• International Journal of Advanced Culture Technology
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• v.7 no.4
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• pp.104-110
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• 2019

Since 1986, domestic sewage treatment plants have installed and operated biogas plants that produce biogas (digested gas) using food, livestock manure and sewage sludge as part of the use of alternative energy for energy independence. Despite concerns about safety accidents and risks of large-scale accidents due to the continuous expansion of biogas plants, the Ministry of Environment has managed and supervised biogas plants to be environmental plants, focusing on environmental management. There is a lack of safety awareness of workers' processes. Only recently has the process safety management (PSM) system been implemented in biogas plants, but workers' perceptions of process safety have changed. As there is a difference in the degree of safety process management and safety awareness among workers, it is necessary to establish clear and systematic safety management standards. Therefore, The purpose of this study is to examine whether the application of the plant safety management (PSM) system to biogas plants is effective for workers' safety awareness in order to ensure safe operation of biogas plants and prevent workers' safety accidents in advance.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2004.11a
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• pp.369-370
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• 2004

• Journal of Korean Society of Environmental Engineers
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• v.29 no.1
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• pp.8-16
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• 2007

• Journal of Korean Society of Water and Wastewater
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• v.30 no.3
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• pp.233-240
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• 2016

Control degree and property changes of dissolved organic matter (DOM) were conducted by coagulation of chemical treatment for 2 sewage treatment plants with different technical methods. As the result, SUVA value of the second treated water (supernatant of the second settling pond after biological treatment) was increased and DOC was reduced in comparison with supplied raw water. And, SUVA value and DOC were reduced by coagulation after coagulation treatment of the second treated water. Properties of dissolved organic matter for 2 sewage treatment plants's DOC were divided. As the result, there was lots of hydrophilic component with hydrophilicity in case of plant A. In case of the second treated water, Plant A showed fulvic acid with little molecular weight was reduced among the hydrophobic component with hydrophobicity, but numic acide with lots of molecular weight was increased. However, in case of plant B, both fulvic acid with little molecular weight and humic acid with lots of molecular weight were increased among the hydrophobic components with hydrophilicity. Before the operation of phosphorus facility, properties of dissolved organic matter after biodegradation with effluent water showed hydrophilic components were reduced and hydrophobic components were increased. However, after coagulation treatment of the second treated water, hydrophilic components and hydrophobic components were outstandingly decreased or increased. During the biodegradation after coagulation treatment, hydrophilic components were significantly decreased and hydrophobic components were increased.

• Proceedings of the Korean Society of Environment and Ecology Conference
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• 2003.10a
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• pp.105-126
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• 2003

