• Journal of Bio-Environment Control
• /
• v.12 no.4
• /
• pp.184-189
• /
• 2003

This research was conducted to determine the effect of mixing ratio of aquafarm waste water sludge (AWWS) in the growing medium as a source of fertilizers on growth of plug seedlings of pepper (Capsicum annuum L.) and tomato (Lycopersicum esculentum Mill.). Increased mixing ratio of AWWS resulted in increased fresh and dry weights, leaf area, plant height, and total chlorophyll content, although there were slight differences in growth characteristics at 20 and 40 days after sowing. Concentration of AWWS affected insignificantly the percent dry matter, number of leaves, and length of the longest root. The addition of AWWS increased pH and decreased EC in the medium as compared to that of chemical fertilizer. Compared to the control of a liquid fertilizer, 4 or 8 kg AWWS${\cdot}45L^{-1}$ medium (Sludge 4) gave a similar or slightly better growth. Above results suggested that addition of about 4 kg AWWS${\cdot}45L^{-1}$medium is sufficient for seedling growth and the AWWS can be used as a substitute for the liquid fertilizer in plug seedling production.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.14 no.2
• /
• pp.91-100
• /
• 2016

The neutron activation inventories in reactor vessel and its internals, and bio-shield of a PWR nuclear power plant were calculated to evaluate the effect of impurity elements contained in the structural materials on the activation inventory. Carbon steel is, in this work, used as the reactor vessel material, stainless steel as the reactor vessel internals, and ordinary concrete as the bio-shield. For stainless steel and carbon steel, one kind of impurity concentration was employed, and for ordinary concrete five kinds were employed in this study using MCNP5 and FISPACT for the calculation of neutron flux and activation inventory, respectively. As the results, specific activities for the cases with impurity elements were calculated to be more than twice than those for the cases without impurity elements in stainless and carbon steel. Especially, the specific activity for the concrete material with impurity elements was calculated to be 30 times higher than that without impurity. Neutron induced reactions and activation inventories in each material were also investigated, and it is noted that major radioactive nuclide in steel material is Co-60 from cobalt impurity element, and, in concrete material, Co-60 and Eu-152 from cobalt and europium impurity elements, respectively. The results of this study can be used for nuclear decommissioning plan during activation inventory assessment and regulation, and it is expected to be used as a reference in the design phase of nuclear power plant, considering the decommissioning of nuclear power plants or nuclear facilities.

• Korean Journal of Soil Science and Fertilizer
• /
• v.45 no.6
• /
• pp.1037-1042
• /
• 2012

An auxin-producing bacteria (2SJ8-02) was isolated from waste mushroom bed of Agaricus bisporus in Buyeo-Gun, Chungnam. The strain 2SJ8-02 was classified as a novel strain of Pantoea rwandensis based on a chemotaxanomic and phylogeneticanalyses. The isolate was confirmed to produce indole-3-acetic acid (IAA), one of auxin hormones, by TLC and HPLC analyses. The maximum concentration of IAA, $122mg\;L^{-1}$ was detected from the culture in R2A broth containing 0.1% tryptophan for 24 h at $35^{\circ}C$. The molecular weight of the main peak obtained by LC-mass analysis was 175 corresponding to that of IAA. To investigate the growth-promoting effects to the crops, the culture broth of Pantoea rwandensis 2SJ8-02 was infected to water cultures and seed pots of mung bean. In consequence, the adventitious root induction and root growth of mung bean were two times higher than those of the control.

• Clean Technology
• /
• v.29 no.3
• /
• pp.200-216
• /
• 2023

Ginkgo leaves are considered waste biomass and can cause problems due to the strong insecticidal actions of ginkgolide A, B, C, and J and bilobalide. However, Ginkgo leaf biomass has high organic matter content that can be converted into fuels and chemicals if suitable technologies can be developed. In this study, the effect of pyrolysis temperature, minimum fluidized velocity, and Ginkgo leaf size on product yields and product properties were systematically analyzed. Fast pyrolysis was conducted in a bubbling fluidized bed reactor at 400 to 550℃ using silica sand as a bed material. The yield of pyrolysis liquids ranged from 33.66 to 40.01 wt%. The CO₂ and CO contents were relatively high compared to light hydrocarbon gases because of decarboxylation and decarbonylation during pyrolysis. The CO content increased with the pyrolysis temperature while the CO₂ content decreased. When the experiment was conducted at 450℃ with a 3.0×U_mf fluidized velocity and a 0.43 to 0.71 mm particle size, the yield was 40.01 wt% and there was a heating value of 30.17 MJ/kg, respectively. The production of various phenol compounds and benzene derivatives in the bio-oil, which contains the high value products, was identified using GC-MS. This study demonstrated that fast pyrolysis is very robust and can be used for converting Ginkgo leaves into fuels and thus has the potential of becoming a method for waste recycling.

