• Korean Journal of Environmental Agriculture
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• v.14 no.1
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• pp.97-108
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• 1995

Nitrate concentration and ${\delta}^{15}N$ value in the groundwater in Miyakojima Island, Okinawa, were measured during 1992-1993. Water from the shallow and the deep wells at the ten separate sites were sampled. Mineral contents and natural nitrogen isotope abundance(${\delta}^{15}N$) were analyzed using a liquid chromatography and a mass spectrometry (Finnigan MAT 252). Except for waters which were directly influenced by sea water invasion, most of the groundwater showed small variations among their mineral contents and ${\delta}^{15}N$ values. The average nitrate nitrogen concentrations were $1.4{\sim}11.5mgL^{-1}$ and average ${\delta}^{15}N$ values were +4.3${\sim}$+9.7$%_o$. From the nitrate concentration and ${\delta}^{15}N$ value observed, the types of the groundwater could be categorized into four groups, such as high ${\delta}^{15}N$ and high nitrate, high ${\delta}^{15}N$ and medium nitrate, low ${\delta}^{15}N$ and medium nitrate, and low ${\delta}^{15}N$ and low nitrate, reflecting the main source of nitrate contamination, such as animal and domestic waste, animal waste and soil organic matter, soil organic matter and chemical fertilizer, and chemical fertilizer, respectively. It was discussed that the lowest ${\delta}^{15}N$ value was higher than the ${\delta}^{15}N$ value of the chemical fertilizers used in this island(-3.9${\sim}$-1.4$%_o$), then considerable amounts of nitrogen must be lost by ammonium evaporation or denitrification after fertilization.

• Journal of the Korea Organic Resources Recycling Association
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• v.14 no.4
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• pp.113-120
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• 2006

Wastewater generated through the food waste recycling process have known high concentration, BOD 20,000~150,000 mg/L, which has to treat to the proper level because of a ban on reclamation. But it is impossible to treat less than 10 days by existing water treatment plant. Ecodays Ltd. is to treat this wastewater during 2~4 days by ER-1, which can simultaneously induce the modified PFR(Plug Flow Reactor) of the oxygen transfer rate, MLVSS concentration, and influent concentration to top from bottom of reactor. We tested the pilot test about low concentration food wastewater(BOD 16,500 mg/L) and high concentration food wastewater(64,431 mg/L) at the food waste recycling plant of H-Gun(20t/d). Hydraulic retention time(HRT) of ER-1 for low concentration food wastewater is 2.5day. In low concentration conditions, ER-1 treatment efficiency is to appear BOD 99%, COD 98%, TN 97%, and TP 96%. While ER-1 process for high concentration food wastewater treatment is composed 2 stages, which are to be HRT 2.5day for law wastewater and HRT 1.5 day for secondary treatment. In high concentration conditions, ER-1 treatment efficiency is to appear BOD 97%, COD 84%, TN 66%, and TP 95%. It is treated without temperature control about high temperature($50^{\circ}C$) to appear low treatment efficiency in high concentration conditions.

• Journal of the Korea Organic Resources Recycling Association
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• v.18 no.4
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• pp.31-37
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• 2010

Livestock manures have a potential to be a valuable resource with an efficient treatment. In Korea, 42 million tons of livestock manure were generated in 2008, and 84 % of them were used for compost and liquid fertilizer production. Recently recycling of livestock manure for biogas production through anaerobic digestion is increasing, but its utilization in agriculture is still uncertified. In this study, there was applied co-digestate to the paddy for rice cultivation based on N supplement. Co-digestate was fertilizer fermented with pig slurry and food waste combined with the ratio of 70:30(v:v) in its volumetric basis. For assessing the safety of co-digestate, it was monitored the contents of co-digestate for seasonal variation, resulted in no potential harm to the soil and plant by heavy metals. The results showed that soil applied with co-digestate was increased in exchangeable potassium, copper and zinc mainly due to the high rate of pig slurry in co-digestate applied. Considering high salt content due to the combination with food waste, strict quality assurances are needed for safe application to arable land though it has valuable fertilizer nutrient. Leachate after treatment showed that the concentration of nitrate nitrogen washed out within two weeks. Considering the salt accumulation results in soil, it is highly recommended that the application rate of co-digestate should not exceed the crop fertilization rate based on N supplement. With these results, it was concluded that co-digestate could be used as an alternative fertilizer for chemical fertilizer. More study is needed for the long-term effects of co-digestate application on the soil and water environment.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.2
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• pp.177-184
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• 2012

