Can aquatic biomass reduce marine eutrophication and give us clean energy? BUCEFALOS LIFE11 ENV/SE/839 Layman s report 1
BUCEFALOS Blue concept for a low nutrient / carbon system Contact For further information, please contact: City of Malmö: Rasmus Fredriksson, rasmus.fredriksson(at.)malmo.se, +46 708 577 124 Region Skåne: Carina Sühnel, carina.suhnel(at.)skane.se Trelleborg Municipality: Annika Hansson, annika.hansson2(at.)trelleborg.se BUCEFALOS is co-financed by EU LIFE+ (LIFE11 ENV/SE/839) Photo: Sanna Dolck, Colourbox, Open Street Map, Trelleborg Municipality, City of Malmö, Tomaz Lundstedt Published November 2015 www.malmo.se/bucefalos 2
The project partners City of Malmö, Region Skåne and Trelleborg municipality are based in southern Sweden. Background and objectives The Baltic Sea suffers from an overload of nutrients causing a situation called eutrophication. The excess of nutrients results in a buildup of biomass in the shape of algae blooms and large amounts of algae along the beaches. In the project BUCEFALOS the City of Malmö, The municipality of Trelleborg and the Region of Skåne partnered up to investigate new ways of tackling this problem. In the project the partners have demonstrated different ways for this biomass to be used as a resource instead of just handled like a problem. The uses include production of renewable energy, raw material for different industrial processes and as a way of increase the efficiency of municipal sewage treatment plants. In BUCEFALOS the partners has constructed demonstration sites for production wetlands, microalgae- and blue mussel cultivation as well as biogas production from marine plants in Malmö and Trelleborg. On top of this we have investigated the potential for similar activities in other locations of the region and developed methods for this that can be applied for other regions with similar conditions. Through seminars, workshops and conferences we have identified and targeted key stakeholders in order to make these solutions a reality in the future. The methods demonstrated are often more cost-effective than the alternative, more traditional, methods of combatting eutrophication. They also result in valuable rest products that can partly finance the investments to put the facilities in place as well as the running costs. 3
A biogas plant specialized in turning beach cast algae into renewable biogas was demonstrated in the project. 4 Techniques, methods and results Biogas from aquatic biomass All along the beaches around the Baltic Sea there is a growing problem with large buildup of beach cast algae. The unpleasant smell and the unappealing look of the algae has a negative effect on the tourism industry as well as the value of the properties along the coast. The most common way of combatting this problem is by cleaning the beaches, collect the algae in large piles until the end of the season and then return it to the sea. As the algae degrades in the sea, the nutrients that they once absorbed are released back into the system, leading to more algae the next year. In BUCEFALOS we have demonstrated a new, innovative, way of addressing the problem and at the same time producing valuable products. In Smygehuk, just east of Trelleborg on the south coast of Sweden, a facility for producing renewable biogas from beach cast algae was constructed. As the algae have a rough texture and often quite a lot of sand mixed in, the facility was designed as a two-step reactor which can handle a larger portion of sand and debris than usual biogas reactors. The rest products, or residuals, from the biogas process can be sold as biofertilizer to the agriculture sector, adding more value to the process. A full production chain including collection of the algae, transportation, analyses and delivery of the residual has been developed and demonstrated. In addition to beach cast algae, the biogas facility can handle other aquatic materials such as reeds or kelp, or more traditional materials. Production wetlands to stop nutrients The major cause of eutrophication in the Baltic Sea is an outflow of nutrients from farmlands and forest lands in the surrounding countries. The problem is well known and the last decades huge efforts have been made to put in place different constructions to reduce this outflow. The most common method has been to restore wetlands that have previously been drained. These wetlands are usually very productive as they are designed to catch the nutrients and thus become hotspots for wildlife and for recreational purposes. To ensure the continuous function of the wetland, the bio-
mass (plants and vegetation) in the wetland has to be cut and harvested every couple of years. In addition to traditional wetlands there is a concept called production wetlands that are wetlands designed to produce a large amount of biomass and at the same time to be easy to harvest. In BUCEFALOS we have demonstrated two different types of production wetlands, both in Trelleborg, designed to be harvested with ordinary agricultural equipment. One of the types is designed to mimic a two-stage ditch running through agricultural land. The biomass harvested from the wetlands can be used in the agricultural sector or, as demonstrated in the BUCEFALOS project, be used as raw material for biogas production. Blue mussels as natural bio-filters A lot of effort is put into stopping the nutrients from reaching the sea but when they are already there, there are few methods to get them back. One of those methods is by cultivating and harvesting organisms that absorbs the nutrients for example filtering animals such as mussels. One suitable species, the blue mussel, Mytilus edulis, is native to the Baltic Sea and lives in huge banks along the seafloor, especially in the strait between Malmö and Copenhagen called Öresund. In some areas of the sound the density of mussels is so great that they cover every square meter of the natural and man-made structures. The blue mussels are very effective filterers and it has been calculated that the mussels in the shallow area between Malmö and Copenhagen filters all the water flowing out of the Baltic Sea. By using this natural process, or ecosystem service, it is possible to cultivate and harvest mussels in large quantities. By removing the mussels we would then also remove the nutrients absorbed in the meat, or biomass, of the mussels. In BUCEFALOS we demonstrated three ways of cultivating blue mussels off the coast of Malmö. The cultivation site comprised of large net-structures anchored to the seafloor, the mussel larvae found and settled on them completely naturally. We also investigated and tested the possibility to harvest mussels directly from man-made structures in the sound. The harvested mussels are too small to be sold to restaurants and are more suitable for applications such as a substitute for fishmeal in the fish- and chicken fodder industry. Three ways of cultivating blue mussels off the coast of Malmö were demonstrated in the project. 5
