• Journal of Korean Society of Disaster and Security
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• v.12 no.1
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• pp.23-34
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• 2019

It is an urgent issue to manage and reduce non-point pollution sources for improving the water quality of stream and lakes in rural areas. In this study, in order to reduce non-point pollution sources in rural area, Gabion mattresses was proposed to provide protection of riverbanks with anaerobic and aerobic area. The utilization of this was assessed by lab scale model test and pilot plant test. After filling the inside of the gabion mattresses with aggregate, the filtration zone under anaerobic and aerobic conditions was formed to treat the contaminants. In addition, vegetation was deposited on the surfae of the gabion to prevent the inflow of soil and to promote purification by the plant. COD and nitrogen content (T-N, $NH_4{^+}$, -N, $NO_3{^-}N$) were monitored in model and field tests. The lab scale model test showed removal efficiency of 17% of TCOD, 35% of SCOD, 14% of TN, 62% of $NH_4{^+}$, -N, and 33% of $NO_3{^-}$ N. Also, pilot plant test showed removal efficiency of 24% of TCOD, 29% of SCOD, 47% of TN, 50% of $NH_4{^+}-N$, 33% of $NO_3{^-}$, N and 29% of TP.

• Journal of Wetlands Research
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• v.24 no.2
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• pp.142-154
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• 2022

Arsenic (As) contamination in groundwater is one of the main problems in Bangladesh. As toxicity causes serious human health problems such as edema, skin cancer, bladder cancer, lung cancer, hyperkeratosis, premature birth, and black foot disease. As contamination in groundwater mainly originates from the geological characteristics of the area due to the influence of anthropogenic activities. Since most of the people in Bangladesh rely on tube well for drinking water, it is necessary to investigate the current status of As pollution and identify the treatment technologies that can be used to provide arsenic-free drinking water in water-scarce areas. A total of 92 papers were reviewed in this study to present a complete overview of the recent status of groundwater As contamination in Bangladesh and different low-cost remediation technologies. A method for evaluating the relative feasibility of different treatment technologies was also utilized to determine the most appropriate technologies for groundwater As treatment in Bangladesh. The districts with the highest groundwater As contamination include Brahamanbariya, Tangail, Barisal, Pabna, Patuakhali, Kurigram, Magura, and Faridpur, with concentrations exceeding 0.05 mg/L. Only six districts had relatively low groundwater arsenic concentrations (0.01 mg/L), including Kushtia, Khagrachari, Jessore, Dinajpur, Meherpur, and Munshiganj. There were a number of technologies used for treating As in water, but aerated electrocoagulation, Mg-Fe-based hydrotalcite-like compound, and electro-chemical As remediation (ECAR) reactor were found to be the most feasible treatment methods for As. Overall, the investment, operational, and maintenance costs, availability of materials, and expertise requirements should be considered when selecting the most appropriate treatment method for As in water.

• Journal of Environmental Impact Assessment
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• v.32 no.6
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• pp.431-436
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• 2023

As the industry develops, the amount of heavy metals flowing into the ecosystem is increasing. Heavy metals are difficult to decompose and remain in the ecosystem for a long time and cause toxicity, which is removed by physicochemical methods such as adsorption, filtration, and chemical precipitation during water treatment. In this study, Alginate bead was selected as a chelating resin for adsorbing and removing heavy metals, and the Jellyfish Extract at Immunity reaction (JEI) were mixed to evaluate the adsorption efficiency of heavy metals accordingly. beads mixed with JEI showed high adsorption efficiency in lead (79-99%) and copper (64-70%) according to the characteristics of Alginate, and low adsorption efficiency in cadmium (25-37%) and zinc (5-6%). Although heavy metal adsorption did not increase in proportion to the content of JEI, 50% and 100% JEI beads showed significant increases. As a result of applying the reaction rate equation, it was found that it was more suitable for the pseudo-secondary reaction equation than the pseudo-first reaction equation.

