• Membrane and Water Treatment
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• v.14 no.1
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• pp.27-33
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• 2023

In previous studies, solely ferric (Fe³⁺) and calcium (Ca²⁺) ions were commonly used for removal of PO₄-P (considered as T-P in this study) in wastewater via chemical precipitation. Herein, the removal of total phosphorus (T-P) in wastewater was performed using various mineral and lime dissolved solutions. The dissolution kinetics of different minerals (feldspar, olivine, elvan, illite, sericite, and zeolite) and lime was compared and used their solutions for T-P removal of real wastewater. The highest T-P removal (almost 90%) was obtained by the lime dissolved solution and followed by zeolite, illite, feldspar, and others. We observed a significant co-relationship (R of 0.96) between the amount of initial Ca²⁺ and T-P removal. This was induced by formation of hydroxyapatite-like mineral via Ca-P precipitation reaction at high pH solution. Furthermore, additional removal of suspended solid (SS) and chemical oxygen demand (COD) was achieved by only lime dissolved solution. Finally, the lime-feldspar dissolved solutions were prepared at different ratios (10-50%), which showed a successive T-P removal up to two times by samples of 40 and 50%.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.10
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• pp.684-693
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• 2012

The stormwater runoff from the increasing paved roads and vehicles resulted in the increase in the pollutants load to adjacent water bodies. The granular media filtration facilities are the most widely adopted to minimize the non-point source pollution from motorways. It is essential to consider the severe variation of hydraulic condition, suspended solid (SS) characteristics, and the medium characteristics for stormwater management filter. In this study, different types of media, including sand, were tested and the performance of downflow sand filters was investigated under various linear velocity and influent solid particle size. Results showed that the best medium is the coarse sand with large grain size, which showed the specific SS removal before clogging of more than $8.498kg/m^2$, the SS removal of higher than 95%, and minimum head loss. Linear velocity did not affect the total solid removal, while the performance was improved when fine solid was introduced. It is suggested that the life of a downflow sand filter bed can be extended by deep bed filtration when influent particles are fine. However, the captured particles can be washed out after a long period of operation.

• International Journal of Highway Engineering
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• v.16 no.6
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• pp.9-17
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• 2014

PURPOSES : The purpose of this study is to assess removal efficiency of non-point pollutants and applicability for non-point pollutant reduction facilities by conducting the demonstration project operation. METHODS : In order to analyze removal efficiency of non-point pollutants for facilities such as a grassed swale, a small constructed wetland, a free water surface wetland, a horizontal sub-surface flow wetland, and a sand filtration, the field data including specifications of facilities, rainfall, inflow and runoff rainfall effluent etc. was acquired after occurring rainfall events, and the acquired data was analyzed for removal efficiency rate to assess road non-point pollutants facilities using event mean concentration (EMC) and summation of load (SOL) methods. RESULTS : The results of analyzing rainfall effluent, non-point pollutant sources showed that total suspended solid (TSS), chemical oxygen demand (COD), biochemical oxygen demand (BOD), total nitrogen (TN), total phosphorus (TP), chrome (Cr), zinc (Zn), and lead (Pb) can be removed through non-point pollutant reduction facilities by 60.3% ~ 100%. Especially removal efficiency of TSS, COD and BOD is relatively higher than removal efficiency of other non-point pollutant sources in all kind of non-point pollutant facilities. CONCLUSIONS : Based on the result of this study, even though natural type of non-point pollutant reduction facilities for roads occupy small areas comparing with drainage basin areas, most of non-point pollutant sources would be removed through the facilities.

• Korean Journal of Environmental Agriculture
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• v.31 no.4
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• pp.328-343
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• 2012

BACKGROUND: For effective subwatershed management, it is very important to select the tributaries for improving water quality and understand the characteristics of tributaries. Until now, however, the case study of main streams has been managed. 17 tributaries in Geum river subwatershed were monitored to regulate the source of water contaminations and identify their current situations in this study. METHODS AND RESULTS: As pollution indicators, such as biological oxygen demand($BOD_5$), chemical oxygen demand($COD_{Mn}$), suspended solid(SS), total nitrogen (T-N), total phosphate(T-P) and total organic carbon(TOC) in Geum river were examined from January to December in 2011. The results were as follows : The annual average concentration of nutrients in Yongdam reservoir upsteam was 0.7 mg/L for BOD, 3.0 mg/L for COD, 8.4 mg/L for SS, 2.905 mg/L for T-N, 0.035 mg/L for T-P and 1.6 mg/L for TOC. Water quality of Daechung reservoir upstream was mostly similar tendency in comparison to Yongdam reservoir upstream. Among the 22 tributaries, water quality in Daechung reservoir downstream was more polluted. T-N contents were significantly high in Miho B4 located Daechung reservoir downstream(annual average concentration: 13.53 mg/L). In cases of Miho A1, A2 and C1, pollution degree was worsened during rainy season expecially. CONCLUSION(S): For improving water quality of Geum river subwatershed, the tributaries in the Mihocheon area should be preferentially considered. Mihocheon tributary is the highest in pollution site, and thus a study on long-term effects should be research.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.10 no.6
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• pp.88-98
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• 2007

