Abstract This study aimed to select the optimal microbial agents for ammonia gas reduction in Chinese cabbage cultivation and evaluate their ammonia reduction efficiency. By selecting the optimum microorganism to reduce ammonia emissions, the ammonia emission reduction efficiencies of the nitrification microorganisms, Alcaligenes faecalis subsp. faecalis and Brevibacillus sp. were 21 and 31%, respectively, which were superior to those of other microorganisms. The best ammonia emission reduction efficiency of the acid-producing microorganisms was 55%. The optimum mixing ratio of microbial agent for removing ammonia gas emitted from NPK-containing soil was: acid-producing microorganism: Alcaligenes faecalis subsp. faecalis : Brevibaillus sp. = 0.70:0.15:0.15. The optimum treatment amount was 500 L/ha, and the optimum number of microbial agents was basal fertilization (also known as pre-planting fertilization) once and additional fertilization three times, for a total of four times. The reduction efficiency of ammonia emissions from NPK-containing soil under optimum conditions in cabbage cultivation was 27% lower than that of the control (only NPK-containing soil). Therefore, the microbial agent developed in this study can be utilized to effectively reduce the emission of ammonia, a secondary fine particle precursor, while maintaining crop yield in agricultural fields.
BACKGROUND:The most common litter materials used in South Korea are sawdust, rice husk, etc.Recently, the cost of litter has been steadily rising, and the maturity test has been strengthened.For this reason, new litter materials are needed for better water control ability to solve the problems.The object of this study was to evaluate the water absorption properties for litter materials. METHODS AND RESULTS:The volumetric water capacity according to the addition of cow manure was investigated to calculate the water absorption speed of litter materials (sawdust, peatmoss, cocopeat, and biochar).The water absorption speed constant (-K) in the first stage was high in the order of cocopeat (0.1190), sawdust (0.0961), biochar (0.0762), and peatmoss (0.0523).The optimal period of the litter use was in the following order: peatmoss (48d), biochar (42d), sawdust (30d), and cocopeat (24d).The water absorption rate (%) of the used litters was high in the order of biochar ≈ cocopeat, sawdust, and peatmoss, which was significantly correlated with the water absorption speed of the first stage.CONCLUSION(S): Considering the water absorption speed and water absorption rate, biochar and peatmoss were found to be the best and optimal litter materials among the tested materials.These litter materials can be used as water control agents in livestock facilities.
BACKGROUND:The main source of ammonia in soils, South Korea is agricultural emissions (e.g., fertilizer application and livestock manure), with the recent emission inventories reporting them to be approximately 80% of the total emissions.Ammonia as a pollutant is originated largely from agricultural activity and is an important contributor to air quality issues in South Korea.The importance of ammonia in agricultural land is also emerging.In this study, the characteristics of ammonia emission from Chinese cabbage cultivation fields with application rates of urea sere were evaluated.METHODS AND RESULTS: The ammonia emission characteristics were investigated at the different urea application rates (0, 160, 320, and 640 kg ha -1 ) and the ammonia emission factor in the Chinese cabbage cultivation field was calculated.As application rate of urea application increased, ammonia emissions increased proportionally.In 2020 and 2021, cumulative ammonia emissions with urea 320 kg ha -1 treatment were 39.3 and 35.2 kg ha -1 , respectively for 2020 and 2021.When urea fertilizer was applied, the ammonia emission factors were 0.1217 and 0.1358 NH 4 + -N kg N kg -1 in 2020 and 2021, respectively.CONCLUSION(S): Ammonia emissions increased as application rate of urea increased, and the average ammonia emission factor of the Chinese cabbage cultivation field for two years was 0.129 NH 4 + -N kg N kg -1 .
Abstract This experiment was conducted to evaluate the adsorption–desorption characteristics and mechanisms of heavy metals by the mealworm frass (MF). The adsorption characteristics of Cd by MF were predominantly influenced by initial pH, MF dosage, temperature, and reaction time. The maximum adsorption capacity of Cd by MF was 48.1 mg/g, which was well described by Langmuir isotherm and pseudo-second-order models. The optimal desorption solution for separating Cd from Cd-adsorbed MF was 0.02 M HCl, which showed a high desorption efficiency of over 90%. In particular, the adsorption mechanism of Cd by MF was confirmed through functional group change, cation exchange, precipitation experiment, and it was found that Cd was predominantly affected by cation exchange and precipitation on the MF surface. The amounts of Cd fractionated by F1 (exchangeable) and F2 (bonded to carbonate) solutions were 58.9 and 25.2% of the total fractionated Cd amount, which means that Cd adsorbed by MF can be easily eluted/mobilized by environmental changes. Considering the above results, it is believed that MF can be used as an effective adsorbent to remove Cd. However, since the adsorption of Cd by MF is sensitive to environmental changes and the bond itself is weak, it is considered that a special management plan is needed.
