Ammonia / Ammonium

Ammonium is a crucial component of the nitrogen cycle. Ammonia is the deprotonated form of ammonium. In drinking water treatment, ammonia monitors are usually situated at the front end of the process and are used for intake protection to the works. On a wastewater treatment works, ammonia is often monitored at both the inlet and the outlet to the works.


Low level online ammonia monitors work on the basis of colorimetry as it is more sensitive to low concentrations. For higher concentrations of ammonia, an ion selective electrode is more commonly used as it has a larger working range.


If colorimetry is the measurement principle, the sample is buffered to the correct pH for the chemistry and both ammonia and ammonium are measured. With an ion selective electrode approach, only the ammonium is measured but by simultaneously measuring pH and temperature, the ammonia concentration can be calculated. Typically, both approaches report the results in terms of mg/l nitrogen to overcome the issue of the form of the ammonia/ammonium in the original sample.

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Products for this application


An industrial colorimeter for wastewater measurement of ammonia.

Online Colorimetric Analyser

3S colorimeter

user friendly ammonia colorimeter for the drinking water industry.

s::can ammo::lyser

An ion selective electrode for ammonium with integrated pH and potassium measurement.

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Established in 1971 PMA is a well-recognised provider of online instrumentation for process control and compliance monitoring. With expertise in analytical techniques such as Photometry, Colorimetry, Ion-selective electrodes (ISEs), Titration, Fluorescence, Ultrasonics and more.

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