Sustainability drive focuses filtration innovation
Anthony Bennett reviews the developments in filtration and separation for the water and wastewater treatment unveiled at Filtech 2007
This year’s 42nd Filtech conference in Wiesbaden, Germany, concentrated on technologies and strategies for three main aspects of filtration: solid-liquid separation by filtration and sedimentation; air and gas cleaning by filtration, settling, electrostatic precipitation and scrubbing; and membrane separation technology.
Sessions on specification of filtration equipment concentrated on software for equipment simulation, and a theme running through the conference was advances in process measurement and control modelling. Models for optimising membrane bioreactor (MBR) systems for wastewater treatment, and also the flux decline of dead-end ultrafiltration on water contaminated with E. coli, were presented.
Steve Tarleton and Richard Wakeman of the Advanced Technologies Group at Loughborough University presented their filter design software. It is capable of ranked equipment selection from more than 70 types of separator, and simulating filtration performance in more than 20 types of vacuum and pressure filters.
Numerous developments in membrane technology were presented, including their use in conjunction with functional water-soluble polymers to remove metal ions. Various studies relating to the use of reverse osmosis (RO) included ways of improving seawater treatment, and the evaluation of silica scaling mechanisms on the RO membrane surface.
Energy-efficiency improvements for membrane technologies were also highlighted, including a study on enhancing liquid-solid separation efficiency by low-energy micro filtration (MF) systems in municipal and industrial wastewater treatment. This area has been the subject of increased research and development by a number of membrane manufacturers, in an attempt to reduce the carbon footprint of the processes.
The importance of effective cleaning procedures for removing bio-films and fouling were covered, including studies of oxygen consumption rate during contaminant removal, and the performance of textile filtration materials as a replacement for traditional membrane materials in MBR systems. Fouling reduction in MBRs by using flux enhancers, and the analysis of filtration mechanisms were also highlighted along with various methods for treating the concentrated sludge from MBR systems.
A evaluation of sludge conditioning and dewatering was presented, along with ways of optimising WwTWs by using chemical pre-treatment.
Advances in depth filtration technology were presented including the removal of heavy metal ions from wastewater using various sources of kaolin, and the eradication of arsenic from drinking water by coagulation and flocculation processes and solid-liquid phase separation techniques. Some interesting developments in the application of magnetic forces on filtration were also presented.
Increasingly stringent worldwide regulations are driving filtration innovation, especially in the water and wastewater industry, where new products are also driving down costs. Removal of high solids can be achieved, porous metal media can be used to increase throughput, and activated carbon is being used as a textile material with a number of interesting applications.
With an almost universal acknowledgement of the increasing pace of climate change in the scientific and business community, it is likely that energy efficiency and sustainable options such as water recycling will become the focus of attention as filtration equipment companies continue to innovate.