• Journal of Animal Environmental Science
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• v.18 no.2
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• pp.63-74
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• 2012

This experiment was carried out to investigate the effect of different stocking rate on growth, cast production and conversion efficiency of organic matter to tissues of earthworm. The carbon and nitrogen ratio (C/N) of tested Korean cow manure was 25.1, it was estimated an adequate ratio as feed for earthworms. The different stocking rates were 1:8(S-1), 1:16(S-2), 1:32(S-3) 1:64(S-4) 1:128(S-5) and 1:256 (S-6) as the ratios of earthworm fresh weight to biomass of Korean cow manure, respectively. A stocking rate of 1:32(S-3) was obtained a significantly highest values of increasing rate and conversion efficiency of organic matter to earthworm tissues. The mean values of increasin g rate of fresh weight and conversion efficiency of organic matter to earthworm tissues were 10.63 mg/day and 6.65% at the ratio of 1:32(S-3) with a rearing volume was $56.6cm^3$. A stocking rate of 1:8(S-1) was obtained a highest ratio of vermicasts, but showed a negative values of increasing rate and conversion efficiency of organic matter to earthworm tissues, it may due to severely food competition between individuals during the rearing periods. The pH, total nitrogen, available phosphorus, cation exchange capacity and exchangeable cations of vermicasts tended to increase with stocking rate. Especially, available phosphorus, cation exchange capacity and exchangeable cations of vermicasts tended to increase with rearing progressed. Vermicasts have the potential for improving plant growth when amended to container medium and soil according to increased availability of nutrients and improved physicochemical properties.

• Journal of Climate Change Research
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• v.3 no.3
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• pp.211-224
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• 2012

Technology for energy recovery from waste can reduce the greenhouse gas emissions. So recently, there are several companies using RDF, RPF, WCF instead of using only coal fuel and it's part of the fuel on the increase. In this study, we developed Wood chip fuel $CO_2$ emission factor through fuel analysis. It's moisture content is 23%, received net calorific value is 2,845 kcal/kg, and received basis carbon is 34%. The result of emission factor is $105ton\;CO_2/TJ$, it's 5.9% lower than 2006 IPCC guideline default factor $112ton\;CO_2/TJ$. The gross GHG(Greenhouse gases) emissions of plant A is $178,767ton\;CO_2 eq./yr$, and Net GHG emissions is $40,359ton\;CO_2 eq./yr$. Therefore, the reduction of GHG emissions is $138,408ton\;CO_2/yr$ through using WCF, and I accounts for 77% of all GHG emissions.

• Korean Journal of Ecology and Environment
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• v.52 no.2
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• pp.81-93
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• 2019

Phytoplankton is one of the important primary producers providing organic matter through photosynthesis in aquatic environments. In order to determine a temporal and spatial variation in primary productivity after weir construction in the Nakdong River, we investigated carbon uptake rates using in-situ $^{13}C$ labeling experiments and identified algal communities contributing to primary productivity using HPLC-CHEMTAX analysis from October to December, 2017. The primary productivity gradually decreased from fall to early winter season ($249{\sim}933mgC\;m^{-2}d^{-1}$ in October, $64{\sim}536mgC\;m^{-2}d^{-1}$ in November and $60{\sim}274mgC\;m^{-2}d^{-1}$ in December, respectively). This is attributed to the temporally declining light intensity and the decreasing biomass and physiological activity of phytoplankton in winter. The contribution of diatoms to the phytoplankton community in the Nakdong River was approximately 63% at all the sampling sites and seasons, while the contribution of cryptophytes increased from 9% in October to 32% in November and December. The temporal changes in the primary productivity and the dominant phytoplankton species in the mid and downstream weirs of the Nakdong River was investigated for the first time, after construction of the weirs, and major environmental factors controlling the temporal variation in primary productivity and phytoplankton communities were identified in this study. We suggest that seasonal field investigations will provide further information on the major environmental factors which affect the annual variation of primary productivity and phytoplankton communities.

• Particle and aerosol research
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• v.15 no.3
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• pp.91-104
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• 2019

