• Korean Journal of Ecology and Environment
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• v.55 no.2
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• pp.156-166
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• 2022

Understanding the characteristics of reservoir water quality is fundamental in reservoir ecosystem management. The water quality of reservoirs is affected by various factors including hydro-morphology of reservoirs, land use/cover, and human activities in their catchments. In this study, we classified 83 major reservoirs in South Korea based on nine physicochemical factors (pH, dissolved oxygen, chemical oxygen demand, total suspended solid, total nitrogen, total phosphorus, total organic carbon, electric conductivity, and chlorophyll-a) measured for five years (2015~2019). Study reservoirs were classified into five main clusters through hierarchical cluster analysis. Each cluster reflected differences in the water quality of reservoirs as well as hydromorphological variables such as elevation, catchment area, full water level, and full storage. In particular, water quality condition was low at a low elevation with large reservoirs representing cluster I. In the comparison of eutrophication status in major reservoirs in South Korea using the Korean trophic state index, in some reservoirs including cluster IV composed of lagoons, the eutrophication was improved compared to 2004~2008. However, eutrophication status has been more impaired in most agricultural reservoirs in clusters I, III, and V than past. Therefore, more attention is needed to improve the water quality of these reservoirs.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.468-468
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• 2023

최근 급격한 기후변화에 의한 이상가뭄 발생 등을 대비하기 위한 비상용수 또는 대체 수자원으로서의 지하수 개발수요가 증가함에 따라 기저유량 확보 및 수질개선 방안을 수립하는 것은 지속가능한 수자원 이용 관리 측면에 있어서 매우 중요하다. 국내 지하수 사용에 따른 하천유량의 변동에 관한 연구는 활발히 진행되었으나, 실질적으로 적용가능한 지하수 저감 방안 및 지하 수질개선방안에 대한 연구는 미비한 실정이다. 이에 본 연구에서는 바이오차를 이용하여 시험포를 설계 및 시공하였으며, 실내 인공강우 실험을 통해 지하 침투수 확보 능력 및 수질개선 효과를 평가하였다. 대조구는 폭 1 m × 길이 1 m × 깊이 0.60 m로 시공하였으며, 바이오차 시험포는 폭 1 m × 길이 1 m, 시험포 상단과 하단 각 0.10 m씩 대조구와 동일한 흙으로 채웠으며, 그 사이 0.40 m만큼은 바이오차를 채워서 시공하였다. 시험의 정밀도를 높이기 위해 동일한 조건으로 대조구와 바이오차 시험포 각 2개씩, 총 4개의 시험포를 시공하여 실내 인공강우 실험을 진행하였으며, 시험포에서 발생한 직접유출수와 기저유출수를 이용하여 바이오차의 지하 침투량 확보 및 수질개선효과를 분석하였다. 시험포 완공 후 총 2번의 실내인공강우 실험 결과 대조구에서 발생한 직접유출량은 총 0.214 m³, 바이오차 시험포에서는 총 0.194 m³로 대조구 대비 총 직접유출량 저감효과는 9.4%로 나타났다. 기저유출의 경우 바이오차 시험포(0.036 m³)에서 대조구(0.003 m³) 대비 약13배 많은 양의 기저유출수가 발생한 것으로 나타났다. 각 시험포에서 발생한 유출수의 오염부하를 산정해 대조구 시험포 대비 바이오차 시험포에서 발생한 직접유출수의 오염부하 저감효과를 분석한 결과 BOD₅ 항목과 COD_Mn 항목, 그리고 TOC 항목의 경우 26.3%과 22.0%, 그리고 27.6%로 저감 된 것으로 나타났으나, SS 항목과 T-N 항목, 그리고 T-P 항목의 경우 저감효과가 없는 것으로 나타났다. 이와 같이 바이오차는 지하 침투수 확보 능력은 효과적인 것으로 나타났으나, 직접유출수의 수질개선 효과는 미비한 것으로 나타났다. 그러나 바이오차의 지하 침투량 및 수질개선 효과는 바이오차 생산 시 사용된 열분해 방식, 사용된 바이오차의 양 등에 따라 편차가 클것으로 판단되며, 바이오차의 생산 방법, 토양 흡착 기간, 바이오차의 양 등 다양한 조건에서의 모니터링을 통해 정량화 되어야 할 것으로 판단된다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1B
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• pp.51-60
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• 2006

