Treatment of pig farm effluents by ultrafiltration

The use of ultrafiltration and nanofiltration membranes for the purification of cork processing wastewater

“…However, other causes are also responsible of this effect, like polarization, adsorption, pore blocking, etc. Similar slight or void influence of the feed flow rate on J v at higher pressure was observed during the ultrafiltration of pig farm effluents [10] and the nanofiltration of dyes [19].…”

“…5. As it is seen for TMP = 3 bar, J v increases when the tangential velocity is increased, probably due to an increase of the turbulence at the membrane interface, which removes some of the accumulated components in the cake layer by hydrodynamical forces, and thus reducing the cake and polarization layer [10]. However, when a TMP higher than 4 bar was applied, an increase in the tangential velocity above 2 m s −1 did not improve membrane fluxes, probably because under these conditions, the permeate flux was limited by the dense structure of the deposited fouling layer [16].…”

“…The decline of the wastewater permeate flux J v with filtration time is represented in Fig. 3 for some experiments performed with the PT membrane, where the TMP was varied at v = 2 m s −1 and 20 • C. These permeate fluxes were obtained by numerical differentiation of the collected mass of permeate versus time data, and the results show that J v decreased gradually with the operating time, which is due to concentration polarization, gel formation, adsorption and pore blocking caused by the high COD wastewater [10,17].…”

“…Membrane processes have been used for the purification of different wastewaters with high organic contents [8][9][10]. More specifically, they have been applied in recent times to wastewater from the olive mill process [11][12][13], which represents one of the greatest environmental problem in the Mediterranean areas due to the high COD values and the presence of phyto-toxic and antibacterial polyphenolic components.…”

Nanofiltration processes applied to the removal of phenyl-ureas in natural waters

“…This initial decline in J v is a direct consequence of the fouling effect that occurs in the membrane, which in the present case, focused on the NF of model compounds dissolved in natural waters, is low to moderate. However, the fouling effect is more significant in the NF of industrial wastewaters [12,15,16] with much higher pollutant contents. As similar decay curves of J v were obtained for the remaining experiments not shown in Fig.…”