Sea change for greywater

摘要

In many respects greywater - that is to say the onboard wastewater produced from baths, showers, laundries, and dishwashers - is the Cinderella of the maritime environmental protection and treatment regime. This is because the focus of governments and the regulatory bodies has, since the emergence of MARPOL in 1973, been on oil, garbage, harmful substances, and sewage. Indeed, the MARPOL Annex, known as Annex Ⅳ, covering sewage - or blackwater waste -only came into force as recently as September 2003. The regulations enforced by this Annex forbade the discharge of sewage into the sea, unless a vessel is fitted with an approved sewage treatment plant, or when it is discharging treated sewage at a distance in excess of 3nm from the nearest land.