ORP is measured in millivolts (mV) using a sensor with two electrodes. The ORP electrode either accepts or donates electrons into the water, depending on the system. The reference electrode has a stable output of electrons as a comparison. The ORP is calculated using these two values. A positive value indicates the presence of oxidizing agents whereas a negative value points to contamination (Lowry & Dickman, 2013).
ORP is not presently a parameter of interest for discharge water. It plays a role during washing of vegetables as research has shown that the higher the ORP, the lower the survival time of certain decay, spoilage, and pathogenic bacteria (Suslow, 2004).
- Bier, A. W. (2009). Introduction to oxidation reduction potential measurement. In Hach Company. Retrieved March 2, 2015, from www.hach.com/asset-get.download.jsa?id=7639984590
- Lowry, R. W., & Dickman, D. (2013). The ABC's of ORP: Clearing up some of the mystery of oxidation-reduction potential. InService Industry News. Retrieved March 4, 2015, from http://www.rhtubs.com/ORP.htm
- Suslow, T. V. (2004). Oxidation-reduction potential (ORP) for water disinfection monitoring, control, and documentation. InUniversity of California Division of Agriculture and Natural Resources. Retrieved March 2, 2015, from http://anrcatalog.ucdavis.edu/pdf/8149.pdf