• Journal of the Korea Organic Resources Recycling Association
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• v.24 no.3
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• pp.45-52
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• 2016

This study is to predict the biogas production and the content analysis of the organic wastes of three islands located in the City of I. Content analysis for a total of six sections, including pH, BOD, COD, three components (Moisture, Ash, Combustibles)was conducted on the specimens of organic wastes from the representative spots of three islands. From the analysis result of organic waste, it is confirmed that more than $1,750,000m^3$ of methane gas per year will be generated through the calculation of the total methane generation for the COD value. Therefore, if the incineration facility for the organic waste in island region is converted into a biogas production facilities which is non-incineration facility, it seems that the organic waste of efficient utilization is available.

• Clean Technology
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• v.15 no.2
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• pp.116-121
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• 2009

In this paper, we investigated the effect of an indirect oxidation zone in an electrolysis reactor that used Ti/$IrO_2$ as the anode and SUS 316L as the cathode. Based on our preliminary results, the electrolysis reactor was operated with pole plate interval of 6 mm, current density 1.0 $A/dm^2L$ and electrolyte concentration 15%. The removal efficiency, COD (chemical oxygen demand), was additionally increased by 55% and 12.5${\sim}$15.0% in the direct and indirect oxidation zones, respectively. The removal efficiencies of T-N (total nitrogen) and T-P (total phosphorus) were found to be 88% and 75%, respectively. It was shown that the additional effect of the indirect oxidation zone on the removal was nearly negligible. Also, as the removal of COD,T-N and T-P took place during the initial2${\sim}$5 days of reaction, it was concluded that there was no need to extend the retention time of the electrolysis reactor.

• KSBB Journal
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• v.8 no.5
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• pp.438-445
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• 1993

Raw cow manure was treated by a 4-step integrated system with phase separation anaerobic digestion and algal culture. When the first methane fermentation was performed by the effluent from the acid fermenter with retention time of 4 days, the elrerage blogas production rate was 977m1/1 culture/day Gas productivity compared to conventional single-stage anaerobic digestion increased up to 31.4%. As the 2nd methane fermenter was fed by the effluent from the first methane fermenter with 4 days of retention time, average amount of 428m1/1 culture/day of biogas was produced. The reduction rate of COD in the effluent from the acid fermenter, the 1st and the 2nd methane fermenter were 71.8%, 42.6% and 24.0% respectively. Finally, we examined algal treatment process for the effluent from the 2nd methane fermenter. A semi-continuous culture of Chlorella sp. PSH3 was conducted by feeding the effluent with retention time of 10days. In this process, the production rate of algal biomass and COD reduction rate were averaged 1.8g/1 culture/day(2.8$\times$106 cells/ml) and 73%, respectively. Through the 4-setp treatments, the total chemical oxygen demand was reduced from 51,300ppm to 85ppm. Therefore, the reduction rate of total chemical oxygen demand reached about 99.8%. The results indicate that the integrated system could be applicable for treatment of organic wastes, concurrently producing biogas and algal biomass.

• Journal of Korean Society on Water Environment
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• v.38 no.2
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• pp.95-102
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• 2022

Studies for improving the efficiency of the traditional anaerobic digestion process are being actively conducted. To improve anaerobic digestion efficiency, this study tried to derive the optimal pretreatment conditions and mixing conditions by integrating the heat solubilization pretreatment of sewage sludge, livestock manure, and food waste. The soluble chemical oxygen demand (SCOD) increase rate of sewage sludge before and after heat solubilization pretreatment showed an increased rate of 224.7% compared to the control group at 170℃ and 25 min and showed the most stable increase rate. As a result of the biomethane potential test of sewage sludge before and after heat solubilization pretreatment, the total chemical oxygen demand (TCOD) and SCOD removal rates increased as the heat solubilization temperature increased, but did not increase further at temperatures above 170℃. In the case of methane generation, there was no significant change in the cumulative methane generation from 0.134 to 0.203 Sm³-CH₄/kg-COD at 170℃ for 15 min. As a result of the integrated digestion of organic waste, the experimental condition in which 25% of the sewage sludge, 50% of the food waste, and 25% of the livestock manure were mixed showed the highest methane production of 0.3015 m³-CH₄/kg-COD, confirming that it was the optimal mixing ratio condition. In addition, under experimental conditions mixed with all three substrates, M4 conditions mixed with 25% sewage sludge, 50% food waste, and 25% livestock manure showed the highest methane generation at 0.2692 Sm³-CH₄/kg-COD.

