• Journal of Korean Society of Water and Wastewater
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• v.11 no.3
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• pp.87-95
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• 1997

A river water quality management model was made by Dynamic programming. This model optimizes the wastewater treatment cost of the application area, and computed water quality with it must meet the water quality standard. And this model takes into consideration tributary input, wastewater treatment plant effluent, withdrawls for several purposes. Modified Streeter-Phelps equation was used to calculate BOD and DO. Optimization problem was solved with particular exceedance probability flow, and the water quality of each point was calculated with the decided treatment efficiencies. At that time, the probability satisfying the water quality standard of constraints to the exceedance probability of the flow. The developed model was applied to the lower part of the Han-River. The reliability to meet the water quality standard is 70 % when 4 wastewater treatment plants of Seoul City are operated by activated sludge system at autumn of the year 2001. Treatment cost of this case is 121.288 billion won per year.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.6
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• pp.1027-1035
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• 2000

This study was carried out to investigate the treatability of landfill leachate having high concentration of ammonium nitrogen with/without the circulation of media in pilot-scale($48m^3basis$) process. Total nitrogen removal efficiency was relatively increased in the media added process (influent ; $1.230{\sim}2,000mg{\cdot}l^{-1}$, effluent ; $120{\sim}250mg{\cdot}l^{-1}$) compared with the control process. The difference of nitrogen removal efficiency between these processes may be due to that stable growth of nitrifiers attached to the media could be achieved 99.3% of ammonium-nitrogen removal efficiency(without ; 98.2%) and 88.5% of total nitrogen removal efficiency(without ; 85.8%) were shown in media added process, respectively. Also, optimum BOD/ $NH_4{^+}$-N ratio was relatively decreased in the media process compared with the control process. Sludge settleability, on the other hand. was shown better in media added process than in control process. This outstanding sludge settleability in the media added process indicates the compatibility of media(zeolite) to the microorganism and the possibility of using media of biofilm process.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.6
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• pp.659-665
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• 2008

This study is about zeolite synthesis from the sewage sludge incinerator fly ash of "S" sewage treatment center located in Seoul. For this purpose, the properties of raw fly ash as starting material, the hydrothermal conditions for zeolite synthesis and the environmental applicabilities of synthesized zeolites were examined. Fly ash from sewage sludge incinerator has large quantities of SiO$_2$ and Al$_2$O$_3$ and their contents are 42.8 wt.% and 21.2 wt.% respectively. So fly ash is considered to be possible starting material for zeolite synthesis. The results from leaching test of fly ash showed that the concentration of hazardous metals were very low as compared with the Korea leaching standard of the Waste Management Law. But the concentration from total recoverable test of fly ash were higher than the fertilizer standard of Fertilizer Management Law. Major zeolite products synthesized by hydrothermal reaction are analcime in teflon vessel and zeolite P1 in borosilicate flask. Optimum conditions for the synthesis of analcime were 1 N of NaOH concentration, 16 hour of reaction time and 135$^{\circ}C$ of reaction temperature. For the zeolite P1 formation, the proper conditions were demonstrated to be 5 N of NaOH concentration, 16 hour reaction time and 130$^{\circ}C$ of reaction temperature in this study. Hazardous metal contents in the analcime product are similar with those in raw fly ash. In case of the zeolite P1, the contents are reduced to nearly a half. Raw fly ash and the analcime product showed NH$_4{^+}$ ion exchange capacity of 0$\sim$1.0 mg of NH$_4{^+}$g$^{-1}$ and 3.0$\sim$7.4 mg of NH$_4{^+}$g$^{-1}$, respectively. However, the zeolite P1 product reached exchange capacity to 14.6$\sim$17.8 mg of NH$_4{^+}$g$^{-1}$. This values are in the range of those of natural clinoptilolite and phillipsite. From this point of view, zeolite synthesis from sewage treatment sludge incinerator fly ash is a good alternative for solid waste recycling.

• Journal of the Korea Organic Resources Recycling Association
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• v.21 no.4
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• pp.33-43
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• 2013

That occur in the ocean and the efficient management of marine litter on marine pollution oil spill response one step further strategies are needed. Marine pollution accidents occurred in 2011, a total of 287 and was found in runoff 369 kL, respectively compared to the previous year decreased by 13% and 39%. Average amount of marine materials during 5-years represent the oil flow of 310.5 kL (heavy fuel oil of 106.0 kL, diesel of 178.9 kL, oily bilge water of 22.3 kL, other oil of 7.7 kL) and the waste of 62.3 tons, the hazardous and noxious substances (HNS) was 510.6 kL. Marine emissions in 2011 by type of waste that a total amount of dumping 3,972 $m^3$, and livestock manure 795 $m^3$(20%), waste water 1,431 $m^3$(36%), sewage sludge 887 $m^3$(22%), wastewater sludge, 813 $m^3$(21%), manure 5 $m^3$(0.1%), other 41 $m^3$(0.9%), respectively. The concept of marine waste and needs to be more clearly defined. Integrated management of hazardous chemicals according to the incident management system should be established. To remove of coastal pollution, response officer needs korean coast response system. Like the marine pollution response, coastal pollution response systems also require step response.

• Journal of Environmental Science International
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• v.21 no.11
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• pp.1379-1388
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• 2012

Odor from sewage treatment plants have the potential to cause significant annoyance and to impact the amenity. In this study, odor emission characteristics at unit process of 48 sewage treatment facilities in 39 plants were evaluated using composite odor concentration and hydrogen sulfide ($H_2S$) concentration. The values of composite odor concentration (geometry mean) and $H_2S$ concentration (median) for sludge treatment processes are higher than those for the other treatment processes. The composite odor concentration and $H_2S$ concentration are distributed over a wide area in each process. Composite odor concentration (dilution ratio) was found to have the significant correlation with $H_2S$ concentration (p=0.000<0.05). The $H_2S$ concentration accounted for 67.1% of composite odor concentration.

