Ammonia monitoring of chloramination systems

The Q45N Dissolved Ammonia Monitor from specialist electrochemical sensor manufacturer Analytical Technology achieves continuous, on-line monitoring of the drinking water chloramination process

Chloramination is increasingly being used during potable water treatment in order to limit trihalomethane (THM) formation and ensure disinfection in large potable water distribution systems.

The innovative Q45N monitor from Analytical Technology enables accurate and dependable measurements of free and total ammonia and monochloramine concentration in potable water.

Effective control of the chloramination process requires the addition of sufficient ammonia to ensure that only monochloramine is formed, while limiting the amount of excess ammonia.

Excess ammonia causes taste and odour problems and reacts with chlorine, therefore decreasing its disinfection efficacy.

As a consequence, a powerful ammonia monitor is required to provide reliable measurements of dissolved ammonia and allow users to control ammonia levels.

The advanced Q45N Dissolved Ammonia Monitor employs two separate sensors, the first measuring monochloramine and the second measuring total ammonia after reagent addition.

Based on these measurements, the monitor calculates the concentration of free ammonia, which effectively represents the excess ammonia that has not been combined with chlorine.

The chloramine concentration is measured using a unique amperometric sensor that responds linearly to chloramines while eliminating interface from excess free chlorine in solution.

The amperometric sensor also provides excellent repeatability over long periods of time.

Reagents are inexpensive and usage is low, and as a consequence the monitor has a very low cost of ownership.

The monitor has two 4-20mA outputs programmable for free ammonia, total ammonia and monochloramine concentration.

This allows all the important parameters to be measured on a single instrument.

The Q45N system consists of a wall mounted chemistry system and an electronic display and alarm package.

The chemistry system contains the necessary metering pumps to provide chemical addition to the sample and delivery of the sample to the sensing element.

The electronic display and alarm package provides the user interface to the system.

Ammonia concentration is displayed on a large format LCD display with secondary display for other operating variables.

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