ABSTRACT

Compliance with MARPOL environmental regulations has required the design of a waste management system to reduce the volume of solid shipboard waste and treat it so that it is safe to carry aboard ship. The U.S. Navy in cooperation with industry has developed a conceptual design of a plasma arc waste destruction system (PAWDS) capable of meeting strict shipboard weight, size and operational criteria that has precluded the use of traditional commercial systems. The innovative system design has involved a thorough examination of candidate materials that should be capable of withstanding the processing of a variable waste stream that may include highly corrosive constituents. The structural components of the PAWDS should insure safety to personnel and ship by resisting degradation through high temperature corrosion, erosion, thermal cycling, and other effects.

INTRODUCTION

U.S. Navy Operational Concept and its strategy Forward --- From the Sea requires the Fleet to execute its presence anywhere in the world at any time. Local, national, and international environmental regulations and statutes controlling overboard discharge of liquid and solid wastes and air emissions have become more stringent for ships deployed at sea. The Navy?s ability to operate in littoral and selected areas around the world may be compromised unless alternative solid waste management processes are utilized. Existing ships do not have sewage and solid waste holding capabilities to hold wastes for more than a few days.

The International Convention for the Prevention of Pollution from Ships in 1973 and the 1978 Marine Pollution Protocol, collectively known as MARPOL 73/78? were early initiatives to control waste disposal in the marine environment.

An integrated technology for Navy ships to comply with this solid waste and liquid waste discharge prohibition is not currently available commercially. The marine environment and Naval warfare requirements present significant and unique challenges for technical solutions of waste disposal problems for U.S. Navy ships deployed at sea without significant impact to operations and deployment. Unlike land-based systems, solutions aboard ships will impose considerable constraints on space and must operate reliably in a corrosive, marine environment. The Navy has significant space, weight, reliability, maintainability, and operational constraints which require that any system minimize its impact on ship operations,. ship systems, manpower requirements, maintenance, and loss of mission-oriented space. The amount of Navy Solid Waste (NSW)2 generated on average (Table 1) has been studied, but the waste stream at any given time is variable. The composition of the ship solid and liquid waste generated on warships at sea can depend in part, on ship size and class, type of mission, length of ship?s mission, and location of deployment.

The Naval Studies Board3 (NSB) has recommended that the Navy continue its program of research into advanced thermal waste destruction technologies that may eventually serve as the principal shipboard waste reduction methodology. A comprehensive survey, as shown in Table 2, of thermal destruction technologies for shipboard solid waste was conducted. The survey identified electrically-heated, plasma-arc pyrolytic thermal destructio

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