The control of nonpoint source pollution from the urban paved areas with high imperviousness in is required to improve the water quality of aquatic resources. This research investigated the characteristics of urban runoffs and evaluate the effectiveness of the continuous deflective separation systems for stormwater best management practice. The systems were installed in the vicinity of a high-level road, an apartment complex, and the Cheonggye stream. Stormwater runoff was sampled in these sites. Biochemical oxygen demand ($BOD_5$), total suspended solid (TSS), total nitrogen (T-N), and total phosphorus (T-P) were analyzed. The removal efficiency of $BOD_5$, TSS, and T-P for the road was 10.9-81.0%, 11.7-93.4%, 0-37.5%, respectively. That of $BOD_5$, TSS, T-N, and T-P for the complex was 12.5-65.8%, 26.5-77.6%, 1.8-28.7%, and 20.0-37.5%, respectively. The abatement efficiency $BOD_5$, TSS, T-N, and T-P for the stream was 7.2-85.2%, 41.7-98.2%, 11.3-65.6%, and 2.0-71.5%, respectively. This study shows that the systems can be used to remove $BOD_5$ and TSS from urban runoffs efficiently.

• Journal of Environmental Impact Assessment
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• v.29 no.3
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• pp.157-181
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• 2020

Sediments from rivers, lakes and marine ports serve as end points for pollutants discharged into the water, and at the same time serve as sources of pollutants that are continuously released into the water. Until now, the contaminated sediments have been landfilled or dumped at sea. Landfilling, however, was expensive and dumping at sea was completely banned due to the London Convention. Therefore, this study applied contaminated sedimentation soil of 'Royal Palace Livestock Complex' as soil purification method. Soil remediation methods were applied to pretreatment, composting, soil washing, electrokinetics, and thermal desorption by selecting overseas application cases and domestically applicable application technologies. As a result of surveying the site for pollutant characteristics, Disolved Oxigen (DO), Suspended Solid (SS), Chemical Oxygen Demand (COD), Total Nitrogen (TN), and Total Phosphorus (TP) exceeded the discharged water quality standard, and especially SS, COD, TN, and TP exceeded the standard several tens to several hundred times. Soil showed high concentrations of copper and zinc, which promote the growth of pig feed, and cadmium exceeded 1 standard of Soil Environment Conservation Act. In the pretreatment technology, hydrocyclone was used for particle size separation, and the fine soil was separated by more than 80%. Composting was performed on organic and Total Petroleum Hydrocarbon (TPH) contaminated soils. TPH was treated within the standard of concern, and E. coli was analyzed to be high in organic matter, and the fertilizer specification was satisfied by applying the optimum composting conditions at 70℃, but the organic matter content was lower than the fertilizer specification. As a result of continuous washing test, Cd has 5 levels of residual material in fine soil. Cu and Zn were mostly composed of ion exchange properties (stage 1), carbonates (stage 2), and iron / manganese oxides (stage 3), which facilitate easy separation of contamination. As a result of applying acid dissolution and multi-stage washing step by step, hydrochloric acid, 1.0M, 1: 3, 200rpm, 60min was analyzed as the optimal washing factor. Most of the contaminated sediments were found to satisfy the Soil Environmental Conservation Act's standards. Therefore, as a result of the applicability test of this study, soil with high heavy metal contamination was used as aggregate by applying soil cleaning after pre-treatment. It was possible to verify that it was efficient to use organic and oil-contaminated soil as compost Maturity after exterminating contaminants and E. coli by applying composting.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.139-147
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• 2021

