Legacy Ponds and Silo Wastes

During the processes of ultra- and micro-filtration shear is normally generated at the surface of the membrane by rapid recycle pumping of the suspension.

During the processes of ultra- and micro-filtration shear is normally generated at the surface of the membrane by rapid recycle pumping of the suspension. This is counter-productive as the entire suspension is being sheared leading to break-up and damage of the suspended material often making it more difficult to filter. It also leads to high pressures and possible problems with seals, tube blockages and other maintenance drawbacks. Moving the membrane is an alternative method for generating shear at the surface between the membrane and suspension, leaving the suspension stationary. This project will investigate vertically oriented filter tubes in resonant oscillation, including the ‘engineering’ of the package to determine the most effective ways to filter: by suction or by over-pressure on the feed side, options for ‘backpulsing’ and other mechanical membrane cleaning strategies. The deliverables include a theoretical understanding of a compact but essentially straightforward system that can be used in a modular way for a variety of different filtration applications. One such is the combination of ion exchange and filtration within the same process equipment, in what has become known as ‘seeded ultra- or micro-filtration’; where it is possible to employ finely divided particles retained on the filter. In the case of finely divided magnetic beads, these may be retained on a coarse pore sized magnetic microfilter; permitting the passage of the residual colloidal waste material whilst recovering the magnetic beads. The project will investigate both practical aspects and kinetic modelling of the coupled mass transfer equations.