FAQ air treatment Frequently Asked Questions

What can we do to prevent air pollution from combustion processes?

During incomplete combustion of a fuel, air pollutants can be released. Many of these pollutants cause environmental problems. An example of an air pollutant that is emitted during combustion processes is sulphur dioxide. To prevent this problem we can switch over to fuels that contain less to no sulphur. We have been reviewing this problem for quite some time now and we have already switched on to natural gas instead of fuel oil for energy conversion, in most cases.
Other air pollutants that are emitted during combustion processes are nitrogen oxides. To prevent nitrogen oxide emissions, we have to pay attention to the concentrations of oxygen that is added during production processes. When the oxygen concentration exceeds a certain limit, oxygen and nitrogen may react to form nitrogen oxides. However, when the oxygen concentrations are too low, other substances such as sulphur dioxide may be released into the air.
To prevent air pollution during production processes, technical measures can be taken, in order to adjust processes. Industries can utilize cleaner production techniques, such as alternative distiller techniques, fume treatment and selective catalytic reduction.

How can we prevent emissions of dust particles?

To prevent emissions of dust particles we can take them away during the production process, by utilizing the forces that influence the dust particles. In a settling basin particles can settle under the influence of gravity. This method can only be applied for substantial dust particles. For smaller particles the centrifugal force can be applied in a cyclone. The air that needs to be freed from dust particles circulates within the cyclone. During this circulation process dust particles are thrown back against the outer walls of the cyclone, after which they will fall through a pipeline, to be caught up in a basin. The particles can be taken away after that.
For the separation of dust particles from air we can also use filters or washers.
Filters use the principle of separate particle sizes. Larger particles will stay behind on the filter, whereas air will flow through.
In washers the air comes in contact with water droplets. The dust that is in the air at that point will stay behind in the droplets and because of that the air is cleaned.

How can gaseous pollutants be removed from air?

Gaseous pollutants can be removed from air by means of gas washing (removal of gas by dissolving it in a liquid), by adsorption on a solid or by converting it to other, less damaging gasses.

Sometimes certain powders or granule solids can absorb an air pollutant. The air that needs to be purified is directed through an active carbon system or through metal oxides. The gasses can be freed again afterwards, by heating the absorbent.

Some gasses can be destroyed through heating.

What measures can we take to prevent air pollution by traffic?

Traffic is the largest source for the emission of greenhouse gasses. A number of measures can be taken to prevent emissions of air pollutants by traffic.
- Car engines can be readjusted, so that air pollution will no longer be emitted.
- Catalysers can be added to car exhausts, to decrease concentrations of combustible gasses.
- Instead of using a diesel- or gasoline-based engine, we can use engines that work on a different fuel type. There are opportunities to make cars drive by using gas, hot air, steam or hydrogen as a car fuel, or by letting cars drive on electricity, for example through solar cells. All these opportunities have been researched and right now the electro engine seems most likely to be the solution of the future.

What can we do against biologically degradable air pollutants from farmland?

On farmland manure is often applied to make sure that the plants a farmer grows will get all the necessary nutrients. However, this manure often causes ammonia to enter the air. When this pollutant ends up in the ground through air, it can cause acidification and over fertilization.
There are a few measures we can take:
- We can make sure that less ammonia enters the air by injecting manure into the ground, instead of spreading it directly on the farmland. Purifying air in stables and manure cellars may also prevent environmental impact.
- Particles that are biologically degradable, such as ammonia, can be caught in a bio filter. In a bio filter we place some compost, mixed with some filler. On this material, in a mucous layer called bio film, microrganisms will become active and start decomposing the contaminants.
- Another method that can be applied is cleaning polluted air in a bio washer. In a bio washer air is absorbed on water that streams along a package. On this package microrganisms are present, which can convert pollutants aerobically.

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