• Journal of Korean Society of Environmental Engineers
• /
• v.39 no.11
• /
• pp.599-606
• /
• 2017

The effects of microbubble-oxygen physicochemical method for the removal of organic pollutants, nitrogen, and phosphorus contained in animal manure were investigated using a laboratory scale single reactor. The characteristics of used livestock manure were $36,894{\pm}5,024mg\;TCOD/L$, $22,031{\pm}2,018mg\;SCOD/L$, $4,150{\pm}35mg\;NH_4-N/L$, and $659{\pm}113mg\;PO_4-P/L$. It was confirmed that the amount of organic pollutants, nitrogen, and phosphorus removal was increased by the use of oxygen rather than air as the gas supplied with the microbubble, and by input of larger oxygen amount. When the oxygen was fed with 600 mL flow rate per minute, TCOD and phosphorus removal were 2.5 times and 5.6 times higher than those of air supplied. As the microbubble-oxygen reaction time was longer, the removal rate of nutrients increased gradually. The removal rates of ammonium and phosphorus reach to $41.03{\pm}0.20%$ and $65.49{\pm}1.39%$, respectively, after 24 hours. When the coagulation treatment method was applied to increase phosphorus removal rate from the effluent of microbubble-oxygen treatment, the phosphorus was removed up to 92.7%. However, the removal rate of organic pollutants (TCOD) was as small as $28.7{\pm}0.2%$ within the first 6 hours, and then the negligible removal of TCOD was recorded. This study suggests that microbubble-oxygen can be applied not only livestock manure but also aeration tank of various wastewater treatment plant, which can reduce the load on the associated unit process and produce stable high-quality effluent.

• Journal of Korean Society of Environmental Engineers
• /
• v.30 no.8
• /
• pp.781-788
• /
• 2008

This study shows how to find out optimum co-substrate conditions and continuous operating parameters for maximum acidification of three different organic wastes - livestock wastewater, sewage sludge and food waste. Design of experiments and statistical analysis were revealed as appropriate optimization schemes in this study. Analyses of data obtained from batch tests demonstrated the optimum substrate mixing ratio, which was determined by maximum total volatile fatty acids(TVFA) increase and soluble chemical oxygen demand(SCOD) increase simultaneously. Suggested optimum mixing ratio of livestock wastewater, sewage sludge and food waste was 0.4 : 1.0 : 1.1 based on COD, respectively. Response surface methodology(RSM) contributed to find out optimum operating parameter - hydraulic retention time(HRT) and substrate concentration - for the semi-continuous acidogenic fermentation of mixed organic wastes. The optimum condition for maximum TVFA increase was 2 days of HRT and 29,237 mg COD/L. Empirical equations obtained through regression analysis could predict that TVFA increase would be 73%. To confirm the validity of the statistical experimental strategies, a confirmation experiment was conducted under the obtained optimum conditions, and relative error between theoretical and experimental results was within 4%. This result reflects that using statistical and RSM technique can be effectively used for the optimization of real waste treatment processes.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.33 no.6
• /
• pp.508-513
• /
• 2000

In an attempt to evaluate the fertilizer of sediments obtained from coastal farming areas, chemical composition, bacteriological quality and heavy metals in the sediments alkalized by quicklime and magnesium hydroxide were analyzed. The optimum conditions of alkalization were also measured. A perfect reaction was possible by the addition of quicklime of $30{\%}$ at the rate of $25{\%}$ of sediment and $100{\%}$ of livestock wastes. According to the classification standard for compost constituent by Higgins, all composts had the intermediate or high grade in $T-N, K_2O,\;CaO\;and\;MgO$, but below the low grade in $P_2O_5$, Stabilization by quicklime and magnesium hydroxide has been known to inhibit bacterial decomposition of organic matter and activity of pathogenic organisms. In this study, raising pH of stabilized sediments to 12 for 2 hours (PSRP rriteria of EPA) allowed $99.9{\%}$ of coliform group, fecal group and viable cell count to be reduced. As a result, sediments of coastal farming areas are likely to be used to produce the organic fertilizer by alkaline stabilization.

