R&D Project

ASHBACK Center for Safe Biofuel Recycling

Ash from combustion of bio-fuel in power plants contains heavy metals and is currently regarded as a waste product only to be recycled to plantations and cultivated fields in small amounts. ASHBACK aims to improve the economy of bio-fuels by enabling more ash recycling through increased knowledge about both its safety and side effects.

Centre Challenges and Scope
How does ash-toxicity depend on biofuel source, receiver-ecosystem, and soil type? ASHBACK examines:

  • three major biofuel sources, Norway spruce, willow, & cereal straw, which differ markedly in several respects. Do their ash toxicity, export of toxic compounds, and organic carbon accumulation in soil also differ?
  • the toxicity to soil organisms of combustion ash as an essential ecosystem impact parameter, with special emphasis on their contents of heavy metals, especially Cadmium (Cd)
  • bioaccumulation of heavy metals in various ecosystems; bioaccumulation eventually leads to export to other environments via plant-feeding, fungal-feeding, carnivorous animals & water percolation
  • effects of ash addition on nutrient content – including organic carbon – and pH of the soil. Different soil types may experience an accumulation or reduction of organic carbon, thus improving or impoverishing the CO2 budget of the whole energy production sector.

ASHBACK Center amends ash at both field scale and in reduced laboratory systems. Coupling natural (field) and controlled (laboratory) efforts is necessary to properly evaluate the long-term effects of enhanced ash recycling.

Based on the center’s results, ASHBACK will provide recommendations to modify toxic ash for recycling, either by addition of organic waste or by immobilization of heavy metals to decrease toxicity. The research and its recommendations will contribute to increasing both the economic and environmental sustainability of biofuels.

Collaboration with ASHBACK Center
Currently ASHBACK Center collaborates with Assens Fjernvarme, a Danish energy producer, as well as Hede Danmark, one of Denmark’s leaders within the reuse of residual products for agricultural purposes.

ASHBACK Center welcomes invitations and initiatives to new projects using our expertise and building on our results.

For more information, please visit the ASHBACK website.

Cover photo: Simon Skov, IGN (Department of Geosciences and Natural Resource Management), UCPH

Primary contact
Søren Christensen

Case location

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