Method for measuring hydrogen peroxide in water

A method of for measuring hydrogen peroxide levels in a water treatment system using a colorimetric assay, the method comprising:

• a. transferring a first water sample to a measuring cell;
• b. determining a first absorbance measurement of light at a selected wavelength as a null measurement;
• c. removing the first sample from the measurement cell;
• d. transferring an aliquot of a of a reagent compound capable of reacting with hydrogen peroxide to form a reaction product, the reaction product adapted to absorb light at the selected wavelength proportional to the amount of hydrogen peroxide in the water sample to the measurement cell;
• e. filling the measurement cell with a second water sample;
• f. determining a second absorbance measurement of light at the selected wavelength as a test measurement;
• g. emptying the measurement cell and rinsing with sample water;
• and
• h. determining the difference between the first and second measurements and comparing the difference against a pre-determined standard curve of diluted hydrogen peroxide to determine and report the concentration of hydrogen peroxide in the water sample.

A method for measuring the concentration of hydrogen peroxide in a water treatment system containing hydrogen peroxide on a periodic basis using a colorimetric assay, the method comprising:

• a. drawing a water sample from the water treatment system through a network of pipes into a buffer jar, the buffer jar comprising an overflow for maintaining a constant water volume and constant head pressure in the buffer jar and for maintaining a turn-over of water in the buffer jar;
• b. controlling a supply valve in a time-dependent manner to cause a first water sample to be received into a measurement cell from the buffer jar and obtaining a first colorimetric measurement;
• c. controlling a supply valve in a time-dependent manner to cause a second water sample to be received into the measurement cell from the buffer jar and reacting the hydrogen peroxide in the water sample with a reagent to form a reaction product, the reaction product adapted to absorb light from a light transmitter at a selected wavelength proportional to the amount of hydrogen peroxide in the water sample;
• g. determining a difference between the first and second measurements, and
• h. comparing the difference against a pre-determined standard curve of diluted hydrogen peroxide to determine the concentration of hydrogen peroxide in the water sample.