• Journal of the Korea Organic Resources Recycling Association
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• v.29 no.4
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• pp.55-65
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• 2021

This study investigated methane productions and a degradation rate of organic matters by German standard method, VDI4630 test. In this study, 11 waste biomasses from agricultural fields were selected for the investigation. The objective of this study was to estimate a distribution of organic matters by using the Double first-order kinetics model in order to calculate the rate of biodegradable organic matters which degrade rapidly in the initial stage and the persistently biodegradable organic matters which degrade slowly later. As a result, all the biomasses applied in this study showed rapid decomposition in the initial stage. Then the decomposition rate began to slow down for a certain period and the rate became 10 times slower than the initial decomposition rate. This trend of decomposition rate changes is typical conditions of biomass decompositions. The easily degradable factors (k₁) were raged between 0.097~0.152 day^-1 from vegetable crops and persistent degradable factor (k₂) were 0.002~0.024 day^-1. Among these results, greater organic matter decomposition rates from VDI4630 had greater k₁ values (0.152, 0.144day^-1) and smaller k₁ values (0.002, 0.005day^-1) from cucumbers and paprika. In a meanwhile, radishes and tangerine rinds which had low decomposition rates showed 0.097 and 0.094 day^-1 of k₁ values and decomposition rates seems to affect k₁ values.

• Journal of Wetlands Research
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• v.6 no.1
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• pp.117-132
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• 2004

Despite its significance in understanding ecological structure and biogeochemical element cycles, there have been few studies on the microbial mineralization of organic matter and mineralization pathway in the intertidal flat of Korea. We measured anaerobic mineralization of organic matter and sulfate reduction rate, and evaluated the significance of sulfate reduction in total anaerobic carbon respiration at the southern part of Ganghwa Island. Depth-integrated carbon mineralization rate down to 6 cm depth ranged from 41.9 to $89.4mmol\;m^{-2}d^{-1}$, which accounted for approximately 216 tons of organic matter mineralization in entire intertidal flat area of Ganghwa($300km^2$). The results indicated that capacity for the organic matter mineralization in the Ganghwa tidal flat is comparable to highly productive salt marsh environments. Mineralization rates in the sediment amended with acetate were 2~5 times higher than in unamended sediment. The results implied that microbial mineralization was limited by the availability of organic substrates, and the organic matter mineralization capacity seems to be higher than estimated at ambient organic substrate level. Depth-integrated sulfate reduction rates within 6 cm depth of the sediment ranged from 20.7 to $45.1mmol\;SO{_4}^{2-}m^{-2}d^{-1}$, and sulfate reduction was mostly responsible for organic matter remineralization. It should be noticed that the increase of $H_2S$ in the sulfate reduction dominated tidal flat may result in the decrease of biological diversity.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.1086-1093
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• 2012

This research was carried out to develop the correction method of VDI4630 method improving accuracy, and investigated the effects of carbonate ion ($CO_3{^{2-}}$) and reactant water ($H_2O$) on anaerobic organic biodegradability in VDI4630 method. Pig blood, pig intestine residue, pig digestive tract content, and cattle rumen content were experimented as waste biomasses. Chemical formulas of pig blood, pig intestine residue, pig digestive tract content, and cattle rumen content were $C_{3.78}H_{8.39}O_{1.46}N_1S_{0.01}$, $C_{9.69}H_{15.42}O_{2.85}N_1S_{0.03}$, $C_{25.17}H_{43.32}O_{15.04}N_1$, $C_{27.23}H_{42.38}O_{15.93}N_1S_{0.11}$, respectively. And amount of reactant moisture for the anaerobic degradation of organic materials were 0.336, 0.485, 0.227, 0.266 mol, respectively. In pig blood, pig intestine residue, pig digestive tract content, and cattle rumen content, anaerobic organic biodegradability presented as $B_u/B_{th}$ were 82.3, 81.5, 70.8, and 66.1%, and anaerobic organic biodegradability (AB) by VDI4630 method were 72.2, 87.8, 74.2, 62.0%, and that were significantly different with anaerobic organic biodegradability presented as $B_u/B_{th}$. The effects of carbonate ion and reactant water on anaerobic organic biodegradability were not significant, But Accuracy of anaerobic organic degradability was expected to able to be improved by the correction method of VDI4630 considering the carbonate ion at digestate and the reactant water quantified.

