LAUSR

This study examined the influence of the application of brewery spent grain (BSG) on biogas production efficiency as well as its kinetics in the co-digestion of acid cheese whey (ACW) and sewage sludge (SS). The experiment was conducted in semi-flow anaerobic reactors under mesophilic conditions (35 °C) with different hydraulic retention times (HRT) of 16.7 d, 18 d and 20 d. The results indicate that the addition of BSG significantly enhanced the biogas yields, ensuring good process stability. The highest value of 0.54 m3 kg-1 VSadded was obtained at HRT of 16.7 d, while for ACW and SS it was only 0.50 m3 kg-1 VSadded at HRT 18 d. However, the decrease in the rate constant k occurred (0.07 h-1) as compared to the two-component system (0.096 h-1). The highest energy profit of 160% was enhanced for the three-substrate co-digestion, indicating it as a cost-effective solution.