To produce hydrochar with less volatile matter (VM) and more fixed carbon (FC) to increase its stability, this study compared the hydrothermal carbonization (HTC) of hen (HM) and swine (SM) manures at typical HTC sub-critical temperature... more
To produce hydrochar with less volatile matter (VM) and more fixed carbon (FC) to increase its stability, this study compared the hydrothermal carbonization (HTC) of hen (HM) and swine (SM) manures at typical HTC sub-critical temperature of 210 °C and slightly super-critical temperature of 400 °C. Physico-chemical properties such as proximate analysis; ultimate analysis; Brunauer–Emmett–Teller (BET) surface area; higher heating value (HHV); chemical oxygen demand (COD); and inorganic nutrients of hydrochar, gaseous, and liquid products were determined. As expected, both VM and yield decreased with temperature. The heats of HTC reactions were estimated to be exothermic, ranging from −5.7 to −8.6 MJ/kg. The FC approximately doubled, while VM significantly decreased with a yield of 42.7%, suggesting the high potential of producing more stable hydrochar via near-critical HTC (NCHTC) treatment of SM. Additional work is needed before recommendations on carbonization temperatures can be ma...
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Although biochars made in laboratory seem to remove H2S and odorous compounds effectively, very few studies are available for commercial biochars. This study evaluated the efficacy of a commercial biochar (CBC) for removing H2S and... more
Although biochars made in laboratory seem to remove H2S and odorous compounds effectively, very few studies are available for commercial biochars. This study evaluated the efficacy of a commercial biochar (CBC) for removing H2S and odorous volatile organic compounds (VOCs). We found that the well-known Ergun equation may not be adequate in predicting pressure drop for properly sizing a ventilation system. The H2S breakthrough adsorption capacity of the CBC was 2.51 mg/g under humid conditions, which was much higher than that for dry conditions. The breakthrough capacity increased with the influent concentration of H2S. The efficacy of a pilot-scale biochar odor removal system (PSBORS) for removing 15 odorous VOCs was evaluated by placing it in a swine gestation stall continually treating the inside air for 21 days. All VOCs in the PSBORS effluent were below detection limit except for acetic acid. However, due to the very high odor threshold of acetic acid, its contribution to the od...
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ABSTRACT We conducted blood flow analysis, using the Fluid-Structure Interaction (FSI) method, to examine how changes in the material properties of blood vessels affect blood flow characteristics, using the carotid artery as the model... more
ABSTRACT We conducted blood flow analysis, using the Fluid-Structure Interaction (FSI) method, to examine how changes in the material properties of blood vessels affect blood flow characteristics, using the carotid artery as the model vessel. The geometry of the blood vessel included 50% stenosis at the center, and blood was modeled as a non-Newtonian fluid. In order to investigate the effects of vessel material properties, linear elastic models with 0.21 MPa, 0.51 MPa, and 1.25 MPa, which are within the typical elastic modulus range of the carotid artery, were used to simulate the blood vessel, and these were compared with the rigid body model. The difference in blood vessel elasticity caused periodic and transient changes in blood flow. The more elastic the blood vessel becomes, the longer the periods of velocity, pressure, and Wall Shear Stress (WSS) change and the smaller the size of the Fluid Recirculation Zone (FRZ). Also, transient changes in blood flow occurred due to the accumulation of differences in flow caused by vessel wall deformation. This is because a change in the stiffness of the vessel wall causes the vessel’s vibration period to change, leading to changes in blood flow. KeywordsFSI–elastic modulus–vessel property–blood flow–stenosis–carotid artery
Research Interests: Materials Engineering, Mechanical Engineering, Chemical Engineering, Materials Science, Mechanics, and 10 moreLinear Elasticity, Fluid structure interaction, Non-newtonian Fluid Mechanics, Blood Flow, Rigid Body, Elastic Modulus, Wall Shear Stress, Carotid Artery, Material Properties, and Blood Vessel
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Research Interests: Environmental Science, Agriculture, Multidisciplinary, Bioreactor, Denitrification, and 15 moreNitrates, Nitrate, Nitrogen, Plant extracts, Polyvinyl alcohol, Emerging Technology, Bioreactors, Industrial Waste, Hydraulic Retention Time, Pilot Projects, Overland Flow, Reaction Kinetics, Nitrogen Removal, agricultural drainage, and Field Test
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Current literature values of 2, 4, 6-trinitrotoluene (TNT) solubility in water vary widely from 100 to 200 mg/L at room temperature. We investigated the effects of temperature and pH on the solubility of both reference TNT and field neat... more
Current literature values of 2, 4, 6-trinitrotoluene (TNT) solubility in water vary widely from 100 to 200 mg/L at room temperature. We investigated the effects of temperature and pH on the solubility of both reference TNT and field neat TNT obtained from the Alabama Army Ammunition Plant (AAAP), Childersburg, AL. The TNT solubility determined from this study was significantly lower than that of Taylor and Rinkenbach, which was cited by several reference chemical handbooks and articles. However, the values reported by the Merck ...