Water quality improvement in mattress/filter system using porous material like slag from industrial activity and zeolite that has been studied for environment improvement and pollution abatement is very useful in polluted stagnant stream channel. Slag is consisted of CaO, $SiO_2$, $Al_2O_3$ and $Fe_2O_3$. Slag with large specific surface area of porosity has been used such as sludge settling and adsorptive materials. Because slag is porous, it can be used for purification filter. As slag is used as filled materials of mattress/filter system and the system has good advantages for the waste water treatment, water recycling, and the improvement of water quality at the same time and so on. Because zeolite has much advantage of cation exchange, adsorption, catalyst and dehydration characteristics, It is used for environment improvement of livestock farms, treatment of artificial sewage and waste water, improvement of drinking water quality, radioactive waste disposal and radioactive material pollution control. In this study, according to verifying effects of water quality improvement of fill materials by porosity that 38.6%, 45.8% and 49.8% respectively in the stagnant stream channel, water quality monitoring of inflow and outflow was conducted on pH, DO, BOD, COD, SS, T-N and T-P. Mattress/filter system was able to accelerate water quality improvement by biofilter as waste water flows through gap of mattress/filter fill materials and by contact catalysis, absorption, catabolism by biofilm. Mattress/filter system used slag and zeolite forms biofilm easily and accelerates adsorption of organic matter. As a result, mattress/filter system increases water self-purification and accelerates water quality improvement available for stream water clean-up.

• Clean Technology
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• v.28 no.1
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• pp.79-93
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• 2022

In this study, an electronics industrial wastewater activated sludge model (e-ASM) to be used as a Water Digital Twin was calibrated based on real high-tech electronics industrial wastewater treatment measurements from lab-scale and pilot-scale reactors, and examined for its treatment performance, effluent quality prediction, and optimal process selection. For specialized modeling of a high-tech electronics industrial wastewater treatment system, the kinetic parameters of the e-ASM were identified by a sensitivity analysis and calibrated by the multiple response surface method (MRS). The calibrated e-ASM showed a high compatibility of more than 90% with the experimental data from the lab-scale and pilot-scale processes. Four electronics industrial wastewater treatment processes-MLE, A2/O, 4-stage MLE-MBR, and Bardenpo-MBR-were implemented with the proposed Water Digital Twin to compare their removal efficiencies according to various electronics industrial wastewater characteristics. Bardenpo-MBR stably removed more than 90% of the chemical oxygen demand (COD) and showed the highest nitrogen removal efficiency. Furthermore, a high concentration of 1,800 mg L^-1 T MAH influent could be 98% removed when the HRT of the Bardenpho-MBR process was more than 3 days. Hence, it is expected that the e-ASM in this study can be used as a Water Digital Twin platform with high compatibility in a variety of situations, including plant optimization, Water AI, and the selection of best available technology (BAT) for a sustainable high-tech electronics industry.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.2
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• pp.137-144
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• 1996

A feasible way to utilize small-scale livestock farm wastewater was explored. In place of common support materials rice straw was employed as a support medium of trickling filter for pig farm wastewater treatment. The straw medium which was humified for 20 days after wastewater treatment and mixed with soil significantly enhanced in general the development of bunching lettuce grown under greenhouse conditions. Improvement of soil chemical properties in terms of fertility was also achieved by the addition of humified straw medium after wastewater treatment. It was found that rice straw served as a satisfactory support medium of trickling filters with the wastewater treatment concerning removals of biological oxygen demand, chemical oxygen demand, and suspended solids.

