The method of calculations of the sedimentation efficiency in tanks with lamella packets

The paper outlines a method to determine the sedimentation efficiency in modernized tanks with incorporated lamella packets. The method takes into account the properties of the suspension (density, viscosity, solid phase distribution and tank design parameters - flow intensity and settling surface). Several types of grain size distributions are considered: the log-normal distribution and generalised gamma distribution. The sedimentation efficiency is investigated in relation to the ratio of tank filling with lamella packets. The lamella ring width in a round Dorr clarifier is taken as an example. The analysis is performed by way of computer simulations. The applied calculation procedure was extensively verified in laboratory tests, pilot tests and industrial-scale tests (Kowalski 2000) and the obtained results were regarded as satisfactory. The error involved in calculations of the sedimentation efficiency is less than 0.05 when the efficiency value exceeds 0.8.