This study utilized a renewable energy source, agricultural waste, in anaerobic digestion (AD) at appropriate conditions to obtain biogas and biomethane as an energy carrier. Maize stalks underwent ultrasound (US) pre-treatment for better accessibility for microorganisms, as lignocelluloses have a stable structure, insoluble in water and resist both mechanical and enzymatic attack. The digestate after an anaerobic digestion process was used for cultivation of algae after adsorption with activated carbon for clarification. Photosynthetic microalgae have industrial and economic perspectives, so their low-cost cultivation has a great potential for many applications. The results showed the impact of US pre-treatment of maize stalks as a sole substrate and codigested with algal biomass. The total yields were 1116 cm 3 /L, 1350.5 cm 3 /L and 1293.25 cm 3 /L for the untreated, ultrasonically pre-treated and microwaved maize stalks. The possibility of accumulating algal biomass using anaerobic digestate as a medium was demonstrated. US pretreatment (400 W) showed high efficiency with respect to the extractives obtained per unit of energy input. Addition of 4 g/L of microalgal biomass as a co-substrate led to an increase in the biogas yield compared to native stalks. A small closed circle system, starting from anaerobic digestion of lignocellulosic substrates followed by microalgae cultivation in the digestate and subsequent return of microalgal biomass back in the bioreactor as a co-substrate was realized, encouraging circular economy. The suggested scheme is a simple and low-cost technology, as the substrate used is freely available and renewable, and algae proved to grow in a waste effluent as medium.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.