In this study, hourly measurements of $PM_{2.5}$ and its major chemical constituents such as organic and elemental carbon (OC and EC), and ionic species were made between January 15 and February 10, 2018 at the air pollution intensive monitering station in Gwangju. In addition, 24-hr integrated $PM_{2.5}$ samples were collected at the same site and analyzed for OC, EC, water-soluble OC (WSOC), humic-like substance (HULIS), and ionic species. Over the whole study period, the organic aerosols (=$1.6{\times}OC$) and $NO_3{^-}$ concentrations contributed 26.6% and 21.0% to $PM_{2.5}$, respectively. OC and EC concentrations were mainly attributed to traffic emissions with some contribution from biomass burning emissions. Moreover, strong correlations of OC with WSOC, HULIS, and $NO_3{^-}$ suggest that some of the organic aerosols were likely formed through atmospheric oxidation processes of hydrocarbon compounds from traffic emissions. For the period between January 18 and 22 when $PM_{2.5}$ pollution episode occurred, concentrations of three secondary ionic species ($=SO{_4}^{2-}+NO_3{^-}+NH_4{^+}$) and organic matter contributed on average 50.8 and 20.1% of $PM_{2.5}$, respectively, with the highest contribution from $NO_3{^-}$. Synoptic charts, air mass backward trajectories, and local meteorological conditions supported that high $PM_{2.5}$ pollution was resulted from long-range transport of haze particles lingering over northeastern China, accumulation of local emissions, and local production of secondary aerosols. During the $PM_{2.5}$ pollution episode, enhanced $SO{_4}^{2-}$ was more due to the long-range transport of aerosol particles from China rather than local secondary production from $SO_2$. Increasing rate in $NO_3{^-}$ was substantially greater than $NO_2$ and $SO{_4}^{2-}$ increasing rates, suggesting that the increased concentration of $NO_3{^-}$ during the pollution episode was attributed to enhanced formation of local $NO_3{^-}$ through heterogenous reactions of $NO_2$, rather than impact by long-range transportation from China.

• Particle and aerosol research
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• v.17 no.4
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• pp.91-106
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• 2021

Daily PM_2.5 was collected during summer period in 2020 in Gwangju to investigate its chemical and light absorption properties. In addition, real-time light absorption coefficients were observed using a dual-spot 7-wavelength aethalometer. During the study period, SO₄^2- was the most important contributor to PM_2.5, accounting for on average 33% (10-64%) of PM_2.5. The chemical form of SO₄^2- was appeared to be combination of 70% (NH₄)₂SO₄ and 30% NH₄HSO₄. Concentration-weighted trajectory (CWT) analysis indicated that SO₄^2- particles were dominated by local pollution, rather than regional transport from China. A combination of aethalometer-based and water-extracted brown carbon (BrC) absorption indicated that light absorption of BrC due to aerosol particles was 1.6 times higher than that due to water-soluble BrC, but the opposite result was found in absorption Ångström exponent (AAE) values. Lower AAE value by aerosol BrC particles was due to the light absorption of aerosol BrC by both water-soluble and insoluble organic aerosols. The BrC light absorption was also influenced by both primary sources (e.g., traffic and biomass burning emissions) and secondary organic aerosol formation. Finally the ATR-FTIR analysis confirmed the presence of NH₄⁺, C-H groups, SO₄^2-, and HSO₄^2-. The presence of HSO₄^2- supports the result of the estimated composition ratio of inorganic sulfate ((NH₄)₂SO₄) and bisulfate (NH₄HSO₄).

• Journal of the Korea Organic Resources Recycling Association
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• v.30 no.2
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• pp.29-42
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• 2022

The government promotes the 2050 carbon-neutral policy. Therefore, the concern to convert livestock manure into energy is increasing for the reduction of greenhouse gases generated in the livestock industry sector. In this study, the economic feasibility of the livestock manure solid fuel power generation facility, which is a major consumer of livestock manure solid fuel, was assessed to expand the demand for livestock manure solid fuel. The production cost of livestock manure solid fuel showed the lowest production cost of 97.4 thousand won/ton when dried using solid fuel at a 200 ton/day scale bio-drying facility. The livestock manure solid fuel power generation facility showed economic feasibility at a REC weight of 1.5 in the case of the bio-drying facility, so it was necessary to set a REC weight of 1.5 or more to expand the demand for livestock manure solid fuel. The conversion of livestock manure into solid fuel has various environmental benefits, such as the reduction of greenhouse gases and the effect of reducing non-point pollutants in the water system. Therefore, in order to expand livestock manure solid fuel production facility, it was required to review the feasibility including various environmental benefits.

• Journal of Korean Society of Forest Science
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• v.111 no.3
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• pp.435-449
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• 2022

Forest canopy height is an indispensable vertical structure parameter that can be used for understanding forest biomass and carbon storage as well as for managing a sustainable forest ecosystem. Plot-based field surveys, such as the national forest inventory, have been conducted to provide estimates of the forest canopy height. However, the comprehensive nationwide field monitoring of forest canopy height has been limited by its cost, lack of spatial coverage, and the inaccessibility of some forested areas. These issues can be addressed by remote sensing technology, which has gained popularity as a means to obtain detailed 2- and 3-dimensional measurements of the structure of the canopy at multiple scales. Here, we reviewed both international and domestic studies that have used remote sensing technology approaches to estimate the forest canopy height. We categorized and examined previous approaches as: 1) LiDAR approach, 2) Stereo or SAR image-based point clouds approach, and 3) combination approach of remote sensing data. We also reviewed upscaling approaches of utilizing remote sensing data to generate a continuous map of canopy height across large areas. Finally, we provided suggestions for further advancement of the Korean forest canopy height estimation system through the use of various remote sensing technologies.

