Abstract
The current study analyzed and optimized the concentration of NaOH for alkaline pretreatment of kitchen refuse for biogas production. Also, the benefits of microwave assistance in enhanced biogasification of kitchen refuse were evaluated. The TS, VS and structural changes were compared using standard experimental techniques. Molecular dynamics was investigated for the molecular level changes leading to higher biogasification in NaOHmicrowave combined pretreatment. The methane and biogas yields were calculated to validate the benefits of microwave assistance in efficient biogasification. The NaOH-microwave combined pretreatment showed higher VS production. Microwave treatment degraded and removed lignin more efficiently. Molecular dynamics studies revealed the induction of configurational instability in lignin and cellulose molecules with variable temperatures. The methane and biogas production increased with 6% NaOH concentration, and decreased at higher NaOH concentration till 10%. Microwave assistance declined the required NaOH concentration further to 4%. Thus, as compared to 6% NaOH concentration required for an efficient pretreatment, the kitchen refuse was efficiently pretreated with 4% NaOH concentration when combined with a 30 min duration microwaving. The experimental and computational data provided a detailed analysis proposing an optimized, novel and promising method to pretreat kitchen refuse for efficient and enhanced biogas production.
Highlights
The demand for environmental safety and chemosphere protection because of harmful effects by the use of non-renewable sources of energy has risen in leaps and bounds in recent days
It was reported that 6 hours chemical pretreatment of 62.0 mEq/L was found to be optimized with 11.5% increase in SCOD and 150 methane yield (mL) CH4/g volatile solids (VS) (172% higher) as compared to an untreated substrate[14,15]
In order to assess the changes in total biomass content of kitchen refuse (KR) after NaOH, and NaOH followed by microwave pretreatment
Summary
The demand for environmental safety and chemosphere protection because of harmful effects by the use of non-renewable sources of energy has risen in leaps and bounds in recent days. One most important benefit of biogas production is the utilization of organic wastes being produced by anthropogenic activities. Www.nature.com/scientificreports produced by day to day life food consumption and cooking wastes[9,10]. They contain a variety of organic sources such as polymers, carbohydrates, proteins and many others. These sources are the inspiration for utilizing them for biogas production via anaerobic digestion. The anaerobic digestion includes basic processes like hydrolysis, acidogenesis, acetogenesis, and methanogenesis Among these different steps, the most critical and rate-limiting one is the hydrolysis[12]. Alkaline (NaOH) pretreatment has shown better results in the solubilization of complex organic matter[18]
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