• Journal of Environmental Science International
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• v.15 no.3
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• pp.271-278
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• 2006

To investigate the variations of physico-chemical factors and microbial population, in ten stations at water region of coastal area of Chagwi-Do, Nutritive salts, water temperature, transparency, suspended solid, salinity, COD, DO, pH, heterotrophic bacteria, coliform group and Vibrio spp. were analysed three times in September, November in 2004 and February in 2005. Heterotrophic bacteria in surface water was $3.5X10^1{\sim}1.16X10^3cfu/ml,\;1.0X10^2{\sim}5.2X10^1cfu/ml\;2.0X10^1{\sim}7.6X10^1cfu/ml$ and bottom water counted $7.0X10^2{\sim}1.0X10^3cfu/ml,\;1.4X10^1{\sim}2.5X10^2cfu/ml\;2.0X10^2{\sim}4.2X10^1cfu/ml$ in September, November in 2004 and February in 2005, respectively. The cell number of total coliform bacteria in the surface water amounted to $0{\sim}4.3X10^2cfu/ml,\;0{\sim}6.0X10^1cfu/ml,\;0{\sim}1.0X10^1cfu/ml$ and bottom water amounted $0{\sim}2.2X10^2cfu/ml,\;0{\sim}5.4X0^2cfu/ml,\;0{\sim}2.0X10^1cfu/ml$ in September, November in 2004 and February in 2005, respectively. As for Vibrio spp., the cell number in the surface water was $1.0X10^1{\sim}2.5X10^2cfu/ml,\;1.0X10^1{\sim}2.0X10^1cfu/ml,\;0cfu/ml$ and bottom water counted $1.0X10^1{\sim}5.2X10^2cfu/ml,\;0cfu/ml,\;2.0X10^1cfu/ml$ in September, November in 2004 and February in 2005, respectively.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.6
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• pp.893-906
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• 2011

The effect of ultrasound pretreatment on sludge degragability was investigated at different condotions: ultrasonic frequency(28, 40, 50kHz), intensity(10, 25, 50W), sonication time(10, 20, 30, 60min). Total suspended solid(TSS) and soluble chemical oxygen demand(SCOD) concentration were measured for the evaluation of pretreatment efficiency. The pretreated sludge was used as the feedstock for anaerobic digestion process. Biogas production and volatile suspended solid(VSS) removal were determined for evaluating the process performance. 1. TSS concentration of the sludge decreased at a constant rate as sonication operation was applied. The degradation rate of TSS increased when ultrasound frequency was decreased from 50kHz to 28kHz and intensity was increased from 10W to 50W. Efficiency of TSS degradation per input energy increased as ultrasonic frequency and intensity were decreased. At the frequency of 28 and 40kHz, SCOD concentration rapidly increased during the initial 30min of sonication time, and then it gradually increased. At 50kHz, SCOD concentration constantly increased for 60min of the sonication time. The SCOD production rate increased with increasing intensity under all ultrasound frequencies. 2. The optimum condition of ultrasound treatment was 28kHz, 50W and 60min for maximizing the biogas production, methane fraction, VSS removal. The highest values in biogas production, methane fraction in biogas, VSS removal were 370ml, 70%, 2.45g, respectively. Methane production rate per input energy increased at ultrasonic frequency and intensity decreased. 3. When raw sludge was pretreated at the condition of ultrasonic frequency of 28 and 40kHz in series, sequential-frequency sonication, intensity of 50W and 60min, biogas production, methane fraction, VSS removal were about the same that of 28kHz single-frequency sonication. When sequential-frequency sonication of 28 and 50kHz was applied in series, biogas production, methane fraction, VSS removal were 356 ~ 423ml, 69 ~ 71%, 2.41 ~ 2.78g, respectively. The pretreatment efficiency of 28-50kHz sequential-frequency sonication which sonication time of 28kHz and 50kHz was 40min and 20min was higher than that of 28kHz single-frequency sonication.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.6
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• pp.914-919
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• 1998

