On-line residual sulphite analyzer
Analytical Technology

ATI's Model A15/66 Sulfite Ion Monitor provides the solution to dechlorination control. The system allows continuous measurement of sulfite residuals over ranges of either 0-2 or 0-20 PPM. An analog output from the monitor can be used for control of the chemical feed system to maintain a safe residual sulfite concentration while reducing chemical expense to a minimum.

The A15/66 Monitor takes a unique approach to the measurement of sulfite ion concentration. In operation, a small amount of sample is pumped into the system and mixed with acid. In acidic solution, the sulfite ion is converted to sulfur dioxide. The mixed sample flows into a special chamber where the sulfur dioxide is stripped from the sample. A sensor located in the gas stream measures the released SO2 concentration and displays the results in terms of equivalent sulfite ion concentration.

Sulfite measurement in dechlorinated effluent has frequently been plagued by fouling problems. An important feature of the A15/66 system is the fact that the sensor never comes in contact with the wastewater sample. The result is a system that will continue to function, regardless of the quality of the effluent, or the presence of sulfur reducing bacteria that can proliferate in water containing excess sulfite.