• Journal of Environmental Science International
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• v.31 no.11
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• pp.911-922
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• 2022

To restore reclaimed land, it needs to be supplemented with organic matter; this is especially true for Korea, where organic matter constitutes only one-tenth of conventional agricultural soils. The giant Miscanthus, a perennial grass known for its extensive biomass, shows signs of being an excellent source of organic matter for restoring reclaimed land. Therefore, the objectives of this study were to (i) evaluate the feasibility of using the giant miscanthus as an organic resource within the context of re-using reclaimed land for agricultural purposes (i.e., potato cultivation), and (ii) determine the optimum fertilization rate for the potatoes while the giant miscanthus is being used as an organic resource. Our results show that after 180 days, giant miscanthus lost 23-47% of its original dry weight, with the extent of the loss dependent on soil salinity. Nutrient concentrations (Mg2+, Na+) continued to increase until the end of the study period. In contrast, potassium (K+) and the ratio of carbon to nitrogen (C/N) decreased until the end of the study period. Specifically, after 180 days, low salinity topsoil treatments had the lowest C/N ratio. In the first year, 150 % of standard N rates were required for the potatoes to achieve maximum productivity; however in the 2nd year, standard rates were sufficient to achieve maximum productivity. Overall, this implies that even though the application of giant miscanthus did eventually improve soil quality, increasing crop yields, N fertilization is still necessary for the best outcomes.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.1
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• pp.23-32
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• 2010

The capacity of natural purification was limited by the interruption of natural flow and the problems such as eutrophication were occurred by nutritive salts accumulation in stagnant stream. Moreover, the inflow of non-point sources causes non-degradable materials to increase in stagnant stream. In this study, an upflow biological activated carbon (BAC) biofilm process comprised of anoxic, aerobic 1, and aerobic 2 reactors were introduced for treatment of stagnant stream and SS, $BOD_5$, $COD_{Mn}$, $COD_{Cr}$, TN, and TP were monitored in the upflow BAC biofilm reactors with continuous cycling. In order to simulate stagnant stream, the lake water of amusement park and golf course were stored as influent in a tank of $2m^3$ and hydraulic retention time (HRT) was changed into 6, 4, and 2 hours. At HRT 4hr and the lake water of amusement park as influent, the removal efficiencies of SS, $BOD_5$, $COD_{Mn}$, $COD_{Cr}$, TN, and TP showed the best water quality improvement and were 69.8, 83.0, 91.3, 74.1, 74.7, and 88.9%, respectively. At HRT 4hr and the lake water of golf course as influent, the removal efficiencies of SS, $BOD_5$, $COD_{Mn}$, $COD_{Cr}$, TN and TP were 78.5, 78.0, 80.2, 74.9, 55.6 and 97.5%, respectively. As the results of polymerase chain reaction - denaturing gel gradient electrophoresis (PCR-DGGE), microbial community was different depending on influent type. Fluorescence in situ hybridization (FISH) showed that nitrifying bacteria was dominant at HRT 4 hr. The biomass amount and microbial activities by INT-DHA test were not decrease even at lower HRT condition. In this study, the upflow BAC biofilm process would be considered to the water quality improvement of stagnant stream.

• Journal of the Korean Wood Science and Technology
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• v.43 no.3
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• pp.374-380
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• 2015

The quality characteristics of the woodpellet manufactured from two domestic pines (Pinus densiflora S. et Z. and Pinus rigida Mill.) were investigated for the efficient energy use of woody biomass resources. Properties of woodpellets such as moisture content, heating value, ash content, apparent density and durability were determined by using the standard test method of woodpellets of Korea Forest Research Institute (KFRI) and elemental analysis. The results of elemental analysis for C, H, O and N showed 61.42% carbon, 5.56% hydrogen, 32.87% oxygen, and 0.15% nitrogen for Pinus densiflora S. et Z. and 61.03% carbon, 5.96% hydrogen, 32.83% oxygen, and 0.18% nitrogen for Pinus rigida Mill. No significant difference between Pinus densiflora S. et Z. and Pinus rigida Mill was observed on elemental analysis. Heating values of each woodpellet were ranged from 19.00 to 19.42 MJ/kg which satisfied the first grade quality standard (${\geq}18.0MJ/kg$) by KFRI. The ash contents of woodpellet were slightly different between Pinus densiflora S. et Z. and Pinus rigida Mill., and satisfied the first grade quality standard (${\leq}0.7%$) by KFRI. Apparent density of woodpellet (Pinus densiflora S. et Z.) was passed the first grade standard level (${\geq}640kg/m^3$), and woodpellets from Pinus rigida Mill. satisfied the second grade quality of the standard. The moisture contents of each woodpellet were satisfied by the first grade quality standard (${\leq}10%$). The durability of woodpellet (Pinus densiflora S. et Z.) was passed the third grade level (${\geq}95%$), but Pinus rigida Mill. woodpellet was insufficient to satisfy the quality standard.