Four experiments to combat marine litter in the Baltic Sea have received support from the City of Helsinki. A startup named Clewat tested a new kind of waste collection ship that effectively collects macro and microplastics from seawater, while Innogreen developed a green wall to filter plastic debris out of stormwater. Bioharbour analysed plastic volumes in cruise ships’ food waste that enters the Baltic Sea, and Bloft Design Lab developed a giant 3D printer to print SUP boards from plastic waste retrieved from shore areas. The experiments were conducted during 2020 in Helsinki’s coastal and sea areas.
Helsinki aims to be a forerunner in the urban transition to a sustainable future. Among other things, the city has pledged to become carbon neutral by the year 2035. Together with the third largest city in Finland, Turku, Helsinki has also been coordinating efforts to protect the Baltic Sea through the cities’ joint Baltic Sea Challenge (BSC) partnership network. Helsinki wants to serve as a testbed for finding sustainable and innovative solutions. This is why the city initiated a series of BSC ‘speedy experiments’ to help find innovative solutions to the marine litter problem plaguing the seas.
Plastic waste is a universal concern affecting all waterways across the globe. The Great Pacific Garbage Patch, a floating mass of plastic debris three times the size of France, is one example of the scale of this crisis.
The Baltic Sea has its own plastic litter problem. Close to 90 million people live in its catchment area and it counts among the world’s busiest sea areas in terms of traffic. The Port of Helsinki is the busiest passenger port in Europe and in addition to regular passenger traffic, it is visited by some 300 international cruise ships each year. In the Baltic Sea region, plastic travels from land to sea through a variety of routes, fed by rivers, stormwater and wind. Some of it is also dumped in the sea directly from the ships. Plastic in the sea is hazardous to both people and the environment. Plastic degrades very slowly and eventually becomes small microplastic particles, which end up in the digestive systems of fish and birds and eventually reach humans through the food chain. Microplastics present an alarming danger to the environment on their own, but they can also carry harmful chemicals.
In Helsinki, Baltic Sea littering is prevented by a variety of means, including maintenance, coordinated measures and volunteer efforts to clean up shore areas. As an example, the City of Helsinki construction service enterprise Stara, which is responsible for keeping Helsinki’s sea areas and archipelago clean, collected 80 cubic metres of waste from the sea off the shore of Helsinki over the course of the last year.
“Even though a lot is already being done in Helsinki to protect the Baltic Sea, more action is needed. We need entirely new kinds of solutions alongside old ones that have been determined to be effective. Funding easily mobilised experiments is a relatively affordable way to quickly determine whether or not new innovations work and are eligible for wider implementation. As such, we all benefit from Helsinki serving as a platform that can be used by start-ups, businesses and organisations to test their innovations in practice,” says Deputy Mayor Anni Sinnemäki.
Local trials can be replicated
Four startups were selected in the spring to conduct speedy experiments that would test solutions and services that could either prevent plastic waste from ending up in the Baltic Sea or remove waste that was already contaminating it.
“The experiments were conducted locally in Helsinki’s land and sea areas, but the methods can be replicated for use outside Finland and more widely across the Baltic Sea and the world’s oceans. Due to the nature of plastic waste, similar methods may be viable on a global scale. For example, plastic bags (PE) and bottles (PET), fragments from their degradation and microplastics are found on beaches and other marine environments around the world. These plastic products may remain in the marine environment even hundreds of years causing many kinds of ecological and economical damage,” says Sanna Suikkanen, senior researcher at the Finnish Environment Institute.
The waste collection vessel developed by Clewat Oy toured sea areas that are challenging to keep clean with current methods in June, August and October. The operation of the vessel is based on the utilisation of water flow and is capable of collecting plastic particles from 0.5 mm in size. The amount of waste collected in all areas was clearly higher during the summer than in October. In the summer the litter collected consisted particularly of food and drink as well as to these related packaging materials. In addition, construction materials were found. As a result of the experiment, several significant modifications were made to the vessel to further improve its operation.
Stormwater carries litter, microplastics and other pollutants into the Baltic Sea from hard surfaces such as roads and streets. Road traffic is the number-one source of microplastics in Finland and many other countries. To counter this environmental threat Innogreen developed a prototype for a new solution which utilised a green wall to filter the stormwater running off the roads. This new method was tested for the first time in real-life conditions by a busy motorway. The trial found that a green wall module can slow down stormwater runoff and significantly reduce the amount of different kinds of microplastics in the water. Green walls can also be used to bring greenery to challenging locations, improving their appeal. Further research will focus on developing the life cycle of the filter material, among other things.
Reusing plastic waste and creating new business
International cruise ships visiting Helsinki have the opportunity to leave their food waste in the Port of Helsinki, but some ships dump the waste in the sea in international waters instead. In the context of regular passenger traffic, food waste is processed sustainably as part of other waste management arrangements, to ensure that none of it ends up in the sea. Food waste is an environmental concern for many reasons, one of which is the plastic it contains. Bioharbour Oy concluded that approximately 0.2 kg of macroplastics can be found in every tonne of food waste. This means that in proportion to inbound international cruise traffic during a normal year in Helsinki, international cruise ships are estimated to dump roughly 2.3–5.3 tonnes of plastic in the sea. Bioharbour is in the process of developing a new method of producing carbon-neutral energy from the food waste and other organic waste matter generated by cruise ships to ensure that even the plastics are recycled for further use.
Reusing plastic waste collected from the sea can reduce the need to produce new plastic materials, but this requires feasible solutions. Bloft Design Lab’s trial consisted of constructing an entirely new scalable 3D printer that can be used to make large objects such as SUP boards from plastic waste. During the trial, volunteer campaigns were organised to collect plastic waste from the shores of Helsinki, so that its viability for 3D printing could be analysed compared to the use of virgin plastic and imported waste plastic. The result was that plastic waste collected from the sea is indeed sufficient for the manufacture of SUP boards.
