Odor Floating Cover: Reduce Ammonia Emissions

Ammonia emissions into the atmosphere occur primarily from livestock buildings, manure storage facilities, during manure handling and treatment, and when manure is applied on land. It is a significant respiratory hazard for workers who experience continuous, long-term exposure to the gas and can cause skin and eye irritation. Long-term exposure to ammonia can cause pneumonia, both in livestock and workers.

The same practices that reduce ammonia emissions also reduce odour emissions. Hydrogen sulfides and other volatile organic compounds are noxious pollutants and are hazardous to workers’ health.

Adding a cover can significantly reduce odors from open manure storage facilities, as determined from both practical farm experience and controlled experiments. It creates an interface between the gas and the liquid constitutes a barrier to gas and odor transfer. The floating cover reduces the transfer of ammonia but also other odorous compounds (H2S) from the liquid to the atmosphere, basically due to an increase of the surface-to-air resistance at the liquid-air interface. The Hexprotect covers up to 99% of the total surface and can reduce odors by up to 90%.

Permeable covers, such as the the Hexprotect covers, have been shown to be more suitable for reducing odor from livestock manure facilities than impermeable material. An aerobic layer is established on the top of the cover, so that some of the odorous compounds that escape may be aerobically broken down before they are released to the atmosphere. Impermeable floating material allows odorous compounds to escape through leaks at joints and near the tank walls.

The main challenge most operators faces is to find an economical solution, both with initial and operating costs, and to minimize maintenance. Covers that have regular or even moderate labor requirements, such as solid covers, are at a definite disadvantage when compared to our modular covers that require no maintenance at all.

Air-filled balls have also been used as a Odor Floating Cover for outdoor manure storage facilities. One study reported about 15% ammonia losses from cattle slurry, and between 5% and 12% from pig slurry as compared to 100% losses from uncovered control tanks.