• Journal of Environmental Impact Assessment
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• v.32 no.5
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• pp.291-304
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• 2023

Harmful algal blooms (HABs) have become an increasing concern in terms of human health risks as well as aesthetic impairment due to their toxicity. The reduction of water pollutants, especially nutrients from non-point sources in a reservoir watershed, is fundamental for HABs prevention. We investigated the pollutant removal efficiencies of a constructed wetland to evaluate its feasibility as a method for controlling non-point sources located in the Annaecheon stream within the Daecheong Reservoir watershed. The overall removal efficiencies of pollutants were as follows: BOD 14.3%, COD 17.9%, SS 50.0%, T-N 19.0%, and T-P 35.4%. These results indicate that constructed wetlands are effective in controlling pollutants from non-point sources. The seasonal variation in removal efficiency depended on the specific pollutants. The removal efficiencies of BOD, COD, and T-N were stable throughout the year, except during winter, which might have been influenced by lower microorganism activity. In contrast, T-P showed a consistent removal efficiency even during the winter season, suggesting that the wetland can reduce external phosphorus loading to the reservoir. Regarding the effects of pollutant loadings on removal efficiency, the effluent concentrations of all pollutants were significantly decreased compared to those in the influent in case of middle and high loadings. This demonstrates that constructed wetlands can handle high pollutant loads, including the initial runoff during rainfall, to prevent reservoir eutrophication. Despite the various strengths of wetland water purification, there are limitations as passive treatment. Therefore, more case studies should be conducted to suggest optimum operational conditions for constructed wetlands, taking into consideration reservoir-specific characteristics.

• Korean Journal of Environmental Biology
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• v.41 no.4
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• pp.683-696
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• 2023

The conservation of wetland ecosystems has a significant role in climate change. Notably, the Han River Protected Area, including the Siam-ri wetland and Janghang wetland, provides high biodiversity value. Thus, it is necessary to comprehensively evaluate the function and value of wetland ecosystems. This study evaluated the ecosystem services of Siam-ri and Janghang Wetlands located in the Han River Protected Area using the Rapid Assessment Wetland Ecosystem Services approach, a function-oriented ecosystem analysis. The results were calculated using the Ecosystem Services Index formula to analyze wetland ecosystem services. We also assessed the key ecosystem services based on a focus group interview. We identified that the supporting and cultural services index scores were relatively high in the study area. The results can provide helpful information for sustainable wetland conservation, conservation planning as primary data, and raising awareness for the Han River Protected Area.

• Journal of Animal Science and Technology
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• v.49 no.1
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• pp.137-146
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• 2007