• Journal of the Korean GEO-environmental Society
• /
• v.15 no.9
• /
• pp.13-18
• /
• 2014

BMP test was carried out to evaluate the characteristics for co-digestion of night soil and food waste. 6 types of sludge were tested in 30 days which were raw, excess, digested, night soil/septic tank (1:1), food waste (food : dilution water = 1:1), and mixed sludge. Bio gas was produced actively after 2 days, and continued in 2 weeks. Gas generation amount was decreased rapidly after considerable space of time. Especially maximum productivity of gas was shown in 7~8 days. The ultimate methane yields of raw, excess, digested, night soil/septic tank, food waste, and mixed sludge were 64.63, 67.49, 66.45, 72.44, 107.85, and 46.71 mL $CH_4/g$ VS respectively from Modified Gompertz model. The lag growth phase time and maximum specific methane production rate of mixed sludge were 1.88 day and 80.4 mL/day respectively. The methane potential of mixed sludge was higher than individual sludge. So high methane potential was expected by controlling mixing ratio of food waste. Besides stable operation of digestion tank and the solution of oligotrophic problem were possible.

• Journal of the Mineralogical Society of Korea
• /
• v.28 no.3
• /
• pp.209-220
• /
• 2015

The aim of this study was leaching valuable metal ions from mine waste rocks which were abandoned mine site using indigenous aerobic bacteria. In order to tolerate the the indigenous aerobic bacteria to the heavy metal ions they were repeatedly adapted in $CuSO_4{\cdot}5H_2O$ environment. As the repeated generation-adaptation progressed, the pH values of the growth-medium were gradually decreased. During bio-leaching experiments with indigenous aerobic bacteria raised in a heavy metal ion environment for 42 days, the pH of the leaching solution was decreased while increasing the adaptation period. The indigeous bacteria were much more active on the surface of Younhwa waste rocks which contained relatively few the chalcopyrite and Cu content than the Goseong mine waste rocks, and also the amount of Cu and Fe ions were leached more in the Younhwa sample(leaching rate of 92.79% and 55.88%, respectively) than the Goseong sample(leaching rate of 66.77% and 21.83%, respectively). Accordingly, it is confirmed that valuable metal ions can be leached from the mine waste rocks, if any indigenous bacteria which inhabits a mine environment site for a long time with heavy metal ions can be used, and these bacteria can be progressively adapted in the growth-solutions containing the target heavy metals.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.18 no.2
• /
• pp.55-61
• /
• 2010

This study was carried out to analyze national and regional distribution of the organic wastes generation and build their distribution maps including food wastes, paper and wood wastes, wastewater and slaughterhouse wastes. The information for the annual waste production was modified using statistics from Ministry of Environment (MOE). Based on waste generation resources data, we established database architecture table about waste generation. The distribution maps for food wastes were built up in both national and regional scales and distribution maps for paper and wood wastes, wastewater and slaughterhouse wastes were also produced, respectively. The distribution maps of waste generation graphically provide the information regarding biomass resources to policy-makers, farmers, general users and it is highly expected to be utilized for policy-making of environmental-friendly agriculture and bioenergy.

