What is ORP measurement and what does it indicate?

ORP (Oxidation-Reduction Potential) measures the tendency of a solution to oxidize or reduce substances, expressed in millivolts. Positive ORP indicates oxidizing conditions; negative indicates reducing conditions. Measured using platinum electrode with reference electrode. Applications: disinfection control (chlorine in water, ORP >650 mV indicates adequate disinfection), wastewater treatment (denitrification monitoring), plating baths, and chemical processes. ORP does not indicate concentration but provides measure of chemical activity related to electron transfer reactions.