Insight into understanding the performance of electrochemical pretreatment on improving anaerobic biodegradability of yard waste

Electrochemical pretreatment is considered a promising technique to reduce recalcitrance nature of lignocellulosic biomass. Yet, a comprehensive knowledge on the performance of alkaline reagents in electrochemical pretreatment and the associated environmental impacts are at an early stage. The present study investigated and compared the effect of electrochemical pretreatment by using NaOH reagent (EN) and electrochemical pretreatment by using Ca(OH)2 reagent (EC). The results showed that, both pretreatment techniques elicited the structural breakdown of the biomass, as evidenced by compositional changes, supernatant properties, SEM, FTIR, and XRD analyses. The batch anaerobic digestion results revealed that the improvement in methane production was highest for the EC pretreatment (434 mL/gVS) followed by the EN pretreatment (346 mL/gVS) and the untreated yard waste (245 mL/gVS). The Modified Gompertz model showed the best fit for untreated and pretreated yard waste. The results of economic analysis confirmed the highest net profit of 8922 rupees (US$ 119.29) for EC pretreatment. The findings of life cycle analysis revealed that the net environmental performance considering the inventory used and the limitations of the system boundary was highest for EC pretreatment followed by EN pretreatment and untreated condition.