• KIEAE Journal
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• v.2 no.3
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• pp.25-32
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• 2002

The demand for water in a city area has enormously increased due to the concentration of population and improvement of the living quality. In this reason, the water shortage and the pollution by city sewage seem to be inevitable. For saving city water and meeting the demands from the city, the wastewater recycling system can be used, which makes used water reusable by a certain purification process. In Korea, the application of a wastewater recycling system to the buildings has continuously been adopted since its first appearance at the Lotte World Complex in 1989. However, the system has not been in fashion because of its high cost and users' negative attitude against recycled water. A research based on literature review and a case study for a recycling water system was carried out and an estimation and evaluation model was proposed. The results from the present study suggest that the optimal size of the recycling water system should be designed within 30-40% of total water demand in a building. Also, it was found that economic benefits could be expected within the payback period of 5.3 years by securing the operation rate over 70%.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.2
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• pp.24-33
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• 2015

This study aims to suggest wastewater treatment options for diaper recycling by identifying characteristic analysis of wastewater from diaper recycling process and efficiency evaluation of wastewater treatment units. The wastewater characteristic analysis showed that the concentration of organic pollutants and ionic materials were very high comparing to seawater. Through the investigation of similar wastewater treatment, six treatment units were identified to reduce pollutants. It is found UF(ultra-filtration), DAF(dissolved air flotation), fenton oxidation, electro-coagulation and chemical-coagulation are effective in reducing organic pollutants while membrane system and ion exchanger are effective in reducing ionic materials. Even though the target of water quality should be secured in terms of managing organic pollutants level, the application of treatment unit for reducing ionic material needs lots of considerations. This result suggests that reuse of pulping wastewater after controlling organic pollutants is better than direct discharge of pulping wastewater. To select the appropriate wastewater treatment unit, an economic analysis about operation condition, wastewater flow, cost, efficiency should be considered.

• Membrane and Water Treatment
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• v.3 no.4
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• pp.221-230
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• 2012

This study employed the modified fouling index (MFI) to determine the performance of a two-step recycling system - a membrane filtration integrated laminar flow water storage (LFWS) tank followed by an ion exchange process to reclaim ultrapure water (UPW) from the wastewater generated from semiconductor wafer backgrinding and sawing processes. The first step consisted of the utilization of either ultrafiltration (UF) or nanofiltration (NF) membranes to remove solids in the wastewater where the second step consisted of an ion exchanger to further purify the filtrate. The system was able to produce high purity water in a continuous operating mode. However, higher recycling cost could be incurred due to membrane fouling. The feed wastewater used for this study contained high concentration of fine particles with low organic and ionic contents, hence membrane fouling was mainly attributed to particulate deposition and cake formation. Based on the MFI results, a LFWS tank that was equipped with a turbulence reducer with a pair of auto-valves was developed and found effective in minimizing fouling by discharging concentrated wastewater prior to any membrane filtration. By comparing flux behaviors of the improved system with the conventional system, the former maintained a high flux than the latter at the end of the experiment.

• Journal of Korean Society of Water and Wastewater
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• v.38 no.1
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• pp.1-15
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• 2024

Occurrence of process environment changes, such as influent load variances and process condition changes, can reduce treatment efficiency, increasing effluent water quality. In order to prevent exceeding effluent standards, it is necessary to manage effluent water quality based on process operation data including influent and process condition before exceeding occur. Accordingly, the development of the effluent water quality prediction system and the application of technology to wastewater treatment processes are getting attention. Therefore, in this study, through the multi-channel measuring instruments in the bio-reactor and smart multi-item water quality sensors (location in bio-reactor influent/effluent) were installed in The Seonam water recycling center #2 treatment plant series 3, it was collected water quality data centering around COD, T-N. Using the collected data, the artificial intelligence-based effluent quality prediction model was developed, and relative errors were compared with effluent TMS measurement data. Through relative error comparison, the applicability of the artificial intelligence-based effluent water quality prediction model in wastewater treatment process was reviewed.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.5
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• pp.581-590
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• 2013

