NEW SENSOR-BASED ON PH EFFECT OF DENITRIFICATION PROCESS

By observing the acid/base addition rate of a pH controller that centr als the pH in a sample of activated sludge mixed liquor at a set point , the proton dynamics of the reactions taking place in the sample can be monitored. Using this technique, the progress of the denitrificatio n reaction car! be monitored, and. the amount of carbon required for t he complete denitrification of the nitrate present in the sample can b e determined. A new sensor based on this principle is able to measure on-line the nitrate concentration, the denitrification capacity, and t he denitrification stoichiometry without the need for any sample pretr eatment. A prototype has successfully been implemented on a full-scale wastewater-treatment plant to automatically control the dosage of an external carbon source.