K. H.
MANCY and D. A, OKUN
Deparfmenf o f Sanitary Engineering, School of Public Health, Universify of North Carolina, Chapel Hill,
P A polarographic method has been developed which permits continuous sampling, recirculation, and automafic recording of dissolved oxygen in aeration processes. In this system the effect of various types of surface active agents on the electrode reaction kinetics has been studied. Surface adsorption of the surface active agents on the dropping mercury electrode interferes with dissolved oxygen determinations in the potential region of the first oxygen wave in the case of anionic compounds; cationic compounds interfere at the second oxygen wave; and in the case of nonionic compounds, interference occurs throughout the entire range of applied voltage. With anionic compounds dissolved oxygen determinations were made at an applied voltage corresponding to the second oxygen wave. With cationic compounds measurements were made at an applied voltage corresponding to the first oxygen wave.
teclinique for of dissolved oxygen in water and waste permits the development of a convenient instrument system for the continuous rccording of dissolxd oxygen concentrations vith many advantages. Results arr immetliatcly avnilabie, the troublesome collection and haiidling of small volumes is eliminated, and the test solution is not dcpletcd. To apply the polarographic technique of dissolved oxygen in a cont’muous recording machine, it was necessary to study:
function of the conccntration of the clpctroactive as in con\rentional -. . . . . ion poiarogrnphy arid of thc Iognritiim of the ratc of flow of thc enliltion past tlic cl~ctrode. The effect of the flomiW solution on current measurement while continuously annlyzing column efflucnts was reported ais0 by I
