Double-stage membrane-assisted anaerobic digestion process intensification for production and recovery of volatile fatty acids from food waste

• Published in: The Science of the total environment 2022-06, Vol.825, p.154084-154084, Article 154084
• Main Authors: Pervez, Md. Nahid, Bilgiç, Begüm, Mahboubi, Amir, Uwineza, Clarisse, Zarra, Tiziano, Belgiorno, Vincenzo, Naddeo, Vincenzo, Taherzadeh, Mohammad J.
• Format: Article
• Language: English
• Subjects: ammonia; Anaerobic digestion; Anaerobic digestion process; Anaerobic membrane bioreactor; Anaerobiosis; batch fermentation; Bioconversion; Bioreactors; Chemical oxygen demand; concentration (parameter); Dissolved oxygen; Double stage; effluent; Effluents; fatty acid synthesis; Fatty Acids, Volatile; Food; Food waste; gas chromatography; inoculation; Microfiltration; nitrogen; Organic chemicals; Organic wastes; oxygen; phosphorus; Process intensification; Purification; Recovery; Refuse Disposal; Resource Recovery; Resursåtervinning; suspended particulate matter; Sustainable production; thermal conductivity; Ultrafiltration; ultraviolet spectroscopy; Volatile fatty acid; Volatile fatty acids; Volatile fatty acids (VFAs); Volatile solid; waste component removal; Waste stream
• ISSN: 0048-9697; 1879-1026; 1879-1026
• DOI: 10.1016/j.scitotenv.2022.154084

The potential of organic waste streams (i.e., food waste) for the sustainable production of precursor chemicals such as volatile fatty acids (VFAs) using anaerobic digestion (AD) has received significant attention in the present days. AD-derived VFAs have great market appeal if the challenges with their recovery and purification from the complex AD effluent is overcome. In this study, a microfiltration immersed membrane bioreactor (MBR) was used for the production of VFAs from food waste and simultaneously in-situ recovery of VFAs. The MBR set-up was applied for 98 days, with a maximum yield of 0.2 gVFA/gVSadded at an organic loading rate (OLR) of 4 g VS/L/d. The recovered permeate was then subjected to further purification using a side stream ultrafiltration unit. It was found that the removal rates of total solids (TS), total suspended solids (TSS), dissolved solids (DS), volatile solids (VS) and volatile suspended solids (VSS) were above 70–80% in both membranes (10 kDa and 50 kDa), and Phosphorus (P), Total Kjeldahl Nitrogen (TKN), chemical oxygen demand (COD), and NH4+-N were also removed partially. Particularly, VFAs concentration (above 6 g/L) was higher for 10 kDa at pH 5.4 in ultrafiltered solution and permeate flux decline was higher for 10 kDa at pH 5.4. These results are also supported by the measurement of UV–Vis spectra of the solution and visual appearance, providing a promising approach towards building a VFAs-based platform. [Display omitted] •Integrated MF-UF membrane technology proves itself as a promising method for VFAs.•With microfiltration iMBR, VFAs can be recovered above 16 g/L (0.2 gVFA/gVSadded).•MBRs can be used for long-term production (>90 days) and recovery of VFAs from AD.•UF can remove 80% solid particles and improve VFAs concentration (7.87 g/L).