Comparative analysis of the effect of thermal and wet oxidation pretreatment of anaerobic digestion of potato peel waste including the effect on life cycle analysis

The potato processing industries generate 4 million tons of waste in the United States. As potato production and processing increase, the waste fraction continues to grow, posing a growing challenge for potato companies and society and requiring a sustainable solution. We examined the valorization of potato peel waste (PPW) using anaerobic digestion (AD) after thermal and wet oxidation pretreatments. AD of the pretreated PPW was evaluated by using mesophilic semi-continuous AD. The AD results showed that wet oxidation at a lower concentration of H2O2, specifically 2 % H2O2 at 175 °C for 15 min, resulted in higher conversion of lignocellulosic polymers with 86, 92, and 26 % conversion of cellulose, hemicellulose, and lignin. The higher samplession of polymers resulted in a methane yield of 345 ml/gVS, an increase of 45.6 % compared to the control sample without pretreatment. Results of life cycle assessment showed that the 2 % H2O2 wet oxidation pretreatment reduced the global warming potential by 34.3 % compared to the untreated control (0.000876 vs 0.001334 kg CO2-eq/mL CH4).