RO feed and concentrate pressures (Pf,RO and Pc,RO), and product water concentration (Cp) can be obtained by a commercial RO design (simulation) software. The input data for the simulation are feed water quality (i.e., ion concentrations, pH, and so on), product flow rate, permeate flux, recovery rate, RO CCT137690 type, number of elements per pressure vessel (PV), and the PV arrangements. In this study, IMSDesign by Hydranautics were used as the RO design software; SWC6-MAX ( Hydranautics) were selected as a common RO element; RO permeate flux was set to a constant common value at 15.3 LMH; and all other input conditions are obtained from the related OMBR simulation results (e.g., Cdd, Qdd, Qp, and so on).
3. Results and discussion
3.1. Effect of FO module type (or DS channel spacers) on water flux
In full-scale OMBR, DS becomes diluted while drawing pure water from feed and osmotic pressures declines as DS flows along the flat sheet DS channel (Fig. 3a; FS1 condition in Table 1). Since complete mixing is assumed in the feed side, the salt concentration at the active layer (c2) is the same as that in the bioreactor (c2 = CR). The osmotic pressure drop by ICP (ΔπICP) takes a significant part in the apparent osmotic pressure drop (Δπa) and the osmotic pressure drop by ECP (ΔπECP) is still non-negligible even if turbulence by spacers in DS channel is considered.