Improving volatile fatty acid yield from sludge anaerobic fermentation through self-forming dynamic membrane separation

Dynamic membrane-assisted fermentation of food wastes for enhancing lactic acid production

“…Moreover, the SCOD and TCOD concentrations in the effluent were almost identical, indicating that few particulate organics remained in the effluent because of the perfect particle interception by the DM. At uncontrolled pH, SCOD in the effluent increased from 14.9 g/L to 22.8 g/L, which might be attributed to the retention of particulate organics and higher solubilisation rate enhanced by the membrane (Liu et al, 2016). When pH was adjusted to 4 and 5, the effluent SCOD gradually increased to 25-30 g/L, indicating a stronger solubilisation, which was consistent with the previous studies (Tang et al, 2016;Wu et al, 2015).…”

“…The conventional batch or continuous LA fermenters are widely used due to their high LA yield and stable operation (Wu et al, 2015;Liang et al, 2014). However, they have several drawbacks: first, they are not suitable for high concentrations of substrate because of their negative effect on the growth of lactic acid bacteria (LAB) (John et al, 2009;Tang et al, 2016); second, the feedback inhibition caused by accumulated free acids may restrict the bacterial activity and decrease the LA yield (Gao et al, 2011); third, substrates cannot be completely utilized and may retain at high levels in the effluent (Liu et al, 2016); and finally, LAB in the fermenter cannot accumulate to increase the population or accelerate the LA productivity. To improve the LA yield, fermentation conditions such as pH, organic loading rate (OLR), temperature, and types of inocula should be optimized (Tang et al, 2016;Wu et al, 2015;Liang et al, 2014).…”

Dynamic Membrane Filtration: Formation, Filtration, Cleaning, and Applications

“…In a sludge fermentation process, a self-forming DM was applied to improve volatile fatty acid (VFA) yields. Suspended solids and proteins were rejected by 99 and 70 %, respectively, with over 90 % VFA transformation [28]. Compared with conventional anaerobic digestion, AnDMBRs provided better sludge reduction and methane production in long-term operation.…”

“…Zhang et al [18] explained the DM concept, DM formation mechanism, materials, fouling, and detailed DM development, giving an overall evaluation of DM technology. But in recent years, more attention was payed to the DM formation [6,[19][20][21][22][23][24][25], filtration [13,14,16,[26][27][28][29][30][31], and cleaning [9,32]. The development of DM technology has attracted interest considering wastewater treatment [5,7,9,29,[33][34][35] and sludge treatment [28,[36][37][38].…”

Alkaline fermentation and elutriation of waste activated sludge for short chain fatty acids abstraction

“…Centrifugal machines, frame filter presses, membrane separation and water elutriation have been adopted to separate solid and liquid fractions. [5][6][7] Among these technologies, water elutriation is both economical and convenient. However, it is difficult to abstract SCFA from fermented sludge since sludge dewaterability is seriously deteriorated after the release of intracellular organics, especially the highly hydrophilic protein.…”