• Journal of Korean Society of Environmental Engineers
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• v.34 no.8
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• pp.517-522
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• 2012

In this study, not only making an effort to find a solution for sewage and wastewater treatment, but also demonstrating a feasibility of wastewater disposal process which is treated with the cohesion and adsorption mechanism of sewage and wastewater using quartz porphyry and zeolite, which is a domestic natural resource. By using a jar test, we evaluated removal efficiency of $COD_{Cr}$ after reation. According to the result of experiment, when we injected 400~1,200 g/L of quartz porphyry and zeolite into a sewage as a coagulant, there was no difference of the rejection rates of $COD_{Cr}$, however, when quartz porphyry and zeolite, which were sintered at $600^{\circ}C$, were treated into urban sewage, removal efficiency of $COD_{Cr}$ had increased by about 15%, 3% respectively. In addition, we applied into a cosmetic tissue wastewater by using mixture of quartz porphyry and natural zeolite in order to analyze the applicability of other wastewater as well as Municipal Sewage.

• Journal of environmental and Sanitary engineering
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• v.12 no.3
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• pp.19-29
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• 1997

The Chemical Oxygen Demand(COD) by potassium permanganate and potassium dichromate is used as a measure of the organic matter content of a sample. Newly proposed $K_{2}Cr_{2}O_{7}$ analysis method to be list at Korean Official Method was made from analysis and comparison of the experimental process on Japanese Industrial Standard(JIS), American Open Reflux and Closed Reflux Methods. New $K_{2}Cr_{2}O_{7}$ method had better the qualitative and reproducible COD results than another methods as a result of the tested four times repeatedly by using Lakes water Plant wastewater. The COD data ratio by $KMnO_{4}$ and $K_{2}Cr_{2}O_{7}$ methods was 2-3, 3, 2-17 and 3-4 times respectively when its data had compared with the lakes water and treated water of domestic and experimental wastewater, and raw wastewater which is generated at the manufacturing process of 6 steps and treated wastewater of chemistry source. Its ratio indicated to 2-4 and 2-3 times respectively on raw wastewater and plant wastewater of Chemistry, rubber and plastic, fiber, metal molding source. Oxidation ratio of benzene and ethyl benzene by $KMnO_{4}$ method was nearly zero, but the oxidation ratio by $K$_{2}Cr_{2}O_{7}$ method was 50%, 70% respectively. Also, Oxidation ratio of phenol by $KMnO_{4}$ and $K_{2}Cr_{2}O_{7}$ methods was 80%, 100% respectively, and trichloroethylene and tetrachloroethylene were not nearly oxidizd by $KMnO_{4}$ and $K_{2}Cr_{2}O_{7}$ methods. As the above contents, oxidation ratio and COD results by $KMnO_{4}$ and $K_{2}Cr_{2}O_{7}$ were different from various from various compounds and samples respectively.

• Journal of Korean Society on Water Environment
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• v.22 no.3
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• pp.534-539
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• 2006

The supply of oxygen for aeration is the largest energy consumer at activated sludge wastewater treatment plants. Replacement of less efficient aeration systems with fine pore aeration devices can save up to 50 percent of aeration energy costs. The purpose of this study was the diagnosis and evaluation of a domestic wastewater aeration system by the off-gas method which had been studied by US EPA and ASCE. For this study, an off-gas analyzer and its hood were made to collect off-gas. Also, a vacuum pump was connected to the analyzer to make suction of off-gas. Experiments were conducted at a domestic activated sludge wastewater treatment plant which had a single spiral roll aeration system installed with P.E tube diffuser. Data on OTE(f), SOTE(pw), OUR, and air flow rate were obtained from these experiments. In case of replacing an aeration system, it is recommended that it should be replaced with perforated membrane disc or ceramic disc fine bubble diffusers installed in a full floor coverage or grid pattern.

• Applied Chemistry for Engineering
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• v.34 no.5
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• pp.541-547
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• 2023

The effect of temperature and influent alkalinity/ammonia (K/A) ratio on the start-up of the partial nitrification (PN) process for an activated sludge-based domestic wastewater treatment was studied. Two different sequence batch reactors (SBR) were operated at 26 ℃ and 32 ℃. The relationship between temperature and the concentration of free ammonia (FA) and free acid nitrite (FNA) was investigated. A stable PN process was achieved in the 32 ℃ reactor when the influent ammonium concentration was lower than 150 mg-N/L. In contrast, the PN process in the 26 ℃ reactor had a higher nitrite accumulation rate (NAR) and ammonium removal efficiency (ARE) when the influent ammonia concentration was increased to more than 150 mg-N/L. Then three different ranges of the K/A ratio were applied to an SBR reactor. In the K/A range of 2.48~1.65, the SBR reactor achieved the highest NAR ratio (75.78%). This ratio helps to achieve the appropriate level of alkalinity to maintain a stable pH and provide a sufficient amount of inorganic carbon source for the activity of microorganisms. At the same time, FA and FNA values also reached the threshold to inhibit nitrite-oxidizing bacteria (NOB) without a significant effect on ammonia-oxidizing bacteria (AOB). Results showed that the control of temperature and K/A ratio during the start-up period may be important in establishing a stable and steady PN process for the treatment of domestic wastewater.

• Proceedings of KOSOMES biannual meeting
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• 2005.11a
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• pp.171-184
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• 2005

As recently, ' International convention for the control and management of ship's ballast water and sediments ' was adopted, it is necessary to accept the international convention in Korea. The systems of foreign countries for ship's ballast water control and management were investigated, and domestic environment-related laws were reviewed and compared regarding the discharge of industrial wastewater and ship's ballast water. Alternative measures of domestic legislation were suggested for acceptance of the international convention.