• Korean Journal of Soil Science and Fertilizer
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• v.28 no.4
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• pp.319-326
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• 1995

This study was conducted to find out the effect of natural zeolite addition on the purification of livestock farming wastewater and the application of zeolite used for purification of livestock farming wastewater on growth of sudangrass. In a semi-continuous process it was found that COD, $NH_4-N$, $NO_3-N$ and T-N contents in the effluent solution decreased with the treatment of natural zeolite. The zeolite addition was effective on the purification of livestock farming wastewater. By the results of application for sudangrass cultivation, the accumulative N-uptake contents by sudangrass were lower than that of control(35kg/10a) at early growth stage, but were higher at the late growth stage.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.4
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• pp.371-377
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• 1996

Utilization of crop residues was investigated in search of ecologically desirable treatment of wastewater from small-scale swine farm. Instead of common materials rice stray was used as a support medium of tricking filter with the farm, wastewater treatment. The treated rice stave medium was dried, crushed, and directly added to soil, where bunching lettuce seedlings were grown under greenhouse conditions. The development of bunching lettuce was significantly enhanced by the application of the straw medium up to 2100 kg/10a. Little changes in soil chemical properties were observed at harvesttime, except the pH which was raised by more than 1 unit, and the content of Mg which was depleted presumably by the uptake of the plant.

• Journal of Food Hygiene and Safety
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• v.32 no.5
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• pp.396-403
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• 2017

The purpose of this study was to investigate water quality for irrigation water used in Napa cabbage cultivation. The water samples were analyzed for physiochemical and microbiological quality for a total of 111 samples including surface water (n = 75) and groundwater (n = 36) collected from five different regions where Napa cabbage is massively grown. As a conclusion, the levels of fecal indicators for surface water were higher than those for groundwater. The numbers of coliform from surface water and groundwater were 1.96-4.96 and 0-3.98 log MPN/100 mL, respectively. Enterococci were detected in 95% (72/75) of surface water samples and 22% (8/36) of groundwater samples. Besides, 97% (73/75) of surface water samples were observed being contaminated with Escherichia coli, and 22% (8/36) of groundwater sample was positive for E. coli. In the case of surface water, E. coli and coliform correlate to T-P, and enterococci showed relevance to the suspended solid (SS) and biochemical oxygen demand (BOD). In groundwater, fecal indicator bacteria showed relevance to the SS and chemical oxygen demand (COD). These results could be provided as fundamental date for establishing microbial standard of water used in leafy vegetables cultivation.

• Journal of Aquaculture
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• v.13 no.1
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• pp.87-99
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• 2000

Field survey on the variational characteristics of water quality and chlorophyll a concentraion were carried out at the 25 stations for four seasons in Kogum-sudo(Straits) southern coast of Korean Peninsula from Feburuary to October in 1993. We made an analysis on biological factor as chlorophyll a concentraion as well as physicio-chemical factors such as water temperature salinity sigma-t transparency dissolved oxygen(DO) chemical oxygen demand(COD) nutrients (ammonia, nitrite, nitrate, phosphate, and silicate) N/P ratio and suspended solid(SS). The waters in the Kogum-sudo were not stratified due to the tidal mixing. And the high productivity in photic layer were supported by high nutrients concentration from bottom waters. The high concen-trations of suspended solid in straits had a bad influence upon marine biology of nature and cultivations. In Kogum-sudo had a sufficient nutrients for primary productivity during a year. Especially phosphate and inorganic nitrogen were high the other side silicate was very low. The source of nutrients supply depend on rather mineralization of organic matters and input of seawater from outside than input of freshwaters from lands. Phytoplankton biomass as measured by chlorphyll a concentratiion was very high all the year round and it was controlled by the combination o f several environmental factors especially of phosphate in summer and dissolved nitrogen in other seasons.

• Journal of the Korean Society of Marine Environment & Safety
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• v.13 no.1 s.28
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• pp.21-28
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• 2007

The purpose of this study was to observe the effect on the water quality and sediment environment by the use of Nano-S for anti-Red tide material. The experiment was performed at subtidal and intertidal zone during six months(from Aug 2005 to Feb. 2006). The experiment sites were divided with concentration of materials. One is lower concentration(0.1%) and the other is higher concentration(1%). The results of experiments didn't show the remarkable influence of the materials effect before and after applying the Nano-S and the red mud. pH, salinity and DO were slowly increased during experiment period but nutrients were conversely decreased in the seawater. In the subtidal zone, qualities of sediments, IL, AVS and COD, were gradually lowered and the similar results were appeared in the intertidal zone. These results showed similar trends over all the experiment sites including control site. The results of heavy metals also did not show the interest different effect before and after applying the Nano-S and red mud compared with control site.