scholarly journals Reduction of odorous compounds emissions from swine slurry by electrolytic treatments and copper addition

2017 ◽  
Vol 48 (1) ◽  
pp. 12-20
Author(s):  
Mauro Podrecca ◽  
Alessandro Chiumenti ◽  
Francesco Da Borso ◽  
Marco Contin ◽  
Maria De Nobili
Keyword(s):  
Volatile Fatty Acids ◽  
Swine Manure ◽  
Threshold Value ◽  
Graphite Electrodes ◽  
Swine Slurry ◽  
Copper Electrodes ◽  
Copper Addition ◽  
Current Passage ◽  
Odour Threshold ◽  
Electrolytic Treatment

Swine livestock farms represent potential sources of emissions of gaseous compounds and odors in relation to slurry management, manure treatment, and particularly, storage. Electrolytic treatments of slurries were proposed to solve this pressing problem. Electrolytic treatment consists of the passage of a low electric current through the liquid phase of swine manure in storage basins determined by two or more electrodes with alternated polarisation. We investigated the mechanisms of odour reduction and evaluated the effects of current intensity and of anodically dissolved copper (Cu2+) ions. Fresh swine slurry was subject to electrolytic treatment in a bench top experiment, at 25 mA and 75 mA for 32 days with either copper or graphite electrodes. Emissions of methane, hydrogen sulphide, and volatile fatty acids were measured. Effects of copper addition to fresh swine slurry were also monitored in a bench top scale trial. Reduction of emissions was found to be due to both current passage and copper dissolution. Reduction of foul emissions in graphite electrodes assays resulted lower than in copper electrodes assays, although the direct additions of Cu2+ ions had a much larger effect than could be predicted from the results of electrolytic treatments with copper electrodes, probably due to the greater uniformity in distribution in swine manure. A simple empiric odour threshold value normalised index, odour offensiveness index of slurries, was found to be effective in differentiating treatments.

scholarly journals Odour-active compounds in liquid malt extracts for the baking industry

2021 ◽  
Author(s):  
Nadine S. Rögner ◽  
Veronika Mall ◽  
Martin Steinhaus
Keyword(s):  
Threshold Value ◽  
Starting Material ◽  
Minor Amount ◽  
Malt Extract ◽  
Important Process ◽  
Gas Chromatography Olfactometry ◽  
Odour Threshold ◽  
A Minor ◽  
Baking Industry ◽  
Insight Into

AbstractAn odorant screening by gas chromatography–olfactometry (GC–O) and a crude aroma extract dilution analysis (AEDA) applied to the volatiles isolated from a light and a dark liquid malt extract (LME) by solvent extraction and solvent-assisted flavour evaporation (SAFE) identified 28 odorants. Fifteen major odorants were subsequently quantitated and odour activity values (OAVs) were calculated as ratio of the concentration to the respective odour threshold value (OTV). Important odorants in the light LME included 3-(methylsulfanyl)propanal (OAV 1500), (E)-β-damascenone (OAV 430), and 4-ethenyl-2-methoxyphenol (OAV 91). In the dark LME, sotolon (OAV 780), 3-(methylsulfanyl)propanal (OAV 550), (E)-β-damascenone (OAV 410), acetic acid (OAV 160), and maltol (OAV 120) were of particular importance. To get an insight into the changes during malt extract production, the quantitations were extended to the malt used as the starting material for both LMEs. Addition of a minor amount of water to malt before volatile extraction was shown to be effective to cover the free as well as the bound malt odorants. Results showed that some LME odorants originated from the starting material whereas others were formed during processing. Important process-induced LME odorants included (E)-β-damascenone and 4-ethenyl-2-methoxyphenol in the light LME as well as maltol, sotolon, (E)-β-damascenone, and 2-methoxyphenol in the dark LME. In summary, the odorant formation during LME production was shown to be more important than the transfer of odorants from the malt.

scholarly journals Analysis of Machinability and Crack Occurrence of Steels 1.2363 and 1.2343ESR Machined by Die-Sinking EDM

