• Korean Journal of Soil Science and Fertilizer
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• v.46 no.6
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• pp.458-462
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• 2013

A drainage ditch is normally a component of drainage networks in farming systems to remove surplus water, but at the same time, it may act as a major conduit of agricultural nonpoint source pollutions such as sediment, nitrogen, phosphorus, and so on. The hybrid turbidity reduction system using biodegradable check dam and synthetic polymer was developed in this study to manage pollutant discharge from agricultural farmlands during rainfall events and/or irrigation periods. The performance of this hybrid system was assessed using a laboratory open channel sized in 10m-length and 0.2m-width. Various check dams using agricultural byproducts (e.g., rice straw, rice husks, coconut fiber and a mixture of rice husks and coconut fiber) were tested and additional physical factors (e.g., channel slope, flowrate, PAM dosage, turbidity level, etc.) affecting on turbidity reduction were applied to assess their performance. A series of lab experiments clearly showed that the hybrid turbidity reduction system could play a significant role as a supplementary of Best Management Practice (BMP). Moreover, the findings of this study could facilitate to develop an advanced BMP for minimizing nonpoint source pollution from agricultural farmlands and ultimately to achieve the sustainable agriculture.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.7
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• pp.916-922
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• 2018

Recently, power plant effluent condensers received a Renewable Energy Certificate as components of hydrothermal energy (weighted 1.5 times) as one target item of the Renewable Portfolio Standard (RPS) policy. Accordingly, more attention is being paid to the value of thermal wastewater as a heat source. However, for utilization of thermal wastewater from power plants in high-turbidity areas like the West Sea of Korea, a turbidity reducing system is required to reduce system contamination. In this study, an experimental test was performed over a month on thermal wastewater from power plants located in the West Sea of Korea. It was found that water turbidity was reduced by more than 80 % and that the concentration of organic materials and nutrient salts was partially reduced due to the reduction of floating/drifting materials. To conduct a comparative analysis of the level of contamination of the heat exchanger when thermal wastewater flows in through a turbidity reducing system versus when the condenser effluent flows in directly without passing through the turbidity system, we disassembled and analyzed heat exchangers operated for 30 days. As a result, it was found that the heat exchanger without a turbidity reducing system had a higher level of contamination. Main contaminants (scale) that flowed in to the heat exchanger included minerals such as $SiO_2$, $Na(Si_3Al)O_8$, $CaCO_3$ and NaCl. It was estimated that marine sediment soil flowed in to the heat exchanger because of the high level of turbidity in the water-intake areas.

• Journal of Environmental Health Sciences
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• v.35 no.1
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• pp.53-57
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• 2009

In order to treat the complex wastewater containing organic compound and solids, pre-treatment system associated with molecular separation process were investigated. The reductions of COD and turbidity were obtained after coagulation processes using Alum (Aluminium sulfate, $Al_2(SO_4)_2{\cdot}18H_{2}O$) and PACl (poly aluminium chloride as 17% $Al_{2}O_{3}$). The results of study were as follows: using variable dosage of Alum, COD removal was highest at 4,000 mg/l, and the reduction of COD and turbidity was 42% and 92%, respectively. The optimum coagulation would be effective at pH 7.3 than pH 9.0 by the addition of alum at a concentration of 6,000 mg/l and PACl was add at 4.25% in raw complex wastewater with 2,000 mg/l alum at pH 7.3, the reduction of COD was reduced by 32%. But coagulation aid experiments indicated that PACl would be more effective in sludge separation ability than COD removal efficiency.

• Proceedings of the Membrane Society of Korea Conference
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• 2003.05a
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• pp.31-38
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• 2003

A pilot scale biofilter pretreatment-microfiltration system (BF-MF) was operated to investigate the effect of biofilter treatment in fouling reduction of microfiltration. Biofiltration was expected to reduce the membrane fouling by removal of turbidity and metal oxides. The hollow-fiber MF module with a nominal pore size of 0.1$\mu$m and a surface area of 8m$^2$ was submerged in a filtration tank and microfiltration was operated at a constant flux of 0.5 m/d. Biofiltration using polypropylene pellets was performed at a high filtration velocity of 320 m/d. Two experimental setups composed of MF and BF/MF, i.e., without and with biofilter pretreatment, were compared. Throughout the experimental period of 9 months, biofilter pretreatment was effective to reduce the membrane fouling, which was proved by the result of time variations of trans-membrane pressure and backwash conditions. The turbidity removal rate by biofiltration varied between 40% to 80% due to the periodic washing for biofilter contactor and raw water turbidity. In addition to turbidity, metals, especially Mn, Fe and Al were removed effectively with average removal rates of 89.2%, 67.8% and 64.9%, respectively. Further analysis of foulants on the used membranes revealed that turbidity and metal removal by biofiltration was the major effect of biofiltration pretreatment against microfiltration fouling.

• Proceedings of the Korean Environmental Health Society Conference
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• 2002.04a
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• pp.54-64
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• 2002

This study evaluated advanced water treatment (AWT) system in Korea. There are currently 16 plants operating with AWT. However, no attempt has been made to evaluate AWT system. This study selected one water treatment plant with AWT (pre-ozonation ＋ BAC). Using the operation data from 1995 to 2001 and pilot study results, the post-evaluation of the AWT system has been conducted. The study found that AWT improved water qualities of organic, ammonia, and turbidity, as expected. However, the extent of the improvement was generally short of the pilot study expectations. Pre-ozonation failed to decrease coagulant consumption. The dosage increased rather than decreased. AWT was, however, successful to decrease chlorine consumption. The chlorine reduction was related to the change in raw water characteristics and AWT introduction. Pre-ozonation failed to decrease coagulant consumption. The dosage increased rather than decreased. AWT was, however, successful to decrease chlorine consumption. The chlorine reduction was related to the change in raw water characteristics and AWT introduction, Both operation of pre-ozonation and reduced ammonia loading were responsible for the reduction. AWT increased the operation cost. Maintenance, raw water, and power cost increased, while labor and chemical cost decreased. Manpower reduction resulting form automation caused the decrease of labor cost. The reduction of chlorine consumption caused the decrease of chemical cost.