• Proceedings of the Korean Society of Organic Agriculture Conference
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• 2009.12a
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• pp.300-300
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• 2009

화학비료를 이용할 수 없는 유기농업에서의 양분관리를 위해서 녹비, 퇴비, 유박 등을 주 원료로 하는 유기질비료 등 다양한 유기물이 농경지에 투입되고 있다. 그러나 다양한 성분 및 탄소/질소비로 이루어진 유기물은 토양 중에서 분해되는 속도가 다르고, 토양수분함량, 통기성, 온도 등과 같은 토양조건에 따라서도 분해속도가 크게 차이가 난다. 본 실험에서는 유기농업에서 시비원으로 자주 이용하는 퇴비, 유박비료, 녹비조건의 알팔파 등을 이용하여 무기화율 및 양분이용률을 화학비료와 비교하였다. 농경지 투입시 유기물은 질소양분양(21kg N/10a)을 동일하게 투입하였으며 화학비료는 기비(전체량의 1/3)만을 투입하였는데 알팔파, 유박비료의 경우 노지조건에서 토양처리 후 1달 내에 가장 높은 무기화율을 보였으며 수분조건이 제한된 무기화통내에서의 무기화도 2개월 내에 대부분 이루어지는 것으로 나타났다. 수딘그라스를 2개월 재배한 결과 화학비료 질소 양분이용율은 70%, 탄질비가 낮은 유박 및 알팔파는 40%내외, 탄질비가 높고 분해가 어려운 가축분 왕겨퇴비는 10%에 불과했다. 즉 화학비료 대비 유기물 양분(질소)의 비효화 율은 알팔파는 60%, 유박비료는 54%, 퇴비는 14% 였다. 또한 화학비료(100%) 대비 인산 이용률(유박: 296%, 알팔파: 660%, 퇴비: 36%로, 인산의 이용율이 높은 것은 유기물로 투입된 인산의 량이 화학비료보다 낮아 상대적으로 유기물질에 의한 작물의 인산이용율이 높고, 화학비료는 토양중 고정화가 작물생육 초기에 일어나는데 비하여 유기물질은 서서히 분해되면서 작물에 흡수되어 인산이용율이 높은 것으로 추정된다. 수단그라스 1차수확 후 포장침수로 인한 생육불량으로 전 생육 과정을 통한 양분흡수율은 측정할 수 없었다.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.487-487
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• 2018

