21.11.2017

Gasum will continue to use sewage sludge in biogas and recycled nutrients production

Gasum will continue to use sewage sludge from municipal wastewater treatment plants in biogas and recycled nutrients production in the future, too. The company currently processes around a quarter of the volume of sewage sludge from Finnish municipal systems. The company is investing in biomass processing solutions and subsequent treatment of digestate for the further refining of nutrients. The aim is to refine nutrient residues from biogas production for purposes such as industrial process needs, creating products such as nitrogen nutrient solutions, and to serve the needs of soil conditioning and agriculture even better. Biogas production is a quick and efficient way of implementing the circular economy where the value of side streams and biowaste can be maximized as energy and organic nutrients. Biogas is used for heat and electricity production in industry, homes and transport.

The feedstocks base used by Gasum in biogas production is already extensive at the moment. Gasum processes a significant proportion currently estimated to be a little under a quarter of the total volume of sewage sludge from Finnish municipal systems. Sewage sludge is and will remain an important feedstock in biogas production. Gasum’s network of several plants enables the centralization of the various types of biomass fractions to specific biogas plants. Demand for organic nutrients is evolving rapidly in a variety of industrial sectors. In cooperation with various actors, Gasum is expanding the opportunities for the utilization of digestate in its production network.

Gasum will continue to use sewage sludge in biogas and recycled nutrients production in the future, too. Sewage sludge undergoes sanitization in the industrial biogas process, destroying any pathogens. Biogas plants using sewage sludge have introduced new processing techniques to be able to refine digestates obtained from sludge into more advanced recycled nutrient products. Wastewater treatment plant processes will also have a key impact on sewage sludge quality in the future.

”The rapid changes in the market situation of recycled nutrients and application difficulties caused by rainy conditions make the situation challenging, and major efforts are being made to develop solutions. For example, in Sweden there is the Revaq certification system for sewage sludge to ensure the quality of recycled fertilizers, which has improved the acceptability and quality of fertilizer use of nutrients produced from sludge. Work to develop a similar quality system has now been launched between actors in the sector in Finland to ensure the quality of recycled fertilizer and nutrient products from biogas production. We’re going to invest in sludge processing solutions and increased efficiency of nutrient residue processing in Finland,” says Ari Suomilammi, Director, Biogas Production and Sourcing, from Gasum.

Biodegradable waste fractions, side streams from food and other industry and various sludges are currently the most important feedstocks in Finnish biogas production. In the future, for example, biomass side streams from agriculture and industry will play key roles in the expansion of biogas production. The circular economy targets set by the EU provide increasing steering towards ways of processing sludges and biowaste where the benefits obtained from side streams are fully utilized. The value of the energy contained in biowaste and sewage sludge is maximized in the transport use of biogas.

Fact box:

• Gasum is the leading processer of biodegradable waste and supplier of biogas in the Nordic countries. Gasum processes an annual total of 800,000 tonnes biomass and produces an annual total of around 650 GWh of biogas at its twelve biogas plants.

• Gasum produces fertilizer products nationwide at its seven industrial-scale biogas plants in Finland at an annual total of around 500,000 tonnes and at five biogas plants in Sweden at an annual total exceeding 400,000 tonnes.

• Biogas production creates fertilizer products for agriculture and gardening soil production as well as nutrient concentrates (such as nitrogen and phosphorus concentrates containing organic carbon) used in agriculture and industry.

• Other organic nutrient products such as nitrogen nutrients containing ammoniacal nitrogen and water are used in industrial applications such as flue gas cleaning at power plants. Demand for organic nutrients is evolving rapidly at a variety of industrial sectors.

• According to the EU's circular economy targets, 65% of municipal waste must be recycled by 2030. The current level in Finland averages 30–35%.

• Gasum’s Finnish biogas plants are located in Huittinen, Honkajoki, Kuopio, Oulu, Riihimäki, Turku and Vehmaa. Gasum also produces biogas with its partners in Espoo, Kouvola and Lahti. In Sweden Gasum has biogas plants in Jordberga, Katrineholm, Lidköping and Örebro as well as a majority shareholding in a production plant located in Västerås. In addition, Gasum has a 50% shareholding in Vadsbo Biogas in Sweden.

• Read more about organic fertilizer products

For more information please contact:
Ari Suomilammi, Director, Biogas Production and Sourcing, Gasum
Phone: +358 400 653 351, firstname.surname(a)gasum.com