Envirotec

It’s still a work in progress

As social and economic views on the environment and the way in which we treat our waste are becoming a part of common culture the importance of odour control is coming to the fore.

As social and economic views on the environment and the way in which we treat our waste are becoming a part of common culture the importance of odour control is coming to the fore

IT can be seen by the increased interest shown by both Government bodies and the media that the issue of odour control is now more apparent.

The introduction of IPPC across a variety of sectors has already led to an increased interest in odour control. The final introduction of IPPC H4 guidance notes on odour regulation and permitting has focused industry attention further. It is also a part of the planning processes along with implementation of odour management plans.
As industries become more regulated the view of odour control is changing. In the past, control was delegated out and a quick, simple and cheap solution was all that was required, often resulting in the most convincing sales pitch being the winner. The resulting odour control systems differ drastically in their performance and suitability and have shaped many of the perceptions seen within today’s industry.
However, the new perspective given to odour control is of a much more scientific nature. Specialists are being employed to manage the problem and increased emphasis is placed on surveying and dispersion modelling. This is especially true of the wastewater industry which in general is a more mature market than that of the other waste treatment processes.
So how does the odour and air pollution control industry match the growing needs of increasing legislation, clients and their neighbours? One company that has responded is OSIL which offers a range of bespoke techniques. “By providing a solution-based philosophy to our customers we have recognised the importance of a scientific approach to match our customers’ requirements. Compare this to the traditional model of a ‘one technology fits all’ scheme,” said technical director Matthew Wilkes.
OSIL has carved out market through an in-house capability to design, manufacture, build, install, commission, service and maintain systems. It has developed its own range of technologies using biofiltration, dry media adsorption, wet scrubbing systems either bio or chemical, or ionisation, simple dosing or a simple change in process to negate odour.
However, the company is aware that when some clients ask for innovation what they are really saying is that they want the cheapest option. “It is a widely seen misconception that odour control has not changed within the last 20 years. It is true to say that there are still the main three categories of odour control: chemical scrubbing, biofiltration/ bio-scrubbing and adsorption. But these have evolved beyond all recognition through the appliance of science,” Wilkes pointed out.
New permanent bio-scrubbing media can halve the footprint of a traditional filter whilst increasing its efficiency from 80% to >98%. Adsorption media such as activated carbons and alumina are constantly under development to improve both adsorption capacity and chemical specificity. A range of impregnated carbons (and to some extent alumina) is now available, allowing selection of the most appropriate for any specific contaminate stream or moisture handling capability. By combining these dry media it is now possible to treat a vast array of compounds within a single stream where once this was not achievable.
Unfortunately, due to inappropriate use – or absence of – service and maintenance for some technologies there has been subsequent schemes being over-complicated, over specified and expensive to both run and maintain with the general perception that some technologies will not be considered at all as a solution route.
Having carried out research and development OSIL managed to push the boundaries that have, traditionally, been the Achilles heel for some technologies. For example, it developed a bio-scrubber handling in excess of 900ppm of hydrogen sulphide with a removal efficiency of 98% in an ambient temperature approaching 48 deg C.
In proposing its own LavaRok bio-scrubbing technology OSIL said it is offering a media life for biofilter media of 25 years coupled together with its own range of biotechnology and CuCARB impregnated carbon technology, can offer a true wastewater odour treatment system able to treat a range of air pollution issues and odour problems.
By developing a range of inoculums that are designed purposely to treat odorous contaminates, the LavaRok hybrid bio-scrubber can now treat a range of compounds to a greater than 97% removal. This includes the standard wastewater contaminates; hydrogen sulphide, mercaptans and the various other organosulphides present, but also includes a variety of other compounds such as VOCs, amines and ammonia. This now allows the use of biological systems within a much wider field and opens up options within, for example, the solid waste industries that have yet to be fully explored.
Taken even further these systems are being used to address the issues found in biogas enrichment, air pollution control and even landfill gas clean up.
This can only be achieved with a strong partner organisation. In this case OSIL partnered with University of Wolverhampton and its school of applied sciences under the leadership of Dr David Hill.
Wilkes went on: “We are, however, only now at the brink of discovering the true range of technologies that can be used within the odour control industry and air pollution control.”
The latest generation of ionised air (plasma) systems that alleviate the potential rise of harmful side emissions such as ozone, NOx or hydroxyls is now available. These new systems can enhance the portfolio of systems and services currently on offer.
The environmental demands now placed on us all increases the interest in more long-term, energy efficient systems and places much more emphasis on consideration of the end of life problems that can be caused by the use of chemical systems.
“The most environmentally friendly method of odour control is to re-use and maintain the existing system. How many systems are all too often simply switched off and never looked at again? Old odour control units can often either be re-furbished or converted into new, more efficient, systems,” Wilkes contends. “Frequently this has the added bonus of being able to increase the airflow treated by the system as newer technologies work on lower retention times. The long-term planned maintenance of these systems not only ensures that they are operational but also elongates their serviceable lifetime and ensures that the system is running efficiently keeping energy requirements at a minimum.
“Further to this, the energy efficiency of the systems being installed is currently being addressed by the use of high efficiency fan motors and lower pressure drops across the newer systems.”
So yes, odour control remains a work in progress. But it has turned into a science that can be applied to reduce air pollution, enrich biogas, and other applications. It isn’t just for getting rid of that smell!

Image – Odour control has moved higher up the agenda.

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