Rendering, is attracting attention as a technology that can stably and quickly process livestock carcasses.However, large amounts of livestock carcass solid residues are discharged in this process and limited methods are available for recycling them.In this study, rendered animal carcass solid residues were pyrolyzed to produce carbonized materials(350℃; RACR-C) and their chemical properties were investigated.Further, RACR-C were applied to cabbage cultivation for investigating their crop growth characteristics and soil improvement effects.RACR-C contained large amounts of fertilizer components such as nitrogen and phosphorus, and showed no toxic effects on the seedling growth of crops.The content of water-soluble nutrients released from RACR-C under the reaction time increased rapidly within 30 min, but was insignificant compared to the total content.Thus, most fertilizer components in RACR-C were not readily soluble in water.The optimal application amount for applying RACR-C to cabbage cultivation based on the changes in cabbage growth, inorganic content, and soil
Food waste (FW) emissions in South Korea amounted to 4.77 million tons in 2021, and continue to increase.Various technologies have been developed to treat FW, with recent research focusing on biochar production through pyrolysis to reduce FW.However, the agricultural application of food waste-biochar (FWBC) is lim-ited by the salt accumulated during pyrolysis.This study investigated salt removal from and the kinetic characteristics of FWBC, and subsequently evaluated its agricultural applications.FW was pyrolyzed at 350°C for 4 h, and subsequently washed for 0.1, 0.25, 0.5, 0.75, 1, 5, 15, and 30 min to remove salt.FWBC had a salt concentration of 5.75%, which was effectively removed through washing.The salt concentration decreased rapidly at the beginning (1 min) and then slowly decreased, unlike in FW, in which the salt decreased continuously and slowly.The salt removal speed constant (K) was 1.5586 (Stage 1, FWBC) > 0.0445 (Stage 2, FWBC) > 0.0026 (FW).In a lettuce cultivation experiment, higher biomass was achieved using washed
To solve the odor problem occurring in cattle barns, it was evaluated how the inputs of sawdust, peat moss, cocopeat, and biochar affect the odor derived from cattle barns. The odor removal experiment was performed on 22 specified offensive odor substances. In the concept of complex odor, the odor substances mainly generated from cattle manure were trimethylamine, dimethyl sulfide, hydrogen sulfide, butanoic acid, acetaldehyde, pentanal, etc. Also, trace amounts of ammonia, propanoic acid, 3-methylbutanoic acid, propanal, styrene, m-xylene, butanone, and methyl isobutyl ketone were generated. For all odor substances, biochar and peat moss generally showed high odor removal efficiency, and cocopeat and sawdust had low odor removal efficiency. The odor removal rate for the complex odor unit was biochar (70.7%) > peat moss (62.2%) > cocopeat (52.9%) > sawdust (29.2%), confirming that biochar and peat moss are effective odor-reducing livestock litter.Odor emission and removal rate of complex odor at different livestock litter in cattle barn.
The fine particulate structure of biochar limits its use as a heavy metal adsorbent, and makes separation of the biochar from the solution technically challenging, thereby reducing recovery of the heavy metals.To address this issue, this study prepared biochar beads under various mixing conditions and investigated their efficiency in removing Pb from aqueous solutions using adsorption models.The biochar beads were produced by mixing alginate and biochar at different ratios: alginate bead (AB), 1% biochar + bead (1-BB), 2.5% biochar + bead (2.5-BB), and 5% biochar + bead (5-BB).The results revealed that the Freund-lich isothermal adsorption pattern of the biochar beads to Pb was of the L-type.The highest Langmuir isothermal adsorption capacity (28.736 mg/g) was observed in the 2.5-BB treatment.The dominant mechanism among the kinetic adsorption characteristics of biochar beads for Pb was chemical adsorption.Additionally, the optimal pH range for Pb adsorption was found to be between 4 and 5.5.The highest Pb removal efficiency (97.9%) was achieved when 26.6 g/L of biochar beads were used.These findings suggest that biochar beads are an economical and highly efficient adsorbent that enables separation and recovery of fine biochar particles.
Abstract This study was conducted to evaluate the phosphate sorption properties of eggshell (ES) and calcined ESs (C-ESs) in a high-concentration phosphate solution. The C-ESs yield decreased rapidly at 900 °C, indicating that the CaCO 3 constituting the ES was converted to CaO by the high calcination temperature. The optimum calcination temperature for phosphate removal using C-ES was 900 °C. The actual sorption amount of phosphate by ES and C-ES900 was in agreement with the Langmuir isothermal sorption equation, and the maximum sorption capacities derived from this equation were 178.6 and 270.3 mg/g, respectively. The sorption rate of phosphate by ES and C-ES900 was divided into two stages: an initial fast sorption stage, followed by a slow sorption stage. The sorption of phosphate by ES was dominantly influenced by the initial pH and salt concentration, whereas C-ES900 exhibited a constant sorption capacity regardless of environmental changes. The SEM–EDS and XRD results demonstrated that phosphate was successfully adsorbed on the ES and C-SE900 surfaces. In this study, it was found that the sorption of phosphate by ES occurred via ion exchange and precipitation reactions and that the sorption of phosphate by C-ES900 was dominantly affected by precipitation. Above all, C-ES can be applied as an effective adsorbent for removing high concentrations of phosphate under a wide range of environmental conditions.
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