• Journal of Korean Society of Water and Wastewater
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• v.29 no.4
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• pp.503-510
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• 2015

The objective of this study is to analyze the investment adequacy of the projects implemented according to the master plan on sewerage rehabilitation at Seoul. The planned and actually implemented ratio of invested money on sewage treatment plants (STPs) to sewers were compared in two temporal periods. Though the planned ratio of investment on STPs to sewers was 50:50 (in 2009-2020), the actual implemented ratio in 2009-2013 was 34:66. Until 2020, the greater investment ratio on STPs to sewers should be made considering the necessity of coping with stricter legal compliance on advanced treatment, stormwater treatment and so on. The priority of the planned and partially implemented projects among four STPs and at each STP was evaluated. Considering only the performance indicator of reduced load of BOD, T-N, T-P per the capacity of each STP facility, the performance among four STPs was shown as Jung-Rang>Tan-Cheon>Seo-Nam>Nan-Ji. The reverse order of the performance results in the past may be considered for future investment priority, but the efficiency of operation implemented at each STP, deteriorated status of each STP, investment in the past and so forth should also be considered. As for the priority of projects conducted within each STP, projects related to legal compliance (such as advanced tertiary treatment, stormwater treatment, etc.) have highest priority. Odor-related project and inhabitant-friendly facility related projects (such as building park on STPs, etc.) has lower priority than water quality related projects but interactivity with end-users of sewerage should also be important.

• Journal of Environmental Science International
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• v.27 no.2
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• pp.99-107
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• 2018

In order to design the improvement process for T-N removal, the treatment process of Suyoung, Gangbyeon, and Noxan sewage treatment plants (STP) in Busan was anlayzed. Suyoung STP shows a T-N removal efficiency of about 69.8% with MLE(Modified Ludzack ettinger) and A2O+MBR. However, it is necessary to improve the process to maintain over DO of 1 mg/L and is required to install a flow control tank to minimize the rainfall effect. Gangbyun STP shows a about 70.2% T-N removal efficiency with A2O+GFF(gravity fiber filtration). However, in order to improve T-N removal efficiency, it is needed to install MLE process to treat recycle water. Noksan STP shows a T-N removal efficiency of about 71.0% with MLE+Chemical treatment and shows stable T-N concentration in effluent. However, it is required a toxic chemical management process because bad wastewater flows into the STP, also is necessary a process improvement in order to increase internal recycling ratio. Especially, it is required a process improvement to increase HRT of nitrification tank because Suyoung and Gangbyeon STPs shows low nitrification efficiency during winter season.

• Journal of Environmental Science International
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• v.23 no.7
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• pp.1253-1268
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• 2014

This study was investigated twenty two hazardous chemicals compounds for effluents of nine sewage treatment plants (STPs) and one waste water treatment plant (WWTP) in the Nakdong Ri-ver Basin. They are eleven phthalates(DMP, DEP, DIBP, DBP, BEEP, DNPP, DHP, DCP, DEHP, DNOP, Dinonyl phthalate, seven aliphatic hydrocarbons(n-Tridecane, n-Tetradecane, n-Pentadecan-e, n-Hexadecane, n-Heptadecane, n-Octadecane, n-Nonadecane, Isoquinoline, 2-Chloropyridine, 2-N-itrophenol, and Benzophenone. The twenty two compounds were analyzed by gas chromatograp-hy mass spectrometry (GC/MS) with liquid-liquid extraction (LLE). Twenteen of twenty two subs-tances were detected. They were DMP, DEP, DIBP, DBP, DEHP, n-Tetradecane, n-Pentadecane, n-Heptadecane, n-Octadecane, n-Nonadecane, Isoquinoline and Benzophenone. Among these, DEHP, DEP and Benzophenone were most frequently observed. They were obtained as $ND{\sim}36.881{\mu}g/L$, $ND{\sim}0.950{\mu}g/L$, $ND{\sim}2.019{\mu}g/L$, respectively. When the substances were calculated the average concentration at 10 points, the maximum average detection concentration was investigated at the Dalseocheon STP.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.2
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• pp.223-232
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• 2013

