2020
1st International Conference of Soil and Agriculture:
TOWARDS SOIL SUSTAINABILITY
11–13 June 2024 • Lublin–Nałęczów, Poland
https://doi.org/10.24326/ICSA1.PP.04
Published online: 4 October 2024
Effect of digestate after two-stage, H2, and CH4 yielding anaerobic digestion on wheat germination
Aleksandra Chojnacka1*, Anna Detman-Ignatowska2, Anna Sikora2, Martyna Paul2,
Jerzy Jonczak3
1 Department of Biochemistry and Microbiology, Warsaw University of Life Sciences, Nowoursynowska 159, 02-776 Warsaw, Poland
2 Laboratory of White Biotechnology, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland
3 Department of Soil Science, Warsaw University of Life Sciences, Nowoursynowska 159, 02-776 Warsaw, Poland
* Corresponding author:
Abstract
Organic fertilizers can be derived from many different wastes and by-products including a digestate – specific effluent simultaneously produced with biogas during the anaerobic digestion (AD) process. Biogas production is possible thanks to the interactions of many groups of microorganisms. In conventional applications (biogas plants – one-stage AD), all these microorganisms are kept together in a single reactor system. However, processing organic compounds in two separate reactors can enhance AD process. In this case, besides the increased stability, two-stage AD provides also the combined production of H2 and CH4. In general digestate fertilization improves germination, plant growth, crop yield as well as plant immunity to biotic and abiotic stress. Nevertheless, improperly selected doses can also lead to digestate toxicity. The objective of this study was to investigate the possible phytotoxic effects of digestate obtained as a result of the two-stage AD process in comparison to digestate obtained as a result of traditional one-stage AD. The master hypothesis in this experiment was that digestate obtained as a result of two-stage AD has a positive or neutral effect on plant germination. Digestate was produced as follows: In the first stage, substrate was fermented in PBR reactor to hydrogen-rich biogas and organic acids. In the second stage, non-gaseous products were methanized in UASB reactor to biogas and final digestate. In one-stage system, all stages were conducted in UASB reactor. Then, the final digestates were used for the germination test. It was carried out with wheat seeds (Triticum aestivum L.) using five different concentrations of digestates (100%, 75%, 50%, 25%, and 10%). The experiment was done in Petri dishes in 10 replications. Water was used as a control. Germination (any visible sprouting) was measured after 7 days (25°C, growth chamber). In the results, both one-stage and two-stage digestates had phytotoxicity in concentrations of 100%, 75%, and 50% and did not induce a phytotoxic effect at the lowest dilution. Digestate obtained as a result of two-stage AD showed statistically significantly higher toxicity than digestate obtained as a result of one-stage AD. In summary, the final digestate obtained as a result of the two-stage AD process can be used as a soil amendment, but this requires further research. Special attention should be paid to issues related to phytotoxicity, particularly in the early stages of plant growth.
Keywords: digestate, organic fertilizers, two-stage H2-CH4-yielding system, germination
How to cite
Chojnacka A., Detman-Ignatowska A., Sikora A., Paul M., Jonczak J., 2024. Effect of digestate after two-stage, H2, and CH4 yielding anaerobic digestion on wheat germination. 1st International Conference of Soil and Agriculture: Towards Soil Sustainability. https://doi.org/10.24326/ICSA1.PP.04
