What functions produce waste biomass?
Biodegradable waste is generated by households, the trade and service sectors, agriculture and forestry, construction and demolition, and industry – the food industry in particular. All biologically degradable food and kitchen waste generated by households, restaurants, catering services and retail outlets, as well as other similar waste generated by food production and biologically degradable waste from gardens and parks, are classified as biowaste. In addition to biowaste, there are other biodegradable waste fractions, such as paper and cardboard waste, wood waste, natural fibre waste, and sewage sludge from wastewater treatment plants.
Biodegradable municipal waste comprises biodegradable waste from households and the service sector, including schools, hospitals, shops, restaurants, etc. It also includes biodegradable waste from, for example, social facilities at industrial plants, offices or workplace cafeterias. Actual biodegradable waste from industrial operations – such as waste from slaughter, animal fat, bark waste, excess sludge, stumps, wooden pallets, bales of cardboard, newspaper waste and other similar waste – does not comprise biodegradable municipal waste; rather, it is biodegradable waste assigned to each specific sector.
As of the beginning of 2016, biodegradable municipal waste cannot be deposited on landfill sites. As a result, new waste-to-energy plants have been built. Biodegradable municipal waste also ends up at waste-to-energy plants along with mixed municipal waste. Approximately one third of all municipal waste is estimated to be biowaste (i.e. food waste and waste from gardens). If paper and cardboard, textiles and wood waste are included, biodegradable waste accounts for two thirds of all municipal waste.
Biowaste is used for producing biogas and manufacturing soil improvement material. In the Helsinki region, for example, biowaste processing by the Helsinki Region Environmental Services Authority (HSY) is based on part-stream dry digestion, in which biowaste is both digested and composted. The most suitable part of the biowaste is directed to both processes. The digestion of biowaste consisting of food waste and waste from gardens has increased in recent years. Biogas produced in the digestion process is used in gas power plant producing electricity and heat. Digestion residues (digestates) and water that is generated in the digestion process, are directed to composting process and used thereafter as fertilisers, soil improvement material or landscaping material. Often, biowaste is digested at biogas plants together with manure, biodegradable industrial waste and sewage sludge.
Waste paper is used as raw material for manufacturing newspaper material and tissue paper as well as insulation wool, while cardboard waste is used for manufacturing cores for rolls of toilet paper and fabrics, as well as new packaging material.
Municipal sewage sludge is usually treated by means of digestion and composting. The amount of digested sludge and digested municipal biowaste has increased. Biogas produced in the digestion process is used as electricity and heat. Treated sewage sludge is mainly used for landscaping purposes.
The majority of sludge from the food industry is processed at composting and biogas plants, after which some of it is used as fertilisers in agriculture and, for example, as a soil improvement material. Some of the sludge from the forest industry is processed and used as fertiliser in soil improvement, and some of it is used for landscaping. However, the largest part of forest industry sludge ends up in energy production.
Biodegradable waste is a good raw material for new products, such as fertilisers.
With regard to waste from business operations, the companies that produce waste should be contacted when planning new concepts for the use of waste. When it comes to biodegradable municipal waste, parties responsible for its collection or processing, or the service providers that produce waste, should be contacted.
Properties of waste biomass
There is high variation in the composition of waste, even if waste fractions are in the same waste category. For example, waste fractions with the same name may have different water content, and many waste fractions involve properties that change according to the time of the year. In autumn, biowaste contains a much higher amount of leaves and plant waste than during other seasons. The quality of waste produced by companies may vary, for example, due to production failures or testing. Household waste and separately collected sorted waste may contain various impurities and foreign elements, such as metal and plastic, resulting from sorting errors. These may cause problems in recovering of waste.
Biodegradable waste data for the year 2018 has been obtained from the Compliense monitoring system YLVA which was maintained by the Centres for Economic Development, Transport and the Environment (ELY Centres) until the year 2018. Nowadays the database is called YLVA- environmental protection database, and maintained by ELY Centres and municipalities. Companies and enterprises having an environmental permit for their operation, are obligated to report annually waste data to environmental authorities. Reported data includes information on three waste streams: 1) Wastes that are generated by the enterprise and placed thereafter elsewhere to be recovered or disposed of, 2) Wastes which are generated at enterprise’s own production or unloaded from it’s storage, or received from outside, and 3) Storage of the wastes in the end of the reporting year.
Companies report their annual waste amounts to the database during the spring following the year being reported. The database is supplemented throughout the year. Information for the year 2018 has been updated in the Biomass Atlas in 2020. Biomass Atlas also includes calculated amounts of biodegradable municipal waste. The calculation method is based on municipal waste and population statistics and research data from Statistics Finland.
In the YLVA system, reported data on waste amounts is classified into 20 waste classes and their subclasses in accordance with the Waste Decree. The six-digit EWC (European Waste Catalogue/List of Wastes) code used in the classification indicates the origin of waste and the type of waste. EWC-codes for the biodegradable wastes are aggregated for Biomass Atlas according to their material composition into 5 main categories: Waste of animal and vegetation origin, Sludge, Paper and cardboard waste, Wood waste and Mixed municipal waste.
Regarding to the waste fractions generated by the business operations, the coordinates in which companies are located are known. However, the locations in which biodegradable municipal waste is generated are not reported to the database since these operators (such as households, schools, offices etc.) are not obligated to report their waste amounts to the authorities. However, amounts of municipal biodegradable wastes that are been disposed of or recovered by waste management companies/enterprises, are reported to the database, and such locations are known.
For Biomass Atlas, the amounts of biodegradable municipal waste have been calculated based on statistical and research data and population figures. Waste produced in the service sector is included in the amount of biodegradable municipal waste, similarly to waste from business operations, which can be considered to be similar to household waste in terms of quantity and quality. This includes waste from offices and workplace cafeterias.
Amounts of biodegradable municipal waste have been calculated over grids of 1 km × 1 km based on population figures and the production multipliers defined for biodegradable municipal waste. These multipliers are 89 kilos per capita per year for separately collected biodegradable municipal waste, and 320 kilos per capita per year for other biodegradable municipal waste. Municipal biowaste includes waste from kitchens, cafeterias, gardens and parks. Other biodegradable municipal waste includes separately collected biodegradable waste fractions, such as paper and cardboard waste, as well as biodegradable matter among mixed municipal waste. This proportion has been estimated based on research data.
Information on the amounts of biodegradable waste for the waste management sector is based on data reported by composting and biogas plants and waste-derived fuel production plants. Some of this information is overlapping with the amounts of biodegradable waste from business operations (since waste management operators are part of the business sector), while some may come from locations that are not obligated to report their waste data to the supervisory authority. Therefore, information on waste management sector is not included in the waste amounts for companies. It is added to Biomass Atlas separately. In terms of quality and usage of the Biomass Atlas information, waste that has undergone waste management processes is usually better in quality than without management processes, and therefore more suitable for example in landscaping or soil improvement material.
Amounts of biodegradable waste from companies or waste management sector and amounts of biodegradable municipal waste should not be viewed simultaneously in the Biomass Atlas, or at least they should not be added together, since the calculated amount of biodegradable municipal waste also includes biodegradable waste fractions from business operations, such as paper and cardboard waste from offices, biowaste from workplace cafeterias, etc. Otherwise, some waste fractions would be calculated twice. This also applies to waste amounts from companies and waste management. These should not be added together to identify the total amount generated.
Picture on top of the page: Photo bank of Environmental administration.