve. These systems are commercially available in various sizes from manufacturers with extensive marine experience.