Contribution of Anaerobic Digestion Coupled with Algal System towards Zero Waste

Abstract

Global environmental protection is of immediate concern and it can only be achieved by avoiding the use of fossil fuels. In addition, waste disposal and management could be made remunerative through the generation of renewable energy so that sustainable development is ensured. India is an agriculture-based country, and paddy residues such as rice straw and rice husk are the largest agricultural wastes in India. Currently, the common practice to dispose paddy residues is through field burning, but this has adverse effects on the air quality and consequently on people’s health. However, utilization of lignocellulosic and non-food agricultural residues such as paddy residue for biogas generation by solid-stated anaerobic digestion (AD) is promising and this can substitute fossil fuels. Paddy residues for biogas production via AD has not been widely adopted because of its complex cell wall structure making it resistant to digestion by microbial attack. In addition, sequestration of carbon dioxide from biogas by algal biomass cultivated in an integrated algal bioreactor could be a promising option for biogas enrichment due to its unmatched advantages. This chapter presents the overview on utilization of non-edible residues for biogas production and its enrichment via algal biomass by means of circular bioeconomy.