D21.1 Treatment Units and Instrumentation for CSO Treatment Solutions – Confidential
Deliverable D21.1 is defined as a prototype of ‘Treatment units and instrumentation for CSO treatment solutions’. According to FP7 definitions, a prototype is ‘intended as a man-made object which shows the scientific and technical feasibility of a concept’. As such, it can not be submitted or distributed, but this report describes and documents the model setup and findings of thorough model tests on a prototype of a cross-flow lamella settlers. This type of plate settler is claimed to show less sediment re-mixing compared to the more common upflow or counter-current settlers.
The objective of the model tests using spherical plastics beads as model sediment was to investigate basically the behaviour of sediments and to establish efficiency curves for a given flow and sediment characteristics. The experiments were conducted using tap water as well as salt water of different density in order to vary the settling velocity as the most essential parameter. Steady-flow efficiency curves were gained which showed that the efficiency decreases with increasing surface load as well as with decreasing settling velocity. The evaluation was made in dimensionless form to allow scaling and possibly transfer to prototype size.