본 연구에서는 2017년 5월부터 12월까지 주단위로 낙동강 수계 5개 보 구간(칠곡보~창녕함안보)에서 본류와 유입지천의 유기물(BOD, $COD_{Mn}$, TOC) 분석 및 상관관계 조사하였으며, 강정고령보~창녕함안보의 대표지점에 대해서는 용존유기물(DOC)의 분해특성을 조사하였다. 본류의 유기물 농도는 BOD $2.7mgO_2/L$($2.3{\sim}3.1mgO_2/L$), $COD_{Mn}$ $5.6mgO_2/L$($5.0{\sim}6.2mgO_2/L$), TOC 4.7 mgC/L($4.2{\sim}5.2mgO_2/L$), 유입지천은 BOD $3.4mgO_2/L$($1.1{\sim}5.6mgO_2/L$), $COD_{Mn}$ $7.1mgO_2/L$($2.5{\sim}10.9mgO_2/L$), TOC $5.7mgO_2/L$(2.3~8.7 mgC/L)로 각각 나타났다. 유기물간 상관성 분석결과 본류의 BOD와 COD, TOC 상관계수(r)은 각각 0.97, 0.98, COD와 TOC는 0.91, 유입지천의 BOD와 COD, TOC는 각각 0.81, 076, COD와 TOC는 0.99로 나타났다. 본류 구간에서 탄소로 환산된 BOD-C/TOC 산화율은 21.5%(20.4~22.5%), COD-C/TOC 45.7%(44.3~48.0%), 유입지천의 BOD-C/TOC 산화율은 23.6%(13.1~31.0%), COD-C/TOC 48.0%(41.3~53.3%)로 각각 나타났다. 강정고령보~창녕함안보 대표지점의 DOC 분해특성은 DOC 중 R-DOC가 86.9%(74.5~94.3%), L-DOC 13.0%(5.7~25.5%)로 나타났다. L-DOC의 분해속도(k)는 0.21 /day(0.11~0.38 /day)로 계산되었으며, 보별 평균 분해속도는 합천창녕보(0.25 /day) > 강정고령보(0.22 /day) > 창녕함안보(0.21 /day) > 달성보(0.18 /day)순으로 나타났다. 유기물 농도는 본류에서는 하류로 갈수록 증가하는 경향을 보였으며, 유입지천은 지점별로 다양하게 나타났다. 유기물간 상관성은 유입지천보다 본류구간이 상관계수가 높게 나타났다. TOC에 대한 BOD와 $COD_{Mn}$산화율은 본류구간 보다 유입지천에서 큰 변동을 보였으며, 실제 유기물 총량 대비 BOD와 $COD_{Mn}$은 각각 77.0%, 52.7% 낮게 나타났다. DOC 중 난분해성 유기물이 대부분을 차지하였으며, 타 보 대비 달성보 내에 난분해성 유기물이 높은 것으로 나타났다.

• Journal of the Korea Organic Resources Recycling Association
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• v.3 no.2
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• pp.47-57
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• 1995

The purpose of this study was to investigate the effect of mechanical mixing intensity on composting. The major parameters investigated were the mixing intensity and initial moisture content. Laboratory scale composting reactors with mixing equipment were used in this study. Wastes used for the study were raw nightsoil sludge, nightsoil sludge after vacuum evaporation treatment and pig manure. When moisture contents were 60% and 63%, amount of organic material degraded in the continuous mixing reactors was higher than that in the intermittent mixing reactors. Compost produced from reactors with continuous mixing had better texture than that obtained from reactors with intermittent mixing. When moisture content was 68%, organic waste was kneaded rather than mixed in the continuous mixing reactors. Amount of organic material degraded in the continuous mixing reactors also was lower than that in the intermittent mixing reactors.

• Korean Journal of Environmental Agriculture
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• v.7 no.2
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• pp.136-145
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• 1988

To investigate the seasonal changes of various organic and inorganic compounds in compost, carbon compounds in compost were analyzed at various composting periods. Contents of organic matter, cellulose, total carbon, organic carbon and biodegradable carbon in compost were decreased with the progress of composting. In contrast, contents of lignin and nonbiodegradable carbon were increased a little with the progress of composting, but effective contents of lignin were decreased with the lapse of composting time, while effective contents of nonbiodegradable carbon were not changed. Total carbon contents in organic matter in compost were decreased within 9 weeks after composting, and then increased thereafter. Difference between average values of total and biodegradable carbon contents was 6.2%. Actual decay rates of all the carbon compounds were higher than decay rates of the compounds at all the experimental periods. Both of actual decay rate and decay rate of all the carbon compounds were increased rapidly within 2 weeks after composting, and thereafter the rates were increased slightly with the lapse of composting time. Especially the decay rates of cellulose were increased from 9 to 21 weeks after composting. Actual degradation capacity showed the same tendency to degradation capacity of all the carbon compounds in compost. Decay rate and degradation capacity of lignin in compost had minus values, while actual decay rate and actual degradation capacity had plus values. Highly positive correlations were observed among organic matter, cellulose, total carbon and biodegradable carbon one another. Nonbiodegradable carbon showed highly negative correlation with organic matter, cellulose, total carbon, organic carbon and biodegradable carbon, respectively. The same tendencies were observed between lignin and organic matter, cellulose, total carbon, organic carbon and biodegradable carbon. Highly positive correlation was observed between lignin and nonbiodegradable carbon in compost.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.26 no.2
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• pp.110-123
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• 2021

