Impact of thermobaric pre-treatment on the continuous anaerobic digestion of high-fat cattle slaughterhouse waste

Harris, Peter W. and Schmidt, Thomas and McCabe, Bernadette K. (2018) Impact of thermobaric pre-treatment on the continuous anaerobic digestion of high-fat cattle slaughterhouse waste. Biochemical Engineering Journal, 134. pp. 108-113. ISSN 1369-703X


Thermobaric pre-treatment of a combination of dissolved air flotation (DAF) sludge and slaughterhouse wastewater was evaluated for performance over 50 days of continuous anaerobic digestion. Continuous digestion was conducted over three phases represented by varying fat, oils and grease (FOG) concentrations and organic loading. In comparison with earlier biochemical methane potential (BMP) investigations using thermobaric treated substrate by Harris, Schmidt and McCabe (Harris et al., 2017) which yielded an 8.32% increase in specific methane production, pre-treated DAF sludge produced negative impacts on digestion under continuous conditions. Average pH was consistently lower by 0.04, and loss of volatile organics during pre-treatment reduced methane yield by 12.1%. H2S concentration was 56% higher on average with 795 ppm compared with 510 ppm in the controls owing to enhanced protein degradation. Alkalinity was low due to insufficient replacement from the substrate. Fresh substrate containing double the fat content (236 mg/L) and reduced organic loading rate (OLR) caused both control and treatment reactors to fail, highlighting the need for consistent substrate characteristics. Magnesium hydroxide addition effectively recovered both pH and biogas production within digesters rapidly, addressing the underlying complication of insufficient alkalinity contribution by the substrate.

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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Restricted access to published version in accordance with the copyright policy of the publisher.
Faculty / Department / School: Current - Faculty of Health, Engineering and Sciences - School of Agricultural, Computational and Environmental Sciences
Date Deposited: 17 Apr 2018 02:50
Last Modified: 12 Jun 2018 05:30
Uncontrolled Keywords: fat; oil and grease; abattoir; thermal; dissolved air flotation sludge
Fields of Research : 10 Technology > 1001 Agricultural Biotechnology > 100199 Agricultural Biotechnology not elsewhere classified
07 Agricultural and Veterinary Sciences > 0701 Agriculture, Land and Farm Management > 070199 Agriculture, Land and Farm Management not elsewhere classified
Socio-Economic Objective: B Economic Development > 85 Energy > 8505 Renewable Energy > 850599 Renewable Energy not elsewhere classified
Identification Number or DOI: 10.1016/j.bej.2018.03.007

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