• KCID journal
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• v.8 no.2
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• pp.105-107
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• 2001

• Journal of environmental and Sanitary engineering
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• v.23 no.4
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• pp.55-64
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• 2008

In this study, the management and improvement of public small-scale sewage treatment facilities was investigated. In order to improve the effective management of the operation of small-scale sewage treatment facilities, treatment methods and the problems associated with sewage treatment were carefully addressed based on the data and literature. The investigation results showed that sewer pipes in rural areas should be repaired to prevent sewage from leaking and small-scale operations should be required to have effective management for pollutant loads less than 50%. Also, new methods should be developed for low concentrations of sewage. A law associated with FRP treatment facilities should be established and local governments need to supervise these operations to avoid insufficient and faulty construction. It is recommended that new facilities are built with advanced treatment techniques when the old facility can not comply with nitrogen and phosphorous discharge limits. Moreover, the study shows that nutrient and coliform treatment efficiency improves when abandoned facilities are renovated with the installation of nitrification/denitrification and disinfection processes or another advanced process.

• Environmental Engineering Research
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• v.24 no.2
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• pp.202-210
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• 2019

In order to maximize the utilization of sewage sludge, a waste from wastewater treatment facility, the residual sewage sludge generated after lipid and carbohydrate extraction for biodiesel and bioethanol production was used to produce bio-oil by pyrolysis. Thermogravimetric analysis showed that sludge pyrolysis mainly occurred between 200 and $550^{\circ}C$ (with peaks formed around 337.0 and $379.3^{\circ}C$) with the decomposition of the main components (carbohydrate, lipid, and protein). Bio-oil was produced using a micro-tubing reactor, and its yield (wt%, g-bio-oil/g-residual sewage sludge) increased with an increase in the reaction temperature and time. The maximum bio-oil yield of 33.3% was obtained after pyrolysis at $390^{\circ}C$ for 5 min, where the largest amount of energy was introduced into the reactor to break the bonds of organic compounds in the sludge. The main components of bio-oil were found to be trans-2-pentenoic acid and 2-methyl-2-pentenoic acid with the highest selectivity of 28.4% and 12.3%, respectively. The kinetic rate constants indicated that the predominant reaction pathway was sewage sludge to bio-oil ($0.1054min^{-1}$), and subsequently to gas ($0.0541min^{-1}$), rather than the direct conversion of sewage sludge to gas ($0.0318min^{-1}$).

• Journal of Korean Society of Disaster and Security
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• v.12 no.3
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• pp.35-49
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• 2019

Currently in 2018, Korea has over 600 operating sewage disposal facilities. The law requires a sewage treatment plant to treat 500 tons or more of water per day, and a small-decentralized sewage treatment facility in a community to treat 50 tons or more to less than 500 tons of water per day. However, most facilities fulfill neither the quantity nor the quality requirements from the original design for such reasons as inflow of rainwater and ground water due to deterioration of pipelines and unauthorized input of wastewater in the pipelines. The research has selected 2 representative cases among the technical diagnosif sewage pipelines in many regions within the country to use it as the baseline of: hourly flowrate and BOD water quality analysis in both clear and rainy days, proper plant operation through inflow rate and ratio calculation, and diagnostic evaluation for deterioration of the pipelines and their accessary structures. This also suggests facilities that treats 500 tons or more of inflow per day to sample and analyze the water hourly for 24 hours once a week in both clear weather and rainy weather considering the influence of rainfall on a regular basis.

• Journal of The Korean Society of Agricultural Engineers
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• v.47 no.3
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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.

• Nuclear Engineering and Technology
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• v.50 no.8
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• pp.1355-1363
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• 2018

Many radionuclides exist in normal environment and artificial radionuclides also can be detected. The radionuclides ($^{131}I$) are widely used for labeling compounds and radiation therapy. In Korea, the radionuclide ($^{131}I$) is produced at the Radioisotope Production Facility (RIPF) at the Korea Atomic Energy Research Institute in Daejeon. The residents around the RIPF assume that $^{131}I$ detected in environmental samples is produced from RIPF. To ensure the safety of the residents, the radioactive concentration of $^{131}I$ near the RIPF was investigated by monitoring environmental samples along the Gap River. The selected geographical places are near the nuclear installation, another possible location for $^{131}I$ detection, and downstream of the Gap River. The first selected places are the "front gate of KAERI", and the "Donghwa bridge". The second selected place is the sewage treatment plant. Therefore, the Wonchon bridge is selected for the upstream of the plant and the sewage treatment plant is selected for the downstream of the plant. The last selected places are the downstream where the two paths converged, which is Yongshin bridge (in front of the cogeneration plant). In these places, environmental samples, including sediment, fish, surface water, and aquatic plants, were collected. In this study, the radioactive iodine ($^{131}I$) detection along the Gap River will be investigated.

