• Advances in environmental research
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• v.4 no.3
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• pp.155-172
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• 2015

In this study, a complete set of recirculating cooling water system and the required instruments were built in a semi-industrial-scale and a 50 g/h ozone generation plant and a chlorine system were designed for cooling water treatment. Both chlorination and ozonation treatment methods were studied and the results were analyzed during two 45-days periods. The concentrations of ozone and chlorine in recirculating water were constant at 0.1 mg/lit and 0.6 mg/lit, respectively. In ozone treatment, by increasing the concentration cycle to 33%, the total water consumption decreased by 26% while 11.5% higher energy efficiency achieved thanks to a better elimination of bio-films. In case of Carbon Steel, the corrosion rate reached to 0.012 mm/yr and 0.025 mm/yr for the ozonation and chlorination processes, respectively. Furthermore, consumptions of the anti-corrosion and anti-sedimentation materials in the ozone cooling water treatment were reduced about 60% without using any oxidant and non-oxidant biocides. No significant changes in sediment load were seen in ozonation compared to chlorination. The Chemical Oxygen Demand of the blow-down in ozonation method decreased to one-sixth of that in the chlorination method. Moreover, the soluble iron and water turbidity in the ozonation method were reduced by 97.5% and 70%, respectively. Although no anaerobic bacteria were seen in the cooling water at the proper concentration range of ozone and chlorine, the aerobic bacteria in chlorine and ozone treatment methods were 900 and 200 CFU/ml, respectively. The results showed that the payback time for the ozone treatment is about 2.6 years.

• Journal of Korean Society on Water Environment
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• v.22 no.5
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• pp.905-912
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• 2006

In this paper, simulation methods of the system dynamics model developed by Das et al. (1997) for activated-sludge wastewater treatment plants are illustrated in an attempt to determine the operating rules and the policies related to capacity expansion of an activated-sludge wastewater treatment plant. For existing conditions, the analyses were performed by varying activated-sludge return rate to observe changes in effluent water quality and treatment efficiency. The effluent water quality is also analyzed for various average daily inflow conditions and activated-sludge return rates. As a result, without expanding the aeration tank, maximum average daily inflow that can satisfy the effluent water quality standard of BOD $0.02kg/m^3$ was determined as $2,840m^3/hr$, subject to 100% of activated-sludge return rate while other factors remain constant. When the activated-sludge return rate is less than 100%, expansion of the aeration tank is necessary and minimum sizes of the aeration tank to satisfy the effluent water quality standard were determined for various activated-sludge return rates. In addition, the total operating and maintenance as well as unit treatment cost regression equations for activated-sludge wastewater treatment plants are suggested by using the cost data that are obtained from Water and Wastewater Division, Ministry of Environment. The regression analyses showed that the economies of scale phenomena exist in the operating and maintenance costs of activated-sludge wastewater treatment plants.

• Journal of Korean Society on Water Environment
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• v.23 no.5
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• pp.756-760
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• 2007

Most of the sewage treatment plants in Korea are being operated by using the conventional activated sludge process. Recently, as the water criteria have been strict with regard to such main culprits of eutrophication, the existing sewage treatment plants are obliged to upgrade their treatment technology to meet the criteria. Under such circumstances, this study was aimed at analyzing the conditions of an existing sewage treatment plants in Korea, and thereupon, test its treatment performance for the actual sewage water by operating a pilot plant. When the pilot plant was operated with the NPR process at the capacity of $30m^3/day$, the average contents of BOD, $COD_{Mn}$, SS, T-N and T-P in the effluents were 7.0 mg/L, 9.7 mg/L, 5.1 mg/L, 8.0 mg/L and 0.23 mg/L, respectively, which were very stable in general. Accordingly, if the NPR process used for this pilot plant to upgrade the treatment technology for the sewage treatment plat could be adopted, the effluent water quality criteria effective beginning from 2008 would be met.

