Use of trace elements addition for anaerobic digestion of brewer's spent grains

• Published in: Journal of environmental management 2018-10, Vol.223, p.101-107
• Main Authors: Bougrier, Claire, Dognin, Delphine, Laroche, Cécile, Cacho Rivero, Jesús Andrés
• Format: Article
• Language: English
• Subjects: Anaerobic digestion; Brewery spent grains; Methane production; Semi-continuous reactors; Trace elements
• ISSN: 0301-4797; 1095-8630
• DOI: 10.1016/j.jenvman.2018.06.014

The brewery industry generates a large amount of by-products and notably Brewer's Spent Grain (BSG) which seems an attractive substrate for anaerobic digestion. Nevertheless, previous studies have shown risk of inhibition in the mono-digestion of lignocellulosic substrates. One way to stabilize the reaction is the addition of trace elements. The current study evaluates and compares the stability of BSG anaerobic mono-digestion with and without addition of trace elements for several BSG samples. Based on the average composition of the BSG, two levels of nutrients addition were defined and tested on 4 different BSG samples. Control reactors, without addition of nutrients, showed signs of instability after 3 months or less of operation, with a decrease in performance and even collapse. On the contrary, supplemented reactors led to a COD removal rate of 60–65% and a methane production ranged between 220 and 350 NL CH4.kg−1 VSadded, depending on the sample. According to these results, guidelines for nutrients solution addition adapted to BSG degradation were defined. •Brewery spent grains monodigestion has been tested with trace elements addition.•Maintaining stable performance was not possible without trace elements additions.•Trace elements additions stabilized anaerobic digestion for the 4 samples tested.•Recommendations on trace elements addition have been defined.