• Journal of Wetlands Research
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• v.25 no.2
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• pp.91-98
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• 2023

Some concrete wastewater generated during construction is in the form of non-point pollution sources that workers, managers, and users are unaware of, and it is not easy to manage as it flows through sewage pipes. Due to these characteristics, construction sludge is inflow into rivers and sewage pipes in the form of non-point pollution sources in an unmanaged state. This study applied the D.W.S method to the concrete retaining wall removal method installed on the road, and the resulting concrete wastewater was physically and chemically treated through a mobile sewage treatment facility, and it was examined whether it met the removal efficiency and wastewater discharge acceptance standards. Accordingly, it is intended to meet the standards for effluent concentration of wastewater during construction by removing 73.5% of BOD and 89.1% of SS through physical and chemical treatment through portable sewage treatment facilities during construction. In addition, we would like to review the adequacy and economic analysis of calculating environmental conservation costs for physicochemical treatment through portable sewage treatment facilities and sewage treatment generated during construction.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.24 no.1
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• pp.73-78
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• 2006

Cheongju city is executing a basic sewage maintenance plan for the systematic understanding of the sewage facilities, efficient preservation management, and reformation of the existent sewage facilities, in order to prevent the contamination of water and to preserve the neighboring environments. The new business constitute approximately 6% of the entire facility production, and renovation business constitute approximately 1.5% every year according to the statistics information of the last five years. This research provides effectiveness and reliability for sewage construction, and improvement in service for the civilians, through the efficient management of various documents, construction fees, design drawings, photographs, and construction background for the annually made constructions with the development of the effective management system for the sewage work.

• Journal of Environmental Science International
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• v.18 no.6
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• pp.603-608
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• 2009

Activated sludge sewage treatment processes are difficult to be controlled because of their complex and nonlinear behaviour, however, the control of the dissolved oxygen level in the reactors plays an important role in the operation of the facility. For this reason, this study is designed to present a system which accurately measures DO, MLSS, pH and ORP in the aeration tank to alleviate situations above and provide the automatization of a sewage treatment plant (STP) using new DO control system. The automatic control systems must be guaranteed the accuracy. Therefore, the proposed automatic DO control system in this study could be commercial applications in the aeration tanks by means of operating cost analysis and user-friendly for operation and maintenance. We could get accurate data from the lab tank which has water quality checker because there was no vortex and air bubble during the measurement process. Improvement of confidence in the lab tank enabled effective and automatic operation of sewage treatment plants so that operation costs and manpower could be saved. If this result is put in place in every sewage treatment plant nationwide for practical purposes, it is estimated to cost 18.5 million dollars in installing the lab tank and to save 9.8 million dollars in management cost a year, except for cost saved by automation.

• Journal of Korean Society on Water Environment
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• v.23 no.5
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• pp.756-760
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• 2007

Most of the sewage treatment plants in Korea are being operated by using the conventional activated sludge process. Recently, as the water criteria have been strict with regard to such main culprits of eutrophication, the existing sewage treatment plants are obliged to upgrade their treatment technology to meet the criteria. Under such circumstances, this study was aimed at analyzing the conditions of an existing sewage treatment plants in Korea, and thereupon, test its treatment performance for the actual sewage water by operating a pilot plant. When the pilot plant was operated with the NPR process at the capacity of $30m^3/day$, the average contents of BOD, $COD_{Mn}$, SS, T-N and T-P in the effluents were 7.0 mg/L, 9.7 mg/L, 5.1 mg/L, 8.0 mg/L and 0.23 mg/L, respectively, which were very stable in general. Accordingly, if the NPR process used for this pilot plant to upgrade the treatment technology for the sewage treatment plat could be adopted, the effluent water quality criteria effective beginning from 2008 would be met.