Liquid digestate features as fertilizer: carbon fractions, phytotoxicity and microbiological analysis
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Keywords

Anaerobic digestates, humic acids, germination index, organic fertilization, nitrogen fractions, pathogens.

Abstract

The circular economy promotes the use of renewable fuels as an alternative to natural gas. Anaerobic digestion for waste management produces methane, carbon dioxide and a residue-the digestate- which must be recovered. This residue can be separated into two parts, namely the liquid and solid fractions, the former characterized by its large volume, presence of nutrients in mineral forms, and highly variable composition. Here we studied the fertilizing capacity of the liquid fractions obtained from the waste derived from artichoke canning (LF-Ar), orange juice manufacturing (LF-Or) and pig slurry (LF-Sl). To this end, we examined the physical-chemical parameters, carbon fractions, phytotoxicity and presence of pathogens in these fractions. The liquid fraction derived from fruit and vegetables had a low nutrient content compared to that of slurry ( ̴1.0 kg total-N m-3 vs. 5.6 kg total-N m-3 respectively). The NH4+-N content of the fractions ranged between 70-93% of total N. Given the permissible dose in non-vulnerable areas, LF-Sl, LF-Ar and LF-Or would provide 0.9-1.0 t of organic matter ha-1 and 134, 128 and 98 kg of C ha-1 from the total humic extract, respectively. The proportion of humic acids in the total humic extract was 59%, 51% and 34% respectively. The slurry digestate showed phytotoxicity probably due to high salinity, so it should be diluted based on the needs of the crop. On the basis of our findings, the characterized liquid fractions could be recovered in agricultural soils in line to circular economy principles.

 

https://doi.org/10.3232/SJSS.2020.V10.N3.08
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References

Akhiar A, Battimelli A, Torrijos M, Carrere H. 2017. Comprehensive characterization of the liquid fraction of digestates from full-scale anaerobic co-digestion. Waste Manage. 59:118-128. DOI: 10.1016/j.wasman.2016.11.005.

Alburquerque JA, De la Fuente C, Ferrer-Costa A, Carrasco L, Cegarra JH, Abad M, Bernal MP. 2012. Assessement of the fertiliser potential of digestates from farm and agroindustrial residues. Biomass Bioenerg. 40:181-189. DOI: 10.1016/j.biombioe.2012.02.018.

AOAC. 2010. Association Official Analytical Chemists. Official Methods of Analysis of Association of Official Analytical Chemists. 18th Edition. Washington, DC.

Council Directive 91/676/EEC of 12 December concerning the protection of waters against pollution caused by nitrates from agricultural sources. Off. J. Eur. Communities: L375. Brussels, Belgium.

Coelho JJ, Prieto ML, Dowing S, Hennessy A, Casey I, Wookcock T, Kennedy N. 2018. Physical-chemical traits, phytotoxicity and pathogen detection in liquid anaerobic digestates. Waste Manage. 78:8-15. DOI: 10.1016/j.wasman.2018.05.017.

Dabin B. 1971. Étuded’uneméthode d'extraction de la matière humique du sol. Science du Sol 1:47-63.

Huan L, Youkang L, Chenchen L. 2017. Evolution of humic substances during anaerobic sludge digestion. Environ Eng Manag J. 16(7)1577-1584. DOI: 10.30638/eemj.2017.171.

ISO 7251:2005 Microbiology of food and animal feeding stuffs -- Horizontal method for the detection and enumeration of presumptive Escherichia coli -- Most probable number technique.

Jiang Y, Dennehy C, Lawlor PG, Huc Z, Yang Q, McCarthy G, Pin Tan S, Zhan, Gardiner GE. 2018. Inactivation of Salmonella during dry co-digestion of food waste and pig manure. Waste Manag. 82:231-240. DOI: 10.1016/j.wasman.2018.10.037.

Luo Y, Liang J, Zeng G, Chen M, Mo D, Li G, Zhang D. 2018. Seed germination test for toxicity evaluation of compost: its roles, problems and prospects. Waste Manage. 71:109-114. DOI: 10.1016/j.wasman.2017.09.023.