• Journal of Environmental Science International
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• v.12 no.3
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• pp.281-286
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• 2003

This study was conducted to evaluate the feasibility of ammonia removal by zeolite adsorption in drinking water treatment. In generally, drinking water treatment process is conducted coagulation/flocculation, sedimentation, sand filtration and disinfection. We tested feasibility with two method, one is powdered zeolite dosing to coagulation tank and the other is to substitute granular zeolite for sand of sand filter. In powdered zeolite test, raw water is used tap water with putting of 2 mg/l of NH$_4$$\^$+/-N. Filtration of granular zeolite was conducted with 80 cm of effective column high and 120 m/d of flow rate. At above 100 mg/1 of zeolite dosage, ammonia concentration was decreased below 0.5 mg/l of NH$_4$$\^$+/-N in powdered zeolite test. But, turbidity was increased to 30 NTU by powdered zeolite dosage. That turbidity was scarcely decreased in generally coagulant using condition in drinking water treatment. In granular zeolite test, ammonia was not detected in treated water until 8 days. This result suggest that using of granular zeolite in sand filter could be removal ammonia in winter. But we need regeneration at zeolite filtration for ammonia removal. So, it is to make clear that zeolite regeneration ability was compared KCl with NaCl. The result reveal that KCl was more excellent than NaCl. Optimum regeneration concentration of KCl was revealed 100 mM. Regeneration efficient was not increased at pH range 10∼12.5.

• Journal of the Korean Burn Society
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• v.24 no.1
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• pp.7-13
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• 2021

Purpose: Currently, the most recommended method for burn first aid is the cool running water for 20 minutes (CRW20). If CRW20 is not practicable, cooling dressing products with tea tree oil are used as substitutes. In this study, we analyze the effect of various burn first aids, including CRW20, cooling products, on the treatment period. Methods: This study was conducted on patients who suffered burns and visited Hangangsoo Hospital from March 2019 to March 2020. The study conducted in a retrospective method. The duration of treatment was analyzed by dividing the experimental group. Results: The treatment period was shortened when first aid was given (P<0.001). Cold water, ice, and ice packs resulted in reduced treatment periods (P<0.001, P=0.004). The treatment period was reduced when cooling dressing products were used in all groups (P=0.041). The implementation of first aid has reduced the duration of burn treatment. This means that cooling helps burn treatment. CRW20 did not show statistically meaningful results. This is the result of a failure to fully control the temperature and time of tap water. In addition, the change in temperature of tap water according to season, the use of water is higher than that of animal testing, and the general lack of information on proper burn first aid may have affected. Conclusion: The treatment period was statistically significantly reduced in the group that performed first aid. Among the various first aid methods, cold water and ice reduced the treatment period.

• Journal of Korean Society of Water and Wastewater
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• v.30 no.3
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• pp.233-240
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• 2016

Control degree and property changes of dissolved organic matter (DOM) were conducted by coagulation of chemical treatment for 2 sewage treatment plants with different technical methods. As the result, SUVA value of the second treated water (supernatant of the second settling pond after biological treatment) was increased and DOC was reduced in comparison with supplied raw water. And, SUVA value and DOC were reduced by coagulation after coagulation treatment of the second treated water. Properties of dissolved organic matter for 2 sewage treatment plants's DOC were divided. As the result, there was lots of hydrophilic component with hydrophilicity in case of plant A. In case of the second treated water, Plant A showed fulvic acid with little molecular weight was reduced among the hydrophobic component with hydrophobicity, but numic acide with lots of molecular weight was increased. However, in case of plant B, both fulvic acid with little molecular weight and humic acid with lots of molecular weight were increased among the hydrophobic components with hydrophilicity. Before the operation of phosphorus facility, properties of dissolved organic matter after biodegradation with effluent water showed hydrophilic components were reduced and hydrophobic components were increased. However, after coagulation treatment of the second treated water, hydrophilic components and hydrophobic components were outstandingly decreased or increased. During the biodegradation after coagulation treatment, hydrophilic components were significantly decreased and hydrophobic components were increased.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.4
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• pp.367-376
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• 2014

This study assessed the removal efficiency of NOM which is known as the precursors of DBPs in advanced water treatment using the ceramic membrane filtration, introduced the first in the nation at the Y water treatment plant (WTP). It is generally well-known that the removal of NOM by MF Membrane is very low in water treatment process. But, the result of investigation on removal efficiency of NOM in advanced water treatment using the ceramic membrane was different as follows. The removal rate of organic contaminant by the ceramic membrane advanced water treatment was determined to be 65.5% for the DOC, 85.8% for UV254, and 77 to 86% for DBPFP. The removal rate of pre-ozonation was found to be 6 to 15% more effective compared with the pre-chlorination. The removal rate of DOC and $UV_{254}$ in biological activated carbon(BAC) process was over 50% and 75%, respectively although the rate was decreased 10 ~ 20% according to analysis items in converting from GAC to BAC.