• Applied Chemistry for Engineering
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• v.7 no.2
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• pp.371-378
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• 1996

A prototype of expert system which can support the operation for the municipal waste water treatment plant located at Kyoung-Ki Do, Kwang-ju Kun was developed and tested. This system provides (i) tracking the cause of the problem, (ii) analysis, and (iii) solution Knowledge-base consists of about 100 production-rules for the biological wastewater process, such as bio-reactor and final clarifier. Rules were obtained from the analysis of the problems such as sludge bulking. The system provides stable process control and management and effectively helps inexperienced operators with advanced and standard technologies. Future works will focus to develop a statistical process control model and associate with expert system. The control model can process the operation data statistically; analyze the relationship between affecting factors and control variables; and provide optimum operation parameters.

• Journal of Korean Society on Water Environment
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• v.22 no.2
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• pp.222-229
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• 2006

The treatment performance and operational parameters of a tertiary wastewater treatment process a biological filtration system were investigated. The biological filtration system consisted of a nitrification filter (Fiter 1) and a polishing filter with anoxic and aerobic parts (Filter 2). SS, T-C-BOD, and T-N in effluent were kept stable at less than 3, 5 mg/L, and 5 mgN/L, respectively, under a HRT in Filter (filter-bed) of 0.37~2.3 h. T-N at the outlet of Filter 2 were about 1~5 mgN/L under the condition of LV of 50~202 m/d. In Filter 2, denitrification was accomplished under LV of 50~168 m/d in a 1 m filter-bed. However, the denitrification capacity reached the maximum when the linear velocity was increased to 202 m/d. Relationship between increase in microorganism and headloss was clearer in Filter 2. As a result, the denitrification rate increased from 1.0~2.3 kgN/($m^3-filter-bed{\cdot}d$) as the headloss increased. The COD removal rate was 6.0~9.6 kgCOD/($m^3-filter-bed{\cdot}d$) when operated with Filters 1 and 2. These results mean that captured bacteria contributed a part of COD consumption and denitrification. The maximum nitrification and denitrification rate was 0.5 and 4 kgN/($m^3-filter-bed{\cdot}d$) in Filter 1 and 2.The ratio of backwashing water to the treated water was about 5~10 %. In Filter 1, wasted sludge in backwashing was only 0.7~5.3 gSS/($m^3$-treated water). In Filter 2, added methanol was converted into sludge and its value was 8.0~24 gSS/($m^3$-treated water). These results proved that this process is both convenient to install as tertiary treatment and cost effective to build and operate.

• Journal of the Korean Society of Hazard Mitigation
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• v.11 no.3
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• pp.91-96
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• 2011

The design, construction and management of underground facilities as infrastructure of nation should be properly carried out. One of reasons for underground facilitie's failure is a non-proper construction of backfill materials. This is common for circular underground pipes. A non-proper compaction is the cause of settlement and decrease of performance of underground facilities. The use of controlled low strength materials is an alternative to reduce the couple of failure problems. The flowability, self-cementation, and non-compaction are the major advantages to use the controlled low strength materials. In this research, couple of recycled materials, such as in-situ soil, water-treatment sludge, and crumb rubbers, were adopted. The basic properties of each materials were determined according to KS or ASTM. Also, couple of laboratory tests were carried out to get the design parameters for geotechnical and roadway area.

• Analytical Science and Technology
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• v.19 no.2
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• pp.172-180
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• 2006

This study was performed to establish new methods for hazardous substances and to develop an analytical method in specified wastes for preventing the environmental pollution caused by hazardous wastes. Therefore, the trends of international management, regulatory criteria, and items of hazardous wastes in various countries were investigated. Based on this study, target priority of new hazardous substances in specified wastes was established. An analytical method was developed using the waste standard reference materials of sludge, oil, bottom ash, etc., which contain the new hazardous substances (Ba, Be, Cr(VI), F, Ni, Sb, Se, and V). A total of 37 waste samples from the representative facilities, which are emitting new hazardous substances, were analyzed.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.3
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• pp.15-25
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• 2023

In this study, silicon sludge from semiconductor dicing process is recycled to fabricate silica nanoparticles, which are applied as dispersing materials for electro-responsive (ER) smart fluid. In specific, metal impurities are removed from silicon sludge by acid washing to obtain the high-purity silicon powder. And then, silica nanoparticles are synthesized by facile hydrothermal method employing the silicon powder as reactant material. To control the size of silica nanoparticles, the reaction time of hydrothermal method is varied as 8, 15, 20, and 30 hours are applied to control the size of silica nanoparticles. Sizes of silica nanoparticles are increased proportionally to the reaction time owing to the increased numbers of hydrolysis and condensation reactions. As-synthesized silica nanoparticles are prepared as electro-responsive smart fluids by dispersing into silicon oil. Silica nanoparticles synthesized by 30 hours of hydrothermal reaction (SiO₂-H30) exhibit the highest shear stress of 21.4 Pa under an applied electric field strength of 3.0kV mm^-1. Such enhancement in ER performance of SiO₂-H30 among various silica nanoparticles are attribute to the reinforcing effect originated from the mixed particle size, which allowing the formation of rigid chain-like structures. Accordingly, this study successfully propose a recycling method of silicon sludge to synthesize silica nanoparticles and their derived ER fluids, which may suggest new possibility to ESG management emphasizing the eco-friendliness.