• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.4
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• pp.13-28
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• 2023

This study assessed the biochemical methane potential (B_u-P) of three grass species-Poa pratensis (PP), Zoysia japonica (ZJ), and Agrostis stolonifera (AS). B_u-P values were determined as 0.330 Nm³/kg-VS_added for PP, 0.297 Nm³/kg-VS_added for ZJ, and 0.261 Nm³/kg-VS_added for AS. Notably, PP exhibited superior suitability for methane production. The investigation also examined the impact of silage storage duration on PP grass clippings, revealing a 19% decline in B_u-P from an initial value of 0.269 Nm³/kg-VS_added on day 0 to 0.217 Nm³/kg-VS_added on day 180. Throughout the storage period, there were significant increases in neutral detergent fiber (NDF), acid detergent fiber (ADF), and crude protein (CP) contents, rising from 67.59%, 39.68%, and 3.02% on day 0 to 77.12%, 54.65%, and 6.24% on day 180, respectively. These findings highlight the influence of storage duration on the anaerobic digestibility of PP grass clippings. To effectively utilize grass clippings as a renewable resource for methane production, further studies considering factors such as initial moisture content, pretreatment methods, and potential effects of residual pesticides are necessary to optimize anaerobic digestion efficiency for herbaceous biomass.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.4
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• pp.51-58
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• 2023

In this study, anaerobic co-digestion was carried out using desulfurization sludge and sewage sludge (primary sludge) to evaluate the effects of sulfur compounds in anaerobic digestion. The experiment was carried out in the form of a batch test using 500 mL duran bottle, and the mixing ratio of the feedstock was selected based on the ratio of COD/SO₄. As a result of the experiment, it was confirmed that the amount of biogas generated and the yield decreased at the mixing ratio of COD/SO₄ 20 or less. In particular, below COD/SO₄ 10, it was lower than seed (283.5 mL) which was set without feedstock to correct biogas generated by itself from seed sludge. Methane yield tended to decrease from a ratio of COD/SO₄ 20 or less to 0.135 m³/kg VS compared to 0.396 m³/kg VS of COD/SO₄ 50. In addition, compared to 0.0097 m³/kg VS of hydrogen sulfide yield from COD/SO₄ 50, the ratio of COD/SO₄ 20 increased sharply to 0.0223 m³/kg VS, and in particular, the highest result was 0.0855 m³/kg VS in COD/SO₄ 10. Based on these results, it is judged that the effect of sulfide in anaerobic digestion can have an adverse effect if the COD/SO₄ ratio decreases to less than 20.

• Journal of Applied Biological Chemistry
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• v.57 no.1
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• pp.65-72
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• 2014

Biochar (BC) from biomass pyrolysis is a carbonaceous material that has been used to remove various contaminants in the environment. The eliminatory action for burcucumber (Sicyos angulatus L.) as an invasive plant is being consistently carried out because of its harmfulness and ecosystem disturbance. In this study, burcucumber biomass was converted into BCs at different pyrolysis temperatures of 300 and $700^{\circ}C$ under a limited oxygen condition. Produced BCs were characterized and investigated to ensure its efficiency on antibiotics' removal in water. The adsorption experiment was performed using two different types of antibiotics, tetracycline (TC) and sulfamethazine (SMZ). For the BC pyrolyzed at a high temperature ($700^{\circ}C$), the values of pH, electrical conductivity, and the contents of ash and carbon increased whereas the yield, mobile matter, molar ratios of H/C and O/C, and functional groups decreased. Results showed that the efficiency of BCs on antibiotics' removal increased as pyrolysis temperature increased from 300 to $700^{\circ}C$ (38 to 99% for TC and 6 to 35% for SMZ). The reaction of ${\pi}-{\pi}$ EDA (electron-donor-acceptor) might be involved in antibiotics' adsorption to BCs. BC has potential to be a superior antibiotics' adsorbent with environmental benefit by recycling of waste/invasive biomass.

• Journal of Environmental Science International
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• v.21 no.11
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• pp.1389-1394
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• 2012

This study was carried out to evaluate the physicochemical properties of topsoil from forest development area. The results of physicochemical properties of topsoil from forest development area shown on the average loamy sand~sandy clay loam in soil texture, 5.3~7.1 in pH, 0.02~0.18 dS/m in EC, 0.7~1.8% in OM, 0.03~0.11% in T-N, 11~15 $cmol^+/kg$ in CEC, 0.02~0.04 $cmol^+/kg$ in $K^+$, 4.51~8.18 $cmol^+/kg$ in $Ca^{2+}$, 0.93~2.77 $cmol^+/kg$ in $Mg^{2+}$, 6~49 mg/kg in available phosphate. And the results of physicochemical properties of topsoil from forest non-development area shown on the average sandy loam~sandy clay loam in soil texture, 4.4~5.3 in pH, 0.03~0.05 dS/m in EC, 3.1~4.6% in OM, 0.13~0.23% in T-N, 14~18 $cmol^+/kg$ in CEC, 0.02~0.04 $cmol^+/kg$ in $K^+$, 0.78~3.82 $cmol^+/kg$ in $Ca^{2+}$, 0.29~1.31 $cmol^+/kg$ in $Mg^{2+}$, 3~31 mg/kg in Av. $P_2O_5$. On the other hand, forest development area of topsoil sand content higher than 8~18% sand content than the forest non-development area. This trend is thought to be the absence of topsoil management development projects. Consequently, the results suggested a high potential of recycling of the topsoil from forest non-development area for planting soil. Therefore, in construction of the conservation and management of topsoil from forest non-development area is very important.

