Ship-Generated Greywater: A Known Problem We Choose to Ignore

A recent study from Chalmers University of Technology and the University of Gothenburg in Sweden has shed light on the serious issue of greywater from ships in the Baltic Sea. The findings reveal that levels of contaminants often exceed the IMO MEPC 227(64) standards for treated sewage effluent. When we consider pollutants like Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD5), Total Suspended Solids (TSS), nitrogen (N), and phosphorus (P), the data shows that untreated greywater frequently contains higher concentrations of these contaminants than the permitted limits for treated blackwater.

Given that the volume of greywater generated on ships is about four times larger than blackwater, it represents a significant source of potential pollution in marine environments, especially in sensitive water bodies with low circulation, such as the Baltic Sea and the Mediterranean.

These findings clearly highlight the need for action. The lack of regulations for greywater discharge is a major gap in our efforts to protect marine ecosystems. It's time for the maritime industry to adopt guidelines for managing and treating ship-generated greywater to prevent further damage to our oceans.

Read the whole article here:
https://www.sciencedirect.com/science/article/pii/S0025326X24009706