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Research Interests: Engineering, Environmental Science, Energy Conservation, Waste Management, Industrial Engineering, and 12 moreEnergy Conversion, Municipal Solid Waste, Sewage sludge, Energy Balance, CHEMICAL SCIENCES, Net Energy, Moisture Content, Poultry Litter, Industrial Chemistry/Chemical Engineering, Swine waste, Manure Management, and Swine Manure
Research Interests: Chemistry, Catalysis, Magnetic Resonance Spectroscopy, Multidisciplinary, Environmental science and technology, and 10 moreEndocrine disruptors, Tandem Mass Spectrometry, High Performance Liquid Chromatography, High Pressure Liquid Chromatography, Hydrogen Peroxide, Estrogens, Endocrine Disruptors, Environmental, Peroxide, and Peroxides
Research Interests: Environmental Science, Irrigation, Agriculture, Medicine, Multidisciplinary, and 15 morePhosphorus, Seasonality, Animals, Nitrogen, Nitrogen Fertilizer, Manure, Mineral content, Seasons, Cynodon Dactylon, Energy Transfer, Soil Pollutants, Manure Management, Bioresource technology, energy density, and NUTRIENT COMPOSITION
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Hydrothermal carbonization (HTC) reactor systems used to convert wet organic wastes into value-added hydrochar are generally classified in the literature as liquid water-based (HTC) or vapor-based (VTC). However, the distinction between... more
Hydrothermal carbonization (HTC) reactor systems used to convert wet organic wastes into value-added hydrochar are generally classified in the literature as liquid water-based (HTC) or vapor-based (VTC). However, the distinction between the two is often ambiguous. In this paper, we present a methodological approach to analyze process conditions for hydrothermal systems. First, we theoretically developed models for predicting reactor pressure, volume fraction of liquid water and water distribution between phases as a function of temperature. The reactor pressure model predicted the measured pressure reasonably well. We also demonstrated the importance of predicting the condition at which the reactor system enters the subcooled compression liquid region to avoid the danger of explosion. To help understand water–feedstock interactions, we defined a new solid content parameter %S(T) based on the liquid water in physical contact with feedstock, which changes with temperature due to chang...
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Traditionally, livestock manure has been used to provide nutrients for plant growth and to improve soil conditions [...]
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In this study, the economic feasibility of producing ethanol from gasification followed by syngas fermentation via commercially available technologies was theoretically evaluated using a set of selected livestock and agricultural and... more
In this study, the economic feasibility of producing ethanol from gasification followed by syngas fermentation via commercially available technologies was theoretically evaluated using a set of selected livestock and agricultural and forest residuals ranging from low valued feedstocks (i.e., wood, wheat straw, wheat straws blended with dewatered swine manure, and corn stover) to high valued oilseed rape meal. A preliminary cost analysis of an integrated commercial system was made for two cases, a regional scale 50 million gallon (189,271 m3) per year facility (MGY) and a co-op scale 1–2 MGY facility. The estimates for the minimum ethanol selling prices (MESP) depend heavily on the facility size and feedstock costs. For the 1–2 MGY (3785–7571 m3/y) facility, the MESP ranged from $5.61–$7.39 per gallon ($1.48–$1.95 per liter) for the four low-value feedstocks. These high costs suggest that the co-op scale even for the low-value feedstocks may not be economically sustainable. However, ...
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In-house windrowing between flocks is an emerging sanitary management practice to partially disinfect the built-up litter in broiler houses. However, this practice may also increase ammonia (NH) emission from the litter due to the... more
In-house windrowing between flocks is an emerging sanitary management practice to partially disinfect the built-up litter in broiler houses. However, this practice may also increase ammonia (NH) emission from the litter due to the increase in litter temperature. The objectives of this study were to develop mathematical models to estimate NHemission rates from broiler houses practicing in-house windrowing between flocks. Equations to estimate mass-transfer areas form different shapes windrowed litter (triangular, rectangular, and semi-cylindrical prisms) were developed. Using these equations, the heights of windrows yielding the smallest mass-transfer area were estimated. Smaller mass-transfer area is preferred as it reduces both emission rates and heat loss. The heights yielding the minimum mass-transfer area were 0.8 and 0.5 m for triangular and rectangular windrows, respectively. Only one height (0.6 m) was theoretically possible for semi-cylindrical windrows because the base and ...
