A dual approach of membrane cleaning based on physico-chemistry and hydrodynamics

Principles of Membrane Filtration

“…For this the cake resistance can be determined from the rate of flux decline due to cake build-up, and the contribution of fouling to the overall cake layer resistance can be estimated by measuring pure water flux after fouling has established (Mikulásek et al ., 2004;Rabiller-Baudry et al ., 2008).…”

“…The term sustainable flux has been introduced to refer to the operational and economic sustainability of a membrane process that minimises fouling to avoid frequent cleaning (Bacchin et al ., 2006;Rabiller-Baudry et al ., 2008).…”

On the origin of flux dependence in pH-modified skim milk filtration

“…Our previous experiments on UF membrane cleaning fouled by skim milk at natural pH showed that no acid step is needed for a long-term use (more than 30 consecutive cycles of skim milk UF followed by an alkaline cleaning and already partial validation at industrial scale) [9] that is fully coherent with the analysis of the irreversible fouling, evidencing only proteins on the membrane in this particular case [3,22,27]. Further analysis of irreversible fouling of UF membranes fouled by pH modified skim milk in the range 5.0-6.7 would be done to confirm whether some small amount of inorganic components enter in the irreversible fouling or not.…”

“…Complementary in-depth study of the PES-UF membrane cleaning when fouled by unmodified skim milk has confirmed that minerals are not discernable in the irreversible part of the fouling layer, and thus we have suggested that acid cleaning step is not needed for such filtrations [10,22]. Then, a single step of alkaline cleaning can be sufficient for filtrations performed with modified milks in the 6.7-11.5 pH (an additional disinfection step must be added for the safety of equipment of food industry).…”

“…As lactose is not a pH-dependent component, its role is not discussed here. As it is easy to solubilise in water, it was already proved that lactose does not enter in the composition of the irreversible fouling at natural pH of milk in UF [6,22,27]. For the mineral fraction of milk, the pH-dependent components mostly correspond to calcium and phosphate salts, the role of which will be discussed in the following section.…”