• Journal of Animal Environmental Science
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• v.17 no.sup
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• pp.1-6
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• 2011

Korean Government announced 'The Roadmap to realize a low carbon green society on year 2020' on July 12, 2011 in order to mitigate greenhouse gas (GHG) emissions. Non-energy category of Food, Agriculture, Forestry and Fishery (FAFF) should mitigate 1,349 kilo $CO_2$-equivalent ($CO_2$-eq.) tonnes which is 7.1% of Business-As-Usual on year 2020. The mitigation from animal manure treatment system (AMTS) comprises ca. 45% of the total mitigated amount of Non-energy category of FAFF. Hence, the precise evaluation of GHG emissions from AMTS is important to find effective mitigation measures. Life cycle assessment was used to evaluate GHG emissions from AMTS. The most GHG emitter was a composting/liquid fertilizer/activated sludge system (1,649.45 kg $CO_2$-eq./head/year) and the least GHG emitter was a activated liquid fertilizer system (1,024.46 kg $CO_2$-eq./head/year). Thermophilic oxic process showed the highest ratio (34.9%) of GHG emissions by the use of electricity to total GHG emissions from systems. Energy efficiency should be considered to mitigate GHG emissions from AMTS.

• Clean Technology
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• v.28 no.1
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• pp.63-78
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• 2022

Electronics industrial wastewater treatment facilities release organic wastewaters containing high concentrations of organic pollutants and more than 20 toxic non-biodegradable pollutants. One of the major challenges of the fourth industrial revolution era for the electronics industry is how to treat electronics industrial wastewater efficiently. Therefore, it is necessary to develop an electronics industrial wastewater modeling technique that can evaluate the removal efficiency of organic pollutants, such as chemical oxygen demand (COD), total nitrogen (TN), total phosphorous (TP), and tetramethylammonium hydroxide (TMAH), by digital twinning an electronics industrial organic wastewater treatment facility in a cyber physical system (CPS). In this study, an electronics industrial wastewater activated sludge model (e-ASM) was developed based on the theoretical reaction rates for the removal mechanisms of electronics industrial wastewater considering the growth and decay of micro-organisms. The developed e-ASM can model complex biological removal mechanisms, such as the inhibition of nitrification micro-organisms by non-biodegradable organic pollutants including TMAH, as well as the oxidation, nitrification, and denitrification processes. The proposed e-ASM can be implemented as a Water Digital Twin for real electronics industrial wastewater treatment systems and be utilized for process modeling, effluent quality prediction, process selection, and design efficiency across varying influent characteristics on a CPS.

• Journal of Korean Society on Water Environment
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• v.23 no.5
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• pp.689-696
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• 2007

Kinetic analysis was important to develope the biological nutrient removal process effectively. In this research, anoxic-anaerobic-aerobic system was operated to investigate kinetic behavior on the nutrient removal reaction. Nitrification and denitrification were important microbiological reactions of nitrogen. The kinetics of organic removal and nitrification reaction have been investigated based on a Monod-type expression involving two growth limiting substrates : TKN for nitrification and COD for organic removal reaction. The kinetic constans and yield coefficients were evaluated for both these reactions. Experiments were conducted to determine the biological kinetic coefficients and the removal efficiencies of COD and TKN at five different MLSS concentrations of 5000, 4200, 3300, 2600, and 1900 mg/L for synthetic wastewater. Mathematical equations were presented to permit complete evaluation of the this system. Kinetic behaviors for the organic removal and nitrification reaction were examined by the determined kinetic coefficient and the assumed operation condition and the predicted model formulae using kinetic approach. The conclusions derived from this experimental research were as follows : 1. Biological kinetic coefficients were Y=0.563, $k_d=0.054(day^{-1})$, $K_S=49.16(mg/L)$, $k=2.045(day^{-1})$ for the removal of COD and $Y_N=0.024$, $k_{dN}=0.0063(day^{-1})$, $K_{SN}=3.21(mg/L)$, $k_N=31.4(day^{-1})$ for the removal of TKN respectively. 2. The predicted kinetic model formulae could determine the predicted concentration of the activated sludge and nitrifier, investigate the distribution rate of input carbon and nitrogen in relation to the solid retention time (SRT).

