The food system consists of various phases and processes, in which a large amount of nutrients flow along with raw materials and products. Primary production acts as the engine of nutrient recycling in the system, as it recycles leakages from both its own and other phases back into new growth. In the short cycle of primary production, animals utilise feed in the fields, and some of the nutrients contained in the feed end up in manure and again in the production of new feed. Feed-grade by products from food industry are used for feeding, and if the by-products are not suitable for feed, they can be recycled into plant production through biogas plant, or if medium risk materials, through rendering process. In addition, spoiled feed from primary production, ineligible food from processing and retail, as well as food waste from food services and consumers should be recovered as accurately and cleanly as possible, so that the valuable nutrients and organic matter it contains can be returned to the system, e.g. through biogas production.
Meat production is often seen as a water pollution problem rather than the engine of nutrient recycling. The unnecessarily high phosphorus fertilization of recent decades due to the lack of knowledge is still challenging today’s farmers in the form of high phosphorus levels in certain fields, posing a risk of water pollution. Increased rainfall due to climate change further challenges this. However, manure is also a valuable fertilizer with multiple positive effects on the environment. In addition to the main nutrients, it contains organic matter and trace elements that support soil fertility and biodiversity. Indeed, well-maintained arable land produces high yields and reduces the risk of water pollution.
Sustainable nutrient recycling requires consideration of both regional and local conditions and the various aspects of sustainability. For example, methane emissions are formed during the storage of manure, which can largely be avoided if the manure is treated fresh in a biogas plant. On the other hand, mixing, handling and non-optimal spreading methods of manure or digestate can cause ammonia emissions or nutrient runoff, so from the perspective of overall sustainability, all phases from animal feeding, manure storage, processing, and application to the field must be properly managed. Manure processing is not mandatory; manure is beneficial for fields as it is when used properly. At the farm level, low-tech solutions can also significantly improve both nutrient utilization and nutrient self-sufficiency.
Biogas plants are often proposed as a simple solution to nutrient surplus in the areas of intensive livestock production. However, from the perspective of nutrient recycling, the biogas production phase is only a throughput process, where the mass remains almost the same and the total amount of nutrients does not change. Nutrients do not disappear, but the proportion of plant available nitrogen increases – both important aspects of nutrient recycling. So, if the target is to solve a regional nutrient surplus, a digestate processing phase is required after the biogas process, where the nutrients are separated into more concentrated end-products. These products can be transported more cost-effectively over longer distances than raw manure and digestate, thus enabling the transfer of surplus phosphorus to crop-producing areas to replace chemical fertilisers. If carefully planned and managed, the combination of biogas production and digestate processing can significantly reduce greenhouse gas emissions from meat production and the need for imported fertilisers, thereby increasing nutrient self-sufficiency in primary production, improving security of food supply, and reducing the risk of water pollution.
From the perspective of the environmental sustainability of the food system, it is important that regulations support the sustainable use and recycling of nutrients in primary production. Regional and farm-specific differences must be considered, as the same solutions are not suitable everywhere and for everyone. It must be ensured that, e.g., biogas investments also consider the processing of digestate and support the adoption of processing technologies and new innovations. There must also be room for farm-scale low-tech solutions. Highlighting the positive effects of various measures encourages actors to implement them.
Atria, as a leading food company in Northern Europe, has actively collaborated with research institutes, universities, foundations and other stakeholders and companies, and is participating in the current Finnish government’s Archipelago Sea program, aiming to promote the sustainable use and recycling of nutrients both in its own operations and in supply chains. Atria is currently building a biogas plant producing liquefied biogas and recycled nutrients from manure and food industry by-products near its Nurmo slaughterhouse in collaboration with Suomen Lantakaasu Oy.
Teija Paavola
Sustainability Manager, Atria Finland Ltd
Finland