Coatings ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 406
Author(s):  
Katerina Mouralova ◽  
Libor Benes ◽  
Josef Bednar ◽  
Radim Zahradnicek ◽  
Tomas Prokes ◽  
...  
Keyword(s):  
Surface Quality ◽  
Regression Equations ◽  
Graphite Electrodes ◽  
Copper Electrodes ◽  
Good Surface ◽  
Transmission Electron ◽  
Hardness Change ◽  
Pulse On Time ◽  
Pulse Off Time ◽  
Machined Surfaces

Die-sinking electric discharge machining (EDM) is an indispensable technological operation, especially in the production of molds and all internal and external shapes and cavities. For this reason, the effect of machine parameter settings (open-voltage, pulse current, pulse on time, and pulse off time) on the machining of two types of steels, 1.2363 and 1.2343ESR, was carefully investigated using graphite or copper electrodes in 10 mm × 10 mm or 100 mm × 100 mm shapes. For this purpose, a two-level half factor experiment was performed with one replication at the corner points and two replications at the central points, with a total of 80 rounds. The subject of the evaluation was the topography and morphology of machined surfaces including a detailed analysis of surface and subsurface defects in the form of cracks including the creation of regression equations describing the probability of crack occurrence. Furthermore, a study of the local hardness change in the subsurface area was performed, and lamellas were also made and studied by transmission electron microscopy. It has been found that by using die-sinking EDM, it is possible to effectively predict the probability of cracking on machined surfaces and also on machine 1.2363 and 1.2343ESR steels with a very good surface quality of Ra 1.9 and 2.1 µm using graphite electrodes. These findings will ensure the production of parts with the required surface quality without cracks, which is a crucial aspect for maintaining the required functionality and service life of the parts.

scholarly journals Biological Control of Hog Waste Odor through Stimulated Microbial Fe(III) Reduction

2005 ◽  
Vol 71 (8) ◽  
pp. 4728-4735 ◽  
Author(s):  
John D. Coates ◽  
Kimberly A. Cole ◽  
Urania Michaelidou ◽  
Jennifer Patrick ◽  
Michael J. McInerney ◽  
...  
Keyword(s):  
Volatile Fatty Acids ◽  
Swine Manure ◽  
Cost Effective ◽  
Complete Removal ◽  
The United States ◽  
Geobacter Sulfurreducens ◽  
Swine Waste ◽  
Geobacter Metallireducens ◽  
Pure Cultures ◽  
Production Facilities

ABSTRACT Odor control and disposal of swine waste have inhibited expansion of swine production facilities throughout the United States. Swine waste odor is associated primarily with high concentrations of volatile fatty acids (VFAs). Here, we demonstrate that stimulated Fe(III) reduction in hog manure can rapidly remove the malodorous compounds and enhance methane production by 200%. As part of these studies, we enumerated the indigenous Fe(III)-reducing population in swine waste and identified members of the family Geobacteraceae as the dominant species. These organisms were present at concentrations as high as 2 × 105 cells g−1. Several pure cultures of Fe(III) reducers, including Geobacter metallireducens, Geobacter humireducens, Geobacter sulfurreducens, Geobacter grbiciae, Geothrix fermentans, and Geovibrio ferrireducens, readily degraded some or all of the malodorous VFAs found in swine manure. In contrast, Shewanella algae did not degrade any of these compounds. We isolated an Fe(III) reducer, Geobacter strain NU, from materials collected from primary swine waste lagoons. This organism degraded all of the malodorous VFAs tested and readily grew in swine waste amended with Fe(III). When raw waste amended with Fe(III) was inoculated with strain NU, the VFA content rapidly decreased, corresponding with an almost complete removal of the odor. In contrast, the raw waste without Fe(III) or strain NU showed a marked increase in VFA content and a rapid pH drop. This study showed that Fe(III) supplementation combined with appropriate bioaugmentation provides a simple, cost-effective approach to deodorize and treat swine waste, removing a significant impediment to the expansion of pork production facilities.