• Korean Journal of Microbiology
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• v.38 no.1
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• pp.1-6
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• 2002

$\alpha$-Amylase producing bacteria were isolated from activated sludge of corn processing wastewater plant and paddy field soil samples and selected by the direct iodine reaction. The isolate was identified as Bacillus sp. after morphology, API system and fatty acid analyses. To enchance $\alpha$-amylase productivity, a successive mutation of Bacillus sp. AIV 19 was performed using the treatment of nitrosoguanidine(NTG).The mutant, Bacillus sp. AIV 1940, showed about 1.8-fold level of amylase activity compared with parental strain. The isolate was Gram-positive and rod (2.8-3.0 $\mu$m long, 0.5-0.6 $\mu$m wide) type. The strain increased the bacterial mass at 3000 mg/l starch concentration. Organic substance removal rate was 40.2, 72.3% respectively after 1 and 3 day reaction using starch synthetic wastewater (intial CODcr was 4,455 mg/l).

• Journal of Korean Society of Water and Wastewater
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• v.25 no.1
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• pp.95-106
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• 2011

Even though MBR processes have many advantages such as high quality effluents, a small footprint and convenience for operation compared to conventional activated sludge processes, there are some shortcomings in terms of the cost and potential fouling incident that keeps MBR (Membrane bioreactor) processes from being widely applied. To reduce these problems, PTFE (Polytetrafluoroethylene) flat sheet membranes that have excellent permeability and durability were tested instead of PVDF (Polyvinylidene fluoride) membrane which is being used widely in water treatment. Low concentration of sodium hydroxide (NaOH) was also added into the membrane modules in order to prevent the membrane fouling as well as to provide the alkalinity. With conditions mentioned above, a pilot-scale MBR system based on the MLE (Modified Ludzack Ettinger) process was operated at flux of 40 $L/m^{2}/hr$ and over 15,000 mg/L MLSS concentration for about 8 months. And coagulant(alum) was added into the membrane tank to remove phosphorus. Although the more coagulant is added the more effectively phosphorus is removed, that can lead to fouling for a long operation(Ronseca et al.,2009). By the way there is a research that fouling grow up after stopping injection of coagulant(Holbrook, 2004). Stable operation of MBR systems was achieved without major chemical cleaning and the effluent quality was found to be good enough to comply with the treated waste water quality regulations of the Korea.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.343-346
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• 2000

This study was carried out to investigate the effects of influent $NH_4^{\;+}-N$ load, C/N ratio and superficial air velocity on the nitrogen removal efficiencies. Laboratory scale upflow biological aerated filter(BAF) was consisted of an anoxic-aerobic filter packed with porous ceramic media and operated with synthetic wastewater. BAFs requires less energy and space for the system when compared to conventional activated sludge process. The influent C/N ratios were varied from 0 to 1 by adjusting acetate. Various superficial air velocity had been applied to investigate aeration effect on nitrogen removal. The BAF reactor showed more than 90% average $NH_4^{\;+}-N$ removal efficiencies at $NH_4^{\;+}-N$ loading in the range of $0.26{\sim}1.33$ kg $NH_4^{\;+}-N/m^3{\cdot}d$ and 62% average T-N removal efficiencies at the C/N ratio of 1. Moreover, average T-N removal efficiencies increased as the superficial air velocity increased, because of the increase $NH_4^{\;+}-N$ removal efficiencies.