A research was performed for zero discharge system of waste water which is produced from energy recovery process of waste and biomass. Leachate and all kinds of waste water should be separated and integrated into three categories in addition to converting existing leachate treatment facility into waste water treatment facility as well as introducing a management system of reverse osmosis membrane facility and bioreactor landfill. Following these conditions to better water treatment process, it was likely to produce over 3,000 tons of low-grade recycling water and 2,000 tons of high-grade recycling water per day when zero discharge system of waste water is applied starting from 2016. Economical efficiency was also surveyed in total treatment fee. Present system costs 18,129 million won per year, and suggested zero discharge system would cost 15,789 million won per year.

• Proceedings of the Membrane Society of Korea Conference
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• 2001.05a
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• pp.33-43
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• 2001

• Resources Recycling
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• v.16 no.1 s.75
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• pp.68-72
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• 2007

The influences of reduction time, potential difference and ionic concentration flow rate have been investigated on the electrolytic recovery of silver from artificial photographic wastewater in continuous flow reactor system. As the initial concentration of silver ion and applied potential were increased, the amount of silver recovered was observed to be raised. Also, the electrolytically recovered material from artificial wastewater was proved to be pure silver based on the qualitative analyses by EPMA and XRD.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.40 no.3
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• pp.42-47
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• 2008

For the purpose of reduction of production cost in the industrial papermaking process, the use of waste paper has been more and more increased as a fibrous raw material, and the closed system of white water became closed more than ever. "Scum" indicates the floated sludge by a flotation during primary wastewater treatment process in paper mills. If the scum is used as the raw material, it could reduce both the raw material and solid waste treatment cost with even small quantity. In this study, the element survey and the toxicity measurement was carried out for recycling scum. A load factor of stock preparation process in paper mills was measured by somerville screen. Physical properties of paper sheet containing the accepted scum from the stock of AOCC or KOCC were evaluated. The result of this study shows that recycling scum has potential to be used in paper making system. It also might be able to reduce the required energy used by the pressing or drainage process, the raw material cost, and solid waste treatment cost due to the recycling of scum.

• Journal of the Korean Society for Marine Environment & Energy
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• v.12 no.1
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• pp.1-8
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• 2009

EMMC(Entrapped Mixed Microbial Cell) process which is a kind of active cell immobilizing method was applied to treat fisheries processing wastewater biologically. Kinetic constants were calculated for organic and nitrogen removal and effect of effluent recycling on system performance was evaluated also. Yield coefficient, Y showed relatively low value compared with Y value obtained from conventional activated sludge process. It means that EMMC process can reduce amount of excess sludge significantly compared with conventional activated sludge process. Endogenous respiration coefficient $k_e$ of EMMC process also showed relatively low value compared with that of conventional activated sludge process. Yield coefficient Y, endogenous respiration coefficient $k_e$ and half saturation constant $k_s$ obtained from EMMC process in terms of nitrification were compared with reported value from literature based on suspended growth nitrification system. The value of Y obtained from this study has no difference compared with values obtained from literature review and $k_e$ of this study was low but $k_s$ of this study was high compared than values obtained from suspended growth nitrification system. To evaluate the effect of internal recycling on system performance, system was operated with internal recycling ratio of 1.5Q, 2.0Q, 2.5Q and 3.0Q. increase of internal recycling ratio effect more greatly on improvement of denitrification efficiency than that of nitrification efficiency. Accordingly, optimization of internal recycling ratio has to be based on improvement of anoxic reactor performance.

• Journal of Korean Society of Water and Wastewater
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• v.22 no.1
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• pp.169-174
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• 2008

In this study a trickling filter system was developed by using polypropylene media and polypropylene nylon media that has recently been developed. The experiment analyzed an ability of water purification of the two plastic media and the effects of biomass on the final effluent. As recycling ratio increases, polypropylene nylon suspender showed higher efficiency by 20%; and, when media height was lengthened twice, efficiency increased about 10%. EPS and biomass increased in proportion to the increase of recycling ratio, and bound-TOC showed a similar trend with bound-EPS (extra-cellular polymeric substances) concentration.