Title: Influence of total solid concentration for methane production of cocoa husk co-digested with digested swine manure

Authors: Darwin; Jay J. Cheng; Jorge Gontupil; Zhimin Liu

Addresses: Department of Agricultural Engineering, Syiah Kuala University, Banda Aceh 23111, Indonesia ' Department of Biological and Agricultural Engineering, North Carolina State University, Raleigh, NC 27695, USA ' Department of Biological and Agricultural Engineering, North Carolina State University, Raleigh, NC 27695, USA ' Department of Biological and Agricultural Engineering, North Carolina State University, Raleigh, NC 27695, USA

Abstract: This study aimed to investigate potential methane production through anaerobic co-digestion of cocoa husk and digested swine manure with different total solids concentration. The research was conducted in batch experiments. Anaerobic co-digestion processes were carried out at different level of solids concentration including 2%, 3%, and 4% total solids concentration. The anaerobic co-digestion process was run at 500 mL batch reactors under constant temperature (35°C) and agitation (270 rpm). Based on the results, volatile solids reduction of control and cocoa husk co-digested with digested swine manure (CH) reactors were 22.69 ± 0.16% and 40.51 ± 0.69%, respectively. In terms of total solids reduction, control and CH reactors had 19 ± 0.34% and 22.7 ± 2.23%, respectively. This condition lead CH reactors run at 4% TS to produce more methane within 30 days of digestion, where in terms of total methane production they generated about 50.68% higher compared with that produced under 2% TS, and around 22.33% higher compared with that produced in 3% TS. In terms of methane yield, CH reactors achieved the highest methane yield at 2% TS which was 60.25 ± 1.60 mL CH₄/g VS added, and the lowest methane yield was obtained at CH reactors operated in 4% TS which was around 38.99 ± 1.57 mL CH₄/g VS added.

Keywords: anaerobic co-digestion; cocoa husk; total solids concentration; methane production; swine manure; anaerobic digestion.

DOI: 10.1504/IJEWM.2016.076432

International Journal of Environment and Waste Management, 2016 Vol.17 No.1, pp.71 - 90

Received: 21 Dec 2014
Accepted: 08 Jan 2016
Published online: 06 May 2016 *

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