• Journal of Korean Society of Environmental Engineers
• /
• v.37 no.10
• /
• pp.558-562
• /
• 2015

This study was tested to evaluate the effect of the six different combinations of microbubble, catalyst, and air as oxidant on the sludge and organic matter reduction. When all of microbubbles and catalyst, and an oxidizing agent (under Conditions 1) such as air were used, the sludge was removed more than 99%, and TCOD and SCOD removal was 58% and 13%, respectively. This result was the highest value of six conditions. In the following order, the sludge reduction of the microbubbles with air (Condition 2) and catalyst with air (condition 4) was 95% and 93.1%, respectively. TCOD removal was found to be each 53% and 47%. When the microbubbles were used with oxidant like air, the removal of sludge and organic matter was high. All of these values were higher than that of using only microbubbles and catalyst without air. In the microbubbles and catalyst react under air supply condition, OH-radicals were generated in the reaction process. These OH-radicals in the reaction process decomposed the pollutants by the strong oxidizing power. In all conditions with air, the sludge reduction was high removal rate more than 93% and TCOD removal was over 47%.

• Asian-Australasian Journal of Animal Sciences
• /
• v.13 no.11
• /
• pp.1548-1553
• /
• 2000

An experiment was conducted to study the nutritional quality of whole crop corn silage ensiled with cage layer manure in sheep. Treatments were designed as a $3{\times}3$ Latin square with 16-day periods. Sheep were allotted in one of three diet-treatments, which were whole crop corn silage (CS), whole crop corn+30% cage layer manure (CLM) silage (based on DM; MS) and rice straw+concentrate (SC) mixed at 8:2 ratio (on DM basis). Silage ensiled with CLM significantly increased (p<0.05) digestibilities of crude protein, NDF and ADF, TDN over the other treatments. Ruminal pH in sheep fed SC was significantly (p<0.05) higher than that of the other diets at 0.5, 1, 2, 4 and 8 h after feeding. Ruminal ammonia nitrogen concentration of the MS treatment was significantly (p<0.05) higher than that of the other treatments at 0, 1, 2 h after feeding. The MS treatment highly increased (p<0.05) feed intake, digestibility of organic matter and crude protein, nitrogen intake and retained nitrogen. The MS treatment highly increased (p<0.05) purine derivative (PD) excretion leading to higher microbial protein synthesis.

• Korean Journal of Veterinary Service
• /
• v.40 no.4
• /
• pp.259-264
• /
• 2017

In this study, the changes of low molecular weight compounds during natural decay process for 4 weeks were analyzed. Natural corruptions were observed in the slate warehouse with summer humidity and temperature throughout the rainy season by using commercially available compound feeds. Koiganal was detected from 14 days of natural decay and corruption with chicken, pig, and Korean cattle feed. Ethyl palmitate, Ethyl pentadecanoate and, Methyl elaidatel were detected from chicken, pig, and Korean cattle feed. So, Koiganal can be useful for monitoring the degree of pollution of corruption of livestock feeds in advance.

• Food Science of Animal Resources
• /
• v.36 no.4
• /
• pp.547-557
• /
• 2016

This review discusses the status, antimicrobial mechanisms, application, and regulation of natural preservatives in livestock food systems. Conventional preservatives are synthetic chemical substances including nitrates/nitrites, sulfites, sodium benzoate, propyl gallate, and potassium sorbate. The use of artificial preservatives is being reconsidered because of concerns relating to headache, allergies, and cancer. As the demand for biopreservation in food systems has increased, new natural antimicrobial compounds of various origins are being developed, including plant-derived products (polyphenolics, essential oils, plant antimicrobial peptides (pAMPs)), animal-derived products (lysozymes, lactoperoxidase, lactoferrin, ovotransferrin, antimicrobial peptide (AMP), chitosan and others), and microbial metabolites (nisin, natamycin, pullulan, ε-polylysine, organic acid, and others). These natural preservatives act by inhibiting microbial cell walls/membranes, DNA/RNA replication and transcription, protein synthesis, and metabolism. Natural preservatives have been recognized for their safety; however, these substances can influence color, smell, and toxicity in large amounts while being effective as a food preservative. Therefore, to evaluate the safety and toxicity of natural preservatives, various trials including combinations of other substances or different food preservation systems, and capsulation have been performed. Natamycin and nisin are currently the only natural preservatives being regulated, and other natural preservatives will have to be legally regulated before their widespread use.