• Journal of fish pathology
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• v.4 no.1
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• pp.15-21
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• 1991

The environmental factors and the distribution of coliform group were investigated in Suyeong bay on the summer, 1989. The ranges of environmental factors were as follows : Dissolved oxygen $0.54{\sim}6.82m{\ell}/{\ell}$, COD(Chemical Oxygen Demand) 0.28~9.84ppm, Salinity 14.7~33.5%, Nitrite $0.13{\sim}20.49{\mu}g-at/{\ell}$, Nitrate $0.89{\sim}62.77{\mu}g-at/{\ell}$, Ammonia $3.81{\sim}246.98{\mu}g-at/{\ell}$, Silicate $6.12{\sim}177.5{\mu}g-at/{\ell}$. The coliform group ranged $10^4{\sim}10^5/100m\ell$ in the mouth and it was decreased in the open sea. Among the composition of coliform group, E. coli I type was dominent at distance area. The correlation between coliform group and ammonia was r=0.629. There were negative correlation between salinity, dissolved oxygen and coliform group during study period.

• Journal of the Korean Society for Marine Environment & Energy
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• v.3 no.1
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• pp.52-61
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• 2000

The field surveys and the seawater analyses were conducted over the southern waters of Cheju island every month from July 1997 to June 1988. The distributions of dissolved inorganic nitrogen(DIN), dissolved inorganic phosphorus(DIP), chemical oxygen demand(COD) and dissolved oxygen(DO) in the southern water area of Cheju island were simulated and reproduced by an ecosystem model. In order to estimate the environmental capacity of the southern coastal area of Cheju island, the simulations for predicting the situation of unfavorable environment in which marine water quality might not be satisfied with Korean standards were performed with an ecosystem model by controlling quantitatively the pollution loads of discharge sources including streams flowing into the sea. The more the loads of 4 major pollution sources flowing into model region increase, the more evident appear the increases of COD, DIN and DIP concentrations around the water areas adjacent to pollution sources. In case the pollution loads of all 4 discharge sources including streams become 3 times as high as the present loads, the concentration of DIN at near-shore waters appears to be increased to about 14.5mmol/m³(=0.20mg/ℓ) which is the third class criterion of Korean standards for marine water quality. In case of 10 times as high as the present loads, COD at near-shore waters appears to be increased to about 1.0mg/ℓ which is the first class criterion of Korean standards. In case of 20 times as high as the present loads, DIP at near-shore waters appears to be increased to about 0.50mmol/m³(=0.015mg/ℓ) which is the second class criterion of Korean standards.

• Korean Journal of Environmental Biology
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• v.31 no.2
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• pp.96-104
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• 2013

The objectives of this study were to analyze chemical the water quality related to the fish community and to evaluate the ecosystem health based on the faunal composition and guild structure in 2007 in Baekma River. Mean concentrations of biological oxygen demand (BOD) and chemical oxygen demand (COD) were 2.8 and $4.0mg\;L^{-1}$, respectively and total nitrogen (TN) and total phosphorus (TP) were $5.0mg\;L^{-1}$ and $158{\mu}g\;L^{-1}$, which is indicating that the river is in an eutrophic state. Especially, organic pollution and eutrophication occurred in the downstream reach of Baekma River. A total of 19 fish species were collected during the study and the most dominant species was Opsariichthys uncirostris amurensis accounted 48% of the total abundances. The proportion of sensitive species was low (2.3%), compared with that of tolerant species (71.8%). These results suggest that tolerant species and the biotic quality of the fish community was severely degraded. According to the multi-metric model, the Index of Biological Integrity (IBI), the mean model value of the fish community in Baekma River was estimated as 14.8 indicating a "poor" condition. The minimum values of the IBI were observed in the downstreams, and this was mainly attributed to chemical pollutions of nutrients (N, P) and organic matters.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.8
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• pp.655-662
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• 2009

