Rights statement: This is the author’s version of a work that was accepted for publication in Journal of Environmental Chemical Engineering. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of Environmental Chemical Engineering, 7, 3, 2019 DOI: 10.1016/j.jece.2019.103138
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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
}
TY - JOUR
T1 - The effect of acidogenic and methanogenic conditions on the availability and stability of carbon, nitrogen and phosphorus in a digestate
AU - Fagbohungbe, M.O.
AU - Onyeri, C.
AU - Adewale, C.
AU - Semple, K.T.
N1 - This is the author’s version of a work that was accepted for publication in Journal of Environmental Chemical Engineering. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of Environmental Chemical Engineering, 7, 3, 2019 DOI: 10.1016/j.jece.2019.103138
PY - 2019/6/1
Y1 - 2019/6/1
N2 - Acidification and drying of digestate are important post-treatment for, respectively, improving nutrient availability and hygiene. These approaches are expected to reduce digestate soil application mass and increase its value. This study compared eleven organic feedstocks under acidogenic and methanogenic conditions as a sustainable approach to improving phosphorus availablity, organic carbon and stabilising ammoniacal nitrogen of the resulting digestate under thermal drying. The result showed increases in phosphate concentration under acidogenic conditions and reduction in ammonium nitrogen after drying at 100 °C. The highest phosphate values of 3.2 ± 0.38 g/kg were achieved using whey permeate substrate while the effect of drying on ammonium nitrogen concentration was lowest for acidogenic bird seed fermentation with an ammonium loss of 59.7%. Both results were facilitated by high total volatile fatty acid concentration produced from available organic carbon which reached a maximum value of 5.71 ± 0.53 g/L, respectively. Increases in phosphate and ammonium nitrogen stability under acidogenic conditions was a consequence of lower pH, a condition synonymous with acidogenic only fermentation. The accumulated volatile fatty acid contributed to higher carbon to nitrogen ratio under acidogenic fermentation. Higher labile carbon to nitrogen ratio can trigger immobilization of ammonium nitrogen in the soil and this presents a case for subsequent experimentation into acidogenic digestate application in soil.
AB - Acidification and drying of digestate are important post-treatment for, respectively, improving nutrient availability and hygiene. These approaches are expected to reduce digestate soil application mass and increase its value. This study compared eleven organic feedstocks under acidogenic and methanogenic conditions as a sustainable approach to improving phosphorus availablity, organic carbon and stabilising ammoniacal nitrogen of the resulting digestate under thermal drying. The result showed increases in phosphate concentration under acidogenic conditions and reduction in ammonium nitrogen after drying at 100 °C. The highest phosphate values of 3.2 ± 0.38 g/kg were achieved using whey permeate substrate while the effect of drying on ammonium nitrogen concentration was lowest for acidogenic bird seed fermentation with an ammonium loss of 59.7%. Both results were facilitated by high total volatile fatty acid concentration produced from available organic carbon which reached a maximum value of 5.71 ± 0.53 g/L, respectively. Increases in phosphate and ammonium nitrogen stability under acidogenic conditions was a consequence of lower pH, a condition synonymous with acidogenic only fermentation. The accumulated volatile fatty acid contributed to higher carbon to nitrogen ratio under acidogenic fermentation. Higher labile carbon to nitrogen ratio can trigger immobilization of ammonium nitrogen in the soil and this presents a case for subsequent experimentation into acidogenic digestate application in soil.
KW - Acidogenesis
KW - Ammonium nitrogen
KW - Anaerobic digestion
KW - Digestate
KW - Methanogenesis
KW - Organic carbon
KW - Phosphorus
KW - Drying
KW - Fermentation
KW - Nitrogen
KW - Soils
KW - Volatile fatty acids
KW - Acidogenic fermentation
KW - Carbon-to-nitrogen ratio
KW - Phosphate concentration
KW - Total volatile fatty acids
U2 - 10.1016/j.jece.2019.103138
DO - 10.1016/j.jece.2019.103138
M3 - Journal article
VL - 7
JO - Journal of Environmental Chemical Engineering
JF - Journal of Environmental Chemical Engineering
SN - 2213-3437
IS - 3
M1 - 103138
ER -