3. Pulsebackwashmodel
The hydraulicaccumulatorusedinthepresentsystemconsists
of gasandliquidcompartmentsseparatedbyarubbertypeblad-
der [41]. Thehydraulicaccumulatorischargedwithliquidthatis
pressurized(fromtheROconcentrateline, Fig. 2) suchthatthe
pressureinthegaschamber(Pg) alsoincreasesasitsvolume(Vg)
decreases.Thetotalaccumulatorvolume, Vacc, isthesumofthe
gas (Vg) andliquid(Vl) compartmentvolumes