Continuous biogas production from fodder beet silage as sole substrate

2003 ◽  
Vol 48 (4) ◽  
pp. 229-233 ◽  
Author(s):  
P.A. Scherer ◽  
S. Dobler ◽  
S. Rohardt ◽  
R. Loock ◽  
B. Büttner ◽  
...  
Keyword(s):  
Volatile Fatty Acids ◽  
Biogas Production ◽  
Swine Manure ◽  
Gas Production ◽  
Methane Content ◽  
Organic Loading Rate ◽  
Feeding Time ◽  
Reactor Performance ◽  
Fodder Beet ◽  
Gas Volume

Since April 2000 a two-step anaerobic plant with two subsequent 500 m3 reactors has been producing biogas from fodder beet silage (pH 4.1) as the sole substrate. The plant is located at Kirchlengern near Bielefeld, Germany. Initially the reactors were inoculated with swine manure at 37°C. After a start-up phase the process was sustained at pH 7.5-8.0 by feeding with the silage as sole substrate twice a day. Parallel to the biogas plant at Kirchlengern four one-step laboratory reactors were continuously driven at temperatures of 37°C, 45°C, 60°C and 65°C. They were fed with the same silage, but only once per day (one impulse). The organic loading rate (OLR) was adjusted to 3.9 g volatile solids (VS)/(l*d) with a concomitant hydraulic retention time (HRT) of 27 d. There was no problem with starting the reactors, but after 86 days the volumetric gas production of the 65°C reactor ceased and a high amount of approximately 130 mM propionate could be determined. By decreasing the temperature down to 60°C a stable reactor performance was recovered for a period of at least 250 further days. During impulse feeding it was observed that the quickest recovery of gas production could be observed at 37°C or at 45°C. Recovery of 75% gas volume (related to the value before or after impulse feeding) was obtained after 5.5 and 7.5 h of feeding time point whereas the 60°C reactor needed 16 h. Slight significant differences were seen in the spectrum of volatile fatty acids (VFA) reaching at 37° or 45°C its maximum with 10-30 mM total VFA at 2-3 h after feeding. After this the VFA level declined to nearly zero (except for the 60°C reactor). Therefore the 37°C reactor was favoured. A double experiment with a second 37°C reactor was started by a somewhat different inoculation procedure from the remaining 3 reactors, but revealed similar results. By increasing the temperature no significantly different specific gas production rates and methane yields could be observed, e.g. it gave 600-700 l biogas from 1 kg VS. The corresponding methane content ranged between 62-64%. With a methane content of 63 ± 1% a yield of 40.1 ± 2 m3 methane/ton fresh fodder beet silage was obtained.

concentrations of odorcxis carpaunds with annoyance have still to be impro­ ved. At this mcment the knowledge in this field is far inferior to the knowledge for the sense of view and the sense of hearing. But there is no reason why we would not acquire the same understanding. Although knowledge on the correlation of odorous compounds concen­ tration and odour impression is still limited, it is used in all types of olfactometry. Indeed diluting this concentration by adding pure air is a general practice. Also many investigations were performed where che­ micals are added to air and used in psychophysical experiments. Many spea­ kers in this workshop will present data in this field. Here only chemical analysis will be dealt with. 2. PRINCIPES The goal of chemical analysis of odorous compounds in air is to de­ termine all substances, which interact with odour perception cells in our nose, both qualitatively and quantitatively. However, with a few excep­ tions all carpcunds with certain vapor pressure have an odour, meaning that their volatilized molecules react with the membrane of odour recep­ tor cells. As will be shewn, always hundreds of compounds are present in air; this means that the analysis would be very complex. However as was said before, our sense of smell is selective : for some products it is very sensitive for other compounds it is much less sensitive. Table I : Odour threshold values (ppb) of some organics Compounds Odour threshold Compound Odour threshold butane 1.3 106 acetic acid 40 butane 500 propionic acid 190 butanol 300 butyric acid 38 butanal 15 valeric acid 8 butanethiol 0.8 hexanoic acid 42 Several extensive lists of threshold values, i.e. the minimum concentration in air, that is detected by 50% of the population, have been published (1, 2,3,4). However published threshold values for a particular compound can vary over a number of orders of magnitude, so they have to be treated with scepticism. This selectivity makes chemical analysis of odour easier : many com­ pounds, although present in ambient air, and although they have an odour in pure form, are not contributing to the odour, while their concentration is far inferior to the threshold value. On the other hand the sensitivity is high for a range of compounds, higher than any chemical analysis can cope with directly. These canpaunds have to be concentrated frcm the odorous air, so that higher amounts are available for the analytical technique. If this concentrating could be done with the same selectivity of odour recep­ tor cells, there would not be much of a problem. Hcwever the actual know­ ledge of this interaction is far too limited - in fact it is inexisting -to speculate on an analytical application. With all of the biochemical de­ velopments, it is not excluded that at a certain mcment it beccmes feasible, but right new the only way is to use crude physicochemical methods, such as