This study was conducted to evaluate the purification efficacy by filter and ultra violet (UV) irradiation against inlet and outlet seawater of the land based fish farm. Purification efficacies for inlet seawater (50$\ell$/min) has been examined with filter of 60$\mu$m pore size and UV irradiation at an average dose 0.5 mWS/$cm^2$ for 5 months. For outlet seawater filter of 90 $\mu$m pore size only was used. Temperature, salinity, pH, $NO_3-N,\;NO_2-N,\;NH_4-N,\;PO_4-P$, DO and COD of inlet and outlet seawater in the system were not influenced. However, the removing rate of suspended solid and turbidity of inlet seawater were appeared to be $48.7\~65.6\%$ (average $51.9\%$) and $33/3\~42/5\%$ (average $34.8\%$) after passing through screen filter respectively. Also, germicidal efficiency to the total bacteris and Vibrio species were $16.7\~20.2\%$ (average $19.2\%$) $20.0\~21.9\%$ (average $20.9\%$) respectively after passing through UV irradiation. After passing through drum filter of 90$\mu$m pore size, suspended solid and turbidity of outlet seawater were appeared to be $42.7\~52.6\%$ (average $46.9\%$), $27.7\~29.9\%$ (average $28.3\%$), respectively.

• Environmental Engineering Research
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• v.23 no.1
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• pp.114-119
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• 2018

Yarn dyed wastewater has to be treated prior to disposal into the water bodies due to its high content of harmful organic compounds. In this study, the performance of Chemical Oxygen Demand (COD) removal and kinetic rate constant are investigated via hybrid electrocoagulation-Fenton in a continuous system using wastewater discharged from a yarn dyed industry in Surabaya city. The wastewater was treated in a batch mode using electrocoagulation to reduce Total Suspended Solid, followed by Fenton method in a continuous system to reduce COD level. Various Fe(II) feeding modes, molar ratio of $Fe(II)/H_2O_2$, initial pH of wastewater, and flow rate are used in this study. The results show that COD removal process obeys a pseudo-first order kinetics. At $Fe(II)/H_2O_2$ ratio of 1:10, initial wastewater pH of 3.0, and feed flow rate of 30 mL/min, the COD removal efficiency was observed to be 80%, and the kinetic rate constant is $0.07046min^{-1}$. The chemical cost for the treatment estimated to be IDR 160 per L wastewater, which is cheaper than the previously reported batch system of IDR 256/L.

• Advances in environmental research
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• v.7 no.1
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• pp.1-11
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• 2018

Textile factories are one of the industries which its wastewater treatment is a challenging issue, especially in developing countries and a conventional treatment cannot treat all its pollutants properly. Using chemical coagulants is a technique for physical and chemical primary treatment of the wastewater. We applied jar test for selection of suitable coagulant among the five coagulants including alum, calcium hydroxide, ferrous sulfate, ferrous chloride and barium chloride for the effluent of wastewater in Mazandran textile factory located in Mazandran Province, Iran. In addition, jar test, we also used analytic hierarchy process (AHP) method considering criteria which included coagulation cost, sensitivity to pH change, the amount of sludge generation and side effects for coagulation. The results of the jar test indicated that calcium hydroxide was proper among the coagulants which it removed 92.9% total suspended solid (TSS), 70% dye and 30% chemical oxygen demand. The AHP analysis presented that calcium hydroxide is more suitable than other coagulants considering five criteria.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.1
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• pp.47-54
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• 2012

This study analyzed influence factors and the correlation among pollutants which affect occurrence of leaked pollution based on the long-term runoff flow and water quality investigation results to understand the characteristics of highway rainfall runoff pollution load. According to the result of correlation analysis on TSS (Total Suspended Solid) concentration, anteceded dry days, rainfall intensity, traffic volume and etc. as major influence factors of highway rainfall runoff pollution loads, the correlations were weak or scarce in most items. These results might be attributed that runoff pollutant concentration changes vary severely on changes of rainfall intensity and rainfall duration within rainfall and it is affected by disturbances of vehicles and street cleaning and etc. as characteristics of the highway. While Cu, Fe and Zn which are discharged with high concentrations out of heavy metals showed high correlation with particulate matter, organic matter(COD), nutrient(TN, TP), Ni and Pb showed relatively low correlation in a correlation evaluation by pollutant. Significant correlation with traffic volumes was not shown and TSS concentration even decreased in accordance with increase of the traffic volume. In the comparison with precedent studies, it was considered necessary additional analysis of the effects of rainfall section analysis, road type, disturbances of surface contaminants by vehicles, rainfall and climate conditions, surrounding terrains etc.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.3
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• pp.247-253
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• 2003

