• Journal of Korean Society of Environmental Engineers
• /
• v.34 no.3
• /
• pp.214-222
• /
• 2012

Several acidogenesis batch tests, and BMP (Biochemical Methane Potential) with food waste leachate was tested at various organic loading rates (OLRs) on the mesophilic ($35^{\circ}C$) and thermophilic ($55^{\circ}C$) conditions. In acidogenesis batch test, VS removal efficiencies were 27.3% and 30.6% at $35^{\circ}C$ and $55^{\circ}C$, respectively. Removal efficiency of VS at $55^{\circ}C$ was higher than that at $35^{\circ}C$. With decrease in VS, SCOD increased as reaction time increased. Solubilization efficiency of VS were 27.4% and 33.4% at each reaction temperature within 4 days acid fermentation. Methane yield were 461 and 413 $mLCH_4/gVS$ at mesophilic and thermophilic BMP test, respectively. SCOD solubilizations in the themophilic acid fermenter showed 8~17% higher than those in the mesophilic fermenter. COD removal efficiency showed higher in the mesophilic acid fermenter at low organic loading rate. While at high organic loading rate, it was higher in the thermophilic acid fermenter. VS removal efficiency was higher at the mesophilic temperature, however, it decreased at OLR higher than 6 kg $COD/m^3{\cdot}day$. On the contrary, VS removal efficiency did not decrease but maintain at thermophilic temperature. The amount of methane gas generated from mesophilic methanogenesis digester was 12.6, 21.6, 27.4 L/day at OLR of 4, 5, 6 $COD/m^3{\cdot}day$, respectively. The amount of methane gas generated from themophilic methanogenesis digester was 14.3, 20.6, 25.2 L/day at each OLR, respectively, which is about 15~20 L/day lower than those generated at mesophilic digester.

• Journal of Environmental Impact Assessment
• /
• v.28 no.2
• /
• pp.152-168
• /
• 2019

The element arsenic, which is abundant in the Earth's crust, is used for various industrial purposes including materials for disease treatment and household goods. Various human activities, such as the disposal of soil waste, metal mining and smelting, and combustion of fossil fuels, have caused the pollution of the environment with arsenic. Recently, guidelines for arsenic in rice have been adopted by the Korean ministry of food and drug safety to prevent health risks based on rice consumption. Because of the exposure to arsenic and its accumulation in the human body through various channels, such as air inhalation, skin contact, ingestion of drinking water, and food consumption, integrated multimedia risk assessment is required to adopt appropriate risk management policies. Therefore, integrated human health risk assessment was carried out in this study using integrated exposure assessment based on multimedia (e.g., air, water, and soil) and multi-route (e.g., oral, inhalation, and dermal) scenarios. The results show that oral uptake via drinking water is the most common pathway of arsenic into the human body, accounting for 57%-96% of the total arsenic exposure. Among various age groups, the highest exposures to arsenic were observed in infants because the body weight of infants is low and the surface areas of infant bodies are large. Based on the results of the exposure assessment, the cancer and non-cancer risks were calculated. The cancer risk for CTE and RME is in the range of 2.3E-05 to 6.7E-05 and thus is negligible because it does not exceed the cancer probability of 1.0E-04 for all age groups. On the other hand, the cancer risk for RME varies from 6.4E-05 to 1.8E-04 and from 1.3E-04 to 1.8E-04 for infants and preschool children, exceeding the excess cancer risk of 1.0E-04. The non-cancer risks range from 5.4E-02 to 1.9E-01 and from 1.5E-01 to 6.8E-01, respectively. They do not exceed the hazard index 1 for all scenarios and all ages.

• Korean Journal of Organic Agriculture
• /
• v.22 no.4
• /
• pp.731-742
• /
• 2014

