• Journal of Korean Society of Water and Wastewater
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• v.21 no.1
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• pp.83-89
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• 2007

A biological anoxic-aerobic reactor filled with porous media was operated in lab scale for the advanced wastewater treatment. The experiments were conducted for 6 months with three HRTs (4, 6, 8hr) and temperature of $23{\sim}25^{\circ}C$. Some other experimental conditions were as follows; nitrification reactor (MLSS 4,500mg/L, DO 3.3mg/L, $23{\sim}28^{\circ}C$), denitrification reactor(MLSS 8,000mg/L, ORP -100mV, Temp.$19{\sim}23^{\circ}C$). Average removal efficiencies of SS, $BOD_5$, $COD_{Cr}$, T-N, and T-P were 97.8%, 95.5%, 94.5%, 80.2%, and 60.6%, respectively. The reactor filled with porosity media showed stable removal capacity for organics and nutrients. Fast and complete nitrification and denitrification were accomplished. Maintaining high MLSS with porous media in the nitrification and denitrification reactor appears to enhance the nitrogen removal process. For the higher T-P removal, some coagulant addition process will be needed.

• KSBB Journal
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• v.23 no.6
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• pp.541-545
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• 2008

This paper was studied to research regarding the removal of contained nitrogen in industrial wastewater which uses the A2O4 advanced water treatment process. The field researches of two companies' wastewater occurred in each wastewater treatment site to apply the A2O4 process system, it was observed them for 20 days. As a result of the A2O4 system advanced wastewater process which applied an altitude control process obtained $10{\sim}76\;mg/L$, and 20 mg/L total nitrogen compound concentration in the two wastewater plants. In conclusion, it applied the A2O4 system in the two companies' wastewater system.

• Journal of Korean Society of Water and Wastewater
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• v.29 no.4
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• pp.511-517
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• 2015

Korea's modern waterworks began with construction of DDukdo water treatment plant in 1908 and has been growing rapidly along with the country's economic development. As a result, water supply rates have reached 98.5% based on 2013. Despite multilateral efforts for high-quality water supply, such as introduction of advanced water treatment process, expansion of waterworks infrastructure and so on, distrust for drinking tap water has been continuing and domestic consumption rate of tap water is in around 5% level and extremely poor comparing to advanced countries such as the United States(56%), Japan(52%), etc. Recently, the water management has been facing the new phase due to water environmental degradation caused by climate change, aging facilities, etc. Therefore, K-water has converted water management paradigm from the "clean and safe water" to the "healthy water" and been pushing the Smart Water City(SWC) Pilot Project in order to develop and spread new water supply models for consumers to believe and drink tap water through systematic water quality and quantity management combining ICT in the whole water supply process. The SWC pilot projects in Pa-ju city and Go-ryeong county were an opportunity to check the likelihood of the "smart water management" as the answer to future water management. It is needed to examine the necessity of smart water management introduction and nationwide SWC expansion in order to improve water welfare for people and resolve domestic & foreign water problems.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.4
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• pp.579-589
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• 2012

To reduce extensive energy costs of the internal recycling for the purpose of denitrification in the advanced wastewater treatment, a post-treatment process using an electro-coagulation to treat nitrate in the secondary effluents is evaluated in this study. Removals of phosphorus and organics in the secondary effluents by the electro-coagulation were also evaluated to propose an alternative advanced wastewatert treatment process. A series of experiments of the electro-coagulation were carried out with the following 4 different samples: synthetic solution containing nitrate only, synthetic solution containing nitrate as well as phosphorus, secondary effluents from activated sludge cultivated in laboratory, and secondary effluents from real wastewater treatment plants. Removals of nitrate and phosphorus in the synthetic solution were 30 and 97 % respectively, which verified the feasibility of the process. Removals of nitrate, phosphorus and COD in the secondary effluents from the cultivated sludge in laboratory were 49, 90 and 19 % respectively. Removal efficiency of the total nitrogen, nitrrate, phosphorus and COD in the secondary effluent from real wastewater treatment plant were 50, 61, 98 and 80 % respectively. The removal of the total nitrogen was less than the nitrate as expected, which is due to the formation of ammonia nitrogen in the cathode. But the proposed scheme could be an energy saving and alternative process for the advanced wastewater treatment if further studies for the process optimization are carried out.

