Odour control in industry: from complaint to working solution

Many industrial processes come with a smell. That has always been the case, but tolerance in the surrounding area has changed considerably. Where local residents used to accept that the factory in town simply smelled, they now file a complaint with the municipality or environmental authority much sooner. At the same time, standards are becoming stricter. For manufacturers, odour control is no longer a side issue but a precondition for continuing production undisturbed. In this blog, you will read where industrial odour nuisance comes from, which approach works and why one large central filter is not always the best choice.

Why odour complaints around industry are increasing

Residential areas are moving ever closer to industrial estates, and many older companies have always been located in the middle of built-up areas. On top of that, people have become more vocal and more critical, and rightly so. Nobody sitting in their back garden at a barbecue wants the smell of rotten eggs from a sewage pumping station or a production hall. In addition, an unfamiliar smell quickly raises the question of whether the air is harmful, even when it is purely an odour issue.

Odour is also subjective. The smell of fresh bread or roasting meat is pleasant when you walk past occasionally, but anyone exposed to it every day soon experiences it as a nuisance. That is exactly why industrial odour control is always tailored: it is not only about what is in the air, but also about where and how often local residents smell it.

The most common odour sources in industry

In practice, we mainly encounter three groups of odorous substances:

• VOCs (volatile organic compounds), such as solvents and other chemical compounds. These are common in the process industry and the food industry.
• H2S (hydrogen sulphide) and other sulphides, which are produced by decay processes and occur mainly in (industrial) wastewater treatment and the meat processing industry.
• NH3 (ammonia), among others in wastewater treatment and manure processing.

More and more large manufacturers also operate their own wastewater treatment plant. As a result, the odour issues known from municipal sewage treatment plants now also arise within factory walls. Read more on our page about water treatment and sewage works.

An odour filtration system matched to the production process

Good advice starts with knowledge of the exhaust air. Which substances does it contain and in what concentration? But it does not stop there. Temperature, relative humidity and how the load varies over the day also determine which filter medium works and how long it lasts. Once these data are known, we can calculate the expected service life and carbon consumption quite accurately.

The extraction method is at least as important. That a certain medium captures a certain gas is not rocket science. Determining the right extraction capacity at the source is. If, for example, you extract a tank too hard without a proper air supply, you force air out of the tank that would otherwise not escape. Often it is enough to relieve the overpressure and create a limited air change rate. With decades of experience in air technology, this is exactly where our team makes the difference.

Central or decentralised: why smaller is often smarter

The traditional approach is central extraction: all odour sources are connected via one ductwork system to one large central filter. That seems efficient, but it has clear drawbacks:

• Every odour source has its own characteristics, while a central filter is designed for one mixed air stream.
• An extensive ductwork system has to be balanced carefully. Air always takes the path of least resistance: adjust one damper and something changes at another.
• The investment in ductwork is high.
• If the fan or filter fails, the entire odour control system comes to a standstill.

With a decentralised approach, we place smaller, stand-alone odour filtration systems at one or a few odour sources. That means shorter ducts, a lower and faster investment and less vulnerability: if one unit fails, the others keep working. You can also work in phases.

Example: step by step within the limit

In the food industry, we have applied a decentralised approach at several company wastewater treatment plants. First, we tackle the sources causing the most nuisance, within the investment budget available at that moment. The installation is then refined further, source by source, until total emissions fall within the permitted limit. This delivers immediate results in the surrounding area, without having to build one large central system in one go.

For larger air flows, we supply filtration systems of up to 50,000 m³/h per unit, such as our DBS multi-stage deep bed scrubber. Several units can be installed in parallel, making flow rates of around 100,000 m³/h achievable.

Odour legislation and regulations

Which requirements apply depends on the company's environmental permit, location and process. Outside the plant, environmental legislation applies, with the environmental authority as the supervisor; in the Netherlands, this is the Environment and Planning Act. Inside the factory, occupational health and safety legislation also applies to employee exposure. With a well-founded justification of the chosen solution, and measurements before and after the filter where needed, you can demonstrate to the authorities that odour emissions are under control.

Conclusion: odour control as an investment in your operations

Industrial odour control starts with understanding your odour sources and ends with an installation that suits your process, your budget and your surroundings. A decentralised setup with targeted odour filters per source is often faster, cheaper and more reliable than one central system. Would you like to know which approach suits your production site? Take a look at our solutions for industry and odour control, or schedule a free consultation with one of our specialists.