CONTROL OF PH DURING DENITRIFICATION USING AN ENCAPSULATED PHOSPHATE BUFFER

Acidic phosphate granules encapsulated within a pH-sensitive wall were used to demonstrate pH control during denitrification. Characterizati on of the distribution of microcapsule mass and percent potassium cont ent of the core showed that the wall was an average of 30.3% of the to tal microcapsule mass. A stochastic model using Monte Carlo methods wa s developed describing the kinetics of release of the microcapsule cor e in solution. The model satisfactorily predicted the pH drop and pota ssium release as a function of time for experiments performed at vario us pH values in the absence of biological activity. Although the model only fairly predicted the actual values of pH and potassium released during the denitrification experiments, the model predicted the pH tre nds quite well as shown by the similar predictions in the increase and decrease in pH. The experimental data demonstrate that pH control usi ng the microcapsules was effective because the pH rise caused by denit rification was counteracted by the release of the acidic microcapsule core. (C) 1998 Elsevier Science Ltd. All rights reserved.