• Journal of Korean Society on Water Environment
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• v.26 no.3
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• pp.406-412
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• 2010

Concentrations and speciations of Trihalomethanes (THMs) and Haloacetic acids ($HAA_5$) that can be formed during chlorine disinfection by-product (DBPs) in full-scale drinking water treatment plants were investigated. Jeon-ju D water treatment plant that adopted conventional water treatment processes was chosen for investigation. SUVA values according to water treatment process changes were observed from 1.3 to 2.1. The process average concentrations of THMs was 7.4 ppb, 9.0 ppb and 14.7 ppb respectively, while the average concentrations of $HAA_5$ by each process which are precipitation water, filterater water, treated water, were 15.5 ppb, 14.9 ppb and 25.8 ppb respectively. DBPs concentrations was lower in the winter than summer. The major species of THMs was chloroform and the second highest was bromodichloromethane (BDCM) and the third highest was dibromochloromethane (DBCM). In case of $HAA_5$, the rate of trichloroacetic acid (TCAA) was detected. The species disribution of THMs is related to the change of SUVA and species disribution of $HAA_5$ is related to the concentrations of bromine and injection position of chlorine and injection quantity.

• Journal of Korean Society on Water Environment
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• v.21 no.1
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• pp.7-13
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• 2005

With the appearance of pathogenic microorganisms, which were resistant to free chlorine, the significant attention to the necessity of powerful alternative disinfection methods such as ozone, chlorine dioxide, LTV irradiation to inactivating pathogens has been increased in water treatment. Among these alternative disinfection methods, ozone is well known as strong biocidal method and the usage of ozone is also increasing in Korea. However, in Korea, there has been no report on the quantitative study of Cryptosporidium parvum with ozone and its evaluation in advanced drinking water treatments. This study reports on the methodology for predicting the ozone inactivation of Cryptosporidium parvum by ozone disinfection in advanced drinking water treatment. The method is based on the fact that a specific inactivation level of microorganisms is achieved at a unique value of ozone exposures, independent of ozone dose and type of water, and quantitatively described by a delayed Chick-Watson model. The required values ${\bar{C}}T$ for 2 log inactivation of Cryptosporidium parvum was $6.0mg/L{\cdot}min$ and $15.5mg/L{\cdot}min$ at $20^{\circ}C$ and $5^{\circ}C$, respectively. From this obtained Cryptosporidium parvum inactivation curves and calculated ${\bar{C}}T$ values of advanced drinking water treatment water in Korea with FIA (Flow injection alaysis), we can predict that water treatment plant can achieve a 1.1~1.8 log inactivation and 0~0.4 log inactivation at $20^{\circ}C$ and $5^{\circ}C$, respectively. This methodology will be useful for drinking water treatment plants which intend to evaluate the disinfection efficiencies of their ozonation process without full scale test and direct experiments with Cryptosporidium parvum.

• Journal of Korean Society on Water Environment
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• v.36 no.6
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• pp.500-507
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• 2020

This study examined the wastewater at a livestock farm, and found that the dairy wastewater from the milking parlor had a lower concentration than the piggery wastewater, and that it was produced at a rate under 1.3 ㎥/day in a single farmhouse. The amount of dairy wastewater was determined based on the performance of the milking machine, the maintenance method of the milking parlor, and the amount of milk production allocated for each farmhouse, not by the area. The results confirmed that both dairy wastewater treatment processes, specifically those using Hanged Bio-Compactor (HBC) and Sequencing Batch Reactor (SBR), can fully satisfy the water quality standards of discharge. The dairy wastewater has a lower amount and concentration than piggery wastewater, meaning it is less valuable as liquid fertilizer, but it can be easily degraded using the conventional activated sludge process in a public sewage treatment plant. Therefore, discharging the dairy wastewater after individual treatment was expected to be a more reasonable method than consigning it to the centralized wastewater treatment plant. The effluent after the SBR process showed a lower degree of color than the HBC effluent, which was attributed to biological adsorption. In the case of the milking parlor in the livestock farm, the concentrations of the effluents obtained after HBC and SBR treatments both satisfied water quality standards for the discharge of public livestock wastewater treatment plants at 99% confidence intervals, and the concentrations of total nitrogen and phosphorous in untreated wastewater were even lower than the water quality standards of discharge. Therefore, we need to discuss strengthening the water quality standards to reduce environmental pollution.