• Journal of Korean Society of Water and Wastewater
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• v.29 no.3
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• pp.337-345
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• 2015

Two step rapid filter system as a pre-treatment for the injected water into aquifer storage and recovery (ASR) in Korea was developed to reduce physical blockage and secure the volume of the injected water. First, single rapid sand filters with three different media sizes (0.4~0.7, 0.7~1.0 and 1.0~1.4 mm) were tested. Only two sizes (0.4~0.7 and 0.7~1.0 mm) satisfied target turbidity, below 1.0 NTU. However, they showed the fast head loss. To prevent the fast head loss and secure the volume of the injected water, a rapid anthracite filter with roughing media size (2.0~3.4 mm) were installed before a single rapid sand filter. As results, both the target turbidity and reduction of head loss were achieved. It was determined that the media size for a rapid sand filter in two step rapid filter system (i.e. a rapid anthracite filter before a rapid sand filter) was 0.7~1.0 mm. In addition, the effects of coagulant doses on the removal of natural organic matter (NOM), which might cause a biological clogging, were preliminarily evaluated, and the values of $UV_{254}$, dissolved organic carbon (DOC) and SUVA were interpreted.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.4
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• pp.535-543
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• 2006

The Ozone oxidation process was applied to increase the efficiency of reuse process when treating the secondary effluent by the membrane system. This paper focus on decreasing efficiency of membrane fouling, because of membrane fouling reduction by ozone and evaluation of application of the ozone oxidation. The feed water was secondary effluent from BNR process. The result shows that the ozone pretreatment can reduce membrane fouling effectively. Also, the improvement of treated water quality was obvious. The reduction of the membrane fouling led decrease of following pollutant and increase of lnner adsorptive ability of hydrophilic organic matter and decrease of molecular weight. MF membrane process alone can meet the domestic reuse water standards. And ozone pretreatment process also can increase the removal rates of turbidity, COD, nitrogen, and color.

• Journal of environmental and Sanitary engineering
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• v.18 no.4
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• pp.1-5
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• 2003

For studying out the method of the effective purification of waste waters such as dying, paper pulp and plating wastewater, we measured the COD removal efficiency, color and turbidity of those pollutants by the physical and chemical method using the Inorganic Coagulating Agent (CM, RM) and a High Voltage Generator. The COD removal efficiency measured when applying the Inorganic Coagulating Agent (CM, RM) was mush higher than that using the Existing Coagulating Agent In addition to, when using those two methods above mentioned at the same time, both the COD removal efficiency and the reduction-effect of the inserting quantities of Coagulating Agent were higher than those were used singly. The system using both an Inorganic Coagulating Agent and a High Voltage Generator will be useful in various fields of wastewater treatment.

• Journal of Korean Society on Water Environment
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• v.20 no.4
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• pp.346-351
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• 2004

Because of being produced a great deal of excess sludges from biological wastewater treatment process, the subject regarding treatment and disposal of them has been significantly handled in real plants. It should be considered the alternative treatment with easy operating and cost effective process in rural areas. For the thickening of wasted activated sludge from small scale wastewater treatment facilities, thus, the provisional sludge thickening system was developed by the application of mesh filter module. Three meshes with different pore size(100, 150, $200{\mu}m$) were prepared for filter modules that were used to withdraw effluent from thickening system. A filter module with $100{\mu}m$ mesh was chosen as the most effective thickening material in the viewpoint of volume reduction and effluent quality: the volume reductions of initially injected sludge with 3,600 mg/L and 9,100 mg/L were 95% and 85%, respectively, and the filtered effluents were enough good to be shown below 1.0 mg/L of SS and 1.0 NTU of turbidity. Since the filtration of thickening was influenced by the cake layer formed on mesh filter module and this system was operated in the combination of sludge thickening with gravity settling, the filter modules with smaller pore size and the larger floc size were required for long term operation safely.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.1
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• pp.101-112
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• 2013

Integrated process with coagulation and microfiltration as an advanced water treatment has been expanded its application in recent years due to its superb removal of particles and natural organic matter. In usual, effectiveness of coagulation sometimes determines performance of the whole system. Several new polymeric coagulants introduced to water utilities for better efficiency were studied in this paper. Three polymeric coagulants (i.e., PACl, PACs, and PAHCs) along with alum were evaluated for removal of natural organic matter, especially for reduction of trihalomethane formation potential, for which regulation has become stringent. Turbidity removal was closely related to pH variation showing the reduced turbidity removal by PACs due to the decreases in the pH of supernants at high doses. The four coagulants showed different organic matter removal during coagulation and affected the removal in microfiltration. For instance, DOC concentration was not reduced by microfiltration when PAHCs were used however 10 % of DOC removal was observed by microfiltration with alum coagulation. Coagulation pretreatment also impacted the THM removals, i.e., approximately 30 % of THMs and 13 % of DOC was removed by microfiltration only, but 40 to 67 % of THMs and 30 % of DOC was removed by the integrated process. Strategies on selection of coagulants are needed depending on characteristics of target pollutants in raw waters.