Pretreating anaerobic fermentation liquid with calcium addition to improve short chain fatty acids extraction via in situ synthesis of layered double hydroxides

Abstract

In situ synthesis of layered double hydroxides (LDHs) was proved to be an effective way to extract short chain fatty acids (SCFAs) from anaerobic fermentation liquid (AFL) as carbon source for biodenitrification, but the SCFAs content in SCFAs-LDH was unsatisfactory because of the existence of much carbonate in AFL. Pretreatment of AFL with calcium addition was investigated to remove carbonate and improve SCFAs extraction via LDHs synthesis. Results of batch tests showed that, the carbonate removal efficiency was as high as 76.6% when the calcium addition was 0.06 mol/L at pH 12. When using the optimal SCFAs/Al ratio of 3.0, the total SCFAs content in SCFAs-LDH with pretreatment was improved to 46.5 mg COD/g LDH, which was 4.5 times of the control (10.4 mg COD/g LDH). These results suggest that adding calcium to AFL was an effective way to eliminate the negative effect of carbonates on SCFAs-LDH synthesis.

Food waste-derived volatile fatty acids platform using an immersed membrane bioreactor

“…This shortage of industrial VFA-based processes originating from organic waste is attributed to difficulty in recovery of the VFAs from the culture medium and the low product yields (Kim et al, 2018;Rebecchi et al, 2016). Indeed, several reports in literature have focused on VFA production from food waste using batch cultivations in which key operating conditions were studied (Chen et al, 2013;He et al, 2019;Hussain et al, 2017;Sheng et al, 2019;Xu et al, 2012). However, these processes were not scaled up to continuous operations that are suitable for modeling large-scale procedures.…”

Volatile Fatty Acids (VFA) Production and Recovery from Chicken Manure Using a High-Solid Anaerobic Membrane Bioreactor (AnMBR)

“…Simultaneously, in theory, the conversional process in AD from organic wastes to VFA instead of methane can be promoted through not only enhancing the hydrolysis/acidogenesis activity by control the pH [10,11] but also through inhibiting VFA consumption, by inhibiting the activities of methanogens [7]. Many research studies have reported the acidogenic fermentation (AD with the inhibition of the methane formation step) of different substrates, such as food waste [12], citrus waste [13], straw [14], municipal sludge [15] and cow manure [16,17]. However, these processes have not been extended to continuous operations or scaled up to assess their suitability for engineering applications [18][19][20], or they have not been efficient in the recovery of VFA-rich streams from the complex effluent [19,21].…”