This study was conducted to determine fertilizer nutrient and pollutant production of Holstein dairy cattle by estimating manure characteristics. The moisture content of feces was 83.9% and 95.1% for urine. The pH of feces and urine were in the ranges of 7.0～7.4 and 7.5～7.8, respectively. The average BOD5, COD, SS, T-N, T-P concentrations of the dairy feces were 18,294, 52,765, 102,889, 2,575, and 457mg/ℓ, respectively. Dairy urine showed lower levels of BOD5(5,455mg/ℓ), COD(8,089mg/ℓ), SS(593mg/ℓ), T-N(3,401mg/l), and T-P(13mg/ℓ) than feces. The total daily produced pollutant amounts of a dairy cow were 924.1g(Milking cow), 538.8g(Dry cow), 284.4g(Heifer) of BOD5, 2,336.5g (Milking cow), 1,651.8g(Dry cow), 734.1g(Heifer) of COD and 4,210.1g(Milking cow), 2,417.1g(Dry cow), 1,629.1g(Heifer) of SS and 194.8g(Milking cow), 96.4g(Dry cow), 58.3g(Heifer) of T-N and 24.0g(Milking cow), 10.2g(Dry cow), 6.1g(Heifer) of T-P. The calculated amount of pollutants produced by a 450kg dairy cow for one year were 181.3kg of BOD5, 492.5kg of COD, 899.9kg of SS, 36.0kg of T-N and 4.1kg of T-P. The total yearly estimated pollutant production from all head(497,261) of dairy cattle in Korea is 90,149 tons of BOD5, 244,890 tons of COD, 447,491 tons of SS, 17,898 tons of T-N and 2,008 tons of T-P. The fertilizer nutrient concentrations of dairy feces was 0.26% N, 0.1% P2O5 and 0.14% K2O. Urine was found to contain 0.34% N, 0.003% of P2O5 and 0.31% K2O. The total daily fertilizer nutrients produced by dairy cattle were 197.4g (Milking cow), 97.4g(Dry cow), and 57.9g(Heifer) of Nitrogen, 54.2g(Milking cow), 22.2g(Dry cow), and 14.2g(Heifer) of P2O5 and 110.8g(Milking cow), 80.4g (Dry cow), and 39.5g(Heifer) of K2O. The total yearly estimated fertilizer nutrient produced by a 450kg dairy animal is 36.2kg of N, 8.8kg of P2O5, 24.6kg of K2O. The estimated yearly fertilizer nutrient production from all dairy cattle in Korea is 18,000 tons of N, 4,397 tons of P2O5, 12,206 tons of K2O. Dairy manure contains useful trace minerals for crops, such as CaO and MgO, which are contained in similar levels to commercial compost being sold in the domestic market. Concentrations of harmful trace minerals, such as As, Cd, Hg, Pb, Cr, Cu, Ni, Zn, met the Korea compost standard regulations, with some of these minerals being in undetected amounts.

• Korean Journal of Ecology and Environment
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• v.47 no.4
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• pp.247-257
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• 2014

The construction of eight large weirs in the Nakdong River, Korea, caused a decrease in the water flow velocity and several physical changes to the water environment. Here, changes in phyto- and zooplankton communities and water quality in the areas near the eight weirs were investigated from 2011 to 2013, and relationships between phytoplankton abundances and environmental factors were analyzed. Special emphasis was given to the succession patterns in algal abundance based on temperature fluctuations. At the eight weirs, 24 dominant species were found. The most abundant phytoplankton species was Stephanodiscus sp. (39.4% of dominant frequency). Cyanobacteria of the genus Microcystis dominated during the summer, with an dominant frequency of 8.5% and cell abundance ratio of 36.6%. Significant correlations were observed between temperature and abundance of eight of the main dominant species; seven species showed positive correlations with temperature. Stephanodiscus sp., however, showed a negative correlation with temperature (r=-0.26, p<0.01). In addition, this species showed a significant negative correlation with the dominant algal species-Aulacoseira granulata and Aphanizomenon flos-aquae, with the zooplankton Copepoda and with Cladocera. On the contrary, seven other dominant species of algae showed significant positive correlations with zooplankton. Thus, we showed that the seasonal succession of plankton communities in the Nakdong River was related to the water temperature changes.

• Journal of Korean Society of Forest Science
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• v.89 no.1
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• pp.55-64
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• 2000

This study was carried out to analyze the characteristics of pH and electrical conductivity(EC) at each stand and soil depth by the artificial acid rain sprinkling in the upper watershed of Mt. Palgong and furthermore to clarify the relationships between forest soil and water purification function. The results obtained in the experimental sites of Quercus acutissima and Larix leptolepis were summarized as follows ; 1. The average soil pH at each soil layer(0~5cm, 0~10cm, 0~20cm in depth) were 4.8, 4.3 and 4.5 for the Quercus acutissima soil and 5.15, 5.19 and 5.21 for the Larix leptolepis soil. The soil pH of Larix leptolepis stand was higher than that of Quercus acutissima stand. In addition, the deeper soil depth was, the higher soil pH was. 2. The soil solution pH of Larix leptolepis stand was higher than that of Quercus acutissima stand. It was due to the high soil pH of Larix leptolepis stand itself and the difference of humus layer thickness. 3. It took time to show the pH buffer capacity of forest soil after application of artificial acid rain in the forest soil. The pH value of soil solution in each experimental site was maximum at this time and then did not increase pH value any more. 4. Soil solution EC increased slowly with pH 3.0 treatment, but it decreased slowly with pH 5.0 treatment over time. It was assumed that the amount of the leached cation and the ions leading buffer action changed at the stands with ranges of acidity treatment. 5. From the trend of soil solution EC at each soil depth, it seemed that the water buffer capacity of the forest soil increased as the soil depth increased.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.31 no.1
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• pp.8-15
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• 2021

