- The Filtration Society - https://www.filtsoc.org -

2008 Programme

4 March 2008 – New Developments in Filtration Technologies
Loughborough, UK

This well attended one day technical meeting, organised by the Filtration Society, brought together people with diverse interests in filtration in order to update them with the latest advances in filter technologies. Speakers described how issues ranging from tightening legislation to the growing number of finer, more demanding, filtration processes are driving the need for new developments that satisfy potential customer needs.

David Dubbin from GEA Process Engineering started the meeting by giving an overview of the manner in which filtration technology has impacted upon our daily lives. David used several examples, including power station and vehicle emissions, flue gas desulphurisation and water treatment and supply, to illustrate how recent advances have improved the environment in a positive way and how filtration practitioners can make a real difference. Jack Taylor of Carbon Cloth International continued with an authoritative presention concerning the varied applications of activated carbon impregnated filter cloths. Although originally conceived to protect against chemical, biological and nuclear threats, these cloths now find widespread use in medical applications such as wound dressings. Recent developments in placing chemical species into the cloth opens new possibilities for enhanced chemisorption capacity.

Two presentations concerning the separation of organic solvents with nanofiltration membranes completed the morning programme. Osama Farid from the University of Nottingham described how solvent induced swelling of polymeric membranes can stongly influence their selectivity and permeability. The degree of swelling is affected by mixture composition and the type of organic in contact with the membrane. In many cases the swelling behaviour is far from intuitive. Steve Tarleton from Loughborough University developed the theme further with descriptions of how nanofiltration can be used to improve the quality of fuels. The results of filtration experiments and engine tests showed how unwanted solutes can be removed from solvent mixtures and how up to 50% reductions in combustion chamber/valve deposits and 10-15% reductions in carbon monoxide and NOx emissions can be achieved.

Christopher Finn from Fibra Ltd kicked-off the afternoon session with a talk concerning a novel fibrous filter which has been developed for particle removal and coalescence applications in water, wastewater, and process treatment. The filter bed is formed from a bundle of fine fibre, potted at one end, and compressed mechanically. After the bed has become loaded with filtered solids, a cleaning cycle is initiated using a short forward flush with the bed expanded. Particle removal efficiency is high and typically >90% for particles above 1 µm.

Mike Stillwell of Micropore Technologies described a new surface modified and slotted microfilter. The results of filtration experiments with yeast suspensions were presented to illustrate the salient performance features. The meeting concluded with a talk by Yogesh Gupta from Loughborough University. Yogesh highlighted the benefits of using polyanaline membranes for gas/gas separations and showed that productivity can be significantly increased by using ultra-thin membranes of higher permeability and gas flux whilst maintaining separation efficiency for gas pairs such as O2-N2, CO2-O2 and CO2-N2.

20 May 2008 – Membrane Filtration: Innovations and Applications
Runcorn, UK

This one day meeting organized by the Filtration Society attracted a knowledgeable audience representing users, suppliers and academia both from the UK and further afield.  The meeting covered a technology update on a number of established membrane applications, as well as an overview of other membrane related techniques, with which some were less familiar but which play a vital role in the overall separation spectrum.

The first paper by Nicholas Heinen from Alfa Laval Product Centre, Denmark was entitled ‘Membrane bioreactor (MBR) technology and its influence on biological treatment’.  Nicholas presented a new microfiltration system developed by Alfa Laval that operates at very low pressures.  He went on to describe the outstanding issues in optimising the process and the consequences of MBR technology on the biological and sludge behaviour.

There then followed an informative paper from Richard Lewis of GE Water and Process Technologies entitled ‘Recent ERD applications’.  Richard explained that electrodialysis reversal is an electromechanical separation process in which ions are transferred through an ion exchange membrane by means of an electrical driving force.  Examples were presented covering a number of water and wastewater applications and illustrating where the technology can be used in place of,  and in combination with, reverse osmosis.

