Organic loading rate effect on the acidogenesis of cheese whey: a comparison between UASB and SBR reactors

Abstract

Volatile fatty acids (VFA) production and degree of acidification (DA) were investigated in the anaerobic treatment of cheese whey by comparison of two processes: a continuous process using a laboratory upflow anaerobic sludge blanket (UASB) reactor and a discontinuous process using a sequencing batch reactor (SBR). The main purpose of this work was to study the organic loading rate (OLR) effect on the yield of VFA in two kinds of reactors. The predominant products in the acidogenic process in both reactors were: acetate, propionate, butyrate and valerate. The maximum DA obtained was 98% in an SBR at OLR of 2.7 g COD L d, and 97% in the UASB at OLR at 15.1 g COD L d. The results revealed that the UASB reactor was more efficient at a medium OLR with a higher VFA yield, while with the SBR reactor, the maximum acidification was obtained at a lower OLR with changes in the VFA profile at different OLRs applied.

Volatile fatty acids production from cheese whey: influence of pH, solid retention time and organic loading rate

“…The SBR showed a good performance in comparison with other types of reactors, considering the lactose degradation rate, the VFA production rate obtained and microbial populations …”

“…Fang and Yu observed a maximum rate of 0.18 g COD g VSS −1 h −1 in an upflow reactor. According to the literature, the difference in kinetic results depends on factors such as reactor configuration, microbial population and type of wastewater …”

“…6 The SBR showed a good performance in comparison with other types of reactors, considering the lactose degradation rate, the VFA production rate obtained and microbial populations. [22][23][24] Table 3 summarizes results from various studies focusing on lactose biodegradation.The specific rate observed for lactose degradation and VFA production were in the same range as has previously been reported for acidogenic fermentation. Fang and Yu 24 observed a maximum rate of 0.18 g COD g VSS −1 h −1 in an upflow reactor.…”

“…According to the literature, the difference in kinetic results depends on factors such as reactor configuration, microbial population and type of wastewater. 16,[22][23][24]…”

Acidogenesis/methanogenesis from acid cheese whey in hybrid-UASB reactors

“…Acidification is intensified due to the low bicarbonate alkalinity in cheese whey (∼50 meq/L) (Mockaitis et al, 2006;Gannoun et al, 2008;Diamantis et al, 2014). These aspects exert a negative impact on methanogenesis; because methanogenic archaea are sensitive to low pH environments, and develop better within a range of 6.5-8.2 (Calero et al, 2018b). Another consequence is the loss of the inoculum, due to the difficulty of forming granular sludge (Kalyuzhnyi et al, 1997;Carvalho et al, 2013), generating effluents with a high content of suspended solids, consequently reducing treatment effectiveness (Diamantis et al, 2014).…”