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:
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.
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.
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