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Assessing biochar's ability to resist oxidation is fundamental to understanding its potential to sequester carbon. Chemical oxidation exhibits good performance in estimating the oxidation resistance of biochar. Herein, oxidation... more
Assessing biochar's ability to resist oxidation is fundamental to understanding its potential to sequester carbon. Chemical oxidation exhibits good performance in estimating the oxidation resistance of biochar. Herein, oxidation resistance of 14 types of biochars produced from four feedstocks at different pyrolysis conditions (hydrothermal versus thermal carbonization) was investigated via hydrogen peroxide oxidation with varying concentrations. The oxidation resistance of organic carbon (C) of hydrochars was relatively higher than that of 250°C pyrochars (P250) but was comparable to that of 450°C pyrochars (P450). Both hydrochars and P450 from ash-rich feedstocks contained at least three different C pools (5.9-18.3% labile, 43.2-56.5% semi-labile and 26.9-45.9% stable C). Part (<33%) of aromatic C within 600°C pyrochars (P600) was easily oxidizable, which consisted of amorphous C. The influence of pyrolysis temperature upon oxidation resistance of biochars depended on the fe...
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Abstract Remediation of TNT contaminated soil by phytoremediation and bioremediation in aqueous medium is often limited by TNT desorption from the soil. Understanding the desorption of TNT from the contaminated soil is needed in order to... more
Abstract Remediation of TNT contaminated soil by phytoremediation and bioremediation in aqueous medium is often limited by TNT desorption from the soil. Understanding the desorption of TNT from the contaminated soil is needed in order to employ effective soil remediation strategies. TNT (2, 4, 6‐Trinitrotoluene) desorption was investigated using a flat sheet flow leaching bed reactor in the laboratory. Deionized water advective flow was pumped over the contaminated soil matrix in the form of a sheet flow. Concentrations of ...
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ABSTRACT
ABSTRACT We investigated the adsorption characteristics of hydroxyatrazine (HA) and introduced a relatively simple method to analyze and extract the compound from wetland sediment. Although concentration of HA could be easily measured... more
ABSTRACT We investigated the adsorption characteristics of hydroxyatrazine (HA) and introduced a relatively simple method to analyze and extract the compound from wetland sediment. Although concentration of HA could be easily measured using an amino‐phase HPLC column, one should be cautious not to use solvent programs that interfere with atrazine (A). The adsorption characteristic of HA on wetland sediment was roughly linear with a distribution coefficient of 0.057 L/g. About 90% of HA adsorbed on the sediment was recovered using our heated extraction method.
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In this study, hydrochars and pyrochars prepared from animal manures were characterized and were used to remove Sb (III) and Cd (II) from aqueous solution. Fourier transform infrared spectroscopy (FTIR) analysis revealed the interaction... more
In this study, hydrochars and pyrochars prepared from animal manures were characterized and were used to remove Sb (III) and Cd (II) from aqueous solution. Fourier transform infrared spectroscopy (FTIR) analysis revealed the interaction between Cd (II) and CO and CO groups within biochars and between Sb (III) and CO, CO and OH groups, respectively. Additionally, the lower absolute value of zeta potential of biochar after loading Sb (III) and Cd (II) suggested the occurrence of surface complexation. Existing primarily in the form of Sb (OH)3, the maximum adsorption capacities (Qmax) for Sb (III) were lower than those for Cd (II). Due to the lower contents of surface polar functional groups and less negative surface charge, hydrochars exhibited lower Qmax for Sb (III) and Cd (II) than pyrochars. However, hydrochars in this study had higher sorption capacities for Cd (II) than most of plant-based pyrochars reported by other literature.
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This study investigated the sorption potential of hydrochars, produced from hydrothermally carbonizing livestock wastes, toward organic pollutants (OPs) with a wide range of hydrophobicity, and compared their sorption capacity with that... more
This study investigated the sorption potential of hydrochars, produced from hydrothermally carbonizing livestock wastes, toward organic pollutants (OPs) with a wide range of hydrophobicity, and compared their sorption capacity with that of pyrochars obtained from conventional dry pyrolysis from the same feedstock. Results of SEM, Raman, and (13)C NMR demonstrated that organic carbon (OC) of hydrochars mainly consisted of amorphous alkyl and aryl C. Hydrochars exhibited consistently higher log Koc of both nonpolar and polar OPs than pyrochars. This, combined with the significantly less energy required for the hydrothermal process, suggests that hydrothermal conversion of surplus livestock waste into value-added sorbents could be an alternative manure management strategy. Moreover, the hydrochars log Koc values were practically unchanged after the removal of amorphous aromatics, implying that amorphous aromatic C played a comparable role in the high sorption capacity of hydrochars com...
