pH Adjustment of the Feed to Each Pass

WAVE provides the possibility for increasing or decreasing the pH of a Feed to a given Pass as shown below (and in Figure 1):

Click on the Reverse Osmosis Tab if you are in a different Tab or Window.
Select the Pass of interest (Pass 1 or Pass 2 in WAVE).
Click on the “Add Chemicals/Degas” button. The Chemical Adjustment Popup Window will appear. This Window includes options for adjusting pH, degasification, addition of Antiscalants/SMBS (only the 1st Pass), specifying the process temperature and Pass recovery. This Window also includes a Table with the Feed composition (before adjustment) and the Concentrate composition calculated by WAVE.
Click on either of the “pH” buttons. The gray dots on the buttons would turn green. The Table in the Chemical Adjustment Popup Window would now include a column named “After pH”
Click on the entry fields for either pH or S&DI (Stiff & Davis Index) and specify the desired pH or S&DI value. WAVE would populate the “After pH” columns in the Table in the Chemical Adjustment Popup Window. This would be reflected in the RO/NF/ROSC Process Flow Diagram after the user clicks “OK” (arrows in the feed streams to each pass with named chemicals).
Choose the appropriate chemical from dropdown list. This list would be different for increasing pH vs. decreasing pH.
Click “OK”.

Figure 1: Specification of RO/NF/ROSC System Pass Feed pH Adjustment

Notes:

In WAVE, pH adjustment can be deactivated by choosing either of “pH” buttons a second time. The green dots would turn gray.
In WAVE, pH specifications are limited to between 0 and 14.
The list of chemicals used for pH adjustment is defined by the user as described in Section 1.
WAVE allows addition of Antiscalants and SMBS only in the 1st Pass and does not allow pH adjustment between stages
WAVE does not prevent the simultaneous selection of “pH” without an intermediate degasification step. Thus the user is urged to review the pH adjustment selections carefully.