Synergy of selective buffering, intermittent pH control and bioreactor configuration on acidogenic volatile fatty acid production from food waste.

The production of volatile fatty acids (VFAs) and biohydrogen (bio-H) from food waste (FW) by acidogenic process is one of the promising strategies. The present study was performed to evaluate the role of initial (phase I) and intermittent pH (phase II) control strategies utilising combination of sodium hydroxide (NaOH) and sodium carbonate (NaCO) as buffering/neutralizing agents on VFAs and bio-H production from FW. The study was carried out in two bioreactor configurations (biofilm (UAFBB) and a suspended mode bioreactor (UASB)). Intermittent pH adjustment (phase II) increased hydrolysis and FW acidification compared to the initially adjusted pH (phase I), but had a detrimental influence on bio-H generation in both the studied bioreactor configurations. Combining NaOH and NaCO resulted in higher buffering capacity and VFA production. The studied parameters in UAFBB aided in higher VFA (14.05 g/L; 48 h of cycle operation) and bio-H (56%; 12 h of cycle operation) production during phase II and phase I operation, respectively. Overall, the results showed a synergy between the examined parameters, resulting in increased VFA production from FW.