Improved effect of manure acidification technology for gas emission mitigation by substituting sulfuric acid with acetic acid

Fuchs, Andrea; Dalby, Frederik R.; Liu, Dezhao; Kai, Peter; Feilberg, Anders

doi:10.1016/j.clet.2021.100263

Cited by 13 publications

(8 citation statements)

References 47 publications

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“…Therefore, some other acids are being considered as well, such as organic acids. Fuchs et al (2021) have described that acetic acid even gives a better result probably because of the antimicrobial activity of acetic acid. Since these acids can be converted to methane, the cost of their use can be compensated by the yield of methane.…”

Section: Acidification Of Manure Storagesmentioning

confidence: 99%

Options to improve the nitrogen use efficiency in the Dutch agriculture sector

Lesschen

Sanders

2023

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Section: Acidification Of Manure Storagesmentioning

confidence: 99%

Options to improve the nitrogen use efficiency in the Dutch agriculture sector

Lesschen

Sanders

2023

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“…In untreated slurry, H 2 S is produced mostly from sulfate reduction, but slurry acidification with H 2 SO 4 and hydrochloric acid has been found to inhibit sulfate reduction. Although laboratory studies indicate that H 2 SO 4 has only minor effects on total odor emissions, , the effects of slurry acidification on the odor profile should be documented to avoid pollution swapping.…”

Section: Introductionmentioning

confidence: 99%

Low-Dose Acidification as a Methane Mitigation Strategy for Manure Management

Dalby

Feilberg

et al. 2022

ACS Agric. Sci. Technol.

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Excreta from housed animals are typically stored before land application, and storage is an important point source of CH4, N gases, and odor. This study explored acidification as a strategy for greenhouse gas (GHG) mitigation, specifically the potential to reduce the acid dose to improve cost-effectiveness and minimize environmental impacts. Pig slurry was stored with five doses of concentrated sulfuric acid [1.2–6.0 kg (m3 of slurry)−1] for 63 days. Emissions of CH4 and NH3 were reduced by 46–96% and 33–78%, respectively, with an increase in the acid dose. Odorant emissions, dominated by 4-methyphenol and H2S, were strongly suppressed by acidification. Below pH 6, methanogen inhibition was most likely due to undissociated VFAs, and above pH 6, the inhibition could involve competition from sulfate reducers and inhibition by undissociated H2S. If 1, 3, or 10 acidification treatments were needed, the annual costs for GHG mitigation across the five acid doses were 28–47, 44–57, and 93–134 € (ton of CO2 equivalents)−1, respectively. With 1 or 3 treatments, the most cost-effective acid dose was 2.1 kg m–3, or 3.2 kg m–3 with 10 treatments. This study strongly suggests that low-dose acidification is a viable strategy for GHG mitigation.

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“…Lowering the slurry pH also reduces CH 4 emission, but the mode of inhibition is not completely understood. Common practice is to lower the pH to 5.5 with H 2 SO 4 with reported CH 4 reductions of 63–99% [ 6 ]. Proposed inhibition mechanisms include H 2 S-mediated inhibition [ 7 ], which is mainly derived from sulfate reduction [ 8 ], uncoupling of the cell membrane by protonated fermentative products [ 9 , 10 ], or competitive inhibition of methanogens by microorganisms able to respire more energetic electron acceptors [ 11 ].…”

Section: Introductionmentioning

confidence: 99%

“…It appears difficult to avoid N 2 O emission from sole HNO 3 treatment, but combining acids might generate synergistic effects. Lately, CH 4 emission from slurry was reduced by combining H 2 SO 4 with acetic acid as compared to pure H 2 SO 4 treatment to pH 5.5 [ 6 ]. This effect was possibly related to protonated acetic acid uncoupling the cell membrane [ 9 , 10 ] and draws attention to the idea of combining organic and inorganic acids to achieve synergistic mitigation effects.…”

Section: Introductionmentioning

confidence: 99%

Reducing greenhouse gas emissions from pig slurry by acidification with organic and inorganic acids

2022

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Methane (CH4) emission from pig slurry is a large contributor to the climate footprint of livestock production. Acidification of excreta from livestock animals with sulfuric acid, reduce CH4 emission and is practiced at many Danish farms. Possible interaction effects with other acidic agents or management practices (e.g. frequent slurry removal and residual slurry acidification) have not been fully investigated. Here we assessed the effect of pig slurry acidification with a range of organic and inorganic acids with respect to their CH4 inhibitor potential in several batch experiments (BS). After careful selection of promising CH4 inhibitors, three continuous headspace experiments (CHS) were carried out to simulate management of manure in pig houses. In BS experiments, more than <99% CH4 reduction was observed with HNO3 treatment to pH 5.5. Treatments with HNO3, H2SO4, and H3PO4 reduced CH4 production more than acetic acid and other organic acids when acidified to the same initial pH of 5.5. Synergistic effects were not observed when mixing inorganic and organic acids as otherwise proposed in the literature, which was attributed to the high amount of acetic acid in the slurry to start with. In the CHS experiments, HNO3 treatment reduced CH4 more than H2SO4, but increased nitrous oxide (N2O) emission, particularly when the acidification target pH was above 6, suggesting considerable denitrification activity. Due to increased N2O emission from HNO3 treatments, HNO3 reduced total CO2-eq by 67%, whereas H2SO4 reduced CO2-eq by 91.5% compared to untreated slurry. In experiments with daily slurry addition, weekly slurry removal, and residual acidification, HNO3 and H2SO4 treatments reduced CO2-eq by 27% and 48%, respectively (not significant). More cycles of residual acidification are recommended in future research. The study provides solid evidence that HNO3 treatment is not suitable for reducing CO2-eq and H2SO4 should be the preferred acidic agent for slurry acidification.

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Improved effect of manure acidification technology for gas emission mitigation by substituting sulfuric acid with acetic acid

Cited by 13 publications

References 47 publications

Options to improve the nitrogen use efficiency in the Dutch agriculture sector

Options to improve the nitrogen use efficiency in the Dutch agriculture sector

Low-Dose Acidification as a Methane Mitigation Strategy for Manure Management

Reducing greenhouse gas emissions from pig slurry by acidification with organic and inorganic acids

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