pH and ORP Measurement

pH value determines whether the character of the measured sample is acid or alkaline. A sample with a pH value of 7 is neutral. Swimming pool water has approximately such a pH value (pH 6.8 to pH 7.2). Samples with higher pH value are alkalis. A one-unit pH change represents a tenfold change in hydrogen ion concentration.
pH value is one of the most important electrochemical parameters and one of the most frequent measurements. pH value significantly influences the course of chemical reactions and the corrosive properties of the water produced. Alkalinisation and neutralization are among the most widespread processes. pH value significantly determines the behavior of microbiological systems. Therefore it is important for the functioning of biological wastewater treatment plants, fish breeding, food production and for monitoring surface and wastewater.
The oxidative reduction potential value expresses the oxidation or reduction intensity of a sampled affection. Positive potential (against the hydrogen electrode) reveals oxidative affection of the sample, whereas negative potential reveals reductive affection. This measurement is utilized, for example, for the control and monitoring of denitrification processes in biological wastewater treatment plants, for control and monitoring of the neutralization processes or for permanganate dosing in water treatment plants. This measurement method can also be used for measuring low chlorine concentration, chlorine dioxide or ozone in pure water.