Page 371 - Water and wastewater engineering
P. 371

9-10   WATER AND WASTEWATER ENGINEERING

                                      Stage 1:  Stage 2:
                                     24 Vessels  12 Vessels
                                    144 Elements  72 Elements
                                                   Permeate






                                                            Feed         Concentrate
                               Feed
                                                 Concentrate
                                         Plan view              End-perspective view
                            (a)


                                                               Permeate
                                                               (product)



                                                       Concentrate
                                                        (reject)
                                                        (brine)
                            (b)



                                                           Concentrate

                                                      Permeate
                                               Permeate
                                        Permeate
                            (c)
                              FIGURE 9-7
                             Example array arrangements: (a) a 4     2 stage arrangement showing 12 pres-
                            sure vessels, each with 6 elements per vessel; ( b ) a schematic of a 4     2 array;
                            ( c ) a schematic of a 4     2     1 array.

                                 Acid
                                      Antiscalant
                                                                      Energy
                            Raw water                                recovery            Concentrate
                                      Prefiltration  Feed  Membrane         Break tank   disposal
                                                pumps     arrays      CO
                                                                        2
                                                                          Corrosion
                                                                           inhibitor
                                                                        Base  Disinfectant
                                                              Air
                                                                                Treated water
                                                                  CO  stripping
                                                                    2           to distribution
                                                                    tower
                                                                                  system
                            FIGURE 9-8
                             Schematic of typical reverse osmosis facility.
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