In this study, carbon emissions and energy consumption were evaluated to establish a design strategy which has low energy consumption and carbon emission production, by using life cycle energy (LCE) and life cycle $CO_2(LCCO_2)$ calculation methods in life cycle management(LCM) tools. After improvement design projects, the energy consumption and $CO_2$ emission were calculated and compared in three sewage treatment plants (STPs), which are A STP, B STP, and C STP. The reduction of carbon emissions was 28,020.1 ton $CO_{2-}e/yr$, 37,399.6 ton $CO_{2-}e/yr$ and 8,788.3 ton $CO_{2-}e/yr$, respectively. Production of energy was 792 TOE/yr, 1,235 TOE/yr and 1,023 TOE/yr, respectively. As a result, the estimation of energy and energy self-sufficiency was 5.1 %, 14.5 % and 23.5 %, respectively. The result of this study shows the LCM can be contributed to establish strategy for energy and carbon emission reduction in sewage treatment plants.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.6
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• pp.743-752
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• 2009

One of the major problems associated with operation of domestic sewer lines involves hydraulic problems such as insufficient conveyance capacity, exceeding maximum velocity, and deficiency of minimum velocity. It has also been pointed out that influent concentration lower than design concentration of pollutants, which is mainly caused by unidentified inflow and infiltration, degrades the operational efficiency of many sewage treatment plants (STPs). A computer-added analysis method supporting a coupled simulation of sewage quality and quantity is essentially required to evaluate the status of existing STPs and to improve their efficiency by a proper sewer rehabilitation work. In this study, dynamic water quality simulations were conducted using MOUSE TRAP to investigate the principal parameters that governs the changes of BOD, ${NH_4}^+$, and ${PO_4}^{3-}$3- concentrations within the sewer networks based on data acquired through on-site and laboratory measurements. The BOD, ${NH_4}^+$ and ${PO_4}^{3-}$3- concentrations estimated by MOUSE TRAP was lower than theoretical pollution loads because of sedimentation and decomposition in the sewer. The results revealed that sedimentation is a most important factor than other biological reactions in decreasing pollutant load in the sewers of C-city. The sensitivity analysis of parameters pertaining to water quality changes indicated that the effect of the BOD decay rate, the initial DO concentration, the half-saturation coefficient of dissolved BOD, and the initial sediment depth is marginal. However, the influence of settling rate and temperature is relatively high because sedimentation and precipitation, rather than biological degradation, are dominant processes that affect water quality in the study sewer systems.

• Journal of Environmental Science International
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• v.21 no.9
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• pp.1131-1138
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• 2012

The aims of this study were to investigate and confirm the occurrence and distribution patterns of iodinated X-ray contrast media (iopromide) in Nakdong river basin (mainstream and its tributaries). Iopromide was detected in 16 sampling sites. The concentration levels of iopromide on February 2011 and on October 2011 in surface water samples ranged from not detected (ND) to 1481.1 ng/L and ND to 1168.2 ng/L, respectively. The highest concentration level of iopromide in the mainstream and tributaries in Nakdong river were Goryeong and Jincheon-cheon, respectively. The sewage treatment plants (STPs) along the river affect the iopromide levels in river and the iopromide levels decreased with downstream because of dilution effects.

• Journal of Environmental Impact Assessment
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• v.22 no.6
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• pp.581-589
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• 2013

Generally, Sewage Treatment Plants(STPs) are complexes systems in which a range of physical, chemical and biological processes occur. However, their performance strongly depends on the know-how acquired by the field-engineer. Recently, in order to solve this situations, various operation and management technologies based on the Instrumentation, Control and Automation(ICA) have been developed. As a economies-environmental affect point of view, this study was for the performance evaluation and assessment of results from the Smart Operation System(SOS) in full-scale STP. The SOS in STP consisted of the process monitoring module, including real-time influent prediction and effluent simulation, and the Smart Air Control(SAC) module. According to the results from field test for 2 years, the results of economical evaluation, amount of benefits and cost saving by the SOS have shown to be much higher than that of traditional operation. Nevertheless, the removal load(kg/yr) of BOD 13.3 %, COD 28.2 %, TN 44.4 % and TP 20.8 % were increased, respectively. Remarkable improvement of removal load could be achieved after the SOS was adapted. It was concerned that the SOS offer a user friendly functionalities and cost saving needed by the field-engineers. In addition, it was expected that the results of this study would supply helpful information for design and cost saving for the SOS in full-scale STP.

