Title:
Ecotoxicity of Biogas Plant Digestate
Author(s):
Malk, V., Saario, T., Paakkari, M., Soininen, H., Turmola, L.
Document(s):
Paper
Poster
Abstract:
The use of biogas plant digestate as a fertilizer enables the recycling and return of nutrients and organic matter to the soil and reduces the need for the use of mineral fertilizers. However, spreading digestate to fields can also cause environmental risks. The quality and safety of fertilizer products are regulated by legislation, and the maximum concentration of harmful substances. In addition, ecotoxicity tests provide information on the combined effects and bioavailability of harmful substances. The Aliivibrio fischeri toxicity test was used to test the ecotoxicity of birch-based biochar and biowaste and sewage sludge-based digestates. The Lepidium sativum germination and growth tests were used in the laboratory to assess the effects of digestates on plants. No toxicity was observed in the aqueous suspension of biochar, but the EC50 values in the digestate samples varied between 0.01–58.96 percent dilution. The strongest luminescence inhibition was observed in samples with high conductivity, ammonium and total nitrogen content. When using digestate as a soil conditioner, attention should be paid to the dosage to avoid toxicity effects. Digestates are often composted after the biogas process, and as the compost matures, the toxicity effects may disappear. Digestate-based products still require further research and development work.
Keywords:
recycling, digestate, biofertilisers
Topic:
Biomass Conversion to Biomaterials and Chemicals
Subtopic:
Processes for biomaterials and bio-based chemicals
Event:
33rd European Biomass Conference and Exhibition
Session:
6BV.2.19
Pages:
1114 - 1117
ISBN:
978-88-89407-25-7
Paper DOI:
10.5071/33rdEUBCE2025-6BV.2.19
Price:
FREE
