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Aili Hamzah AF, Hamzah MH, Mazlan NI, Che Man H, Jamali NS, Siajam SI, Show PL. Optimization of subcritical water pre-treatment for biogas enhancement on co-digestion of pineapple waste and cow dung using the response surface methodology. WASTE MANAGEMENT (NEW YORK, N.Y.) 2022; 150:98-109. [PMID: 35810730 DOI: 10.1016/j.wasman.2022.06.042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2022] [Revised: 06/28/2022] [Accepted: 06/30/2022] [Indexed: 06/15/2023]
Abstract
The optimal pre-treatment method and conditions depend on the types of lignocellulose present due to the complexity and the variability of biomass chemical structures. This study optimized subcritical water pre-treatment to ensure maximum methane production from pineapple waste prior to anaerobic co-digestion with cow dung using the response surface methodology. A central composite design was achieved with three different factors and one response. A total of 20 pre-treatment runs were performed at different temperatures, reaction times and water to solid ratios suggesting optimum values for subcritical water pre-treatment at 128.52℃ for 5 min with 5.67 to 1 water to solid ratio. Under these conditions, methane yield increased from 59.09 to 85.05 mL CH4/g VS with an increase of 23% biogas yield and 44% methane yield from the untreated. All pre-treatments above 200℃ showed reductions in biogas yield. Compositional analysis showed slight reduction of lignin and increase in α-cellulose content after the pre-treatment. Analysis using Fourier transform infrared spectroscopy and thermogravimetric analysis verified the presence of cellulosic material in pre-treated pineapple waste. Most of the hemicellulose was solubilized in the liquid samples after SCW pre-treatment. The crystallinity index of pineapple waste was reduced from 57.58% (untreated) to 54.29% (pre-treated). Scanning electron microscopy confirmed the structural modification of pre-treated pineapple waste for better microbial attack. Subcritical water pre-treatment is feasible as a promising method to enhance the anaerobic co-digestion process. Further study should be conducted to assess the scale-up of the process from pre-treatment to anaerobic digestion at the pilot plant level.
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Affiliation(s)
- A F Aili Hamzah
- Department of Biological and Agricultural Engineering, Faculty of Engineering, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia
| | - M H Hamzah
- Department of Biological and Agricultural Engineering, Faculty of Engineering, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia; Smart Farming Technology Research Centre, Faculty of Engineering, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia.
| | - N I Mazlan
- Department of Biological and Agricultural Engineering, Faculty of Engineering, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia
| | - H Che Man
- Department of Biological and Agricultural Engineering, Faculty of Engineering, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia; Smart Farming Technology Research Centre, Faculty of Engineering, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia
| | - N S Jamali
- Department of Chemical and Environmental Engineering, Faculty of Engineering, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia
| | - S I Siajam
- Department of Chemical and Environmental Engineering, Faculty of Engineering, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia
| | - P L Show
- Department of Chemical and Environmental Engineering, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, 43500 Semenyih, Selangor, Malaysia
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