Lactic acid from mixed food wastes at a commercial biogas facility: Effect of feedstock and process conditions

Buhlmann, Christopher H. and Mickan, Bede S. and Tait, Stephan and Renton, Michael and Bahri, Parisa A. (2021) Lactic acid from mixed food wastes at a commercial biogas facility: Effect of feedstock and process conditions. Journal of Cleaner Production, 284:125243. pp. 1-9. ISSN 0959-6526


Abstract

Anaerobic digestion facilities can become biorefineries to produce higher-value products together with biogas energy and nutrient-rich digestate. To inform future biorefinery concepts with lactic acid recovery, the current study monitored organic acids in a pre-fermentation stage at a commercial anaerobic digestion facility. The study assessed lactic acid production performance and the impact of mixed food waste feedstocks and process conditions. Feed rate and feedstock composition varied weekly with waste availability. Normal operating conditions of the pre-fermentation stage included warm ambient conditions (24–35 °C), low pH (3.45 ± 0.03), a short hydraulic retention time (1–3.5 days) and stable organic loading rate (12 ± 2 kgVS.m−3.day−1). These conditions favoured lactic acid, being dominant at an encouraging average concentration of 21.70 g L−1, notably without any process optimisation or control. Lactobacillus constituted the majority of the microbial community in the pre-fermentation stage (98.1 %–99.1 % relative abundance) with an unknown Lactobacillus species and L. reuteri being the major species present. Grain processing waste and milk paste were positive influencers of LA concentration. The monitoring results, together with a simple economic evaluation, indicated that lactic acid recovery from a commercial food waste anaerobic digestion facility had baseline feasibility. In addition, there would be significant opportunities to increase economic performance by targeted process control and optimisation.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Faculty/School / Institute/Centre: Current - Institute for Advanced Engineering and Space Sciences - Centre for Agricultural Engineering (1 Aug 2018 -)
Faculty/School / Institute/Centre: Current - Institute for Advanced Engineering and Space Sciences - Centre for Agricultural Engineering (1 Aug 2018 -)
Date Deposited: 17 Feb 2021 22:36
Last Modified: 23 Jun 2021 07:48
Uncontrolled Keywords: Lactic acid; Biorefinery; Biogas; Food waste; Fermentation
Fields of Research (2008): 09 Engineering > 0907 Environmental Engineering > 090703 Environmental Technologies
Fields of Research (2020): 40 ENGINEERING > 4011 Environmental engineering > 401102 Environmentally sustainable engineering
40 ENGINEERING > 4011 Environmental engineering > 401106 Waste management, reduction, reuse and recycling
Socio-Economic Objectives (2008): D Environment > 96 Environment > 9609 Land and Water Management > 960912 Urban and Industrial Water Management
D Environment > 96 Environment > 9611 Physical and Chemical Conditions of Water > 961101 Physical and Chemical Conditions of Water for Urban and Industrial Use
Socio-Economic Objectives (2020): 18 ENVIRONMENTAL MANAGEMENT > 1899 Other environmental management > 189999 Other environmental management not elsewhere classified
Identification Number or DOI: https://doi.org/10.1016/j.jclepro.2020.125243
URI: http://eprints.usq.edu.au/id/eprint/41383

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