Specific Resistance Measurements: Methods and Procedures

Abstract

A computer‐aided data acquisition system was used with three sludges, two chemical‐conditioning systems and nine support media to investigate the effect of slurry solids concentration on specific resistance, the effect of initial time and filtrate volume readings on filtration data, and factors affecting the precision and accuracy of specific resistance measurements. The results of the study show that: (1) The specific resistance of a flocculent slurry is a very strong function of suspended solids concentration at low concentrations and relatively independent of concentration at high values; (2) improper determinations of the onset of filtration or errors in filtrate volume measurements produce slurry filtration data that do not fit the standard model (nonsynchronous data); and (3) specific resistance values are not as accurate and translatable as they might be because of differences in methods used in different laboratories. Several suggestions for improving the translatability of specific resistance measurements are presented.