• Journal of the Korean GEO-environmental Society
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• v.15 no.8
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• pp.45-50
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• 2014

The microorganism decomposition experiment of sewage in the underground sewer has the limit of experiment condition and time. The way to reproduce the microorganism decomposition in the underground sewer was studied using batch reactor setting up the DO as a limiting condition. The DO concentration in the sewer is controlled by reaeration. It is possible to obtain correlation between flow condition and reaeration coefficient through the reproduction of reaeration phenomenon by controlling the flow condition in the sewer using this phenomenon. And it is possible to set the flow condition and agitation intensity (velocity gradient) that has the same reaeration coefficient using the correlation between the reaeration coefficient with the flow condition and reaeration coefficient with the agitation intensity. The circumstances in the sewer system was reproduced using batch reactor setting up the DO as a limiting condition from these results.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.17 no.2
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• pp.1-14
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• 2014

The purpose of this study is to identify the efficiency of LID technologies for controlling non-point source pollution from urban areas. The recent technical responses to managing water resource and urban areas according to the influence of climate change is an important national policy, along with green growth. Through various reference studies reasonable ways to consider a wholistic plan on urban-eco-friendly river management, the Low Impact Development (LID) as the adequate river management method is being undertaken in foreign countries to technically apply to urban plans. However, the LID is at the initial stage in Korea, with no specific studies implemented. Thus, this study explored whether LID technologies can be efficient measures to control non-point source pollution on the cost side. Ulsan's Namgu and Bukgu have been chosen as case studies that illustrate the efficiency of the LID technologies. On investigation, if LID technologies are designed properly, the efficiency of them is expected to higher than that of sewage treatment plant.

• Journal of Korean Society of Water and Wastewater
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• v.34 no.2
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• pp.149-159
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• 2020

Cured-in-place-pipe(CIPP) is the most adopted trenchless application for sewer rehabilitation to extend the life of the existing sewer without compromising both direct construction and indirect social costs especially applied in the congested urban area. This technology is globally and domestically known to be the most suitable for partial and full deteriorated pipe structure rehabilitation in a sewer system. The typical design of CIPP requires a significant thickness of lining to support loading causing sewage flow interruption and increasing material cost. This paper presents development of a high strength glass fiber composite lining material for the CIPP application and structural test results. The test results exhibit that the new glass fiber composite lining material has 12 times of flexural strength, 6.2 times of flexural modulus, and 0.5 Creep Retention Factor. These test results can reduce lining design thickness 35% at minimum. Even though taking into consideration extra materials such as outer and inner films for actual field applications, the structural capacity of the composite material significantly increases and it reduces 20 percent or more line thickness as compared to the conventional CIPP. We expect that the newly developed CIPP lining material lowers material costs and minimizes flow capacity reduction, and fully replaceable to the conventional CIPP lining materials.

• 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.

• Journal of Microbiology and Biotechnology
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• v.25 no.9
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• pp.1547-1554
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• 2015

The potential of microalgae biofuel has not been realized because of the low productivity and high costs associated with the current cultivation systems. In this study, a new low-cost and transparent attachment material was tested for cultivation of a filamentous algal strain, Stigeoclonium sp., isolated from wastewater. Initially, the different materials tested for Stigeoclonium cultivation in untreated wastewater were nylon mesh, polyethylene mesh, polypropylene bundle (PB), polycarbonate plate, and viscose rayon. Among the materials tested, PB led to a firm attachment, high biomass (53.22 g/m², dry cell weight), and total lipid yield (5.8 g/m²) with no perceivable change in FAME profile. The Stigeoclonium-dominated biofilm consisted of bacteria and extracellular polysaccharide, which helped in biofilm formation and for effective wastewater treatment (viz., removal efficiency of total nitrogen and total phosphorus corresponded to ~38% and ~90%, respectively). PB also demonstrated high yields under multilayered cultivation in a single reactor treating wastewater. Hence, this system has several advantages over traditional suspended and attached systems, with possibility of increasing areal productivity three times using Stigeoclonium sp. Therefore, multilayered attached growth algal cultivation systems seem to be the future cultivation model for large-scale biodiesel production and wastewater treatment.

• Proceedings of KOSOMES biannual meeting
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• 2006.11a
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• pp.217-219
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• 2006

This study focused an water quality response to land-based pollution loads and the appropriate pollutant load reduction in Chinhae Bay using an eco-hydrodynamic model. Land-based discharge foam urban areas, industrial complex and sewage treatment plant was the greatest contributor to cause red-tide blooms and summer hypoxia. Tidal currents velocity af the ebb tide was about 10 cm/s stronger than that of the flood tide. A residual current was simulated to. have a slightly complicated pattern with ranging from 0.1 to. 2.7 cm/s. In Masan Bay, pollutant materials cannot flaw from the inner to the outer bay easily because af residual currents flaw southward at surface and northward at the bottom. The simulation results of COD distribution showedhigh concentrations aver 3 mg/L in the inner part of Masan Bay related pollutant discharge, and charge, and lower levels less than 1.5mg/L in the central part of Chinhae Bay. For improvement water quality in Chinhae Bay, it is necessary to reduce the organic and inorganic loads from paint sources by mare than 50% and ameliorate severe polluted sediment.