This experiment was carried out to investigate soil properties and the requirement of livestock manure compost in a large-scale environment-friendly agricultural complex (EFAC), Gosan, Wanju-gun, Jeonbuk. Total cultivation area of major crops was 2,353 ha. This complex area included different types of environment-friendly cropping sections (402.9ha) and livestock farming including 21,077 Korean beef cattle, 1,099 dairy cow, and 32,993 hog. Amount of livestock waste carried in to Resource Center for Crop and Livestock Farming (RCCLF) was 32 Mg per day and the production of manure compost was 9,600 Mg per year. The manure contained 1.4% total nitrogen (T-N), 2.7% phosphorus as $P_2O_5$, 2.1% potassium as $K_2O$, 0.9% magnesium as MgO, 2.5% calcium as CaO. Amount of compost used in the EFAC was 6,588 Mg per year. Soil pH values in the EFAC were varied as follows: 78.1% of paddy field soil, 58.2% of upland soil, 60.3% of orchard field soil, and 62.1% of greenhouse soil were in proper range. For the content of soil organic matter, 41.7% of paddy field soil, 46.5% of upland soil, 40.5% of orchard field soil, and 81.4% of greenhouse soil were higher than proper range. The content of available phosphorus was mostly higher than proper value on the different fields except upland soil. The contents of exchangeable $K^+$, $Ca^{2+}$, and $Mg^{2+}$ were also exceeded in the orchard field and greenhouse soils. In addition, microbial population, especially aerobic bacteria, in the EFAC was higher than that in regular farming land.

• Korean Chemical Engineering Research
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• v.51 no.1
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• pp.80-86
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• 2013

In this study, the photocatalytic reactor system equipped with photocatalyst-carrying-silica-media cartridges [photocatalytic reactor system (1)] was used to perform the treatment of waste air containing malodor and volatile organic compound (VOC). The result of its performance was evaluated and compared with that of the photocatalytic reactor system equipped with commercial photocatalyst-carrying-nonwoven filter-media cartridges [photocatalytic reactor system (2)]. In case of photocatalytic reactor system (1), at the 1st stage of run the removal efficiencies of ethanol and toluene continued to be 80% and 20%, respectively. However, unlike toluene, the removal efficiency of ethanol dropped to 40% at the end of the 1st stage of run. The removal efficiency of hydrogen sulfide decreased from 100% to 90%. At the 2nd stage of its run the removal efficiency of ethanol decreased to 10% while the removal efficiencies of hydrogen sulfide and toluene remained as same as 90% and 20%, respectively, even though the inlet load of toluene increased by factor of four. In the 3rd stage of its run, as the result of application of aluminium-coated reflector film to the inner wall of photocatalytic reactor system, the removal efficiencies of ethanol and toluene increased by 5% to be 15% and 25%, respectively. In case of photocatalytic reactor system (2), at the 1st stage of its run, the removal efficiencies of ethanol, hydrogen sulfide and toluene continued to be 10%, 97% and 100%, respectively. However, at 2nd stage of its run their removal efficiencies became 5%, 95% and 2~3%, respectively, which showed that the removal efficiencies of ethanol and hydrogen sulfide decreased insignificantly while the removal efficiency of toluene dropped significantly from the perfect elimination. Moreover, the reflector film did not affect the performance of photocatalytic reactor system (2) at all. Therefore the removal of ethanol, hydrogen sulfide and toluene by photocatalytic reactor system (2) was mainly attributed to hydrophobic adsorption of its nonwoven filter media and its extent of photocatalytic removal turned out to be negligible, compared to that of photocatalytic reactor system (1).