• Membrane Journal
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• v.21 no.3
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• pp.277-289
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• 2011

Since 1980s, wastewater treatment facilities in Korea have been rapidly expanded by 90 percent as the government invested them continuously. Considering social and environmental factors such as the needs of alternative water resources for water shortages, energy saving and new energy production sources for decrease of greenhouse gases, and the demand for the improvement of the water quality in rivers and lakes, advanced technologies in wastewater treatment are essential in the 21st century. In this aspect, new conceptual technology is systematically combined with the advanced treatment technology such as the control and treatment technology of hazardous and toxic material, customized reusing skill, and energy saving/recovery technology. The new R&D project for advanced technology of wastewater treatment and reuse will focus on these advanced technologies which will improve the water quality and foster the competitiveness in world environmental markets, building a solid foundation particularly in the market of developing countries. The project will be divided up into high quality reusing of wastewater, energy self-sufficiency, and integrated management system. It will be carried out for five years, 2011~2015, as Phase I.

• 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 Industrial Technology
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• v.25 no.A
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• pp.133-139
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• 2005

In this study, as MBBR(Moving Bed Biofilm Reactor) process using waste tire media is suggested for retrofitting with advanced wastewater treatment and the removal property of organic matter and nutrient and the capacity of media are evaluated through long-term operation with pilot plant following seasons, the application capacity of retrofitting with MBBR process to a existing wastewater treatment is studied. As a result of the long-term operation of the process, it is proved that there is no loss and abrasion of media, and also that it is possible to secure the sufficient attached bio-mass. The values of organic matter and nutrient in effluent are suitable for the strict discharged water quality standards in every season including winter.

• Journal of Korean Society of Water and Wastewater
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• v.34 no.4
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• pp.239-250
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• 2020

In this study, effects of five raw water quality parameters (turbidity, odor compounds caused by algae, filter clogging caused by algae, pH increase caused by algae, and organic matter) on improvements and operations costs of typical water treatment plant (WTP) were estimated. The raw water quality parameters were assumed the worst possible conditions based on the past data and costs were subsequently estimated. Results showed that new water treatment facilities were needed, such as a selective intake system, an advanced water treatment processes, a dual media filter, a carbonation facility, and a re-chlorination facility depending on water quality. Furthermore, changes needed to be made in WTP operations, such as adding powered activated carbon, increasing the injection of chlorine, adding coagulation aid, increasing the discharge of backwashed water, and increasing the operation time of dewatering facilities. Such findings showed that to reliably produce high-quality tap water and reduce water treatment costs, continuous improvements to the quality of water sources are needed.

• Journal of the Korean Chemical Society
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• v.58 no.1
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• pp.76-79
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• 2014

Petroleum refinery effluents are waste originating from industries primarily engaged in refining crude oil. It is a very complex compound of various oily wastes, water, heavy metals and so on. Conventional processes are unable to effectively remove the chemical oxygen demand (COD) of petroleum refinery effluents. Supercritical water oxidation (SCWO) was proposed to treat petroleum refinery effluents. In this paper, methanol was used to investigate co-oxidative effect of methanol on petroleum refinery effluents treatment. The results indicated that supercritical water oxidation is an effective process for petroleum refinery effluents treatment. Adding methanol caused an increase in COD removal. When reaction temperature is $440^{\circ}C$, residence time is 20 min, OE is 0.5 and initial COD is 40000 mg/L, and COD removal increases 8.5%.

• Journal of Korea Foundry Society
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• v.26 no.1
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• pp.17-26
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• 2006

The substitution of cooling method from water quenching to air cooling after solution heat treatment was aimed for the development of a convenient and economical heat treatment process of duplex stainless steels without deterioration of mechanical and corrosion resistant properties for the industry. In order to achieve this goal, the mechanical properties and corrosion properties of a ASTM A890-4A duplex stainless steel were systematically investigated as functions of casting condition and cooling method after solution heat treatment. A 3-stepped sand mold and a permanent Y-block mold were used to check the effects of solidification structure and cooling rate after solution heat treatment. The microstructural characteristics such as the ferrite/austenite phase ratio and the precipitation behavior of ${\sigma}$ phase and carbides were investigated by combined analysis of OM and SEM-EDX with an aid of TTT diagram. Hardness and tension test were performed to evaluate the mechanical properties. Impact property at $-40^{\circ}C$ and corrosion resistance were also examined to check the possibility of the industrial application of this basic study. Throughout this investigation, air-cooling method was proved to effectively substitute for water-quenching process after the solution heat treatment, when the duplex stainless steel was sand mold cast with a thickness below 15 mm or permanent mold cast with a thickness below 20 mm.