Livestock manure is used as an organic fertilizer to replace chemical fertilizers after sufficient fermentation in an aerobic bioreactor. On the other hand, liquid manure disposal problems occur repeatedly because soil spraying is restricted during the summer when the crops are growing. To use liquid fertilizer (LF) as an additional nutrient source for crops, it is necessary to reduce the amount of suspended solids (SS) in the liquid fertilizer and secure stability problems against pathogenic microorganisms. This study examined the effects of the simultaneous SS removal and E.coli sterilization in the LF using the microbubble (MB) generator (FeMgO catalyst insertion). The remaining SS were further removed using the integrated microbubble and microfilter system. During the floating process in the MB device, the SS were removed by 57.9%, and the coliform group was not detected (16,200→0 MPN/100 mL). By optimizing the HRT of the integrated system, the removal efficiency of the SS was improved by 92.9% under the 0.1h of HRT condition. After checking the properties of the treated LF, 64.5%, 70.1%, 54.9%, and 51.5% of the TCOD, SCOD, PO4-P, and TN, respectively, were removed. The treated effluent from such an integrated system has a lower SS content than that of the existing LF and does not contain coliforms; therefore, it can be used directly as an additional fertilizer.

• Ecology and Resilient Infrastructure
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• v.3 no.1
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• pp.70-75
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• 2016

The purpose of this study was to develop water-purification vegetation mats consisting of the eco-friendly materials and to validate their water purification capabilities with the objective of reducing nonpoint pollution into streams. The developed vegetation mats are made of coconut fiber shell and filling consisted of zeolite, diatomaceous earth or a mixture of calcinated foam media. The bench scale assessment of the water purification capability of the three filling materials showed that the removal efficiencies of suspended solid (SS), total nitrogen (T-N) and total phosphorus (T-P) were higher in the foam media than in zeolite or diatomaceous earth. From the results of the field experiment, the removal efficiencies of the vegetation mats filled with the foam media were 60.1% in SS, 32.2% in T-N and 20.2% in T-P. Therefore the vegetation mats filled with the foam media calcinated from zeolite and diatomaceous earth should have higher efficiencies in controlling the nonpoint source pollutions in streams.

• Magazine of the Korean Society of Agricultural Engineers
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• v.45 no.6
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• pp.194-206
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• 2003

A pilot study was performed to examine the feasibility of the pond system for further polishing of treatment wetland effluent to agricultural reuse of reclaimed water. The constructed wetland and pond system was installed in Konkuk University and the effluent from septic tank of school building was used as an influent to the wetland system. The effluent of the wetland was used as an influent to pond systems. The influent concentrations of total coliform(TC), fecal coliform (FC), and E. coli were about $10^5$MPN/100 ml, and they were reduced to less than 10,000 MPN/100 ml on average after wetland treatments, showing over 95 % removal. And they were further reduced to less than 1,000 MPN/100 ml in average, showing over 85∼93 % removal after pond treatment. Turbidity and SS were improved effectively on average and their pond effluent concentration was about 4.5 NTU and 9.8 mg/L in average, respectively Average $BOD^5$ concentrations were also reduced substantially to 9.3 mg/L with about 83 % removal rate after wetland and pond treatment systems. Nutrients removal was relatively low and removal rate for T-N and T-P was less than 43 and 44%, respectively after wetland and pond treatment. Considering stable performance and effective removal of bacterial indicators as well as other water quality parameters, low maintenance, and cost-effectiveness, pond system was thought to be an effective and feasible alternative for agricultural reuse of reclaimed water. This paper describes a preliminary result Iron pilot study and further investigations are recommended on the optimum design parameters before full scale application.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.2
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• pp.225-233
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• 2007

Road runoff water is one of the non-point sources (NPSs) of pollution negatively influencing drinking water source. Numerous road runoff NPS waters have been studied for over the last decade. However, the sources of pollution can be conditional, seasonal, or accidental. Therefore, measurement of pollutant loadings in different site is necessary to estimate the effect of road runoff water. The objective of this study was to examine the quality of road runoff water from a city bridge in Seoul, Korea. This study was conducted for two years to assess annual discharge pollution loads. In this study, key water quality parameters including chemical oxygen demand ($COD_{Cr}$), biochemcial oxygen demand ($BOD_5$), total nitrogen (T-N), total phosphorus (T-P), and suspended solid (SS) were measured at 18 different events. The results showed that typically the pollutant concentrations are higher at the beginning of each event and decrease afterwards. The first 20% of the volume of the runoff from each event is transporting 46% ($COD_{Cr}$), 48% ($BOD_5$), 50% (T-N), 34% (T-P), 30% (SS), respectively. The event mean concentrations (EMCs) were $COD_{Cr}$ (199 mg/L), $BOD_5$ (41.2 mg/L), T-N (7.97 mg/L), T-P (0.42 mg/L) and SS (113 mg/L). Although the results were consistent with the previous study (Barbosa and Hvitved-Jacobsen, 1999), $COD_{Cr}$, $BOD_5$, T-N exhibit a stronger first flush effect compared to the other contaminants.