• Economic and Environmental Geology
• /
• v.43 no.6
• /
• pp.555-564
• /
• 2010

Remediation process by using the bio-carrier (beads) with dead Bacillus sp. B1 and polysulfone was investigated for heavy metal contaminated groundwater. Sorption batch experiments using the bio-carrier were performed to quantify the heavy metal removal efficiencies from the contaminated solution. The analyses using SEM/EDS and TEM for the structure and the characteristic of precipitates on/inside the beads were also conducted to understand the sorption mechanism by the bio-carrier. Various amounts of freeze-dried dead Bacillus sp. B1 were mixed with polysulfone + DMF(N,N-dimethylformamide) solution to produce the bio-carrier (beads; less than 2mm in diameter) and 5% of Bacillus sp. B1 in the bio-carrier was optimal for Pb removal in the solution. The removal efficiency ratings of the bio-carrier for Pb, Cu and Cd were greater than 80% after adding 2g of bio-carrier in 50ml of aqueous solution (<10mg/L of each heavy metal concentration). Reaction time of the bio-carrier was very fast and most of the sorption reaction for heavy metals were completed within few hours. Batch experiments were duplicated at various pH conditions of aqueous solutions and Cu and Pb removal efficiencies highly maintained at wide pH ranges (pH 2-12), suggesting that the bio-carrier can be useful to clean up the acidic waste water such as AMD. From SEM/EDS and TEM analyses, it was observed that the bio-carrier was spherical shape and was overlapped by many porous layers. During the sorption experiment, Pb was crystallized on the surface of porous layers and also was mainly concentrated at the boundary of Bacillus sp. B1 stroma and polysulfone substrate, showing that the main mechanism of the bio-carrier to remove heavy metals is the sorption on/inside of the bio-carriers and the bio-carriers are excellent biosorbents for the removal of heavy metal ions from groundwater.

• Tribology and Lubricants
• /
• v.30 no.5
• /
• pp.256-264
• /
• 2014

Enhancing the value of fine chemicals based on biomass resources is an important objective for addressing environmental and other concerns such as demand for renewable or green products, as well as from the political perspective to reduce dependence on fossil feedstock associated with the use of petroleum-based products. Based on these considerations, we studied the synthesis of estolide using waste plant-based oil materials and their application as lubricants and pour point depressants. Five estolides were prepared by varying molar ratio of palmitic acid (PA) to oleic acid (OA) using a reaction time of 48 h. The estolides were characterized by size exclusion chromatography (SEC) and nuclear magnetic resonance (NMR). The isolated yields were in the range of 57-78 % and purity was 93-97%, showing iodine values of 18.2-37.8, total acid numbers (TANs) of 75.6-94.2 mg KOH/g and estolide numbers (ENs) of 1.2-1.8. Increasing the ratio of OA to PA in the synthesis decreased the kinematic viscosity and clouding point of the estolides. Four ball wear test of the estolides as a base oil demonstrated that the wear scar diameter (WSD) of the estolides was significantly lower (0.320-0.495 mm) than the WSD of general base oils such as 150N and Yubase (0.735 and 0.810 mm, respectively), indicating better wear resistance of the estolides. However, the lubricant property was found to be independent of the amount of OA in the estolides. These new materials are prospective candidates for application as a lubricant base oil.

• Journal of environmental and Sanitary engineering
• /
• v.20 no.1 s.55
• /
• pp.64-75
• /
• 2005

The total production of food waste was about 11,398ton/day('03) in Korea. Also, food waste was treated by landfill, incineration, reuse and anaerobic digestion. The method of food waste treatment depended primarily on landfill. However, the method of landfill causing social problems was prevented to treat food waste in the first of January 2005.12) Thus, anaerobic digestion is an important method to treat food waste because of possibility of energy recovery as methane gas. In this study, the possibility of food waste treatment containing high organic material and low pH in the one stage anaerobic reactor to save cost and time and energy recovery using $CH_{4}$ gas by the hybrid anaerobic reactor (HAR) was measured. The HAR was designed by combing the merits of the anaerobic filter (AF) to minimize the microorganism shock when food waste of very low pH was injected and up-flow anaerobic sludge blanket (UASB) to prevent from plugging and channeling phenomena by large suspended solids when semi solids were injected. Granule was packed in the section of HAR. The purpose of the BMP experiment was to measure the amount of methane generated when organic material was resolved under anaerobic conditions, to grasp bio resolution of organic material. Total accumulated methane production per VS amount was $0.471(m^{3}/\cal{kg}\;VS)$. So, the value was about $81.2\%$ of theoretical methane production which was $0.58(m^{3}/\cal{kg}\;VS)$ by elementary analysis and organic matter removal velocity (K) was $0.18(d^{-1})$. From these results, food waste was treated by anaerobic treatment. From this study, $CH_{4}$ generation from food waste (11,398 ton/day) could be estimated. By using an energy conversion factor of Braun's study, $5.97KWh/m^{3}\;CH4,\;60\%\;of\;CH_{4}$ gas generation, the amount of total energy producing food waste is to 6,727MWh/day. It could be confirmed that energy recovery using $CH_{4}$ gas was possible. Above these results, food waste containing organic matters of high concentration could be treated in HRT 30 days under an anaerobic condition, using the hybrid anaerobic reactor and reuse of $CH_{4}$ gas was possible.