Sequencing Batch Reactor (SBR) was operated under various experimental conditions to improve the efficiency of biological filters used for the treatment of recycled wastewater from aquaculture. This SBR system was operated for removing COD, ammonia and suspended solid that were the major pollutants in aquaculture wastewater. Aerobic and anoxic conditions after FILL mode were applied intermittently for effective removal of nitrogen. SETTLE and DRAW modes were followed by the complete aerobic and anoxic REACT mode. The total volume of the SBR was 75 liter, while the working volume in a cycle was 35 liters. When the final operating strategy of the SBR was FILL/REACT/SETTLE/DRAW of 0.5/10/1/0.5 hr. the removal efficiencies of TCODcr, $NH_{4}^{+}-N,$ and T-N were 94, 98, and $89\%,$ respectively.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.5
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• pp.763-770
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• 2006

The purpose of this study was to investigate the effects of mechanical(ball-mill) solubilization of excess sludge especially focused on the TSS(total suspended solid) reduction during the conventional aerobic digestion of sewage sludges including primary and/or excess sludge, HRT was examined at the 10 days and 20 days. According to the results of this study, TSS removal efficiency of solubilized excess sludge was almost two times higher than that of non-solubilized excess sludge. And as the proportion of the primary sludge increased, TSS removal efficiency became worse because primary sludge rarely contained microbial cells which could be easily solubilized physically. It was also proved that by the application of proper solubilization techniques to the excess sludge, HRT for the aerobic digestion could be lessened(above 50%) dramatically keeping the same or better digestion performance. The fact that between primary and excess sludges, only the excess sludge is quite effective in the sludge solubilization and in it's reduction says that excess sludge releasing sources are key-point in the sludge cake reduction field as a source control.

• Journal of Environmental Health Sciences
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• v.7 no.2
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• pp.97-105
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• 1981

Water Pollution of Gwangju Stream was examined for four months from 22 March 1981 to 7 June, 1981. For checking the water pollution, 6 sampling positions were selected 5 from main stream. We assumed that the water pollution of Gwangju stream was due to the organic materials, which came from the domestic sewage. The apparatus for this test were pH meter (Orion model 301), Dissolved Oxygen & Temperature meter(Delta model 1010). The results we obtained are as follows: 1. The average range for mid-stream(sp. 3, 4) was 3. 10~2.73ppm of Dissolved Oxygen(DO), 80.23~102.95ppm of Biochemical Oxygen Demand (BOD), 195. 10~165.90ppm of Suspended Solid (SS), 6.6~6.7 of pH. 2. The plankton identification in this survey period showed Cyanophyceae is 4 genera 5 species, Bacillariophycea 11 genera 14 species, Chlorophyceae 8 genera 15 species and Zooplankton 6 genera 7 species: total 29 genera 41 species. 3. To appear dominant plankton in polluted water, there were Paramecium, Euglena and Oscillatoria. 4. The results of biological water analysis were as follows: st. 1 was B-mesosaprobic to oligosaprobic, but st. 4 and st. 5 at stream in the midtown area seemed to be polysaprobic.

• Journal of Information Technology Services
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• v.11 no.sup
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• pp.177-189
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• 2012

We developed the ocean disaster detection system(OD2S) which copes with the occurrences of ocean disasters (e. g. the red and green tide, the oil spill, the typhoon, and the sea ice) by converging and integrating the ocean color remote sensing using the satellite and the information technology exploiting the mass data processing and the pattern recognitions. This system which is based on the cosine similarity detects the ocean disasters in real time. The existing ocean color sensors which are operated in the polar orbit platforms cannot conduct the real time observation of ocean environments because they support the low temporal resolutions of one observation a day. However, geostationary ocean color imager(GOCI), the first geostationary ocean color sensor in the world, produces the ocean color images(e. g. the chlorophyll, the colored dissolved organic matter(CDOM), and the total suspended solid(TSS)), with high temporal resolutions of hourly intervals up to eight observations a day. The evaluation demonstrated that the OD2S can detect the excessive concentration of chlorophyll, CDOM, and TSS. Based on these results, it is expected that OD2S detects the ocean disasters in real time.