• Journal of Biosystems Engineering
• /
• v.27 no.4
• /
• pp.335-340
• /
• 2002

Recently, in Korea, round bale wrapping silage made by fresh rice straw are partially utilized. The colors of stretch film using far wrapping the fresh rice straw round bale are white, green and black. The light transmittance of green and white color stretch film was not founded the difference. However, the light transmittance of black color stretch film was largely difference of two stretch films. This study was carried out to measure qualities of fresh rice straw wrapping silage by softening processing of fresh rice straw and colors effects of wrapping stretch film. The analyzed factors were the light transmittance of stretch film, variation of the temperature in fresh rice straw round bale and qualities of the silage in crude protein, ADF, NDF, organic acid, etc. It was difficult to find in this study the colors effects of stretch film on silage qualities by the silage wrapping. But, when make fresh rice straw wrapping silage, wrapping silage fermentation effect goes well more if handle softening the fresh rice straw.

• Journal of Animal Science and Technology
• /
• v.61 no.3
• /
• pp.122-137
• /
• 2019

Methane, one of the important greenhouse gas, has a higher global warming potential than that of carbon dioxide. Agriculture, especially livestock, is considered as the biggest sector in producing anthropogenic methane. Among livestock, ruminants are the highest emitters of enteric methane. Methanogenesis, a continuous process in the rumen, carried out by archaea either with a hydrogenotrophic pathway that converts hydrogen and carbon dioxide to methane or with methylotrophic pathway, which the substrate for methanogenesis is methyl groups. For accurate estimation of methane from ruminants, three methods have been successfully used in various experiments under different environmental conditions such as respiration chamber, sulfur hexafluoride tracer technique, and the automated head-chamber or GreenFeed system. Methane production and emission from ruminants are increasing day by day with an increase of ruminants which help to meet up the nutrient demands of the increasing human population throughout the world. Several mitigation strategies have been taken separately for methane abatement from ruminant productions such as animal intervention, diet selection, dietary feed additives, probiotics, defaunation, supplementation of fats, oils, organic acids, plant secondary metabolites, etc. However, sustainable mitigation strategies are not established yet. A cumulative approach of accurate enteric methane measurement and existing mitigation strategies with more focusing on the biological reduction of methane emission by direct-fed microbials could be the sustainable methane mitigation approaches.

• Journal of Microbiology and Biotechnology
• /
• v.32 no.3
• /
• pp.269-277
• /
• 2022

Human activities account for approximately two-thirds of global methane emissions, wherein the livestock sector is the single massive methane emitter. Methane is a potent greenhouse gas of over 21 times the warming effect of carbon dioxide. In the rumen, methanogens produce methane as a by-product of anaerobic fermentation. Methane released from ruminants is considered as a loss of feed energy that could otherwise be used for productivity. Economic progress and growing population will inflate meat and milk product demands, causing elevated methane emissions from this sector. In this review, diverse approaches from feed manipulation to the supplementation of organic and inorganic feed additives and direct-fed microbial in mitigating enteric methane emissions from ruminant livestock are summarized. These approaches directly or indirectly alter the rumen microbial structure thereby reducing rumen methanogenesis. Though many inorganic feed additives have remarkably reduced methane emissions from ruminants, their usage as feed additives remains unappealing because of health and safety concerns. Hence, feed additives sourced from biological materials such as direct-fed microbials have emerged as a promising technique in mitigating enteric methane emissions.