Impact of slurry removal frequency on CH4 emission and subsequent biogas production; a one-year case study

Feng, Lu; Guldberg, Lise Bonne; Hansen, Martin N.; Ma, Chun; Ohrt, Rikke Vinther; Møller, Henrik Bjarne

doi:10.1016/j.wasman.2022.06.024

Cited by 7 publications

(10 citation statements)

References 14 publications

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“…Carbon dioxide emission from the manure was not significantly different in any of the sections, and differences in CH 4 /(CH 4 + CO 2 ) fractions between treatments hence reflect primarily differences in methanogenic activity. A CH 4 /(CH 4 + CO 2 ) fraction in the range of 20–40% was recently reported from the slurry sampled from the same measuring campaign as this study . In that study, an assay eliminated slurry surface respiration by incubation of the slurry with nitrogen in the headspace, explaining the large difference from our in situ measurements.…”

Section: Resultssupporting

confidence: 46%

“…However, simulations suggest that with some parameter values, including the best-fit parameter set, there is no increase or even reduction of methane emission from the storage (Figure 5B, storage plots), despite more organic matter being transferred to the outside storage. This results from multiple mechanisms being triggered or enhanced with more frequent slurry removal: (i) lower concentrations of the dominant m1 methanogen in the slurry exported to the storage due to a limited growth period in the barn, which is consistent with Feng et al, 4 measuring lower specific methanogenesis activity in the frequently removed slurry; (ii) hydrolysis of degradable VS is not rate-limiting and hence increased transfer of organic matter has little influence on methane emission; (iii) stronger inhibition of methanogens in the storage, due to increased concentrations of hydrogen sulfide, but reductions were also estimated without inhibition from hydrogen sulfide (not shown). One should be cautious with model interpretations from storage simulations since the datasets used for obtaining the best-fit parameter estimates did not change much in temperature and therefore do not reflect well the temperature effect on microbial activity at low temperatures.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…A CH 4 /(CH 4 + CO 2 ) fraction in the range of 20–40% was recently reported from the slurry sampled from the same measuring campaign as this study . In that study, an assay eliminated slurry surface respiration by incubation of the slurry with nitrogen in the headspace, explaining the large difference from our in situ measurements.…”

Section: Resultsmentioning

confidence: 99%

“…In many regions with intensive livestock production, manure from pigs and cattle is managed as the liquid slurry in pits and channels underneath the barn floor. In such systems, the slurry environment is anaerobic, and anaerobic microbes transform organic matter to methane and carbon dioxide. , The biological processes driving organic matter transformation depend strongly on temperature. − Therefore, strategic removal of slurry from pig houses with a temperature around 20 °C to cold outside storages or anaerobic digesters can reduce net methane emission from the whole management chain. In Danish finisher pig houses, slurry pits underneath the floor are typically 40–60 cm deep, and the slurry is removed with a vacuum flushing system when the pit is nearly full (after 5–6 weeks).…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Simple Management Changes Drastically Reduce Pig House Methane Emission in Combined Experimental and Modeling Study

Dalby

Hansen

Guldberg

et al. 2023

Environ. Sci. Technol.

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Reducing methane from livestock slurry is one of the quickest ways to counteract global warming. A straightforward strategy is to reduce slurry retention time inside pig houses by frequent transfer to outside storages, where temperature and therefore microbial activity are lower. We demonstrate three frequent slurry removal strategies in pig houses in a year-round continuous measurement campaign. Slurry funnels, slurry trays, and weekly flushing reduced slurry methane emission by 89, 81, and 53%, respectively. Slurry funnels and slurry trays reduced ammonia emission by 25–30%. An extended version of the anaerobic biodegradation model (ABM) was fitted and validated using barn measurements. It was then applied for predicting storage emission and shows that there is a risk of negating barn methane reductions due to increased emission from outside storage. Therefore, we recommend combining the removal strategies with anaerobic digestion pre-storage or storage mitigation technologies such as slurry acidification. However, even without storage mitigation technologies, predicted net methane reduction from pig houses and following outside storage was at least 30% for all slurry removal strategies.

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Section: Resultssupporting

confidence: 46%

Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Simple Management Changes Drastically Reduce Pig House Methane Emission in Combined Experimental and Modeling Study

Dalby

Hansen

Guldberg

et al. 2023

Environ. Sci. Technol.

