Journal of Environmental Biology

Effect of spent mushroom substrate and waste paper briquette on methane production from anaerobic digestion

Sethumadhavan P. and? Arul Mozhi Selvan V.*

Department of Mechanical Engineering, National Institute of Technology, Tiruchirappalli ? 620 015, India

*Corresponding Author E-mail: arulmozhi@nitt.edu

Key words

Briquetting process

Co-digestion

Methane production

Spent mushroom substrate

Waste paper

Publication Data

Paper received : 08.09.2016

Revised received : 13.04.2017

Re-revised received : 12.09.2017

Accepted : 29.09.2017

Abstract

Aim: The objective of the study was to assess the methane yield of briquettes prepared from spent mushroom substrate and waste paper mixed in equal proportion.

Methodology: Spent mushroom substrate after cultivation of Pleurotus florida on rice straw and waste paper was milled to less than 5 mm size. They were briquetted in equal mass proportion in a screw type machine. Briquette and individual substrates were assessed for their methane potential under anaerobic conditions in 125 ml bottles incubated at 37^?C for 60 days. Data was statistically analyzed using analysis of variance.? Dunnett's post hoc test was used to assess the significance (P < 0.05).

Results: When waste paper was co-digested with spent mushroom substrate as powder, methane yield of 168 ml CH₄ g^-1 VS was observed. When spent mushroom substrate - waste paper as briquette was used, highest methane yield of 250 ml CH₄ g^-1 VS was observed. Size reduction in briquetting process made the cellulose and other components of plant cell walls more accessible to the microorganisms. SEM and FT-IR studies confirmed the impact of briquetting as a pretreatment step. Volatile fatty acid (VFA) to alkalinity ratio was observed as 0.26 at the end of digestion of briquettes, which confirmed the process stability.? ?      

Interpretation: Methane yield from anaerobic digestion process was found to be enhanced by briquetting of spent mushroom substrate and waste paper

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