Sustainability, Vol. 11, Pages 2819: A New Adjustment Strategy to Relieve Inhibition during Anaerobic Codigestion of Food Waste and Cow Manure (Sustainability)

A new adjustment strategy (controlling temperature, pH, inoculum dose, and liquid supernatant replacement in different digestion stages) was used to relieve volatile fatty acid (VFA) inhibition during anaerobic codigestion of FW and CM. Three digestion stages and groups were designed: initial stage (on days 1–5 the temperature was 45 °C), the second stage (on days 6–10 the temperature was 35 °C and inoculum was supplied), and the third stage (on days 11–50 the temperature was 35 °C and liquid supernatant was replaced). Groups A, B, and C had initial inoculums of 0, 100, and 200 mL and were supplied inoculums of 200, 100, and 0 mL, respectively. Results showed that in the initial stage, Group A had the highest VFA concentration (876.54 mg/L) and the lowest pH (3.6). In the second and third stages, pH (~5.5 and ~7.5) and VFA concentrations showed no significant differences in all groups. The highest VFA concentration (3248 mg/L), volatile solid (VS) removal rate (49.72%), and total methane production (TMP) (10,959 mL), the shortest λ (19.92 d), and the T90% (39.25 d) were obtained in Group B (pH 8.5). Group C had the highest chemical oxygen demand (COD) removal rate (96.91%). Group A obtained the maximal TBP of 25,626 mL (pH 8.0).