FY 1985

New method of wet density and settling velocity determination for wastewater effluent

Ozturgut, E., and J.W. Lavelle

Environ. Sci. Technol., 18(12), doi: 10.1021/es00130a010, 947–952 (1984)

A method has been developed to directly measure the wet density/size spectra of low density but settleable wastewater effluent particles. In this method particles settle to their isopycnic levels in a linear density stratified column. Then samples are drawn, and particle size distributions are determined by Coulter Counter. The wet density/size distribution of particles in a wastewater samples was measured in this manner in the 1.0–1.4 g/cm³ density range and 1.0–64 µm size range. Measurement of size and density outside these ranges permitted construction of a composite settling velocity distribution. We believe these measurements and computed settling velocities are independent of concentration because the density/size spectra of particles can be determined at concentrations low enough to preclude significant flocculation.