1986 ◽  
pp. 168-168
Keyword(s):  
Chemical Analysis ◽  
Threshold Value ◽  
Ambient Air ◽  
Threshold Values ◽  
Minimum Concentration ◽  
Analytical Technique ◽  
Odour Threshold ◽  
Physicochemical Methods ◽  
Odorous Compounds ◽  
Odour Perception

scholarly journals Volatile Fatty Acids in Liquid Swine Manure Can Kill Microsclerotia of Verticillium dahliae

2002 ◽  
Vol 92 (5) ◽  
pp. 548-552 ◽  
Author(s):  
Mario Tenuta ◽  
Kenneth L. Conn ◽  
George Lazarovits
Keyword(s):  
Fatty Acids ◽  
Acetic Acid ◽  
Verticillium Dahliae ◽  
Volatile Fatty Acids ◽  
Swine Manure ◽  
Effective Concentration ◽  
Solution Ph ◽  
Liquid Swine Manure ◽  
Protonated Forms ◽  
The Individual

Liquid swine manure added to acidic soils killed microsclerotia of the wilt fungus Verticillium dahliae. We investigated whether volatile fatty acids (VFAs) in the manure were responsible for this toxicity. The survival of microsclerotia was determined after exposure to various dilutions of manure or its VFA components. Acetic, propionic, and isobutyric acids constituted the major VFAs in the manure, while n-butyric, n-valeric, iso-valeric, and n-caproic acids were present in lesser amounts. Formic acid was not detected. The individual VFAs were more toxic to microsclerotia as the solution pH was decreased, indicating that the protonated forms of the VFAs were toxic (e.g., acetic acid and not acetate). The effective concentration reducing germination of microsclerotia by 95% (EC95) for formic and n-caproic acids was approximately 4 mM, the most toxic of the acids tested; for n-valeric, the EC95 was 9.2 mM, isovaleric was 16.1 mM acids, and acetic, propionic, n-butyric, and isobutyric acids were approximately 30 mM. The toxicity of acetic acid, and likely all the others, was directly related to the duration of exposure. Inhibition of microsclerotia germination followed identical trends in solutions of the manure or in a mixture of VFAs with equivalent concentrations of the individual acids found in the manure. Similarly, germination declined to the same extent in the atmosphere above the manure or the VFA mixture, confirming the toxicity of VFAs to microsclerotia. Thus, under acid conditions, VFAs in liquid swine manure can kill microsclerotia of V. dahliae.

scholarly journals Impact of processing on important cocoa off-flavour compounds

2021 ◽  
Author(s):  
Daniela Füllemann ◽  
Silva D. Neiens ◽  
Martin Steinhaus
Keyword(s):  
Threshold Value ◽  
Flavour Compounds ◽  
Chocolate Industry ◽  
Odour Threshold ◽  
A Minor

AbstractThe compounds responsible for smoky and mouldy–musty off-flavours in fermented cocoa have recently been elucidated; however, their behaviour during further processing into chocolate was still unclear. The compounds 2-methoxyphenol, 3-methylphenol, 4-methylphenol, 3-ethylphenol, 4-ethylphenol, and 3-propylphenol known to contribute to smoky off-flavours showed a tendency towards a minor increase during roasting and processing into cocoa liquor. This increase amounted to 1.4-fold at the most, however, was clearly compensated by losses of 30–63% during further processing into chocolate mass and conching. Among the off-flavour compounds identified in mouldy–musty smelling cocoa, faecal, mothball-like 3-methyl-1H-indole showed a clear decrease during roasting and processing into cocoa liquor, at least at rather high roasting temperatures, and a further decrease during processing into chocolate mass and conching. In contrast, faecal, mothball-like 1H-indole substantially increased during roasting and processing into cocoa liquor, namely from concentrations below its odour threshold value to concentrations up to 8 times beyond its odour threshold value. During processing into chocolate mass and conching, 1H-indole remained virtually unchanged. The data suggested that the monitoring of off-flavour compounds at the incoming goods inspection in the chocolate industry should not be limited to the fermented beans as such but additionally include the analysis of a bean sample after test roasting to correctly assess the off-flavour potential of 3-methyl-1H-indole and 1H-indole.

