Acidification of slurry to reduce ammonia and methane emissions: Deployment of a retrofittable system in fattening pig barns

Veronika Overmeyer; Manfred Trimborn; Joachim Clemens; Richard Hölscher; Wolfgang Büscher

doi:10.1016/j.jenvman.2023.117263

Acidification of slurry to reduce ammonia and methane emissions: Deployment of a retrofittable system in fattening pig barns

J Environ Manage. 2023 Apr 1:331:117263. doi: 10.1016/j.jenvman.2023.117263. Epub 2023 Jan 18.

Authors

Veronika Overmeyer¹, Manfred Trimborn², Joachim Clemens³, Richard Hölscher⁴, Wolfgang Büscher⁵

Affiliations

¹ Institute of Agricultural Engineering, University of Bonn, Nußallee 5, 53115, Bonn, Germany. Electronic address: overmeyer@uni-bonn.de.
² Institute of Agricultural Engineering, University of Bonn, Nußallee 5, 53115, Bonn, Germany. Electronic address: m.trimborn@uni-bonn.de.
³ SF-Soepenberg GmbH, Emil-Fischer-Straße 14, 46569, Hünxe, Germany. Electronic address: j.clemens@soepenberg.com.
⁴ Hölscher + Leuschner GmbH & Co. KG, Siemensstraße 15, 48488, Emsbüren, Germany. Electronic address: R.Hoelscher@hl-agrar.de.
⁵ Institute of Agricultural Engineering, University of Bonn, Nußallee 5, 53115, Bonn, Germany. Electronic address: buescher@uni-bonn.de.

PMID: 36669315
DOI: 10.1016/j.jenvman.2023.117263

Abstract

Livestock farming, and in particular slurry management, is a major contributor to ammonia (NH₃) and methane (CH₄) emissions in Europe. Furthermore, reduced NH₃ and CH₄ emissions are also relevant in licensing procedures and the management of livestock buildings. Therefore, the aim is to keep emissions from the barn as low as possible. Acidification of slurry in the barn can reduce these environmental and climate-relevant emissions by a pH value of 5.5. In this study, an acidification technology was retrofitted in an existing fattening pig barn equipped with a partially slatted floor. The slurry in a compartment with 32 animals was acidified. An identical compartment was used for reference investigations (case-control approach). Several times a week slurry was pumped for acidification in a process tank outside the barn compartment in a central corridor, where sulphuric acid (H₂SO₄) was added. Then the slurry was pumped back into the barn. In contrast to other systems, where acidified slurry was stored mainly in external storage tanks, in this study the slurry was completely stored in the slurry channels under the slatted floor, during the entire fattening period. The emission mass flow of NH₃ and CH₄ was measured continuously over three fattening periods, with one period in spring and two periods in summer. On average 17.1 kg H₂SO₄ (96%) (m³ slurry)^-1 were used for acidification during the three fattening periods. NH₃ and CH₄ emissions were reduced by 39 and 67%, respectively. The hydrogen sulphide (H₂S) concentration in the barn air of the acidification compartment was harmlessly low (0.02 ppm). Thus, despite the storage of the acidified slurry in the barn, the system leads to a lower concentration of detrimental gases, which is beneficial for the animals' as well as for the workers' health. The study shows that it is possible to retrofit acidification technology into existing pig barns. Further investigations shall identify possible measures to reduce the amount of H₂SO₄ used and thus minimise the sulphur input into the slurry.

Keywords: Animal manure; Climate protection; Emission reduction technology; Manure management; Sulphuric acid.

MeSH terms

Ammonia* / analysis
Animals
Gases
Hydrogen-Ion Concentration
Manure
Methane*
Swine

Substances

Ammonia
Methane
Manure
Gases