• Journal of environmental and Sanitary engineering
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• v.19 no.3 s.53
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• pp.1-12
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• 2004

This study was conducted to evaluate the variation characteristics of influent and effluent quality from sewage treatment facilities using activated sludge processes and to assess the impact caused by discharge of treated sewage on the receiving water Monthly data of five water quality items (BOD, COD, SS, T-N, T-P) were used to understand the water quality at three sewage treatment plants in Seoul for five years from 1999 to 2003. Concentration differences of water quality parameters were observed between upstream and downstream site at the sewage treatment plant outfall to investigate the impact of discharge in Tan stream and Han river basin. 1. Due to the effect of continuous improvement in sewer system, the concentrations of influent went on increasing generally. 2. Effluent concentrations of BOD, COD and SS showed the trend of a little decreasing, but the trend of increasing in T-N and T-P. 3. In Tan stream basin, the impact of sewage treatment plant discharge was not observed directly, because concentration of discharge was lower than stream water's. But discharges from sewage treatment plants affected water quality at downstream site in Han river, concentration of T-P especially.

• Applied Chemistry for Engineering
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• v.23 no.3
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• pp.297-301
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• 2012

Microbial fuel cell (MFC) is the major of bio-electrochemical system which can convert biomass spontaneously into electricity through the metabolic activity of the microorganisms. In this study, we used an activated sludge as a microbial inoculum and then investigated the feasibility of using dairy wastewater as a possible substrate for generating electricity in MFC. To examine the performance of MFC as power generator, the characteristics on cell potentials, power density, cyclic voltammetric analysis and sustainable power estimation were evaluated for dairy wastewater. The maximum power density of $40\;mW/m^2$was achieved when the dairy wastewater containing 2650 mg/L COD was used, leading to the removal of 88% of the COD. The results from this study demonstrate the feasibility of using MFC technology to generate electricity while simultaneously treating dairy wastewater effectively.

• Journal of the Korean Society of Marine Environment & Safety
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• v.14 no.2
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• pp.105-109
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• 2008

In our country, limiting nutrient is known as phosphorus in the most lakes. Therefore, the removal of phosphorus is a very important process in sewage treatment. However, many of the sewage treatment plants employ the conventional activated sludge process, known to remove $10{\sim}30%$ of phosphorus. Thus, additional phosphorous removal process will be needed. Oyster shells have been known to remove phosphorus in water. The removal efficiency of phosphorus was highest at smallest size of oyster shells and at the highest pH for batch test. The phosphorous removal rate with various calcium concentrations was increased by increasing calcium concentration. At the 20 mg/l of calcium, more than 90% of phosphorous was removed in two hours. The removal efficiency of phosphorous was increased greatly at 300% of recirculation rate. With 300% of recirculation rate, the removal efficiency reached 80% at pH 11. The negative effects of bicarbonate on crystallization were observed in oyster shells. The effects of bicarbonate on rate constant were also investigated by applying these results to experimental equation. The rate constant was decreased at the inverse logarithm bicarbonate concentration.

• Coupled systems mechanics
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• v.9 no.2
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• pp.111-123
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• 2020

Wastewater treatment plants (WWTPs) with activated sludge system are widely used throughout the most common technologies in the world. Most treatment plants require optimization of certain treatment processes using dynamic modeling. A lot of examples of dynamic simulations require reliable data base of diurnal variation of the inflow and typical concentrations of parameters such as Chemical Oxygen Demand (COD), Total Kjeldahl Nitrogen (TKN), etc. Such detailed data are not available, which leads to problemsin the application of dynamic simulations. In many examples of plants, continuous flow measurements are only performed after the primary clarifier, whereas measurements from influent to the plant are missing, as is the case with the examples in this paper. In some cases, a simpler, faster and cheaper way can be applied to determine influent variations, such as the "HSG-Sim" method ("Hochschulgruppe Simulation"). "Hochschulgruppe Simulation" is a group of researchers from Germany, Austria, Switzerland, Luxembourg, Netherlands and Poland (see http://www.hsgsim.org). This paper presents a model for generating daily variations of inflow and concentration of municipal wastewater quality parameters, applied to several existing WWTPs in Bosnia and Herzegovina (B&H). The main goal of the applied method is to generate realistic influent data of the existing plants in B&H, in terms of flow and quality, without any prior comprehensive survey and measurements at the site. The examples of plants show the influence of overflow facilities on the dynamics of input flow and quality of wastewater, and a strong influence of the problems of the sewerage systems.