In Korea most of annual rainfall is concentrated in several episodic heavy rains during the season of summer monsoon and typhoon. Because of uneven rainfall distribution many dams have been constructed in order to secure water supply in dry seasons. The Han River system has the most dams among Korean rivers, and the river is a series of dams now. Reservoirs need different strategy of water quality control from river water. Autochthonous organic matter and phosphorus should be the major target to be controlled in lakes. In this Paper some problems are discussed that makes efforts of water quality improvement ineffective in lakes of Korea, even after the substantial investment to wastewater treatment facilities.1) Phosphorus is the key factor controlling eutrophication of lakes and the reduction ofphosphors should be the major target of water treatment. However, water quality management strategy in Korea is still stream-oriented, and focused on BOD removal from sewage. Phosphorus removal efficiency remains as low as 10-30%, because biological treatment is adopted for both secondary treatment and advanced treatment. The standard for TP concentration of the sewage treatment plant effluent is 6 mgP/l in most of regions, and 2 mg/l in enforced region near metropolitan water intake point. TP in the effluents of sewage treatment plants are usually 1-2 mg/1, and most of plants meet the effluent regulation without a further phosphorus removal process. The generous TP standard for effluents discourages further efforts to improve phosphorus removal efficiency of sewage treatment. Considering that TP standard for the effluent is below 0.1 mg/l in some countries, it should be amended to below 0.1 mg/l in Korea, especially in the watershed of large lakes.2) Urban runoff and combined sewer overflow are not treated, even though their total loading into lakes can be comparable to municipal sewage discharges on dry days. Chemical coagulation and rapid settling might be the solution to urban runoff in regard of intermittent operation on only rainy days.3) Aggregated precipitation in Korea that is concentrated on several episodic heavyrains per year causes a large amount of nonpoint source pollution loading into lakes. It makes the treatment of nonpoint source discharge by methods of other countries of even rain pattern, such as retention pond or artificial wetland, impractical in Korea.4) The application rate of fertilizers in Korea is ten times as high as the average ofOECD countries. The total manure discharge from animal farming is thought to be over the capacity of soil treatment in Korea. Even though large portion of manure is composted for organic fertilizer, a lot of nutrients and organic matter emanates from organic compost. The reduction of application rate and discharge rate of phosphorus from agricultural fields should be encouraged by incentives and regulations.5) There is a lot of vegetable fields with high slopes in the upstream region of the HanRiver. Soil erosion is severe due to high slopes, and fertilizer is discharged in the form of adsorbed phosphorus on clay surface. The reduction of soil erosion in the upland area should be the major preventive policy for eutrophication. Uplands of high slope must be recovered to forest, and eroded gullies should be reformed into grass-buffered natural streams which are wider and resistant to bank erosion.

• Journal of Korean Society of Water and Wastewater
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• v.19 no.6
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• pp.800-808
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• 2005

It is required to propose an alternatives for appropriate sludge treatment owing to persistent construction of sewage treatment plant and increase of sewage sludge quantity. In order to treat sludge more efficiently, the methods which reduce the cost of sludge treatment have been studied such as sludge reduction and conditioning. Especially ozone treatment reduces solid quantity and improves separation of solid-liquid at the same time. Therefore ozone treatment have a positive effect on reduction and stabilization of sludge. So, this study applied ozone to sewage sludge and induced cell destruction of sludge. By comparing with the correlation between thickening and dewatering, and evaluating moisture content and solubilization of cake, this study verificates the effect of process improvement for ozone pre-treatment. In J-STP case, according to ozone dose solid flux increased about 12 times from $1kg/m^2{\cdot}h$ to $12kg/m^2{\cdot}h$. Also this plant were capable to shorten thickening time from 40 minutes to 6~7 minutes. Thus it is expected to reduce volume and retention time of thickener. On pH effect factor, dewatering at pH4 was more than at pH11, $3.05{\times}10^{11}$ and $3.82{\times}10^{11}(m/kg)$. But effect of pH was analogous to ozone, $2.81{\times}10^{11}(m/kg)$. The effect of pH on thickening was similar to law sludge, $0.68(kg/m^2{\cdot}h)$, and the effect of ozone injection on thickening was the biggest, $3.45(kg/m^2{\cdot}h)$. The COD solubilization rate improved from about 5 to 30%. So it is judged that we are able to utilize most solubilized sludge to another sewage treatment plants.

• Journal of Korean Society on Water Environment
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• v.26 no.6
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• pp.969-975
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• 2010

Estimating the organic matter loadings from individual treated sewage has become important for establishment of effective management strategies to control refractory organic matter (R-OM) in watersheds. For this study, regression equations were constructed using treated sewage data to convert the chemical oxygen demand (COD) concentrations, which are mostly available from open database, into total organic carbon (TOC) and R-OM concentrations. Effluent samples were collected from five major sewage treatment plants (STPs) located upstream of the lake Paldang. Variations in the OM concentrations were not associated with either the location of the STP or the sampling season. The effluent investigated were characterized by higher ratio of R-OM with respect to biodegradable organic matter (B-OM) and higher presence of dissolved organic matters (DOM) versus particulate organic matter (POM). Compared to $COD_{Mn}$, $COD_{Cr}$ exhibited higher oxidation efficiencies and greater variations in the concentrations. The concentrations of $COD_{Mn}$ were positively correlated with dissolved organic carbon (DOC), total organic carbon (TOC), and R-OM concentrations. There was nearly no seasonal and annual variation in the regression equations between $COD_{Mn}$ and TOC or R-OM concentrations. The constructed regression equations for TOC and R-OM were $0.650({\pm}0.071){\times}COD_{Mn}+1.426({\pm}0.575)$ and $0.340({\pm}0.083){\times}COD_{Mn}+2.054({\pm}0.670)$, respectively. The established equations are expected to contribute to estimating OM loadings from the STPs into the lake Paldang and also to compensating for the deficiency of the data for effluent OM concentrations in STP.

