INFLUENCE OF PARTICLE-SIZE AND SIZE DISTRIBUTION IN GRANULAR BED FILTRATION AND DYNAMIC MICROFILTRATION

Particle size and size distribution is an important parameter in solid liquid separation process especially in granular bed filtration and i n dynamic microfiltration. This paper discusses their effects on the a bove processes from extensive experimental data obtained, In granular bed filtration, the experimental results showed that the initial effic iency follows the pattern reported by previous experimental and theore tical studies, i.e., lower efficiency for particles which fall in the range of critical size of 1 mu m. However, the particle removal during the transient stage increased with an increase in particle size for t he range of sizes studied, An attempt was made to quantify these effec ts in granular bed filtration using semi-empirical approach, In dynami c membrane filtration also, the particle size plays a major role in th e retention, However, despite the relative thickness of the membrane ( compared to particle size) dynamic microfiltration appears more as a s ieving process; the retention is mainly related to the largest pore si ze. (C) 1997 IAWQ. Published by Elsevier Science Ltd.