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“…In recent years, efforts have been made to reduce CH 4 and NH 3 emissions from pig houses, leading to the development of low-emission housing systems [ 5 ]. One effective approach to reducing these emissions is frequent daily removal of manure by flushing the pit beneath the slatted floor [ 17 , 18 , 19 , 20 , 21 ]. This measure can be implemented in various forms and at different levels on farms.…”

Section: Introductionmentioning

confidence: 99%

Model Adaptation and Validation for Estimating Methane and Ammonia Emissions from Fattening Pig Houses: Effect of Manure Management System

Sefeedpari,

Pishgar-Komleh,

Aarnink

2024

Animals

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This paper describes a model for the prediction of methane and ammonia emissions from fattening pig houses. This model was validated with continuous and discrete measurements using a reference method from two manure management systems (MMS): long storage (LS) in deep pits and short storage (SS) by daily flushing of a shallow pit with sloped walls and partial manure dilution. The average calculated methane and ammonia emissions corresponded well with the measured values. Based on the calculated and measured results, the average calculated CH4 emission (18.5 and 4.3 kg yr−1 per pig place) was in between the means from the continuous data from sensors (15.9 and 5.6 kg yr−1 per pig place) and the means from the discrete measurements using the reference method (22.0 and 3.1 kg yr−1 per pig place) for the LS and SS systems, respectively. The average calculated NH3 emission (2.6 and 1.4 kg yr−1 per pig place) corresponded well with the continuous data (2.6 and 1.2 kg yr−1 per pig place) and the discrete measurements using the reference method (2.7 and 1.0 kg yr−1 per pig place) from LS and SS, respectively. This model was able to predict the reduction potential for methane and ammonia emissions by the application of mitigation options. Furthermore, this model can be utilized as a predictive tool, enabling timely actions to be taken based on the emission prediction. The upgraded model with robust calculation rules, extensive validations, and a simplified interface can be a useful tool to assess the current situation and the impact of mitigation measures at the farm level.

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Pig manure degradation and carbon emission: Measuring and modeling combined aerobic–anaerobic transformations

Dalby,

Hafner,

Ambrose

et al. 2024

J of Env Quality

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Greenhouse gas emissions from liquid livestock manure storage significantly contribute to global warming. Accurate farm‐scale models are essential for predicting these emissions and evaluating manure management strategies, but they rely on multiple parameters describing carbon loss dynamics. Surface respiration may significantly influence carbon loss and methane emission, yet it is not explicitly included in current models. We conducted experiments to measure pig manure surface respiration rate and its effect on organic matter degradation and methane and carbon dioxide emissions. Manure was incubated for 283 days at 10°C or 20°C under aerobic or anaerobic conditions, while measuring methane and carbon dioxide emission. This was followed by anaerobic digestion at 38°C. Surface respiration reduced the organic matter content, and the effect was temperature dependent. Methane emission was not affected by surface respiration, suggesting that substrate availability was not rate‐limiting for methanogenesis. Surface respiration rates were 18.1 ± 3.5 g CO2 m−2 day−1 at 10°C and 37.1 ± 13.1 g CO2 m−2 day−1 at 20°C (mean ± standard deviation) and were consistent with microsensor measurements of oxygen consumption in different manure surfaces. Based on these results, temperature‐ and surface area‐dependent respiration was incorporated in the existing anaerobic biodegradation model (ABM). Simulations showed that surface respiration accounts for 29% of carbon losses in a typical pig house and 8% for outdoor storage. Developing and refining algorithms for diverse carbon transformations, such as surface respiration, is crucial for evaluating the potential for methane emission and identification of variables that control emissions at the farm scale.

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Impact of slurry removal frequency on CH4 emission and subsequent biogas production; a one-year case study

Cited by 7 publications

References 14 publications

Simple Management Changes Drastically Reduce Pig House Methane Emission in Combined Experimental and Modeling Study

Simple Management Changes Drastically Reduce Pig House Methane Emission in Combined Experimental and Modeling Study

Model Adaptation and Validation for Estimating Methane and Ammonia Emissions from Fattening Pig Houses: Effect of Manure Management System

Pig manure degradation and carbon emission: Measuring and modeling combined aerobic–anaerobic transformations

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