Microalgae cleaning sewage water, all it needs is sunlight and carbon dioxide from the air. Microalgae cultivation as a way of treating sewage water In municipal sewage treatment plants huge amounts of nutrients are handled every day. Modern methods and facilities are very efficient at separating the nutrients and reduces the amount that would otherwise have ended up in the sea. The bi-product from the standard treatment plant, often called sludge, is high in nutrients and organic material but it can often not be used as fertilizer on agricultural land due to different toxic contents. There is however a way of utilizing the high nutrient content in the sewage water by allowing certain species of microalgae to grow in the water before it reaches the treatment plant. Set up as a first stage in the treatment process, the microalgae can use up a portion of the nutrients, minimizing the amount that continues to the treatment plant. A very interesting way of using this technology is by combining it with a biogas facility where the microalgae are used as substrate. The produced biogas will always contain a portion of unwanted carbon dioxide that the microalgae require to be able to grow. By bubbling the biogas through the microalgae cultivation tank, the microalgae uses up the carbon dioxide resulting in an upgraded biogas with a higher energy content and commercial value. The microalgae produced can be used for different purposes depending on the species, the uses varies from bulk substrate for biogas production to very valuable ingredients, such as omega-3, in food supplements. In BUCEFALOS an experimental microalgae cultivation facility was placed at the treatment plant in Smygehamn, right next to the biogas facility. Raw sewage water was used for the microalgae to grow in and different designs with and without artificial light was tested and evaluated. The setup in this project was experimental but with further development the method could be a cost-effective way of using some of the nutrients from a city s sewage water. Regional potential in Skåne In a region as Skåne with a strong agricultural sector, a long coastline and a comparably intensive fishing industry there are many sources for aquatic 6
biomasses to be used according to the principles of the BUCEFALOS project. In order to quantify the potential a desktop and interview study was performed. We chose to focus on the potential for biogas production but in some cases other uses can be more favorable. The study resulted in a GIS tool as well as detailed reports on the potential for five different substrates in all of the coastal municipalities in Skåne. Dialogue activities It has been vital for the project implementation to gather experiences from experts and experienced actors in the different fields. During the project period a total of five workshops with different themes have been organized. Depending on the theme the participants has varied from municipalities, universities, private companies, fishermen and the general public. Assessment of environmental benefits and impact The true value of the BUCEFALOS project lies in its demonstrative and symbolic value as it has proven that it is possible to reduce the eutrophication in the seas and at the same time produce valuable products. The concepts proven in this project have already spread to other municipalities in Sweden and we anticipate similar activities around the Baltic Sea in the near future. While demonstrating this there has also been some direct environmental effects. The biogas facility in Smygehuk has produced renewable biogas from beach cast algae, previously regarded as useless. The production wetlands in Trelleborg have reduced the outflow of nutrients to the Baltic Sea. The mussel cultivation site in Malmö and the harvest of these mussels has resulted in a reduction of the nutrient levels in the Baltic Sea. The projects activities resulted in several offspring projects, something that would not have been possible if the project had not had such a strong focus on dissemination and sharing of experiences. Questions from the audience during the final conference. 7
Panel discussion at the final conference with delegates from the Swedish government, authorities and media. Cost-benefit discussion on the results As the demonstration sites have been prototypes by their nature the investment costs have been rather high. However with further development these costs can be minimized. Today most coastal municipalities spend large amounts on cleaning their beaches in order to attract visitors, both locals and tourists. The algae that are today being transported away from the beach and stored can for a rather small extra amount instead be used to produce renewable biogas. If two or three coastal municipalities would partner up and invest in a shared biogas facility the costs for logistics and running of the plant would be even more decreased. A large number of wetlands are being constructed in the Baltic region each year, largely financed by national or European subsidies. By applying the concept of production wetlands each of these wetlands could, in addition to wildlife and recreational values, result in monetary revenue for the landowner. To cultivate mussels as a way of combatting eutrophication has a comparable effect with that of establishing wetlands, depending on the harvest intensity and the growth speed of the mussels. A very important factor is however that wetlands take up valuable agricultural land that can no longer be used for food or raw material production. That is not the case for most coastal waters in the region, especially since the mussel cultivation sites can be placed beneath the surface, allowing vessels to pass over them. Transferability of project results This project has focused on the region of Skåne with demonstration sites in Malmö and Trelleborg but the problems are the same in most coastal municipalities in the Baltic region as well as in most of coastal Europe. The methods demonstrated can easily be transferred to other regions and adjusted to suite the local conditions. 8