Ammonia Measurement – The Solution
The MS3500 Ammonia analyser is the only instrument in the market that has been specifically designed to analyse the levels of ammonia at the raw wastewater intake. The principle of operation is the measurement of headspace gases from a sample tank containing the waste water to be measured.
The MS3500 works by passing water through a sample tank as shown below. Sodium Hydroxide (NaOH) is added to increase the pH of the waste water, converting NH4+ to Ammonia. Through the use of Henry’s Law the concentration of gases in the headspace is proportional to the concentration of the substance in the water. The Ammonia and other volatiles in the waste water will pass into the headspace above the waste water where it will be trapped. This will continue until equilibrium is reached.
A sample of the headspace gases are then passed across sensors in the MS3500 sensor head which respond to the Ammonia in the headspace but reject other contaminants. This response is then analysed by the instrument and a concentration value is generated based upon the relationship between the concentration present in the headspace and that in the water.