AWWA WQTC64176

This slide presentation outlines a study on the effectiveness of using oxidation-reduction potential (ORP) for process control of manganese oxidation/removal. The drivers for this study included: the need for a practical, accurate method for Mn oxidation that was quality based, not just flow-based; a new remotely-operated microfiltration membrane facility was proposed; and, LT2ESWTR turb standards. Reasons for using ORP included: using KMnO₄ as oxidant for soluble Mn (Mn,sup>+2); no drivers to consider alternatives ( ClO₂, etc.); low total organic carbon (TOC) (< 2 mg/L), TTHM < 30, HAA5 <20, 0 Color units; KMnO₄ is a standard oxidation process that should be "measurable" with ORP; must use isolated feed point; proper downstream sampling point key; and, no other oxidants (i.e. Cl₂) present. Implementation, process evolution, critical elements, ORP cleaning, and operation and maintenance are all outlined in the presentation. The summary of the study includes these points: flow-paced controls resulted in highly variable oxidation results, not qualitative; ORP provides a qualitative means for controlling finished water Mn levels at finite levels; improves many elements of a surface water treatment process (Cl₂, disinfection byproducts (DBP), Turbidity, Filter Ops); and, maintains a constant oxidation potential (as measured in mV) by dosing the correct amount of oxidant to meet the required demand. Includes figures.