Wastewater originating from onboard toilets, kitchens, sinks, bathtubs, and showers is classified as sewage water. This effluent, generated daily by crew and passengers, contains organic matter, pathogenic microorganisms, and chemical residues which, if improperly discharged, can pose serious risks to the marine environment.

Although the main sources of sewage are land-based — such as public sewer systems and treatment plants — sewage discharge from vessels also significantly contributes to ocean pollution, potentially causing:

• Microbiological contamination of coastal waters
• Reduction in dissolved oxygen levels (hypoxia)
• Visual and sanitary impacts in tourist areas
• Risks to public health and marine biodiversity

To mitigate these impacts and comply with international conventions (such as MARPOL – Annex IV), ships are required to properly treat sewage before discharging it into the sea. Periodic analysis of the efficiency of onboard sewage treatment plants is therefore essential to ensure environmental compliance and avoid legal penalties.

Lan Maritime Lab performs specialized testing of treated effluent, ensuring that discharge standards are within the limits set by regulatory authorities.