Plant oils thymol and eugenol affect cattle and swine waste emissions differently

2004 ◽  
Vol 50 (4) ◽  
pp. 207-213 ◽  
Author(s):  
V.H. Varel ◽  
D.N. Miller ◽  
A.D. Lindsay
Keyword(s):  
Fatty Acids ◽  
Volatile Fatty Acids ◽  
Swine Manure ◽  
Environmental Problems ◽  
Coliform Bacteria ◽  
Distinct Advantage ◽  
Plant Oils ◽  
Swine Waste ◽  
Nutrient Emissions ◽  
Working Volume

Wastes generated from the production of cattle and swine in confined facilities create the potential for surface and groundwater pollution, emission of greenhouse gases, transmission of pathogens to food and water sources, and odor. It is our hypothesis that something which inhibits microbial fermentation in livestock wastes will be beneficial to solving some of the environmental problems. Our work has concentrated on the use of antimicrobial plant oils, thymol, thyme oil, carvacrol, eugenol and clove oil. Anaerobic one-litre flasks with a working volume of 0.5 L cattle or swine manure were used to evaluate the effect of thymol and eugenol on production of fermentation gas, short-chain volatile fatty acids, lactate, and bacterial populations. Either oil at 0.2% in both wastes essentially stopped all production of gas and volatile fatty acids, and eliminated all fecal coliform bacteria. In cattle but not swine waste, thymol prevented the accumulation of lactate. However, eugenol stimulated lactate formation in cattle and swine wastes. Thus, eugenol may offer a distinct advantage over thymol, because lactate accumulation in the wastes causes the pH to drop more rapidly, further inhibiting microbial activity and nutrient emissions. We conclude that plant oils may offer solutions to controlling various environmental problems associated with livestock wastes, assuming that they are cost-effective.

scholarly journals Biochemical Conversion and Microbial Community in Response to Ternary pH Buffer System during Anaerobic Digestion of Swine Manure

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2991 ◽  
Author(s):  
Xiaoshan Meng ◽  
Yuxiu Zhang ◽  
Qianwen Sui ◽  
Junya Zhang ◽  
Rui Wang ◽  
...  
Keyword(s):  
Microbial Community ◽  
Anaerobic Digestion ◽  
Relative Abundance ◽  
Volatile Fatty Acids ◽  
Swine Manure ◽  
Total Solid ◽  
Buffer System ◽  
Biochemical Conversion ◽  
Ammonia Release ◽  
Ph Buffer

The ternary pH buffer system with ammonia-carbonates-volatile fatty acids (VFAs) is essential to anaerobes for bioenergy recovery via anaerobic digestion (AD). However, ammonia and VFAs are recognized as potential inhibitors that depress methanogenesis. In this study, biochemical conversion and the microbial community in batch AD at total solid (TS) from 4% to 14% were investigated to reveal their response to the ternary pH buffer system. The rapid ammonia release, probably promoted by Anaerosphaera and Eubacterium inferred from the concurrent peak of their relative abundance, triggered total ammonia (TAN) inhibition with the accumulation of VFAs in the start-up stage of high solid AD (HSAD, TS ≥ 8%). Along with evolution of the microbial community to resist high TAN and VFAs, methanogenesis recovered with improved degradation of VFAs and reduction of COD. When exposed to 3500 mg·N·L−1 TAN at 8% TS, aceticlastic Methanosarcina became dominant first and then together with hydrogenotrophic Methanoculleus, achieved the optimal biochemical conversion. While in HSAD at 11–14% TS, the main pathway of methanogenesis appeared to have shifted from the aceticlastic pathway to the hydrogenotrophic pathway, as inferred by changes in the relative abundance of methanogens, and this could have been induced by the increasing concentration of high free ammonia (FAN, ≥588 mg·N·L−1). Although the anaerobes had acclimatized to high TAN, the propionate-oxidizing bacteria and acetate-oxidizing bacteria might have again been inhibited by high FAN, frustrating the H2 supply for FAN-tolerant Methanoculleus and causing an 8.2–11.3% depression of COD reduction (mainly propionate residual).

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