• Journal of Animal Science and Technology
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• v.47 no.4
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• pp.513-524
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• 2005

This study was conducted to introduce recycling procedures of food waste(FW) as feed according to the dehydration, semi-dehydration fermentation and liquid fermentation methods through the on-site survey of companies related, to trace physico-chemical components and nutritional losses depending upon the processing stage for each method and finally to suggest more desirable methodology for the efficient utilization of FW as animal feed. For the dehydration method, dewatering of FW alone reduced(P<0.05) moisture(approximately 10%) and ether extract contents and increased(P<0.05) fiber contents. Dewatering and subsequent dehydration of FW decreased(P<0.05) contents of ether extract, limiting amino acids such as lysine, methionine and histidine, pepsin digestibility of protein by half, and NaCl content by 40%, increased(P<0.05) contents of fiber, crude ash, Ca and P, and did not alter(P>0.05) pH. The semi-dehydration fermentation method of FW did not affect(P>0.05) the chemical components, pepsin digestibility of protein, pH and NaCl content. For the liquid fermentation method, pasteurization and fermentation of FW decreased(P<0.05) contents of dry matter, ether extract, crude fiber, lysine and NaCl; however, it did not affect(P>0.05) other chemical components, pepsin digestibility of protein and pH. Among the processing methods, nutrient losses were highest for the dehydration method(25% of metabolizable energy loss, 12% of organic matter loss) and little for the semi-dehydration and liquid fermentation methods. The on-site survey of companies related revealed that the existence of foreign materials in FW products were problematic for all the three companies surveyed, thus it was necessary to develop a more efficient screener. Before feeding FW-containing diets to pigs, high quality of protein and energy feedstuffs needed to be fortified for the dehydration method. For the semi-dehydration fermentation method, the scientific diet formulation technology was required at the initial mixing stage. For the liquid fermentation method, possibly most energetic and proteinaceous feeds needed to be supplemented for the normal animal growth.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.3 no.4
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• pp.234-248
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• 1998

Seven box cores from the disposal areas located in the southern part of the East Sea (Stations Band B') and in the offshore to the east of Pusan (Stations J and J'), and from their surrounding areas (Stations J2, J6 and H) were collected to investigate the effect of dumped wastes on the foraminiferal assemblages. The species diversity indices [S, H(S), E] of foraminifera and the total number of foraminifera show significant differences between the ocean waste disposal areas and their adjacent areas. Ocean waste disposal areas located in southern part of the East Sea (Stations Band B') show not only smaller number of foraminifera species but also lower values of coarse fraction content in the sediment and the number of benthic and planktonic foraminifera than the surrounding areas. Another ocean disposal area located offshore Pusan (Station J') contains abnormally greater number of planktonic (approximately 300 000 individuals/lO g dried sediment) and benthic (approximately 300, 000 individuals/10 g dried sediment) foraminifera compared to those of the adjacent areas. The waste dumped at Station J' probably acts as a nutrient causing the greater number of foraminifera. Station J shows low species diversity indices [S, H(S)]. The number of benthic foraminifera decreases from the surface to the downcore at Station J, which indicates that Station J is under stress. However, Stations J', J2 and J6 are under stable conditions as evidenced by the greater species diversity indices [S, H(S)] compared to other stations. No foraminifera were found with biological disease or abnormal chambers, which commonly occur in extremely stressed environment, in both the ocean disposal and adjacent areas. The organic matter decay of the wastes dumped in the study areas has not made the bottom water corrosive.

• Korean Journal of Environmental Agriculture
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• v.19 no.1
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• pp.32-37
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• 2000

Because the household garbage had high water contents, it is difficult to compost it without an additive. Therefore, this study was performed to investigate possibility of using the waste newspapers as a humidity conditioner for the household garbage composting. The maximum temperature was $66.0^{\circ}C$ in spring, $69.2^{\circ}C$ in summer, $60.9^{\circ}C$ in fall and $56.0^{\circ}C$ in winter for composting periods. The seasonal pH value reached around 8.5 after 1 week and then repeated fluctuation at the narrow range in spring and fall, while it was stabilized at the range of $8{\sim}9$ after increasing to 8.5 after 1 week in winter. The water content was reduced little in winter, while decreased significantly in the other seasons. The water content after 8 weeks was 22.2% in spring, 47.6% in summer, 25.5% in fall and 72.5% in winter. The mass was reduced rapidly during the first week of each season, but it did not show much decrease. The volume reduced after 8 weeks to 59%, 32%, 27%, and 34% in spring, summer, fall and winter respectively. Organic matter content decreased over the four seasons. Nitrogen contents were in the range of 0.7% to 2.2% during the four seasons. The contents of inorganic compounds based on dry matyter were in the range of $0.94{\sim}2.59%\;P_2O_5$, $1.23{\sim}1.87%\;CaO$, $0.37{\sim}0.46%\;MgO$, $0.55{\sim}1.98%\;K_2O$. Concentration of heavy metals(Hg, Cd, Pb, Cu, Cr, Zn, As) based on dry matter were less than the limiting value of the by-product compost.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.1
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• pp.85-94
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• 2007