In order to obtain knowledge on the design and operation of practical?scale Cylinder-Shaped Filters, pilot experiments were conducted to observe the effects of stepwise augmentation of production rate on water quality and clogging. A production rate increase from 0.8 L/min to 2.4 L/min did not appear to affect the removal efficiencies of BOD(Biochemical Oxygen Demand), SS(Suspended Solids), and turbidity, as the values were maintained around 80%, over 95%, and over 90% respectively;however, COD(Chemical Oxygen Demand) removal decreased from 44% to 29%. In addition, results indicated an inverse relationship between production rate and detention time required to remove unit contaminant concentration, the observed detention time in the filter to remove 1 mg-COD/L being 83 minutes for the production rate of 0.8 L/min and 45 minutes for the production rate of 2.4 L/min, suggesting that a relatively higher production rate is likely to be more advantageous in the purification of reservoir water when compared to a lower production rate. Clogging was observed to originate from the surface and advance to the center of the filter, and although clogging seemed to increase as the production rate increased, this did not cause any difficulties in normal functioning of the filter for more than 2 years of operation, suggesting that this filter system can be used effectively in the purification of reservoir water.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.5
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• pp.764-771
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• 2012

In order to develop constructed wetlands for treating hydroponic wastewater in greenhouse, actual constructed wetlands were used the obtained optimum condition in previous study, and the removal rate of pollutant in the water according to 4 kinds connection method of piping such as system A (UP-UP stream), system B (UP-DOWN system), system C (DOWN-UP stream) and system D (DOWN-DOWN stream) were investigated. Removal rate of biochemical oxygen demand (BOD), chemical oxygen demand (COD), suspended solids (SS), total nitrogen (T-N) and total phosphorus (T-P) by system A (UP-UP stream) connection method in actual constructed wetlands were slightly higher than other systems. At the system A, the removal rate of BOD, COD, SS, T-N and T-P were 88, 77, 94, 54 and 94%, respectively. Under different hydroponic wastewater loading, the removal rates of pollutants were higher in the order of $75L\;m^{-2}day^{-1}{\fallingdotseq}150L\;m^{-2}day^{-1}$ $$\geq_-$$ $300L\;m^{-2}day^{-1}$. Therefore, optimum connection method was system A for treating hydroponic wastewater in greenhouse.

• Journal of Wetlands Research
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• v.23 no.3
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• pp.242-251
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• 2021

Surface water pollution is a serious environmental problem in developing countries, like India, due to the unregulated discharge of untreated wastewater. To overcome this, the constructed wetlands (CWs) have been proven to be an efficient technology for wastewater treatment. In this study, different existing and experimental facilities were reviewed to be able to determine the current status of constructed wetlands in India. Based on the collected data from published literature, industrial wastewater contained the highest average chemical oxygen demand (COD), biochemical oxygen demand (BOD). In terms of total nitrogen (TN), Total phosphorous (TP), the lowest concentration was found on domestic wastewater. Vertical flow constructed wetlands (VFCW) and Horizontal flow constructed wetland (HFCW) were more effective in removing TSS, BOD, TP in domestic and industrial wastewater, whereas hybrid constructed wetlands (HCW) showed the highest removal for COD. The use of constructed wetlands as advanced wastewater treatment facilities in India yielded better water quality. The treatment of wastewater using constructed wetlands also enabled further reuse of wastewater for irrigation and other agricultural purposes. Overall, this study can be beneficial in evaluating and promoting the use of constructed wetlands in India.