3.1.2. Co-digestion of multiple feedstocks
In order to determine how co-digestion of multiple feedstocks influence the environmental and public health impacts compared to single feedstock digestion, LCIA for six co-digestion scenarios in designated small and large-scale biogas plants were analyzed (Table 2). Human toxicity (HT) impact category accounts for toxic accumulation of substances in the human food chain and toxicity effects of chemicals, like carcinogenic substances. From Table 2, it is shown that the range of variations in the impact category values were lower than for single feedstock digestion (Table 1). For example, the HT impact variation approximately halved from 53.84 kg 1.4-DB-eq between straw (min) and whole wheat plant silage (max) for single feedstock digestion (Table 1), to 13.58 (BaseSS) to 8.93 kg 1.4-DB-eq (Base LS-1) (22.51 kg 1.4-DB-eq between
min and max) for co-digestion of multiple feedstocks, which indicates more stable processes with environmental compatible performance.