MAPA. 1994. Métodos oficiales de análisis. Tomo III: Métodos oficiales de análisis de suelos y aguas para el riego. Madrid: Servicio de Publicaciones del Ministerio de Agricultura, Pesca y Alimentación. p. 205-285.

Möller K, Müller T. 2012. Effects of anaerobic digestion on digestate nutrient and availability and crop growth: a review. Eng Life Sci. 12:242-257. DOI: 10.1002/elsc.201100085.

Monlau F, Sambusiti C, Ficara E, Aboulkas A, Barakat A, Carrère H. 2015. New opportunities for agricultural digestate valorization: current situation and perspectives. Energ Environ Sci. 8:2600-2621. DOI: 10.1039/C5EE01633A.

Náthia-Neves G, Berni, M, Dragone, G, Mussatto SI, Forster-Carneiro T. 2018. Anaerobic digestion process: technological aspects and recent developments. Int J Environ Sci Te. 15(9):2033-2046. DOI: 10.10007/s13762-018-1682-2.

Nkoa R. 2014. Agricultural benefits and environmental risks of soil fertilization with anaerobic digestates: a review. Agronomy for Sustainable Development 34(2):473-492. DOI: 10.1007/s13593-013-0196-z.

Pandey PK, Soupir ML. 2011. Escherichia coli inactivation kinetics in anaerobic digestion of dairy manure under moderate mesophilic and thermophilic temperatures. AMB Express 1:18. DOI: 10.1186/2191-0855-1-18.

Pescod MB, Alka U. 1985. Guidelines wasterwater reuse in agriculture. In: Pescod MB, Arar A, editors. Treatment and use of sewage effluent for irrigation. Proceedings of the FAO Regional Seminar on the treatment and use of sewage effluent for irrigation; 1985 Oct 7-9; Nicosia, Cyprus.

Rajagopal R, Ghosh D, Ashraf S, Goyette B, Zhao X. 2019. Effects of low-temperature dry anaerobic digestion on methane production and reduction in dairy cow manure. Int J Environ Sci Te. 16:4803-4810. DOI: 10.10007/s13762-019-02291-w.

Salminen E, Rintala J, Härkönen J, Kuiyunen, M, Högmander H, Oikari A. 2001. Anaerobically digested poultry slaughterhouse waster as fertiliser in agricultura. Biores Technol. 78:81-88.

SAS Institute Inc. 1999-2001. SAS/TAT. Software V 8.2 Cary. NC.

Seruga P, Kzywonos M, Paluszak Z, Urbanowska A, Pawlak-kruczek H, Niedzwiecki L, Pinkowsa H. 2020. Pathogen reduction potential in anaerobic digestion of organic fraction of municipal solid waste and food waste. Molecules 25:275. DOI:10.3390/molecules25020275.

Tambone F, Orzi V, D’Imporzano G, Adani F. 2017. Solid and liquid fractionation of digestate: mass balance, chemical characterization, and agronomic and environmental value. Bioresource Technol. 243:1251-1256. DOI. 10.1016/j.biortech.2017.07.

UNE-EN ISO 6579-1:2017. Microbiología de la cadena alimentaria. Método horizontal para la detección, enumeración y serotipado de Salmonella. Parte 1: Detección de Salmonella spp. (ISO 6579-1:2017).

Walkley A, Black IA. 1934. An examination of the Degtjareff method for determining soil organic carbon matter and a proposed modification of the chromic acid titration method. Soil Sci. 37:29-38.

Webb J, Sørensen P, Velthof G, Amon B, Pinto M, Rodhe L, Reid J. 2013. An assessment of the variation of manure nitrogen efficiency throughout Europe and an appraisal of means to increase manure-N efficiency. Adv Agron. 119:371-442. DOI: 10.1016/B978-0-12-407247-3.00007-X.

WHO. 2006. Wastewater use in agriculture. Guidelines for the safe use of wastewater, excreta and greywater, Vol. 2. Geneva: WHO.

Zucconi F, Monaco A, Forte M, De Bertoldi M. 1985. Phytotoxins during the stabilization of organic matter. In: Gasser JKR, editor. Composting of agricultural and other wastes. Elsevier. p. 73-85.