The liquid fraction (LF) of digestate has usually been proposed as a substitute for mineral fertilizers because of the presence of high N content, above all in easily available form (ammonia). The LF was reported to contain about 66% of dry matter from the digestate. This study reports the characterization of the organic carbon (OC) contained in the LF of digestates obtained from full scale plants by screwpress solid/liquid separation, to find out about their organic amendment properties. Results indicate that LF contains stable OC because of the concentration during anaerobic digestion of recalcitrant molecules, and that its biological stability, measured by oxygen uptake rate, was similar to that of compost, i.e. 40 ± 15 mg O2 g DM1 20 h1 and 41.1 ± 5.1 mg O2 g DM1 20 h1. 13C NMR indicated that LFs were similar each other and were constituted of recalcitrant Alkyl-C (34.82 ± 5.28% OC) derived from plant and fecal material, Aromatic-C (11.10 ± 2.2% OC) derived from lignin-like structures and O/N-alkyl (44.91 ± 4.87% OC) derived from cellulose/hemicelluloses and protein material. A simple simulation of the real C dosed by using LF as N-fertilizers indicated that amendment properties cannot be ignored. All these results seem to indicate good amendment properties for LFs, contrary to the common opinion.

Measuring the organic amendment properties of the liquid fraction of digestate / F. Tambone, V. Orzi, M. Zilio, F. Adani. - In: WASTE MANAGEMENT. - ISSN 0956-053X. - 88(2019 Apr 01), pp. 21-27. [10.1016/j.wasman.2019.03.024]

Measuring the organic amendment properties of the liquid fraction of digestate

F. Tambone
Primo
;
V. Orzi
Secondo
;
M. Zilio
Penultimo
;
F. Adani
Ultimo
2019

Abstract

The liquid fraction (LF) of digestate has usually been proposed as a substitute for mineral fertilizers because of the presence of high N content, above all in easily available form (ammonia). The LF was reported to contain about 66% of dry matter from the digestate. This study reports the characterization of the organic carbon (OC) contained in the LF of digestates obtained from full scale plants by screwpress solid/liquid separation, to find out about their organic amendment properties. Results indicate that LF contains stable OC because of the concentration during anaerobic digestion of recalcitrant molecules, and that its biological stability, measured by oxygen uptake rate, was similar to that of compost, i.e. 40 ± 15 mg O2 g DM1 20 h1 and 41.1 ± 5.1 mg O2 g DM1 20 h1. 13C NMR indicated that LFs were similar each other and were constituted of recalcitrant Alkyl-C (34.82 ± 5.28% OC) derived from plant and fecal material, Aromatic-C (11.10 ± 2.2% OC) derived from lignin-like structures and O/N-alkyl (44.91 ± 4.87% OC) derived from cellulose/hemicelluloses and protein material. A simple simulation of the real C dosed by using LF as N-fertilizers indicated that amendment properties cannot be ignored. All these results seem to indicate good amendment properties for LFs, contrary to the common opinion.
Biological stability; CPMAS 13C NMR; Digestate; Liquid fraction of digestate; Soil organic carbon
Settore AGR/13 - Chimica Agraria
1-apr-2019
Article (author)
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/657101
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