• Journal of the Korean Society for Marine Environment & Energy
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• v.3 no.3
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• pp.50-57
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• 2000

Budgets of fresh water, salt, DIN and DIP in the Nakdong river estuary were estimated in order to clarify the characteristics of material cycling and fluxes of nutrients with a simple box model. Freshwater inflow into this system was approximately 1.1E＋10m³/y, water exchange was 3.3E＋10m³/y and water residence time was 2.03 day assumed with salinity between estuary and adjacent ocean. Nutrients loadings were 3.2E＋09mol DIN/y3.7×10³, 2.7E＋07mo1 DIP/y, respectively. net ecosystem metabolism was 2.4E＋07mo1 C/y. Although the Nakdong river discharge was the main source of nutrients but Jang-rim sewage treatment plant effluent take parts of 16% of nitrogen and 10.2% of phosphorus loadings.

• The Journal of the Korea Contents Association
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• v.14 no.12
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• pp.744-752
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• 2014

This research analyzed acceptability of local public enterprise management assessment targeting Chungcheongnam-do direct management enterprises. To do this, this research analyzed influence with acceptability of local public enterprise management assessment by composing the area with 5 aspects related to local public enterprise management assessment. More differentiated strategy is required to operate management assessment efficiently, since direct management enterprises have different shape from other public enterprises in respect of organizational structure. In case of water and sewage, it tends to be difficult to return the result of management assessment to the local government organization, so that managers' interest and effort is necessarily required. Also, responsible person's professionalism is required to raise achievement of direct management enterprise through management assessment, politic management plan for this is necessary. Above all, the structure of incentive for management assessment result is difficult in making intended effect as other public enterprises. Therefore, differentiation of compensation system for assessment result is required.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.3
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• pp.347-355
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• 2006

Anyang Stream including its main branch is the biggest branch stream of Han River in Korea. The geological and geomorphological characteristics were investigated to the affected area of Anyang Stream, in which rainfall characteristic was analyzed. The water quality surveyed that the analysis of water pollution used to biotic index and biological water pollution. The rainfall pattern in this area was like to that of typical Korea, but the rate of trigger and runoff during summer season(June~August) is more higher than mean of Korea. Before 2003, a dried stream is severe status, which was due to abundant runoff, but this status are improved. After 1997, water quality of stream is recovering status such as water pollution of stream steeply decreased. Especially after 2003, this trend is more quickly improved. Although, owing to the increasing of a T-N and SS at upstream wastewater were due to bad collection of industrial factories, livestock's and mans living, the water quality worsted at upstream. Water quality in total section of main stream was severely contaminated that water-quality limit is 5 with polysaprobic by water self-purification. That of main branch was 1~3limits with ${\alpha}$- and ${\beta}$-mesosaprobic in Anyang city area, But water quality in all area about another branch of Anyang stream except Anyang city area was almost under of 3 grades. Though trying of Anyang city for recover movement(completion of 2nd Sewage Treatment Plant and Water supply pipe system) on Anyang stream, water pollution states of upper branch in Anyang stream was not better than its of 2002 because it may be difference of control area on other cities.

• Journal of Environmental Health Sciences
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• v.34 no.6
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• pp.423-432
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• 2008

In this study, we investigated the possibility of auto control and the proper operating factors in the BNR(Biological Nutrient Removal) process using an NADH(Reduced Nicotinamide Adenine Dinucleotide) fluorometer, which characterized the emitted fluorescence when activated by flashes of UV light at 460 nm. In terms of finding adequate operating parameters, results indicted that nitrification efficiency decreased in the controlled DO while denitrification efficiency decreased in the controlled pH. The above results indicated that controlled operating condition after combination with NADH, DO and pH was resonable. Result obtained from the correlation between NADH and pH showed that variation trend of influent loading was similar to those of NADH and pH, and also the variation cycle was repeated on a daily basis. Consequently, this result showed the increase of BOD loading caused the nitrification efficiency to decrease because air-flow, required for nitrification, was reduced, and so the NADH value was increased. From these results, it is possible to use NADH flourimetry to assess the variation of organic load and nitrification efficiency in the case of small change in influent pH such as in sewage and also to handle and operate the load variation in the auto control system using the NADH fluorometer.