Particle separation is a key process in water and wastewater treatment, with a vital role in meeting water quality standards around the world, and encompassing a very wide range of particulates in widely varying contexts. Recent research has extended the field of application of particle separation to include the sub-micron scale, but innovative treatments are being developed across the board. All these aspects were addressed at the Particle Separation 2005 conference.

This issue contains 31 papers selected after full peer review that embody the latest advances in particle separation as applied to wastewater treatment technologies.

Papers describe fundamental research in particle separation processes, and new developments in coagulation, sedimentation, flotation, filtration and membrane technologies and complex systems.

The collection constitutes an essential reference for all scientists and engineers involved in fundamental research or the practical application of particle separation processes in wastewater treatment.