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Imprint
Collaborative project: Development of a retrofit solution for application of acid in slurry channels of animal barns. Subproject 1: Coordination (SAFT)
Project
Project code: 281B102316
Contract period: 01.09.2018
- 31.10.2021
Budget: 181,271 Euro
Purpose of research: Applied research
Keywords: emissions
The overall objective of the project is the development of a technology for reduction of ammonia (NH3) and methane (CH4) emissions from animal husbandry, especially from the storage of slurry in animal houses. By acidifying the slurry with a strong acid (e.g. sulfuric acid), the pH can be decreased below 5.5 so that NH4+/NH3-balance is shifted and there is no more NH3 formation in gaseous form. As a result, the manure value of the nitrogen in the slurry remains loss-free up to the field. By the pH shift, the typical microorganisms in the slurry are inactivated, which are located in the excretions or settle in the slurry channel. These include methane-forming microorganisms, which occur in particular in deeper anaerobic layers. Due to the microbial inhibition also a significantly reduced methane formation and thus an emission reduction on barn level is expected. The technology to be developed should consist of five components: - Safe and user-friendly logistics and handling of concentrated acid for application to the slurry, which is stored under the animals within the barn; - protective coatings for new and existing slurry channels made of concrete through plastic paint or synthetic resin paint; - distribution of the acid in the slurry to get a homogeneous pH; - Measurement technology for the continuous pH determination of the slurry; - Process computer for data acquisition and processing as well as for control of acid application (control and documentation of quantities and times). Before starting the investigation, the regulatory, construction and safety relevant questions should be clarified by literature research and expert surveys. Preliminary tests will be carried out to clarify which acids are suitable for the intended purpose, how the value for money and market availability should be classified and which ecological consequences are associated with the application during application. The addition of sulfuric acid to slurry is often discussed to cause increased releases of toxic hydrogen sulfide (H2S) (animal welfare and MAK value: 5 ppm). Therefore, outgassing of H2S from slurry after addition of sulfate and acidification is systematically investigated under laboratory conditions ex ante. First of all, a dosing and distribution system for acid application will be used in a test compartment at the teaching and research station Frankenforst of the University of Bonn. However, the pH of slurry influences the microbial mineralization of organic N compounds and thus has direct and indirect effects on the fertilizer value and the plant compatibility of the slurry. Therefore, the acidified slurry types are analyzed regarding their N fractions (Nt, Norg, Nmin) and tested for compatibility in a vessel experiment with ryegrass.
Section overview
Subjects
- Animal Husbandry
- Agricultural Technology Animal Production
- Climate Change
