MATHEMATICAL-MODELING OF PARTICLE-SIZE DISTRIBUTION IN SECONDARY EFFLUENT FILTRATION

Analysis of various types of secondary effluents revealed a broad range of particle sizes, suggesting that particle size distribution (PSD) should be taken into consideration in deep-bed filtration calculations rather than concentrating exclusively on process parameters. A PSD function is shown to be a more effective and reliable index than the conventional ''mean'' particle diameter. The power law function was found to express effluent PSD well; experimental data confirmed its validity. The application of this function is demonstrated using a recent filtration model based on the Kozeny equation. Prediction of the head loss, based on influent PSD function parameters alone, is possible in the filter working phase, and an equation for this aim is developed.