tailieunhanh - ENCYCLOPEDIA OF ENVIRONMENTAL SCIENCE AND ENGINEERING - MARINE SPILLAGE—SOURCES AND HAZARDS

HÀNG HẢI đổ NGUỒN VÀ NGUY HẠI GIỚI THIỆU SHIP phân loại và mô tả sắp xếp và đặc điểm chung của các loại tàu thương gia khác nhau được mô tả trong các văn bản tiêu chuẩn như tham khảo (1) và trong các tài liệu kỹ thuật, bao gồm các cuộc thảo luận toàn diện trong tham khảo (2) bao gồm Mỹ đóng tàu trong giai đoạn 1976 1936 . Theo đó, các cuộc thảo luận sau đây sẽ bị hạn chế đặc điểm thích hợp cho vấn đề ô nhiễm, ví dụ, bố trí các không gian bồn. Các. | MARINE SPILLAGE SOURCES AND HAZARDS INTRODUCTION Scope Pollution of navigable waterways resulting from operation of commercial and naval vessels may be a consequence of normal service or from casualties such as collisions and groundings. Propulsion system fuel oil and liquid cargoes may be involved in any case and will be considered in this chapter. Waste disposal from shipping is of comparatively small magnitude compared to waterway pollution from shoreside sources and will not be considered. Emphasis will be on description of the pollution problem and on means for prevention. The subject of spill collection and disposal is considered elsewhere in this text. Problem Definition Normal operations A decade ago the primary source of pollution of the world s waterways was the intentional discharge of oily ballast water during routine operations. At that time for virtually all seagoing operations ballast water was taken aboard for a portion of the voyage in order to obtain sufficient draft and trim for propeller immersion adequate steering ability acceptable conditions of seaworthiness and to satisfy mandated operational and regulatory requirements for intact and damaged stability. If assigned ballast tank capacity was inadequate to meet these requirements it was the general practice to ballast empty fuel oil tanks or empty liquid cargo tanks in the case of tank vessels. This procedure resulted in the necessity for pumping overboard large quantities of contaminated ballast water before taking on fuel oil or liquid cargoes. These procedures have been largely outlawed by international agreements developed by the International Maritime Organization IMO of the United Nations and enforced by the national regulatory agencies of the member countries. Casualties Spills resulting from casualties generally receive more attention in the world press than incidents involving operational discharges. Spills may occur from operational mishaps in the pumping of fuel oil bunkers and .