In the current study, we investigated effects of a combination of earthworm casting, environment-friendly by-product fertilizer, and cultivation soil of Gymnocalycium mihanovichii in a heavy fertilizing culture on diameter, height, numbers of tubercles, and chemical properties of soil thereby elucidating optimal mixture ratio for securing production as well as providing nutrients throughout cultivation period. The Gymnocalycium mihanovichii var 'Ihong', one of grafted cactus for export (Rootstock: 9 cm, Scion: $1.5{\times}1.3cm$ grafted cactus) was cultured in plastic houses of Agricultural Technology Center located in Naegok-dong, Seocho-gu, Seoul from June, 2013 through December, 2013. For the control group, a mixture of sand and fertilizer (50:50) was used as this ratio is widely utilized in farmhouses. In contrast, a variety mixtures of sand and earthworm casting that was produced with food wastes was compared; the mixture ratios were 80:20, 60:40, 40:60, 20:80, and 0:100 and pH for these mixtures were found to be similar each other (ranging between 7.1 and 7.4) which is in an appropriate range (pH 6.5-7.5) for cultivation of G. mihanovichii. The organic content was increasing along with increasing contents of earthworm casting ratio while it was lower than the treatment practice group (32-43 mg/kg vs. 55 mg/kg). The content of exchangeable cation was also increasing as the ratio of earthworm casting was elevated; although levels of $K^+$, $Na^+$, and $Mg^{2+}$ were lower than the treatment practice group, the level of $Ca^{2+}$ was higher ($9.1cmol^+/kg$ and $11.5-33.7cmol^+/kg$ in the treatment practice group and the earthworm casting group, respectively). Three months after grafting, diameters of G. mihanovichii were compared with the control group; consequently, there was a significant difference noted in between the earthworm casting group and the control group (31.39 mm vs. 32.46-37.59 mm). After 5 months, growth characteristics of G. mihanovichii were evaluated. Similarly, the diameter of G. mihanovichii was significantly increasing in the group with higher ratio of earthworm casting treatment (32.63 mm vs. 32.49-37.59 mm). The height of tubercles was 2.63 mm in the control group while it was significantly elevating along with the ratio of earthworm casting mixture. The more numbers of tubercles, the more incomes for farm-houses; as results, higher mixture ration of earthworm casting resulted more numbers of tubercles compared to the control group (2.7 vs. 3.2-8.3 ea). In particular, in the earthworm casting groups with 80% and 100% ratios, the numbers of tubercles were 6.2 and 8.3 ea, respectively, which is 2.5 times more than those of the control group. These results indicate that earthworm casting treatment may be utilized in G. mihanovichii farming houses for short term production of tubercles. In the group with 40% and 60% of earthworm casting mixture, the numbers of tubercles were found to be 4.5 and 4.8 ea, respectively which is higher than the control group as well; in these groups, there were no issues with soil drainage as well as moss formation. Given the analysis results of growth characteristics of G. mihanovichii, it was concluded that 40% and 60% of earthworm casting mixture might be the optimal ratios.

• Korean Journal of Soil Science and Fertilizer
• /
• v.42 no.6
• /
• pp.500-512
• /
• 2009

This study was carried out to evaluate the effect of temperature on soil microbial biomass, enzyme activities, and PLFA content in the volcanic(VAS) and the non-volcanic ash soil(NVAS). The soils were treated with organic materials such as organic fertilizer pelleted(OFPL), organic fertilizer powdered(OFPD), pig manure compost(PMC), and food waste compost(FWC). Two grams of organic materials were well mixed with 30g of dried volcanic and non-volcanic ash soil(< 2 mm) with 50% of soil moisture content. And the soils were incubated at 10, 20, $30^{\circ}C$ in incubator. Soils were analysed on the incubation times as followed; soil pH, total nitrogen, organic matter(at 75, 150, 270 days), microbial biomass C and PLFA (at 75, 270 days), microbial biomass N and soil enzyme(at 150, 270 days). pH values of soils treated with PMC and FWC had no changes on soil type, and incubation temperature. However, the pH was increased with temperature in the soils treated with OFPL. The changes in NVAS was higher than in VAS. Soil microbial biomass C content were high in the condition of high temperature and organic fertilizers treatment in VAS. But the contents were gradually decreased with incubation period in both NVAS and VAS. Soil microbial biomass N was high in NVAS treated with organic fertilizers and in VBS treated with PMC and FWC. PLFA content was higher in NVBS than in VBS at 75 days but showed high in VBS at 270 days. Urease activity of NVBS treated with OFPL showed $10^{\circ}C$ (75.0)> $20^{\circ}C$ (16.3)>$30^{\circ}C$ ($4.6ug\;NH{_4-}N\;g^{-1}\;2h^{-1}$) at 150 days. It were decreased gradually high temperature and time passes. And it showed high at $10^{\circ}C$ in VBS. Glucosidase activity was higher in NVBS than in VBS. Correlation coefficient of between soil microbial biomass C and microbial activity indicators showed that PLFA was high significantly at $r^2=0.91$ in NVBS and ${\beta}-glucosidase$ was $r^2=0.83$ in VBS. Soil microbial activities showed differences in the relative sensitivities of soil type and soil temperature.

