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Reduced odour from pig farms

Reduced odour from pig farms

Researchers at Aarhus University are leading a project on biological air purification for pigsties in combination with local exhaust ventilation. The hope is to reduce the nuisance caused by odour from pig farms significantly (Photo: Aarhus Universitet)


An innovative new ventilation system will help Danish livestock production to cope with more of the environmental challenges that the industry is facing.

better indoor environment for employees in the pigsties, a considerable reduction in emissions and the development of an effective biological air purification method with large national and international market potential.

These are the very promising ambitions for a new research project with participation of researchers from Aarhus University who are working on biological air purification for pigsties in combination with a new ventilation principle, so-called local exhaust ventilation, that draws odour from manure out through the floor under the pigsties.

Under-floor air evacuation
Local exhaust extraction from the floor in combination with biological purification make it possible to get rid of large amounts of ammonia and odours from the pigsties in an effective and inexpensive way while, at the same time, reducing the volume of waste water which is today associated with cleaning.

Instead of cleaning all the air in the pigsty, the researchers concentrate on ammonia and odours which are given off in the slurry channel and therefore can be captured in a ventilation flow that only consists of 10-20 percent of the total amount of ventilation.

At the same time, the combined purification and extraction technology can reduce the nuisance caused by odour for the surroundings by up to 80 percent.

No more stench of manure
The method is particularly effective in removing the gas hydrogen sulphide which is one of the most important causes of the nasty smell from pigsties. So far this has been a complicated process if costs are to be kept at a realistic level. But it looks as if the new method can promote oxidation of the hydrogen sulphide so that the total environmental impact from livestock production is reduced significantly.

Smart ventilation

The ventilation system combines mechanical floor ventilation with natural ventilation in a new hybrid system that provides a better indoor environment in the pigsties. This benefits both the animals and humans while at the same time reducing the nuisance caused by odour for the surroundings. The systems are being developed in a way that will consume less energy overall while ensuring that the animals receive fresh air.

Part of the system’s ventilation air is delivered directly into the animals’ inhalation zones and is then evacuated down through the slated floors. In this way, the majority of ammonia is collected, which reduces the air demand and thus also the energy consumption of the ventilation.