|Physical cleaning regime
||Back flush in various modes; 3M P.E.T.™ Technology supports efficiency.
||To increase back flush efficiency air scouring required, no turbulent flow during BF
||1 - 13
||1 - 11
|Chemical cleaning regime
||CEB is very effective; usually only caustic soda (NaOH) is added to dissolve organic matter from the membrane surface.
If required an acidic cleaning step (e.g. HCI), can be executed to remove anorganic matter. Both effluents will neutralize each other and create neutral salt.
|CEB is less effective caused by flow conditions. Moreoften CIO is required. Usually Chlorine is applied to release tenacious debris from the membrane surface. The use of chlorine is causing disinfection by-products such as THMs.
||Asymmetric, leading to high flux rates at low TMP.
||Rather symmetric, higher hydrostatic resistance.
|Pore size and distribution
||True ultrafiltration membrane at very narrow distribution.
||Rather microfiltration membrane with broader pore size distribution.
|Trans membrane pressure
||Frequently between 0,1 bar and 0,6 bar.
||Frequently between 0,5 bar and 1,5 bar.
|Maximum turbidity and particle range
||Maximum particle size: 300 µm maximum turbidity: 100 NTU
||Maximum particle size: 500 µm maximum turbidity: 300 NTU
||High tensile strength and burst pressures. Sufficient elongation at break; (not required since flexibility is not a relevant characteristic).
||Good tensile strength. High elongation at break properties; (required due to air-scouring and shell side feed), danger for permanent elongation.
||Intended to be lower due to lower operating pressures.
||Suspected to be higher due to elevated operating pressures and need for compressed air.
|Pump energy demand
||PES membrane with an inline coagulant dosing proved to remove organic substances.
||PVDF does not tend to benefit a lot from coagulant dosing.