Nutrient recycling circular economy model for large cities water treatment sludge and ashes to biomass to bio-energy

PROJECT DESCRIPTION

BACKGROUND

Sewage sludge from wastewater treatment and ash left after biomass is burned are nutrient-rich waste products with great potential for reuse. Since both materials contain toxic elements and pathogens in addition to sought-after nitrogen and phosphorous, they are not suitable for growing food crops. They could however, be used onbiomass plantations.

Up to 85% of sewage sludge from Lithuanias wastewater treatment plants could be processed into dry pellets if a commercially viable use was found. The countrys rapid shift from natural gas towards biomass-based district heating systems is significantly increasing available volumes of biomass ash.

OBJECTIVES

The NutriBiomass4LIFE project will create and demonstrate a full-scale self-sustainable closed-loop circular economy model for nutrient-rich waste recycling for Vilnius, the largest city in Lithuania. This will involve using municipal sewage sludge and biomass ash on biomass plantations close to the city. The project will seek to develop new business models to make it economically viable to grow woody biomass on land that is marginal or unsuitable for agriculture. By demonstrating an effective and valuable use of municipal sewage sludge and biomass ash, the project will contribute to the implementation of the Roadmap to a Resource Efficient Europe and support the implementation of Sludge Directive, Water Framework Directive, Waste Framework Directive and Nitrates Directive.

Expected results:

900 ha of woody biomass plantations established within a 60 km radius of Vilnius;

1 800 ha of forests / plantations certified for sustainable forest management;

27 000 tonnes of dried sewage sludge and 1 500 tonnes of biomass ash recycled in biomass plantations;

1 350 tonnes of nitrogen and 675 tonnes of phosphorus reused in biomass plantations;

39.4 GWh of renewable energy produced for Vilnius;

42 000 tonnes fewer carbon dioxide emissions;

Impact on soil: 1 800 ha of soil surface improved, 35% increase in soil organic carbon stock and 33% increase in the available pool of plant nutrients;

30% increase in biomass yields;

Transfer of results to entities capable of replication.