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ABSTRACT In the southeastern USA, livestock operations face issues with both manure management and energy. Both issues can be advanced by implementing holistic solutions to manure treatment that involve (1) resourceful energy management... more
ABSTRACT In the southeastern USA, livestock operations face issues with both manure management and energy. Both issues can be advanced by implementing holistic solutions to manure treatment that involve (1) resourceful energy management and (2) green farming systems. In such systems, current and emerging waste-to-energy conversion platforms can contribute to renewable energy solutions, improved crop yields, and sustained natural resources. System-component technologies can manage both wet and dry manures to provide recycled nutrients to crops while minimizing air and water quality impacts. Relative to energy, anaerobic digestion (AD) is the prevalent biochemical platform. It is a mature technology that readily processes wet manure, and it is used on many levels of sophistication throughout the globe. Thermochemical conversion (TCC) processes with smaller physical footprints are versatile, capable of handling wet and dry feedstocks to yield multiple byproducts. They need (1) manure feedstock conditioning to lessen the effects of salts, metals, and sulfur and (2) heat recovery for energy conservation. Additionally, with appropriate downstream processing, the TCC gases and bio-oils can aid in farm energy management to include liquid fuel. The TCC processes also produce a reasonably transportable, nutrient-dense biochar. While AD provides a digestate suitable for land application, wastewaters within these systems can also be treated at different stages with solids-separation and nitrogen-phosphorous recovery technologies. This cleaner effluent offers more options for its use in meeting crop water needs via irrigation. Thus, through holistic thinking coupled with dynamic agribusiness, there are significant opportunities for future livestock farming systems to improve the sustainability of natural resources including energy.
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Page 1. Terminal settling characteristics of bioparticles Kyoung Sin Ro, JB Neethling ABSTRACT: The drag forces on biocoated particles, commonly en countered in biological fluidized beds, are greatly augmented due to in ...
Page 1. RESEARCH NOTES Biofilm density for biological fluidized beds Kyoung Sin Ro, JB Neethling ABSTRACT: The density of biological particles in fluidized beds changes as the biofilm grows due to changes in the biofilm makeup and... more
Page 1. RESEARCH NOTES Biofilm density for biological fluidized beds Kyoung Sin Ro, JB Neethling ABSTRACT: The density of biological particles in fluidized beds changes as the biofilm grows due to changes in the biofilm makeup and morphology. ...
Sorption behavior of acetochlor (ACE), dibutyl phthalate (DBP), 17α-Ethynyl estradiol (EE2) and phenanthrene (PHE) with biochars produced from three feedstocks (maize straw (MABs), pine wood dust (WDBs) and swine manure (SWBs)) at seven... more
Sorption behavior of acetochlor (ACE), dibutyl phthalate (DBP), 17α-Ethynyl estradiol (EE2) and phenanthrene (PHE) with biochars produced from three feedstocks (maize straw (MABs), pine wood dust (WDBs) and swine manure (SWBs)) at seven heat treatment temperatures (HTTs) was evaluated. The bulk polarity of these biochars declined with increasing HTT while the aromaticity and CO2-surface area (CO2-SA) rose. The surface OC contents of biochars were generally higher than bulk OC contents. The organic carbon (OC)-normalized CO2-SA (CO2-SA/OC) of biochars significantly correlated with the sorption coefficients (n and logKoc), suggesting that pore filling could dominate the sorption of tested sorbates. SWBs had higher logKoc values compared to MABs and WDBs, due to their higher ash contents. Additionally, the logKoc values for MABs was relatively greater than that for WDBs at low HTTs (≤400 °C), probably resulting from the higher CO2-SA/OC, ash contents and aromaticity of MABs. Surface polarity and the aliphatic C may dominate the sorption of WDBs obtained at relatively low HTTs (≤400 °C), while aromatic C affects the sorption of biochars at high HTTs. Results of this work aid to deepen our understanding of the sorption mechanisms, which is pivotal to wise utilization of biochars as sorbents for hazardous organic compounds.
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Page 1. J. ENVIRON. SCI. HEALTH, A30(l), 109-120 (1995) ATRAZINE BIOTRANSFORMATION IN WETLAND SEDIMENT UNDER DIFFERENT NUTRIENT CONDITIONS-I: ANAEROBIC Key words: Atrazine, Anaerobic Biotransformation, Wetland Sediment, Nutrients ...