To determine the influence of food waste compost (FWC) application on paddy soil, FWC was applied to the paddy soil and then compared with farmer's practice as to the effects on rice and soil environment. Initially, pig manure compost (PMC) had high content of phosphorus ($15g\;kg^{-1}$) and potassium ($23g\;kg^{-1}$), while FWC had high content of total nitrogen ($13g\;kg^{-1}$) and salinity ($18.5g\;kg^{-1}$). Comparison was also made between chemical fertilizer and FWC use as a trial in the paddy field under the clay loam and sandy loam soil. In the panicle formation stage, chemical fertilizer application was proper in clay loam while PMC application was proper in sandy loam. However, chemical fertilizer produced higher yield compared to compost treatment, both on clay loam and sandy loam with 20~25% and 17~19%, respectively. The lower yield in sandy loam maybe due to slow mineralization of compost such that the crop did not effectively use it. Organic matter content in paddy soil after experiment was higher in FWC and PMC plots compared to that in chemical fertilizer plots. But the other soil properties were comparable. Therefore, the FWC compost had little effect on soil when it use as a trial in paddy field. Likewise, after the application of FWC as a trial, analysis of nitrate nitrogen and ammonium nitrogen in the surface water and 60 cm depth of paddy soil water nine days after planting was done. Results revealed that concentration of ammonium nitrogen was similar to irrigation water while nitrate nitrogen concentration was not detected, and hence did not contribute to water pollution. It is concluded that the application of FWC in the paddy field had not affected on environmental pollution in the paddy field. But its use as compost during rice culture reduced yield quantity. Such study should include selection of compost material, amount and method of compost application.

• Journal of Bio-Environment Control
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• v.31 no.4
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• pp.460-467
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• 2022

The purpose of this study is to enhance utilization of the waste nutrient solution (WNS) disposed at the hydroponic greenhouse. Several sets of testing were conducted to examine the effects of WNS: (a) a fertilizer effect, (b) soil column leaching, and (c) crop cultivation. The fertilizer effect test was applied in young radish cultivation by examining the growth characteristics of young radish and soil based on inorganic nitrogen according to the soil treatment of the nitrogen fertilizer (NF) and the WNS. The fertilizer effects and crop cultivation test were conducted with five treatments (A-E): A, non-treatment (water); B, 100% of NF; C, 70% of NF + 30% of WNS; D, 50% of NF + 50% of WNS; and E, 30% of NF + 70% of WNS. The soil column leaching test was conducted with three treatments: non-treatment (water), 100% of NF, 50% of WNS + 50% of NF. As a result, the chemical properties of the WNS were pH 6.0, EC 2.4dS·m^-1, total phosphorus (T-P) 28mg·L^-1, ammonium nitrogen (NH₄-N) 5.0mg·L^-1, and nitrate nitrogen (NO₃-N) 301mg·L^-1. The chemical properties of the soil were pH 5.51, EC 0.31dS/m, organic matter 2.08g·kg^-1, NO₃-N 9.64mg·kg^-1, and NH₄-N 3.20mg·kg^-1. The results of fertilizer effects showed that the ratio of 50% or less of NF and 50% or more of WNS was high in young radish growth. There was no statistically significant difference between the soil chemistry in the C-E treatments where WNS was mixed with NF and the B treatment where only NF was applied. As a result of the soil column leaching test, there was no significant difference in the concentrations of NO₃ and NH₄ in the treatment of 100% of NF and 50% of NF + 50% of WNS. The study indicates, if the mixed fertilizer of WNS and NF is applied in the soil cultivation of young radish, it will reduce the use of NF and environmental pollution. This also helps reduce production costs on farmers and increase the yield of young radish.