Exploring lignocellulosic biomass for bio-methane potential by anaerobic digestion and its economic feasibility

Abstract

Anaerobic digestion is a process to convert organic biomass into bio-methane. Plenty of produced waste in Pakistan is enough to compensate energy thirst of country and have potential to replace costly fossil fuels. The lignocellulosic biomass such as wheat straw, almond shell, sugarcane bagasse, maize straw and corn cob were subjected to bio-methane potential assay after proximate, ultimate and chemical analysis. These chemical fractions provide better understanding about theoretically predicating bio-methane potentials such as neutral detergent fibre, acid detergent fibre, acid detergent lignin, cellulose, hemicellulose, carbohydrates, proteins and elemental analysis. Experimental bio-methane potentials were found, 267.74 (wheat straw), 255.32 (almond shell), 222.23 (corn cob), 247.60 (sugar cane bagasse) and 293.12 ml/g (maize straw) volatile solids and was much less than predicted methane potential. The energy content on dry basis and methane potential has been assessed to find economic feasibility of biomass. The biodegradability and methane potential inversely related to the lignin content of biomass. Bioenergy production from biomass is economically favourable. The volatile fatty acids were produced in the percentage of 53–58% acetic acid, 30–35% butyric acids and 6–13% propionic acid and showed same metabolic pathway and types of bacteria involved in digestion.