The Filtration Society was founded in London over 40 years ago with the objective of collating existing filtration and separation technologies, actively promoting new developments and providing an important resource centre for all filter related industries.
Although in the past the focus has been on novel filtration technologies driven by commercial considerations, the last few years have seen an exponential increase in environmental related issues. Unfortunately, the mention of the environment to an industrialist often brings with it thoughts of a cost penalty but it is encouraging to see a distinct cultural shift towards environmentally friendly filtration technologies. The motivation has been largely due to a ‘carrot and stick’ approach.
There is little doubt that the environment could not sustain the rate of pollution initiated at the time of the industrial revolution and unless stringent measurements were taken, the world would very soon become poisoned by its own effluent. Legislation was therefore inevitable. Scientific conferences sponsored by The Filtration Society are now becoming very popular. Here it is possible to hear of the latest emission standards and the implication on industrial processing. Contrary to popular belief, working alongside the legislators can have significant commercial advantages, not just in clarifying existing legislation, but in having an insight into proposed new legislations.
Input from the Environment Agency can be commercially very valuable on two counts. Firstly, their wealth of experience, often in similar industries, can result in considerable savings. Secondly, and rather paradoxically, the legislation itself can force industry to ‘think outside the box’ and turn a problem into a solution.
Take for example the cheese industry. Traditionally and quite naturally, cheese was the primary product and the waste, the whey, was the problem because it could no longer be discharged into rivers.
As incineration costs were prohibitively high, the solution was to use the latest ultrafiltration equipment to concentrate the whey and to reprocess it into yoghurts and the latest prebiotic drinks. What used to be the problematic waste suddenly became the most profitable line!
Science or media driven
It is well known that those with the loudest voices get heard, unfortunately very often above the scientific argument. We must be careful therefore that environmental hazards are not ranked according to media pressure. For example, Dioxins are a very emotive group of pollutants from incineration, simply because they have received extensive press coverage. The air emission limit has therefore been set at 0.1 nanograms per cubic meter. Heavy metals, on the other hand, do not sound nearly as dangerous and have received comparatively little press coverage.
Consequently, the limit is 0.5 milligrams per cubic meter, a 5000-fold increase in concentration. It was reported recently that Alzheimer’s disease is increasing at a frightening rate. As rational scientists, we would be foolish to exclude a link to heavy metal atmospheric pollution. A pollution-free environment demands the elevation of science to a role above the media in setting our limits on the various pollutants.
A combination of media attention and legislation can result in an acceleration in the development of novel filtration processes. A major problem in incineration has been in the filtration of hot gases in excess of 400°C. The Dioxin emission problem forced filter manufacturers to develop high efficiency, hot gas filters, which eliminated the costly stage of having to cool the gases before passing through traditional fabric bag filters.
An additional advantage of filtering at high temperature is that the ceramic filters can be chemically profiled to remove harmful heavy metal vapours that would otherwise be released to atmosphere.
The biggest challenge
Without doubt the biggest challenge facing filtration technology, both in terms of scale and complexity, is in the treatment of flue gases from coal fired power stations. Enormous strides have been made in recent years in the desulphurisation process and it is now possible to remove up to 98% of sulphur dioxide from the flue gases. However, the real challenge is to remove the carbon dioxide as well. It is a thought provoking statistic that a single power station in the UK can produce 750 kg of carbon dioxide a second! Multiply that by the number of coal fired power stations in existence and we see the magnitude of the problem facing our environment in the future.
Filtration processes have reached such an advanced stage that carbon dioxide can be filtered out of air on a molecular level. Unfortunately the scale does not yet match that required for power stations but there are encouraging signs that the process will ultimately be scalable. Even if the carbon dioxide could be collected, the next problem is what to do with it.
Bury the evidence
One possible solution, at least from the UK perspective, is to utilise the depleted oil field caverns deep below the North Sea, many of which had stored methane safely for millions of years. There is currently a 2 billion dollars incentive from the government to make the technology work and applications for the grants are at an advanced stage. Unfortunately this can only ever be a temporary solution as these storage facilities are of finite size and limited to the UK’s carbon dioxide waste. Furthermore, the possibility of geological haemorrhaging can never be totally ruled out.
As an independent, not for profit organisation, The Filtration Society is playing an increasing role in catalysing the development and application of new filter technologies. A really encouraging feature of the one day symposia is the extent to which leading companies are prepared to share their knowledge and so advance the development of new technologies.
Published: 01st Jan 2007 in AWE International