The Baltic Sea is one of the most polluted sea areas in the world, but there are large geographical differences. The Baltic Sea has over several decades been supplied with nutrients from agriculture, dioxin from sewage plants, wastewater from polluting companies and other substances from the many rivers that flow into the Baltic Sea.
The problems and action proposals are not new. Many initiatives already appear in the existing Baltic Sea Action Plan. Several regional strategies and improvements, have already been implemented. The biggest environmental challenge now is the discharge of nutrients, especially from agriculture. According to the Helsinki Commission HELCOM (2021) update, it is concluded that agriculture still has the highest reduction potential, and is currently the main contributor to the diffuse load of nutrients to the Baltic Sea. The problem is that large amounts of nutrients are being discharged into the water, especially nitrogen and phosphorus. This creates algal growth and depletion of oxygen on the bottom of the sea, which again affects the entire eco-system in the Baltic Sea area. Consequently, it will reduce water quality, have an impact on biodiversity, less fish to catch and potentially less eco-tourism in the coastal areas etc.
Despite, there already have been made improvement over the last 20-30 years due to major environmental efforts – there are still severe problems with oxygen depletion. Research collaborations have already taken place among Baltic Sea countries in the form of the BONUS program and other international collaborations between different countries. It is not only research projects across borders, but also across disciplines involving biologists, geologists, agricultural researchers and economists. Research indicates that both climate and nutrient input affect the sea in interaction – and a combination of higher temperatures and continuous release of nutrients will probably worsen the situation.
Saving the Baltic Sea still requires a committed effort to handle these challenges, as well as pollution from an increasing activity at sea, leaving plastic and abandoned fishing gear, trawling and other raw materials with noisy and polluting ship traffic. It is therefore, important to look at many factors and to act on them simultaneously. In this regard, there is a continuous need to assess the environmental and economic impact of different measures and to find the most cost-effective measures to be implemented in those areas.
In crop production, only about half of the nutrients in mineral and organic fertilizers are converted to harvested crops, thus better nutrient use efficiency is a key to a more sustainable production. Some nutrient recovery and reuse practices and technologies are already used in the agricultural sector and in wastewater treatment. However, there is still a need for improvements and further incentives to reuse nutrients.
Studies indicate that several, eco-technologies could potentially be economic feasible and reduce the use of finite resources while providing a number of co-benefits to the surrounding society.
Eco-technologies could for example include more efficient recovery and reuse of nitrogen and phosphorous from wastewater, struvite recovery and reuse from digested sludge, anaerobic digestion as well as biogas production and fertilizer production from manure. In addition, different precision farming technologies based on global navigation systems could enable farmers to optimize the distribution of fertilizers within the field.
However, a key question is how to prioritize? What impact does the various eco-technologies have on society – either local or regional, or does the potential benefits outweigh investment and operational costs? One way to deal with it is to find the most economic viable eco-technology solutions. Findings indicate that some eco-technologies for circulating nutrients from agricultural wastes could be economically feasible for the farmers but also for the surrounding society.
Studies dealing with nutrient recovery eco-technologies often focus on merely their market costs and benefits, such as investment and maintenance costs and the revenues from selling products on markets. However, there may also be other benefits. For example, a technology might initially be developed for recovering or saving nutrients in crop production, but it often has other unconsidered environmental benefits (services) from reduced eutrophication, such as more biodiversity, more options for angling and other leisure activities. These benefits are also valuable to the society.
As an example, the cost of recycled phosphorus is often higher than the market price of mineral phosphorus implying that farmers prioritize to use mineral phosphorus, which is a limited resource. By increasing the use of recycled nutrients today increases the option of sustainable food production in the future. There is a need to develop and implement more efficient technologies – but also a need to uncover all environmental and social benefits to the surrounding society from these technologies.
Sometimes, the economic feasibility decreases with increasing complexity of the technology or it may take longer time to adopt. The costs for point source-separation systems are often relatively high and the technology can be complex, although the benefits also can be substantial. Future studies should therefore further explore how sustainable eco-technologies could be implemented in the best way with the highest net-benefits. This would require better quantification of a broader range of co-benefits, hydrological modelling, longer time frame as well as adopting a systemic view that considers a broad spectra of benefits and costs. By doing so, it is possible to quantify multiple impacts not only investment costs and market benefits but also other benefits, risks, and local impacts stemming from different eco-technologies. This is important for making better incentives and policies to reduce and reuse resources safely in a sustainable way.
Søren Marcus Pedersen
Associate Professor, Department of Food and Resource Economics, University of Copenhagen
Denmark