We investigated geochemical constituents of pore-water and sediment, rates of organic carbon (C_org) oxidation and sulfate reduction (SR), and benthic nutrient flux (BNF) to elucidate characteristic of C_org oxidation and its control in the coastal area near Lake Shihwa. The study sites were selected in the vicinity of Soraepogu (E0), Songdo tidalflat (E1) and Oido dock (E3) and in front of floodgate Shihwa tidal plant (E5). The C_org contents in the sediments and concentrations of ammonium and phosphate in pore water exhibited the highest value at EO, and gradually decreased toward the outer sea (E1, E3, E5). Rates of anaerobic C_org oxidation (260.6 mmol C m^-2 d^-1) and SR (91.4 mmol S m^-2 d^-1) at E0 were 4-9 and 6-54 times higher than at the site of outer sea (E1, E3, E5). Rates of SR at E3 and E5 accounted for 11-23% of anaerobic C_org oxidation, whereas it comprised 47-70% of anaerobic C_org oxidation at E0 and E1. Rates of C_org oxidation and SR showed a highly positive correlation with the concentration of dissolved organic carbon (r² = 0.795 and 0.777, respectively). The BNF at E0, E1, and E3 accounted for 120-510% and 26-178%, respectively, of the N and P required for primary production in the water column. Overall results suggest that the C_org oxidation in the sediment controlled by concentration of dissolved organic carbon in the pore water and the excessive C_org oxidation stimulates the benthic nutrient flux, which may cause a phytoplankton bloom in the water column.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.8 no.2
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• pp.210-224
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• 2003

Sulfate reduction is a microbiological process which occurs ubiquitously in anaerobic marine environment. Sulfate reducing bacteria play a significant role in anaerobic decomposition of organic matter and regeneration of inorganic nutrients which supports the primary production in the water column (i.e., benthic-pelagic coupling) and, in special case, could be responsible for the harmful algal bloom in the coastal marine environment. Summary of the sulfate reduction rates reported in various marine sedimentary environments revealed that supply of organic substrates and presence of various electron acceptors (i.e., $O_2$, NO$_{3}$$^{[-10]}$ , Fe(III) and Mn(IV), etc.) for other aerobic and anaerobic respiration directly affect the sulfate reduction rate and relative significance of sulfate reduction in organic matter mineralization. Significance of temperature, macrophytes and bioturbation is discussed as factors controlling supply of organic substrates and distribution of electron acceptors. Finally, we suggest studies on the anaerobic microbiological processes associated with biogeochemical element cycles in the coastal environments of Korea where massive operation of organic enriched fish cage farm, frequent occurrence of toxic algal bloom and hypoxia and conservation of tidal flat are of major environmental issues.

• Journal of the Korea Organic Resources Recycling Association
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• v.11 no.4
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• pp.79-89
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• 2003

The purpose of this study is to investigate appropriate environmental factors when domestic waste is decomposed as aerobic digestion. So stabilization degree was measured after the waste is mixed as certain rates and water content was controlled by 55% and 60%. Variation of VS showed food waste in reactors of number 1, 2, 3, 4 and 5 was decomposed fully except reactor of number 6. Decomposition degree of VS in reactors of number 1, 2, 3 and 4 was not different high because Vinyl and plastic inserted played role bulking agent in reactor number 1, 2, 3 and 4. In reactors, maximum temperature indicated $57{\sim}59^{\circ}C$ and temperatures in reactors 1, 2, 3 and 4 were higher and remained longer than in reactor 5 and 6 for 2~4 days. Variation of $CO_2$ was similar to that of VS. The reduction rate of water content was low because moisture generated by oxidation fever of microorganism did not evaporated well. pH was low in the beginning of the reaction however, as time passed, it increased slightly and remained regular pattern. EC and C/N showed the same pattern as pH. Settlement and weight reduction rates were similar to the factors above. Reactor 1, 2, 3, and 4 showed higher settlement and weight reduction rate than reactor 5 and 6.