title: A net water production model for ultrafiltration including flow direction reversal and chemically assisted backwashing.
abstract: Flow direction reversal (FDR) was proposed as a novel method to increase net water production (NWP) during cross-flow ultrafiltration. The design of the pilot-plant study allowed measurement of specific flux recovery after each chemically assisted backwash (BW) combined with FDR and after each FDR at the midpoint of each BW/FDR cycle. The percent recovery of specific flux was higher following FDR (55%) than combined BW and FDR (53%) at lower chemical dosages; however, the percent increase in specific flux recovery by FDR was much lower (20%) when the chemical dose was doubled. A mathematical model was developed to predict the NWP achieved by any combination ofBW/ FDR and FDR frequency. For example, the advantage of introducing FDR was demonstrated at the lower chlorine dose, whereby the percent increase in NWP by alternating 15-minute intervals of BW/FDR with FDR over BW/ FDR alone was 10% for 30-minute BW/FDR intervals and 2% for 15-minute BW/FDR intervals.
authors.affiliation: Department of Civil Engineering, State University of Maringá, Maringá, Paraná, Brazil.
authors.forename: Sandro R
authors.initials: SR
authors.lastname: Lautenschlager
authors.forename: Francis A
authors.initials: FA
authors.lastname: DiGiano
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Schuler
authors.forename: Sidney Seckler Filho
authors.initials: SS
authors.lastname: Ferreira
mesh_terms: D008962:Models, Theoretical; D010865:Pilot Projects; D014462:Ultrafiltration / Q000379:methods*; D014865:Waste Disposal, Fluid / Q000379:methods*; D018508:Water Purification / Q000379:methods*