Gas is an everyday part of an innovative circular economy

A circular economy featuring a sustainable cycle of raw materials is one of the most important global megatrends of the years ahead. It is also an excellent way of reducing climate emissions. Many gas solutions are based on circular economy models that create a win-win situation – with the environment reaping many of the benefits.

An excellent example of the advantages of the model can be found in Turku, a Finnish city on the Baltic Sea. Wastewater from around 300,000 residents of the city and the neighbouring area is purified at a single central plant. The energy content and nutrients of the sewage sludge can now be recycled.

Sewage sludge containing solids is collected from the wastewater. The sludge is transported to the Turku Gasum biogas plant where it is used as a feedstock for renewable biogas. There are also solids remaining once the biogas process is completed. Compost created at the plant is used for Turku roadside landscaping, among other things.

Everything goes around – Join the cycle

Another product that the plant can separate from the sludge is aqueous ammonia solution (ammonia water). It can be used for environmentally beneficial purposes such as water purification in the paper industry and for removal of nitrogen oxides from flue gases at industrial production facilities.

This is a win-win situation for all. The biogas produced at the plant is liquefied, and turned into LBG fuel for heavy-duty transport. The output of the Turku plant can meet the annual fuel needs of 150 trucks, which corresponds to the annual fuel consumption of up to 75,000 cars.

The ammonia water produced at the plant accounts for around 10% of Finland’s total annual demand for ammonia water. On top of all that, the City of Turku gains a significant cost benefit from the partnership and does not need to make other arrangements for treatment of sewage sludge.

Circular economy solutions are becoming increasingly common

In Finland, Gasum produces biogas from feedstocks including side streams of the food company Valio – and Valio uses that biogas in its own logistics. There are similar partnerships with companies such as IKEA and Lidl. In Sweden, Gasum starts to produce gas from feedstocks including the wastewater of Stora Enso’s paper mill in Nymölla.

In future Gasum will build a new biogas plant in Götene, Sweden. Due for completion by the end of 2022, the plant is expected to produce an annual total of 120 GWh of liquefied biogas, mainly from manure.

29.9.2020