• Journal of Environmental Health Sciences
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• v.39 no.5
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• pp.391-407
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• 2013

Micropollutants emerge in surface water through untreated discharge from sewage and wastewater treatment plants (STPs and WWTPs). Most micropollutants resist the conventional systems in place at water treatment plants (WTPs) and survive the production of tap water. In particular, pharmaceuticals and endocrine disruptors (ECDs) are micropollutants frequently detected in drinking water. In this review, we summarized the distribution of micropollutants at WTPs and also scrutinized the effectiveness and mechanisms for their removal at each stage of drinking water production. Micropollutants demonstrated clear concentrations in the final effluents of WTPs. Although chronic exposure to micropollutants in drinking water has unclear adverse effects on humans, peer reviews have argued that continuous accumulation in water environments and inappropriate removal at WTPs has the potential to eventually affect human health. Among the available removal mechanisms for micropollutants at WTPs, coagulation alone is unlikely to eliminate the pollutants, but ionized compounds can be adsorbed to natural particles (e.g. clay and colloidal particles) and metal salts in coagulants. Hydrophobicities of micropollutants are a critical factor in adsorption removal using activated carbon. Disinfection can reduce contaminants through oxidation by disinfectants (e.g. ozone, chlorine and ultraviolet light), but unidentified toxic byproducts may result from such treatments. Overall, the persistence of micropollutants in a treatment system is based on the physico-chemical properties of chemicals and the operating conditions of the processes involved. Therefore, monitoring of WTPs and effective elimination process studies for pharmaceuticals and ECDs are required to control micropollutant contamination of drinking water.

• Environmental Engineering Research
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• v.14 no.3
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• pp.186-194
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• 2009

Understanding the environmental fate of human and animal pharmaceuticals and their risk assessment are of great importance due to their growing environmental concerns. Although there are many potential pathways for them to reach the environment, effluents from sewage treatment plants (STPs) are recognized as major point sources. In this study, the removal efficiencies of the 43 selected priority pharmaceuticals in a conventional STP were evaluated using two simple models: an equilibrium partitioning model (EPM) and STPWIN$^{TM}$ program developed by US EPA. It was expected that many pharmaceuticals are not likely to be removed by conventional activated sludge processes because of their relatively low sorption potential to suspended sludge and low biodegradability. Only a few pharmaceuticals were predicted to be easily removed by sorption or biodegradation, and hence a conventional STP may not protect the environment from the release of unwanted pharmaceuticals. However, the prediction made in this study strongly relies on sorption coefficient to suspended sludge and biodegradation half-lives, which may vary significantly depending on models. Removal efficiencies predicted using the EPM were typically higher than those predicted by STPWIN for many hydrophilic pharmaceuticals due to the difference in prediction method for sorption coefficients. Comparison with experimental organic carbon-water partition coefficients ($K_{ocs}) revealed that log KOW-based estimation used in STPWIN is likely to underestimate sorption coefficients, thus resulting low removal efficiency by sorption. Predicted values by the EPM were consistent with limited experimental data although this model does not include biodegradation processes, implying that this simple model can be very useful with reliable Koc values. Because there are not many experimental data available for priority pharmaceuticals to evaluate the model performance, it should be important to obtain reliable experimental data including sorption coefficients and biodegradation rate constants for the prediction of the fate of the selected pharmaceuticals.

• Journal of Convergence for Information Technology
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• v.10 no.5
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• pp.117-125
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• 2020

Our study identifies a cost and a benefit incurred in implementing an investment project to offer new public services by use of food waste disposers and direct input of feces in sewers. This is done with identifying costs of each processing division and benefits of the project by objective statistical data and engineering perspective. In summary, cost items identified are as follows: there are house laterals, removal of septic tanks, etc. for sewer pipes system. As to water quality conservation, cost incurs in storm water outfalls and divert chambers, sewage storage tanks, equipment to treat sewer overflows, and so on. With respect to sewage treatment plants(STPs), there are so many items as increase of contaminant loads in influent of STPs, and other items. There are benefit items in health improvement due to odor mitigation, increase of energy productivity, saving cost of food waste treatment and cleaning septic tanks, etc. These estimates will be used as a basic data for its economic effect.