• Journal of the Korean Society of Marine Environment & Safety
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• v.11 no.2 s.23
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• pp.83-96
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• 2005

As recently, 'International convention for the control and management of ship's ballast water and sediments' was adopted, it is necessary to accept the international convention in Korea The movements of foreign countries for ship's ballast water control and management were investigated, and domestic environment-related laws were reviewed and compared regarding the discharge of industrial wastewater and ship's ballast water. Alternative measures of domestic legislation were suggested for acceptance of the international convention.

• Journal of Korean Society of Water and Wastewater
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• v.36 no.2
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• pp.107-119
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• 2022

The frequent detection and occurrence of micropollutants (MPs) in aquatic ecosystems has raised public health concerns worldwide. In this study, the behavior of 50 MPs was investigated in three different domestic wastewater treatment plants (WWTPs). Furthermore, the Kruskal-Wallis test was used to assess the geographical and seasonal variation of MPs in the WWTPs. The results showed that the concentrations of 43 MPs ranged from less than 0.1 to 237.6 ㎍ L^-1, while other seven MPs including 17-ethynylestradiol, 17-estradiol, sulfathiazole, sulfamethazine, clofibric acid, simvastatin, and lovastatin were not detected in all WWTPs. Among the detected MPs, the pharmaceuticals such as metformin, acetaminophen, naproxen, and caffeine were prominent with maximum concentrations of 133.4, 237.6, 71.5, and 107.7 ㎍ L^-1, respectively. Most perfluorinated compounds and nitrosamines were found at trace levels of 1.2 to 55.3 ng L^-1, while the concentration of corrosion inhibitors, preservatives (parabens), and endocrine disruptors ranged from less than 0.1 to 4310.8 ng L^-1. Regardless of the type of biological treatment process such as MLE, A2O, and MBR, the majority of pharmaceuticals (except lincomycin, diclofenac, iopromide, and carbamazepine), parabens (except Methyl paraben), and endocrine disruptors were removed by more than 80%. However, the removal efficiencies of certain MPs such as atrazine, DEET, perfluorinated compounds (except PFHxA), nitrosamines, and corrosion inhibitors were relatively low or their concentration even increased after treatment. The results of statistical analysis reveal that there is no significant geographical difference in the removal efficacy of MPs, but there are temporal seasonal variations in all WWTPs.

• Journal of Korean Society of Water and Wastewater
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• v.32 no.1
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• pp.55-65
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• 2018

It is necessary to develop a mobile water production system in order to provide stable water supply in case of disasters such as floods or earthquakes. In this study, we developed a modular mobile water production system capable of producing water for various uses such as domestic water and drinking water while improving applicability in various raw water sources. The water production system consists of three stages of filtration (sand filtration - activated carbon filtration - pressure filtration) to produce domestic water and an additional reverse osmosis process to produce drinking water. In laboratory and field experiments, the domestic water production system showed excellent treatment efficiency for particulate matter, but showed limitations in the treatment of dissolved substances such as dissolved organic matter. In addition, ultraviolet irradiation was considered as additional disinfection step, because it does not form precipitates of manganese oxides after disinfection. Reverse osmosis process was added to increase the removal efficiency of dissolved substances and the treated water satisfied drinking water quality standards. Fluorescence analysis of dissolved organic matter showed that the fulvic acid-like substances in raw water was successfully removed in the reverse osmosis process. The mobile water production system developed in this study is expected to be used not only in water supply in case of disaster, but also widely used in islands and rural area.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.4
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• pp.453-465
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• 2007

With rapid expansion of the water market and growth of water companies, the recent trends in international water industry show that standardization of service activities concerning management of water and wastewater system (ISO/TC 224, to be issued in the second half year of 2007) is expected to have a large influence on the global water market including liberalization of water service market. In the Draft International Standard(DIS) of ISO/TC224, Performance Indicators(PIs) are suggested to estimate the service activities relating to water and wastewater treatment facilities. PIs have been developed in many countries including some international organization(World Bank, IWA and etc.) for service benchmarking. To evaluate public service level and establish plans to improve service level of wastewater utilities, we developed PIs for 120 items and applied them to 10 sewage utilities in the consideration of their scales, circumstances and conditions. In this study, we verified the applicability of the developed performance indicators(PIs). So, we concluded that PIs developed for the purpose of this study can be a useful tool applicable to objective evaluation of the service level of sewage utilities. Using the evaluation tool of PIs developed, it can also be used as a benchmarking tool in this industry as well as for enhancing the efficiency of operation and management of the sewage system. It will also contribute to the water resource management through determination of investment priorities based on the evaluation results and to raising international competitiveness of the domestic sewage utilities to meet the future opening of the water market.

• Membrane Journal
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• v.18 no.1
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• pp.94-102
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• 2008

For the treatment of the dye wastewater, a polyamide nano-composite membrane and reverse osmosis (RO) membranes were prepared using interfacial polymerization technique, in which piperazine, meta-phenylene diamine, and trimesoyl chloride were used as monomers, Their permselective properties were characterized with aqueous solutions of PEG 600, $Na_2SO_4$, and NaCl, and their performance was compared with that of Osmonics Co, They were found to be a typical nano-composite membrane and a low pressure RO membrane. Using them, a real dye wastewater supplied from the Kyungin Corporation, one of the domestic dye producer, was treated, studying the separation performances of the membranes, Also, during the wastewater treatment, cleaning in place (CIP) of the membranes was carried out regularly to recover the flux of the membranes. Three different chemical cleaners were employed for the CIP process and their performance were compared in this study.