Scientific research reveals that a 15-ppm regulatory limit of oil discharge from shipboard operations has a long-term harmful effect on the marine environment, its biodiversity and eco-system. Yet, operational discharges from machinery spaces remain the largest oil polluting source of the oceans from shipping activities. However, use of technologies can reduce the oil content of the operational discharges from machinery spaces much below the regulatory limit and even almost to zero-ppm. Hence, eliminates the harmful effects of operational discharges into the marine environment. This book provides an ample opportunity for the ship owners, operators and the regulators around the world to act now to meet the future requirements in conserving the marine environment. The separator, filter and other related equipment producing industries will also be immensely benefited if proactive actions taken immediately. The marine scientists, researchers and the environmentalists having interest in protecting and preserving the marine biodiversity and its eco-system, the food chain and the ocean- the Mother Nature in general, will also find this book interesting and enlightening.