TiO2 has been used in various fields such as solar cells, dental implants, and photocatalysis, because it has high physical and chemical stability and is harmless to the body. TiO2 nanofibers which have a large specific surface area also show a good reactivity in bio-friendly products and excellent photocatalysis in air and water purification. To fabricate TiO2 nanofibers, an electrospinning method was used. To observe the diameter of TiO2 nanofibers with fabrication variables, the fabrication variables was divided into precursor composition variables and process variables and microstructure was analyzed. The concentrations of PVP (Polyvinylpyrrolidone) and TTIP (Titanium(IV) isopropoxide) were selected as precursor composition variables, and inflow velocity and voltage were also selected as process variables. Microstructure and crystal structure of TiO2 nanofibers were analyzed using FE-SEM (Field emission scanning electron microscope) and XRD (X-ray diffraction), respectively. As-spun TiO2 nanofibers with an average diameter of about 0.27 ㎛ to 1.31 ㎛ were transformed to anatase TiO2 nanofibers with an average diameter of about 0.22 ㎛ to 0.78 ㎛ after heat treatment of 3 hours at 450℃. Anatase TiO2 nanofibers with an average diameter of 0.22 ㎛ can be expected to improve the photocatalytic properties by increasing the specific surface area. To change the average diameter of TiO2 nanofibers, the control of precursor composition variables such as concentrations of PVP and TTIP is more efficient than the control of electrospinning process variables such as inflow velocity and voltage.

• Journal of the Mineralogical Society of Korea
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• v.16 no.4
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• pp.283-293
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• 2003

Domestic water treatment plants operate the rapid and slow filtering system using the filtering sands. Most of them are composed of beach sands, which have less sorption capacity of heavy metals as well as organic contaminants. Therefore, the development of fortified functional filtering materials with high removal capacity of organic and inorganic contaminants is needed to prevent the unexpected load of contaminated source water. This study aims to test the hydrochemical change and the removing capacity of heavy metals such as Cd, Cu, and Pb on the Jumunjin sand, feldspathic sand(weathering product of Jecheon granite), feldspathic mixing sand I(feldspathic sand mixed with 10 wt% zeolite), and feldspathic mixing sand II (feldspathic sand mixed with 20 wt% zeolite). Feldspathic mixing sand I and II showed the eruption of higher amounts of cations and anions compared with the Jumunjin sand and feldspathic sand. They also showed higher eruption of Si, Ca, $SO_4$ ions than that of Al, $NO_3$, Fe, K, Mg, and P. Feldspathic mixing sand II caused higher eruption of some cations of Na, Ca, Al than feldspathic mixing sud I, which is the result controlled by the dissolution of zeolite. Jumunjin sand and feldspathic sand showed very weak sorption of Cd, Cu and Pb. In contrast to this, feldspathic mixing sand I and II showed the high sorption and removal capacity of the increasing order of Cd, Cu and Pb. Feldspathic mixing sand II including 20% zeolite showed a fortified removal capacity of some heavy metals. Therefore, feldspathic mixing sand mixed with some contents of zeolite could be used as the fortified filtering materials for the water filtering and purification in the domestic water treatment plants.