• Korean Journal of Environmental Agriculture
• /
• v.37 no.2
• /
• pp.141-145
• /
• 2018

BACKGROUND: Agricultural soils are vulnerable from contamination of heavy metal derived from industrial waste. Monitoring on heavy metals on agricultural soils around industrial complexes and evaluation on distributional state on the concentrations of heavy metals in soil have been carried out for problem assessment on soil condition. METHODS AND RESULTS: Soil samples of 1,200, were collected from sixty site of industrial complexes located Gyounggi, Chungbuk, Cheonbuk, and Gyoungnam provinces. Total concentration of Cu, Pb, Zn, Ni, and As were analyzed. Heavy metal concentrations in most soil samples were below warning criteria, except 1 site of Pb, Ni, and As, separately. The comparison of mean values of heavy metal concentrations between soils around industrial complexes and paddy soils, showed similar levels of heavy metals, except Pb. The concentrations of lots of heavy metals were distributed between from warning criteria to one fifth level of warning criteria. However, in the case of Cu and Pb, more than 30% were distributed below one twenties level of warning criteria. These results were very similar with the distribution state of heavy metals in upland soils. The concentrations of heavy metals in surface soil and subsoil were similar among the heavy metals in soils around industrial complexes. CONCLUSION: The concentrations of heavy metals in soils around industrial complexes were distributed close to warning criteria. Long term and continous monitoring and evaluation on heavy metals in agricultural soils are required for food safety and sustainable soil management.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.28 no.2
• /
• pp.202-208
• /
• 1995

Puksin Bay located in the northwestern pan of Tongyeong, Korea has been contaminated by municipal wastewaters. In Puksin Bay, red tides have occured almost every year since the early 1980's. This experiment was carried out two times in a month in the winter in 1990, the summer' 1991, and the winter in 1994 so as to clarify the distribution marine bacteria and coliform groups in Puksin Bay. The water quality of Puksin Bay was not only move polluted than that of any other costal area around Tongyeong, but also its water quality was investigated to keep going bad. Viable cell counts in Puksin Bay were $4.9\times10^3/ml$ in 1990's winter, $3.6\times10^6/ml$ in 1991's summer, and $2.1\times10^4/ml$ in 1994's winter. The variation of seasonal total and fecal coliform MPN/100ml in Puksin Bay were $6.7\times10^2\;and\;2.6\times10^2$ in 1990's winter, $1.5\times10^4$ and $5.4\times10^3$ in 1991's summer, and $1.5\times10^3$ and $5.6\times10^2$ in 1994's winter, respectively. The changes of stational total coliform MPN/100m1 from station 1 to station 8 in Puksin Bay were 95,000, 1600, 1,000, 182, 151, 94, 43 and 13 in winter, and 110,000, 29,000, 2,400, 4,100, 1,700, 1,700, 810 and 150 in 1991's summer, and 3,381, 1928, 1582, 256, 161, 59 and 23 in 1994's winter. During the study period, the number of viable cell was ranged from $10^4\;to\;10^7/ml$ and 307 bacteria strains were isolated from Puksin Bay. The dominant species were Acinetobacter spp. 86 $(28.3\%)$, Pseudomonas spp. 51 $(16.6\%)$, Flavobacterium spp. 41 $(13.4\%)$, Escherichia coli 36 $(11.7\%)$, and Vibrio spp. 27$(8.8\%)$. The results obtained in this study indicate that this bay is getting to contaminate far more with municipal wastewaters and cultivation of the shellfish and finfish in this bay is not proper. When municiple wastewaters keep flowing into this bay, any other coastal area around Tongyeong may be contaminated.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.7
• /
• pp.708-718
• /
• 2020

Offensive odor is recognized as a social environmental problem due to its olfactory effects. Ammonia(NH₃), hydrogen sulfide(H₂S) and benzene(C₆H₆) are produced from various petrochemical plants, public sewage treatment plants, public livestock wastes, and food waste disposal facilities in large quantities. Therefore efficient decomposition of offensive odor is needed. In this study, the removal efficiency of atmospheric-pressure plasma operating at an ambient condition was investigated by evaluating the concentrations at upflow and downflow between the plasma reactor. The decomposition of offensive odor using plasma is based on the mechanism of photochemical oxidation of offensive odor using free radical and ozone(O₃) generated when discharging plasma, which enables the decomposition of offensive odor at ordinary temperature and has the advantage of no secondary pollutants. As a result, all three odor substances were completely decontaminated within 1 minute as soon as discharging the plasma up to 500 W. This result confirms that high concentration odors or mixed odor materials can be reduced using atmospheric-pressure plasma.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.18 no.2
• /
• pp.109-118
• /
• 1985

