Environmental consequences of the treatment of corn contaminated by aflatoxin B1 with co-digestion and co-composting in a life cycle perspective

Global environmental performances of anaerobic co-digestion and co-composting of aflatoxin B1 (AFB1) contaminated corn were investigated by a life cycle assessment approach. Anaerobic co-digestion of pig slurry and corn with 25 μgkg-1 ww AFB1 concentration resulted able to generate 627 NLkgVS-1 of biogas with a reduction of the AFB1 concentration in the digestate of 44%. At AFB1 concentration of 100 μg kg-1 ww, the process resulted strongly inhibited with a biogas generation of 122 NLkgVS-1 and AFB1 concentration reduction in the digestate of 25%. Co-composting of 100 μg kg-1 dw AFB1 contaminated corn with other substrates as organic fraction of municipal waste, pig slurry, and other lignin-cellulosic residues showed a removal efficiency of AFB1 ranging from about 80 up to 95% depending on the different mixtures adopted. Environmental consequences associated to the removal of 1 mg of AFB1 in different scenarios investigated, including also the use on land of the digestate and of the compost, indicated that global warming was affected equally by co-digestion and co-composting, about 95 kgCO2eq. Co-digestion showed also the possibility of achieving avoided emissions of about − 0.007 kgNMVOCeq, − 2.5E-3 kgPeq, and − 30CTUe. Benefits concerning resource depletion resulted higher for co-composting due to the high amount of mineral fertilizer replaced. Contribution of AFB1 in the determination of human health (DALY) resulted lower than about 4% for co-digestion and practically negligible for co-composting.