• Journal of the Korean Institute of Landscape Architecture
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• v.41 no.1
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• pp.34-43
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• 2013

This study aimed to research and analyze the real condition of topsoil management of river development field as a significant case among domestic development fields for topsoil preservation. Through survey with experts, we understood the real condition and problems of topsoil management during river development. In order to verify this, we analyzed the characteristics of soil before and after development focusing on the rivers recently completed as an ecological river restoration project, supervised by Ministry of Environment among domestic river improvement projects. The study results are like below. First, experts preferred collecting and reusing topsoil as the best method to maintain and improve soil for plant growth. Second, realistically collecting and reusing topsoil is not fully conducted due to economical issues and inconvenience in construction. In the soil condition, third, the contents of elements necessary for plant growth like organic matter and total nitrogen declined overall after development.

• Journal of fish pathology
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• v.18 no.2
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• pp.187-195
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• 2005

Effluent of aquaculture industry has caused a growing concern regarding its environmental impact. We assessed the use of flounder farming sewage as supplement of diet, to minimize the impact of aquaculture on the environment or also establish the technique for the recycling of effluent sediment derived from land-based seawater fish farm. In order to investigate the effects of a fermented aquaculture waste on biochemical responses of olive flounder (Paralichthys olivaceus), fermented products of aquaculture wastes were used as test compounds that cause hepatic and renal stress through the induction of oxidative stress in liver and kidney. Hepatosomatic index (HSI), glutathione content and glutathione dependent enzyme were not significantly different and no correlation was found within the different types of fermentation condition or supplement concentration, except for significant increases in 50% fermentation group and 50% concentration group in case of glutathione peroxidase activity and HSI value, respectively. These results showed addition of fermented aquaculture sewage may be an economic artificial sources of diet for fish aquaculture practices without affecting the function and safety in view of biochemical examination.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.9
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• pp.939-946
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• 2011

In thermal power generation companies, the recycling of refined ash (LOI < 6%) obtained from a PC-firing furnace is beneficial for the companies, e.g., it can be used for making lightweight aggregates. However, ash having a high LOI, which cannot be reused, is still buried in the ground. To obtain refined ash, the re-burning of high-LOI ash (LOI > 6%) in a PC-firing furnace can be an alternative. In this study, a numerical analysis was performed to demonstrate the effects of ash re-burning. An experimental constant value was decided by TGA (thermo-gravimetric analysis), and a DTF (drop-tube furnace) was used in the experiment for calculating the combustion of ash. On the basis of the trajectory of the moving particles of coal and ash, it was concluded that supplying ash near the burner, which is located high above the ground, is appropriate. On the basis of numerical results, it was concluded that an ash supply rate of 6 ton/h is suitable for combustion, without affecting the PC-firing boiler.

• Korean Journal of Ecology and Environment
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• v.39 no.4 s.118
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• pp.508-515
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• 2006

This study was conducted from July to December 2004, in order to find measures to improve the water quality and the function of pond ecosystems which are often negatively affected by phytoplankton and suspended particle matters. Most of the time, the management of ponds in Korea does not consider the ecological concepts such as self-purification and nutrient recycling. Instead, conventional methods depend on other factors such as fish farming and the function of fountains and waterfalls. Sustainability of pond ecosystems must be studied with the highest emphasis given to water quality. Water discharges of inflow and outflow as well as balance adjustment for different factors must be thoroughly studied. There is a great need for studies on sustainability because it can be realized through the horizontal or vertical balances of an ecosystem. Our current research offers useful information to the academia and public on maintaining sustainability in terms of structure and function of the pond.

• Journal of the Korean GEO-environmental Society
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• v.15 no.3
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• pp.33-40
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• 2014

In this paper, mechanical and germination characteristics of stabilized dredged soils were investigated to recycle dredged soil in eco-friendly manner such as waterfront construction. Non sintering binder (NSB), which was developed by using interchemical reactions between slag, high-calcium fly ash, alkali activator on the dredged marine clay, was added to dredged soil. Ordinary portland cement was also used for the comparison of two binders. Experimental tests such as flow test and unconfined compressive test were carried out to evaluate characteristics of stabilized dredged soil. Leaching test, pH measure, vegetation germination test were also conducted to consider environmental applicability. The unconfined compressive tests shows that unconfined compressive strength (UCS) also increases with the increase of curing time and mixed ratio. UCS of NSB mixtures were higher than those of OPC mixtures. Germination tests showed that germination and sprouting date are better in NSB mixture than OPC mixture. It can be explained that germination decreased as pH and 7-day strength increased.

• Clean Technology
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• v.14 no.2
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• pp.129-135
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• 2008

Nylon membrane was used to separate ethanol-water by a pervaporation method. Experimental equations were derived to use the simulation of membrane-aided distillation using nylon. The increases in permeation pressure resulted in the decrease in selectivity and energy consumption. The energy cost to enrich ethanol from 94 wt% to 99.5 wt% was calculated to be 53.3 won/kg of ethanol with extractive distillation and 18.9 won/kg of ethanol with a pervaporation method. The saving energy by the pervaporation method is consumed by recycling the permeate residue into the distillation column in the membrane-aided distillation column. Therefore, membrane with the high selectivity to minimize the permeate residue recycle is required to effectively enrich ethanol in the membrane-aided distillation method.