Ever since Croatia has been hosting numerous cruise ships along the coast, the public has been wary of them, constantly repeating the idea that they are incredible polluters, letting their wastewaters out in the Adriatic.
Whenever anything related to those cruise ships is shared on Facebook, for instance, most comments will focus exactly on this aspect of their presence.
Žarko Koboević Ph.D., associate professor at the Department of Nautical studies of the University of Dubrovnik has been researching pollution of the seawater with the wastewaters from these vessels.
His research has given somewhat different results: cruise ships absolutely do not pollute the coastal seawaters, meaning the part of the sea where people swim, where yachts hang around, where any type of activities are being undertaken. Kristina Filičić spoke to him for Slobodna Dalmacija.
Professor Koboević says that current events, such as the situation when a cruise ship near Zlatni rat in Bol was suspected of releasing its wastewater, require more detailed research, similar to what he did four years ago for his doctoral thesis.
He performed research and sampled the water for a full 14 months at 8 popular swimming locations – and all of that research has shown that the cruise ships do not contribute to the pollution of the sea in those areas. The main reason is that the modern cruise ships have new technology which converts faecal wastewater into two components – clean water and gases that are released into the atmosphere, so basically – there is no “dirty” wastewater to be released at all.
All of the water released from the cruise ships is carefully monitored for a number of parameters, and the released water from a cruise ship is usually cleaner than what we consider perfectly clean sea-water on our favourite beaches. Those ships that don’t have such modern technology for wastewater management are not allowed to release their wastewater within 12 nautical miles from the closest land, which is far enough that no consequences can be observed.
None of what we explained in the previous paragraphs applies to the small boats in the national traffic – day-trip boats, yachts, sailboats, and other small vessels, and most of them are usually right next to the land. Where do they empty their wastewater tanks filled with unprocessed waste?
They are not monitored at all, and their tanks need to be emptied, so where are they doing that? In the sea, of course, and almost none of them would even consider going 12 miles from the coast, or going to have their tanks professionally emptied in the ports, where they would have to pay for the service.
Additionally, prof. Koboević that Croatian laws don’t really regulate the field in a significant way, so there’s no way that any fines would be introduced. If you’re a yacht owner, and it isn’t quite clear what you are or are not allowed to do, and there are no fines anyway, why shouldn’t you just do what you think is best?
One of his ideas to mitigate the situation is to include the emptying of the tanks included in the price of admission to the marinas and ports. That would make many yacht owners use that service, so there would be less wastewater to be released in the sea. There is no need to come up with any new ideas, just to copy other countries that already have better regulations.
His final idea is a bit extreme – he says that one of the solutions would be that the tanks on smaller vessels would need to be welded shut, so they can only be emptied in ports. While that would probably be the solution, I’m not sure how exactly that would be done.
