A Settling Column for Turbulence-Induced Flocculation of Cohesive Sediments

Abstract

In this paper we describe a new settling column for the investigation of flocculation of cohesive sediments. In natural water systems, turbulence causes cohesive particles to collide, adhere and grow to form flocs. The flocculation processes (aggregation and break-up) have a strong impact on the overall fate of cohesive sediments and, in particular, on deposition and sedimentation. The new settling column has been designed and built to allow study of these processes. Such experimetnal facility is a useful tool to provide the data necessary to reach a better understanding of the dynamics of cohesive sediment. The components of the settling column, the devices employed in the set-up, the measuring techniques and the data collection are described in this paper. Innovative aspects of the set-up are the time and length scales involved, the measuring techniques employed, and the monitoring of flocculation and settling under temperature and turbulence controlled conditions.