Bioconversion of agro-industrial wastes: Combined compost and vermicompost processes using Eisenia fetida for stabilization of poultry litter

MASIN, CAROLINA; FERNANDEZ, E.; LESCANO, MAIA; ZALAZAR, C.S.

International Journal of Recycling of Organic Waste in Agriculture

Islamic Azad University-Isfahan Branch- Iran

Año: 2020

2195-3228

PurposeA combined treatment of composting and vermicomposting of poultry litter (PL), rice hulls(RH) and/or eucalyptus sawdust (ES) was carried out in order to obtain a high-qualityorganic fertilizer and avoid the environmental problems associated with the use of rawpoultry manure and fresh agricultural waste materials.MethodsThree composting mixtures were made at volume proportions: 1:3 RH/PL (M1); 1:2 ES/PL(M2) and 0.5:1:2 RH/ES/PL (M3). Composting (120 days) followed by vermicomposting(90 days) using earthworms (Eisenia fetida) were conducted during the autumn-winterseason, outdoors and sheltered. Moisture content was kept at 60-70%. Physicochemical(pH, electrical conductivity, lignin, total carbon and nitrogen, organic matter, ammoniumand specific cations), total microbial activity (fluorescein diacetate hydrolysis) andmicrobiological parameters were recorded throughout both processes. Phytotoxicity testswere lastly performed by means of Lactuca sativa, L. seed germination, to compare thequality of the organic fertilizers obtained.Results2A sequential compost-vermicompost process enhanced the properties of the final products.Particularly, electrical conductivity was markedly lower in all vermicomposts (1.81-2.28mS cm-1) and within the values recommended for the growth of sensitive plants; microbialactivity reached 187.1-203.8 μg FDA gsoil-1 h-1. Germination Index values invermicomposts were greater than 60%, indicating the high quality of the products obtained,being the mixture 0.5RH:1ES:2PL, the one which showed better quality and highermaturation degree.ConclusionThe system that combines both processes (composting+vermicomposting) was effective toproduce a stabilized organic fertilizer from poultry litter with other waste organic materials.