In continuation of the theme of ‘non traditional’ membrane technologies, Mario Roza from Sulzer Chemtech presented a most interesting paper on pervaporation and vapour permeation, technologies which are based upon diffusional flow through a dense membrane with partial pressure as the driving force.  Mario explained how the technology had been successfully integrated with distillation to provide an optimum solution for the separation of azeotropic mixtures.

The final speaker of the morning session was Mark Crooks of TSI Instruments who provided an overview of the different techniques available for membrane testing and how they could be applied for quality control and R&D purposes.

The afternoon session commenced with a presentation from Mike Bird of the University of Bath.  Mike commenced with some valuable hints for membrane filtration and chemical cleaning optimisation based upon a wealth of experience.  He went on to review recent papers on the ultrafiltration of tea to address the issue of tea cream, which causes haze and effects colour and taste of ready to drink teas.

We were grateful to Steve Tarleton from Loughborough University who stepped in as a last minute replacement and gave a most informative paper on the work performed at Loughborough on the improvement of fuel quality by means of solvent resistant nanofiltration membranes.  Undesirable solutes in an untreated fuel, which can lead to fouling of inlet valves and loss of combustion efficiency, can be removed by nanofiltration to give a fuel which burns more efficiently to give 10-15% lower CO and Nox emissions.

Back to beverages, but this time beer.  The paper presented by Gary Freeman of BRI entitled ‘Developments in the use of microfiltration in beer clarification’ provided an overview of the state of the technology today.  Clearly there is a big incentive to find an alternative to kieselguhr for environmental reasons, and finally microfiltration, after some 20 years development in this area, appears to offer a viable alternative with commercial installations both as a standalone system and in combination with centrifugation.

Finally, David Dubbin of GEA Process Engineering presented a paper illustrating how high temperature reverse osmosis membranes could be utilised to optimise process economics and to reduce carbon footprint by recovering water and energy from evaporator condensate and other waste streams within the production process.

28 October 2008 – Filter Testing and Standards
Chester, UK

Of all the technical seminars hosted by The Filtration Society over the last 40 years, filter testing has created the most interest and the recent one-day international seminar and exhibition held in the historic city of Chester was no exception. It is not too difficult to see why there is such an interest. Filter testing and pore size measurement, in particular, underpin the entire subject of filtration in all its diversifications.

After an amusing (and loud!) call to order by the husband and wife Town Criers, the seminar was introduced by Christophe Peuchot of IFTS, France and Stephen Smith of Parker Domnick Hunter (UK) who reviewed the current ISO status for wet and dry applications, respectively.

It was notable that in both areas, not only are the number of new standards being increased year on year, but also within the standards much higher precision is being demanded in the characterisation and measurement of particulate contaminants.

The two main methods of measuring pore sizes are challenge testing and porometry.

As the accuracy of challenge testing is dependent on an understanding of particle size, Keith Brocklehurst of LGC presented an enlightening paper entitled ‘Particle size – fact or fiction’ where he investigated many of the misconceptions associated with particle size and shape measurements. There then followed a number of papers discussing the latest techniques for wet and dry particle size measurements. These included optical and laser doppler microscopy, centrifugal sedimentation and laser particle counters.

The recent advances in challenge testing have enabled much more meaningful comparisons to be made with porometry. Whitehouse Scientific presented an interesting review of the latest spherical filter calibration standards and compared the results of challenge testing with porometry. Good comparisons between the techniques were only possible when there was rigorous attention to detail in each of the methodologies. It was encouraging to see three of the latest porometers represented at the conference: from Topas, Benelux Scientific and Porvair. These instruments are a welcome addition to porometry measurements and give the end user a much greater level of sophistication and choice.

One of the most stimulating sessions was the poster presentations where 5 minute ‘bursts’ of highly relevant information were given by 8 recognised experts in their field and resulted in a capacity attendance in the auditorium. To conclude the conference, a comprehensive coverage of filter test rigs, which comply with the various ISO standards was presented by Palas, TSI, IFTS and Topas.

Given the breadth and timeliness of subject matter presented, it is perhaps not surprising that the conference and exhibition attracted record numbers of attendees from all over the world. A book of proceedings of the seminar is available from the Honorary Secretary at richard.wakeman@lineone.net [6].