Nutrient Analysis of Food Waste from Ships’ Greywater in the Baltic Sea

This case study presents the results of assessments of the potential risk of pollution by food waste in different applied shipping scenarios. A four-step model was used to analyse the applied procedures. The first step of the study involved the identification of possible strategies for on-board food waste management. In the second step, physicochemical tests of visually selected greywater detected high contents of nutrients (NTotal ≤ 238 mg·L−1 and PTotal ≤ 71 mg·L−1). Daily nutrient content (DNC) calculations of different food waste management scenarios allowed us to estimate the highest emission value from the discharge of greywater mixed with shredded food waste in the third step. In the final stage of the study, the results obtained made it possible to qualitatively assess the impact of DNC load on food waste management methods in the Baltic Sea environment. This study highlights the potential risk of polluting the Baltic Sea with nutrients and other contaminants in various scenarios, which will impact the marine recovery process. The presented research helps to outline waste management approaches for the reduction of these risks.