scholarly journals Estimating ammonia emission after field application of manure by the integrated horizontal flux method: a comparison of concentration and wind speed profiles

2020 ◽  
Vol 36 (2) ◽  
pp. 338-350
Author(s):  
Paul W. Goedhart ◽  
Julio Mosquera ◽  
Jan F. M. Huijsmans
2019 ◽  
Vol 265 ◽  
pp. 48-55 ◽  
Author(s):  
Ester Scotto di Perta ◽  
Nunzio Fiorentino ◽  
Laura Gioia ◽  
Elena Cervelli ◽  
Salvatore Faugno ◽  
...  

Author(s):  
Jinming Mo ◽  
Wei Ma ◽  
Dandan Li ◽  
Sheji Zhang

A fully mechanized mining face is characterized by serious dust pollution and dust is a major cause of pneumoconiosis that haunts numerous miners. For a fully mechanized face having large mining heights, the main dust source in the pavement area is produced by the moving support frame. To reduce the amount of dust during support's movement, the distribution and dissipation of dust in this process were studied by combining numerical simulations with underground measurements. The results showed that with an increase of the distance from the air inlet, the wind speed of the sidewalk in the fully mechanized face first increased, then decreased, and finally increased again. At the position of the coal cutter, the highest wind speed was 1.78 m/s and the average wind speed of the roadway was about 0.8 m/s. The dust concentration at the dust source was >1000 mg/m3. An area with a high dust concentration and having a length of 15 m was formed on the rooftop, together with a 50 m long dust belt with a dust concentration of 300 to 450 mg/m3 in the pavement area of 10 m from the dust source. Beyond the 45 m radius from the dust source, the dust concentration was stable at about 250 mg/m3. Based on the dust production characteristics of the support frame, an enclosed dust-guiding device was designed and structure-optimized. Based on the on-site field application test results, it was found that the device has a satisfactory dust-guiding effect during support movement and the dust suppression rate near the dust source reached 94.8%.


2018 ◽  
Author(s):  
Daniel J. Varon ◽  
Daniel J. Jacob ◽  
Jason McKeever ◽  
Dylan Jervis ◽  
Berke O. A. Durak ◽  
...  

Abstract. Anthropogenic methane emissions originate from a large number of relatively small point sources. The planned GHGSat satellite fleet aims to quantify emissions from individual point sources by measuring methane column plumes over selected ~ 10 × 10 km2 domains with ≤ 50 × 50 m2 pixel resolution and 1–5 % measurement precision. Here we develop algorithms for retrieving point source rates from such measurements. We simulate a large ensemble of instantaneous methane column plumes at 50 × 50 m2 pixel resolution for a range of atmospheric conditions using the Weather Research and Forecasting model (WRF) in large eddy simulation (LES) mode and adding instrument noise. We show that standard methods to infer source rates by Gaussian plume inversion or source pixel mass balance are prone to large errors because the turbulence cannot be properly parameterized on the small scale of instantaneous methane plumes. The integrated mass enhancement (IME) method, which relates total plume mass to source rate, and the cross-sectional flux method, which infers source rate from fluxes across plume transects, are better adapted to the problem. We show that the IME method with local measurements of the 10-m wind speed can infer source rates with error of 0.07–0.17 t h−1 + 5–12 % depending on instrument precision (1–5 %). The cross-sectional flux method has slightly larger errors (0.07–0.26 t h−1 + 8–12 %) but a simpler physical basis. For comparison, point sources larger than 0.5 t h−1 contribute more than 75 % of methane emissions reported to the U.S. Greenhouse Gas Reporting Program. Additional error applies if local wind speed measurements are not available, and may dominate the overall error at low wind speeds. Low winds are beneficial for source detection but not for source quantification.


2018 ◽  
Vol 11 (10) ◽  
pp. 5673-5686 ◽  
Author(s):  
Daniel J. Varon ◽  
Daniel J. Jacob ◽  
Jason McKeever ◽  
Dylan Jervis ◽  
Berke O. A. Durak ◽  
...  

Abstract. Anthropogenic methane emissions originate from a large number of relatively small point sources. The planned GHGSat satellite fleet aims to quantify emissions from individual point sources by measuring methane column plumes over selected ∼10×10 km2 domains with ≤50×50 m2 pixel resolution and 1 %–5 % measurement precision. Here we develop algorithms for retrieving point source rates from such measurements. We simulate a large ensemble of instantaneous methane column plumes at 50×50 m2 pixel resolution for a range of atmospheric conditions using the Weather Research and Forecasting model (WRF) in large eddy simulation (LES) mode and adding instrument noise. We show that standard methods to infer source rates by Gaussian plume inversion or source pixel mass balance are prone to large errors because the turbulence cannot be properly parameterized on the small scale of instantaneous methane plumes. The integrated mass enhancement (IME) method, which relates total plume mass to source rate, and the cross-sectional flux method, which infers source rate from fluxes across plume transects, are better adapted to the problem. We show that the IME method with local measurements of the 10 m wind speed can infer source rates with an error of 0.07–0.17 t h-1+5 %–12 % depending on instrument precision (1 %–5 %). The cross-sectional flux method has slightly larger errors (0.07–0.26 t h-1+8 %–12 %) but a simpler physical basis. For comparison, point sources larger than 0.3 t h−1 contribute more than 75 % of methane emissions reported to the US Greenhouse Gas Reporting Program. Additional error applies if local wind speed measurements are not available and may dominate the overall error at low wind speeds. Low winds are beneficial for source detection but detrimental for source quantification.


2019 ◽  
Vol 50 (1) ◽  
pp. 12-19 ◽  
Author(s):  
Alberto Finzi ◽  
Elisabetta Riva ◽  
Alda Bicoku ◽  
Viviana Guido ◽  
Seit Shallari ◽  
...  

The reduction of ammonia (NH3) emissions associated with manure management requires identification and implementation of effective techniques. The objective of this study was to measure potential ammonia emissions from animal manure and evaluate emission reductions for five mitigation techniques (straw, sawdust, clay, oil and sulphuric acid). Although numerous studies have evaluated individual mitigation techniques, the variability of their effect with different types of slurries has not been fully investigated. Furthermore, the assessment of ammonia emissions from the subsequent land application of stored manure (or slurry) using different techniques would indicate the practical consequences of the entire slurry management chain. The effects of mitigation techniques were evaluated using a model to simulate field application of slurry. Three techniques were compared: broadcast spreading, band spreading and closed-slot injection. Simulations utilised data from experiments conducted at a controlled temperature on six slurries of three different types: pig, cattle and digestate. Ammonia emissions from the raw slurries (i.e., untreated slurry) were determined using the dynamic chamber technique and compared with those from the slurries treated using each of five mitigation techniques. A subsample of one 1 L of each slurry was transferred into 2 L plastic bottles. An airflow of 1 L min–1 across the headspace was established and then emissions were measured over a period of 24 h. The air outlet was connected to two serial acids traps filled with 1% boric acid. The quantity of NH3 trapped was determined by titration. Acidification and oil addition were the most effective techniques, reducing ammonia emission from raw slurries by more than 95% and 80%, respectively. The mitigation effects of straw and sawdust were higher for cattle slurry and digestate than for pig slurry, while clay had an opposite effect. The overall assessment of ammonia emissions from storage and subsequent field application showed that acidification followed by closed-slot injection emitted at most 12% of the emissions from the reference system, while emissions from acidification followed by band spreading were between 14% and 22% of those from the reference system. The latter appears to be both more effective than broadcast spreading and technically more easily operated than a closed-slot injector.


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