journalArticle Water Research 32 11 Chancelier J.P. Chebbo G. Lucas-Aiguier E. Estimation of settling velocities This paper deals with settling velocities estimation, which is of major importance as settling velocities estimation is a prerequisite for properly dimensioning settling tanks. Several measurement procedures are presented and analyzed here. A general framework for identification which includes modelisation of the settlers and identification techniques is developed hers-in. In this paper, we demonstrate that for a parametric set of settling density functions rho(d nu) = Sigma(i=1)(N) theta(i)rho(i)(d nu) the mathematical relation between the measures M(t(i))(i)=(1,N) and the unknown quantities (theta(i))(i=1,N) take the following linear form M(t(i)) = Sigma(k=1)(N) theta(k)integral(R)phi(x)(t(i), nu)rho(k)(d nu) This relation makes it possible to have access to statistical errors in settling velocity estimates (theta(i)) in assuming that a statistical model of measurement errors (M(t(i))) exists. The consequences of the choice of sampling times (t(i))(i)=(1,N) on the quality of the estimation are also investigated. (C) 1998 Elsevier Science Ltd. All rights reserved. 3461–3471 1998