• 한국기후변화학회지
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• 제7권2호
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• pp.103-110
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• 2016

In this study, we researched the characteristics of $CH_4$ and $N_2O$ emission of the wastewater treatment (WWT) process in the dairy industry. For flux measurements at the air-water interface, a floating dynamic flow-through chamber was used above the water surface. $CH_4$ and $N_2O$ concentration from the WWT process was measured by NDIR (Non-Dispersive Infrared) Analyser. In the study, $CH_4$ and $N_2O$ fluxes results showed a distinct difference for each WWT process. 60% of the GHG emissions which was the highest percentage were from the equalization tank. Reactor tank was second with 27% of the total emissions from the WWT. Aeration tank was third with 12% of the total emissions. The tendency was that the more the wastewater was treated, the less GHGs were emitted. $CH_4$ and $N_2O$ showed the same tendency. This indicates that the concentrations and properties of wastewater could affect the tendency.

• 상하수도학회지
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• 제13권1호
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• pp.51-60
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• 1999

An intermittently-aerated, intermittently-decanted single-reactor process (KIDEA process : KIST intermittently decanted extended aeration process) was applied for nitrogen removal from wastewater. Synthetic wastewater with chemical oxygen demand (COD): nitrogen (N) ratio of approximately 5.25: 1 was used. The average COD removal efficiency reached above 95%, and under optimal conditions nitrogen removal efficiency also reached above 90%. This process consisted of 72 minute aeration, 48 minute settling and 24 minute effluent decanting with continuous feeding of influent wastewater from the bottom of the reactor, and did not require a separate anoxic mixing-phase. In this process, nitritation ($1^{st}$ step of nitrification) was induced but nitratation($2^{nd}$ step of nitrification) was suppressed. Main factors responsible for the accumulation of nitrite ion in the experimental condition were free ammonium and dissolved oxygen. This condition of nitrite build-up accelerated by continuous feed flow in the bottom of the KIDEA reactor because of high concentration of ammonia nitrogen in the influent. This research provides one of answers to control nitrate build-up.

• 한국환경과학회지
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• 제9권4호
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• pp.359-363
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• 2000

This research studied the characteristics and applicability of electrocoagulation using aluminium electrode for the color and COD removal in textile wastewater. Electrocoagulation reactor used two different electrode, Fe and Al, since in the general chemical wastewater treatment, aluminium and ferrous salts were used as coagulants. Aluminium electrode showed higher removal efficiency of color and COD than ferrous electrode did. The COD and color removal efficiency improved at the 0.192A/$dm^2$ current density. Thus, the electrocoagulation process with bipolar aluminium electrode showed better efficiency in the decolorization and COD removal rate of textile wastewater effluent than custom coagulants did.

• 환경위생공학
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• 제10권1호
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• pp.98-105
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• 1995

In the treatment of wastewater or sewage plant sludge with high solid concentration, high rate digestion process in which heating and mixing occur at a time is mainly used, and in the case of wastewater containing solid matter below 1000mg/ℓ the recently developed AF or UASB is developed Recently and commonly utilized. But these processes have weakpoints such as clogging of packing media and need of long period of trial run after microorganism granulation. In this point of view, there are active researches on the ASBR( anaerobic sequence batch reaction ) that is capable of treating of organic matter with reactor that has no packing materials and controlling the inflow time, reaction time sedimentation time and outflow time by time control without loss of microorganisms. The objectives of this study are to evaluate the efficiency of ASBR process according to the reaction time, change of treated water quality and gas output rate in the treatment of wheat plant wastewater.

• 상하수도학회지
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• 제10권2호
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• pp.117-123
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• 1996

A bench-scale continuous activated sludge system was operated in order to study the effects of solid waste landfill leachate on municipal wastewater treatment. The leachate sample was collected from Nanjido landfill. During the 7 weeks of operational period, the leachate content in the influent fed to the system was increased stepwise from 3% to 5% and 7%. The solids retention time was the major process control parameter, and it was 10 days. With the municipal wastewater alone, COD removal was 75%. The removal percents, however, decreased to 60% and 45% when the leachate content was 3% and 7%, respectively. For the wastewater spiked with the leachate, the sludge production was higher than for the municipal wastewater alone. Sludge settleability determined by SVI deteriorated with the increase of leachate content. The specific oxygen uptake rate, however, was measured higher as leachate content increased.