• Journal of Korean Society on Water Environment
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• v.27 no.1
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• pp.36-43
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• 2011

This study is selected two points of combined sewer that occurred Fish Kill after first flush, that analyzed generation of pollutants and stream runoff generation of combined sewer overflows (CSOs) as fine weather and rainfall. In addition, this study was to analyze the relationship between CSOs and sediments, to propose measures to reduce the sediment relevant with CSOs and rainfall runoff from entering sewage treatment plants and measures for discharged directly into streams when indicate relatively good water quality after overflow. Sediments in combined sewer system was discharged about 50~80% as overflows during rainfall and we can reduce the amount of the CSOs at least 50% or more if the sewer does not exist in the sediments because of the amount of discharge about the amount of intercept has been investigated by 3~5 times. Because of velocity at sediment interval in sewer is very low, sewage velocity of about 3~5 times as much as it can increase the amount of sediment can be reduced if the separation wall is installed. Effective control of BOD overflow load is respectively 77.5%, 75.8% at first point, second point by the separation wall is installed. Drainage area greater than area in this study or many combined sewer overflows region is increased the more effective control of separation wall. Turbidity to measure changes in water quality of overflows can be used as an factor to control the intercept flows because the intercept flows(3Q) after the first flush has lowered removal efficiency and increases the operational load of sewage treatment plants. Sewage water quality after a overflow when the reasonable turbidity was measured at this point flows to excluded intercept flow(1Q) can be discharged to stream.

• Proceedings of the Korean Environmental Health Society Conference
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• 2002.04a
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• pp.26.2-39
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• 2002

Tan-Sui River Basin covers Taipei metropolitan area of 2,726 square kilometers with more than six million residents. Since 1988, Taiwan government started to plan and construct an integrated sewerage system, consisted by both separated and concentrated trunk sewers, wastewater treatment plants and ocean outfalls. This presentation will introduce the master plan and major facilities of Tan-Sui River Basin sewerage system. Other measures to protect general water quality and the environment of adjacent river basin area of Tan-Sui River and her tributaries by Taiwan EPA will be presented as well.

• Journal of Environmental Science International
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• v.11 no.4
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• pp.367-373
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• 2002

The polycyclic aromatic hydrocarbons(PAHs) content in sewage sludge was determined by gas chromatography linked to ion trap mass spectrometry(GC/ITMS) with five deuterated PAHs as internal standards. The minimum detection limit was from 1.66 to 7.14 pg for individual PAH by GC/ITMS. For determining total PAHs(∑PAH) in sewage sludge 84 samples from 74 waste water treatment plants in whole country were analyzed. The average content of ∑PAH far whole samples was 3,289$\pm$3,098 $\mu\textrm{g}$/kg, and ranged from 142 to maximum 20,102 $\mu\textrm{g}$/kg. According to the number of population of the city, the areas were classified as five regions, ie. big, large, middle, small, and rural area in which the waste water treated plants were grown. The contents of PAHs were 4,689$\pm$5,503, 5,839$\pm$6,401, 3,725$\pm$2,053, 2,237$\pm$2,069, and 2,475$\pm$1,489 $\mu\textrm{g}$/kg, in big, large, middle, small, and rural area, respectively.