This experiment was carried out to evaluate the water quality in the lower part of the Nagdong river in Korea. Three hundred and sixty water samples were collected from the 15 stations from December 1981 to November 1982 by tide(see Fig.1). Water temperature, pH, chloride ion, salinity, total coliform, fecal coliform, viable cell count and the composition of coliform were observed to evaluate the water quality. The variations of water temperature was ranged from $2.0^{\circ}C\;to\;29.5^{\circ}C$ and as mean value from $15.8^{\circ}C\;to\;18.9^{\circ}C$. The range of pH was 6.00-8.88 and 7.20-7.96 as mean value. The concentration of chloride ion from St. 1 to 5 was higher as 17.51-771 mg/l in flood tide than 13.12-264.58 mg/l in ebb tide. Specially, water quality at St.1 (Samrangjin) which located about 46 km far from Hadan was also influenced by tide. Salinities of water in flood tide were a litte higher ($11.05{\sim}31.08\%0$) than those of in ebb tide ($7.80{\sim}29.28\%0$). Total coliform MPN's ranged from 3.6/100 m/l to 460,000/100ml. The geometric mean value of the upper area (included St. $1{\sim}3$) was $259{\sim}538/100ml$, that of the middle area (included St. $4{\sim}6$) was $1,097{\sim}39,544/100ml$ for it leveled heavy contamination. Specially, in the ebb tide St. 10 was influenced by St. 6 and 7. In the upper area, the geometric mean value of fecal coliform MPN's was $109{\sim}199/100ml$ but in the area in cluded St. 5, 6 and 7 were heavily contaminated by domestic sewage, waste water from the factories area and bird's excrement. Composition of coliform was $17\%$ Escherichia coli group, $33\%$ Citrobacter freundii group, $28\%$ Enterobacter aerogenes group and $21\%$ others. Plate count of samples was varied from <30 to $3.9{\times}10^4/ml$ during the study period.

• Korean Journal of Soil Science and Fertilizer
• /
• v.31 no.3
• /
• pp.277-284
• /
• 1998

The raw food waste of Korea contained markedly high sodium chloride and such high sodium chloride concentration in the soil is a factor limiting plant growth and impairing soil physicochemical properties. This study was carried out to assess the effect of NaCl-containing compost on the growth of lettuce(Lactuca satjva L.) and on the soil chemical properties. For the experiment, six treatments applying 0, 0.5, 1, 3, 6, and 9% NaCl-containing composts at the rate of $20Mg\;ha^{-1}$ were conducted established in a greenhouse. Growth measurements, chemical analysis of lettuce foliage, and soil chemical properties after the harvest were investigated. Lettuce yield in the treatments applied to composts over 3% NaCl was gradually reduced and mortality of lettuce as well as Na concent ration of lettuce foliage progressively increased with successively higher NaCl concentration of composts. With an increase of NaCl concentration of composts, the values of ESP and exchangeable sodium concentration in the surface soil were significantly increased. Especially, ESP of surface soil in the treatment incorporated with 9% NaCl-containing compost after the harvest attained by about 15, suggesting that sodification of surface soil under a greenhouse condition can occur when the compost over 9% NaCl is applied to soil. In conclusion, the application of over 3% NaCl-containing compost at the rates of $20Mg\;ha^{-1}$ can cause undesirable influences in plant growth and also the treatments of over 6% NaCl-containing composts can create conspicuous deteriorations in soil chemical properties in the current year.

• Membrane Journal
• /
• v.24 no.3
• /
• pp.213-222
• /
• 2014

In this study, 2-stage recirculation membrane process was developed for purification of high purity bio-methane for the vehicle fuel application. Pure gas permeation and mixture gas permeation test were done as a function of methane content and pressure in the feed using polysulfone membrane modules. 2-stage membrane plant was designed, constructed in a food waste treatment cite. Dehumidification, dry desulfurization, and desiloxane plants are installed for the removal of $H_2O$, $H_2S$ and siloxane in the biogas. Permeation test were done with the pre-treated methane mixture in terms of methane purity and recovery by adjusting the ratio of membrane area (1:1, 1:3, 2:2) in the first and second membrane modules in the plant. When membrane area of 2 stage increased to $3m^2$ from $1m^2$ at 1-stage membrane area of $1m^2$, the feed rate and $CH_4$ recovery at 95% methane purity were increased from 47.1% to 92.5% respectively. When the membrane area increased two-fold (1:1 to 2:2), $CH_4$ recovery increased from 47.1% to 88.3%. When the feed flow rate was increased, in 1:3 ratio, final purity of the methane is reduced, the methane recovery is increased. When operating pressure was increased, the feed rate was increased and recovery was slightly decreased. From this result, membrane area, feed pressure and feed rate could be the important factor to the performance of the membrane process.