• 상하수도학회지
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• 제19권2호
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• pp.214-220
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• 2005

Errors may occur due to analysis methods and water quality during the application of the on-line particle counter In water treatment process. Errors caused by analysis methods include particle destruction by shear force due to inflow speed and tube friction, as well as interruption by screening, bubbles and contaminants. Since errors happen frequently because of these factors, it is necessary to examine and evaluate such errors during the application of a particle counter. Errors can be large due to screening and bubbles. Measurement values are effective for water analysis after filtration process. However, because of screening, only measurement values for particles above $7{\mu}m$ are valid for water with a turbidity between 3-10NTU. As particle numbers around $10{\mu}m$ increase a lot after ozone treatment, sufficient pretreatment process is necessary. Physical conditions should keep stable for inflow to decrease errors caused by shear force.

• 상하수도학회지
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• 제22권5호
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• pp.541-550
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• 2008

In this investigative study, the unit mass discharge for the major water quality parameters such as flowrate, SS, BOD, CODmn, CODcr, TN, TP from textile spinning/weaving industry nearby Nakdong river basin was estimated. To represent the respective industries, three companies from hundreds of textile spinning/weaving industries located in Nakdong river basin was carefully selected based on its manufacturing goods, flowrate and location for the estimation of unit mass discharge based on unit operation and process. There was a drastic decrease of unit mass discharge estimation between influents and effluents of water quality parameters, which represents the removal capacity of wastewater treatment plant. With the advent of new regulation on the imposed payment proportional to the total amount of pollutants discharge into the water body, the concept of cleaner production technology should be employed in the unit operation/process in wastewater treatment plant as well as textile manufacturing procedure to minimize the levy on the pollutants discharge. Unit mass discharge estimations of unit process (estimated in this study) in major water quality parameters (SS, BOD, COD, TN and TP) based on land were similar to those of composite process (estimated by National Institute of Environmental Research). But the unit mass discharge estimations of unit process in BOD and CODmn based on total sale were much higher than those of composite one while in SS, TN and TP similar to each other. For the detailed estimation of the imposed payment, unit mass estimation based on unit process should be further emphasized.

• 한국농공학회논문집
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• 제47권3호
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• pp.69-76
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• 2005

An Absorbent Biofilter System (ABS) combined with the recirculation process was investigated for the feasible application in additional removing of organics (BOD, SS) as well as nutrients (TN, TP) from small Community wastewater in Korea. Polyurethane biofilter media with high porosity and large surface area were /used for the aerobic system. A part of treated wastewater was recirculated into the anoxic septic tank to promote removal of nutrients. The concentrations of BOD and SS of treated wastewater satisfied the regulations for small on-site wastewater treatment facility (10 mg/L) during the overall experimental period. The effluent concentrations of BOD and SS were decreased with enhancement of removal efficiencies of 95.7 and $96.7\%$. The nitrogen and phosphorus removal efficiencies by the recirculation increased to $52.9\%\;and\;43.2\%$ in average during the overall experimental period, respectively. With the improvement, these values were increased as much as additional 42 and $18\%$ compared with those of non-recirculation. The rates of nitrification and denitrification were enhanced showing $65\~77\%\;and\;42\~92\%$, respectively. The described process modification is a low cost and effective method of enhancing nitrogen and phosphorus removal, especially on existing systems without changing major design components of a treatment facility.

• 한국물환경학회지
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• 제32권3호
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• pp.253-260
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• 2016

To reduce energy consumption in wastewater treatment plants (WWTPs), renewable energy applications such as small hydropower, solar energy, and wind energy are popular. However, it should be noticed that energy originated from operation of wastewater treatment process can be reduced through optimized operation based on analysis of factors affecting energy. In this research, the relationship to the various operational variables and influent factors was explored using correlation analysis and decision tree algorithm. Due to the non-linear characteristics of the process, it was difficult to find clear linear patterns through correlation analysis. However, decision tree algorithm showed its usefulness in uncovering hidden patterns that consume energy. As operational factors, influent flowrate, the amount of aeration, nitrate recycling pumping rate, and sludge wasting pumping rate were selected as important factors. For environmental factors associated with influent compositions and removal rate, BOD and T-N removal rate were selected as significant factors.

• 공업화학
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• 제24권1호
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• pp.38-43
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• 2013

ETA (ethanolamine)는 원자력 발전소 2차계통의 pH 조절제인 암모니아 대체 물질로 2001년부터 이용되고 있다. 환경적 측면에서 난분해성 유기물이며 현재 운영 중인 원자력 발전소 폐수처리설비로 처리가 불가능하다. 본 연구는 현장 시료를 사용하여 N와 COD 제거하기 위한 최적 공정과 사용 약품에 대하여 조사하였다. 폐수 중에 다량 함유되어 있는 ammonium ion은 diffused aeration system을 이용하여 95% 이상을 제거하고 혼합과산화물(sodium persulfate/sodium percarbonate)을 사용하여 산화시키고 응집제를 사용하여 물리 화학적으로 처리 후 90% 이상의 제거효과를 얻을 수 있었다.