• 환경생물
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• 제26권1호
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• pp.47-55
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• 2008

영천, 경주 지역의 도덕산, 구미산, 인내산 주위의 주요 수계 하천의 중 상류 11$\sim$12개 지점에서 저서성 대형 무척추동물을 조사하였다. 수심, 유속, pH, 탁도(NTU), 전기전도도와 DO 등의 이화학적 환경도 측정하였다. 수심은 3.3$\sim$18.6 cm, 전기전도도는 35.5$\sim$223.1${\mu}s$, DO는 5.66$\sim$10.73 $mgL^{-1}$의 분포를 보였다. 대상 조사지점에서 총 78종이 출현하였으며, 수서곤충이 주로 채집되었다. 깔따구류가 전 출현개체수의 59$\sim$65%를 차지하여 가장 많이 조사되었으며, 다음으로는 하루살이류가 12$\sim$19%, 달팽이류가 5$\sim$14%를 차지한 것으로 조사되었다. 조사지점 중에서는 인내산이 가장 다양한 생물이 서식한 것으로 조사되었다. EPT 풍부도는 4$\sim$14로 나타났으며 인내산의 IN2, IN3지점에서 14를 보여 가장 높게 나타난 반면 가장 낮게 나타난 곳은 도덕산의 DD2, DD4지점으로 조사되었다.

• 한국물환경학회지
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• 제26권6호
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• pp.1028-1033
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• 2010

Wastewater reuse for agricultural irrigation needs treatment and control of pathogens to minimize risks to human health and the environment. In order to evaluate the water quality of UV-treated reclaimed water, this study focused on the relationship between micro-pathogens and particulate matters. MS2 was selected as an index organism because it has similar characteristics to human enteric virus and strong resistance to UV disinfection. The turbidity and suspended solid (SS) were selected for test parameters. In this study, it was performed with different UV doses (30 and $60mJ/cm^2$) for estimation of the MS2 inactivation rate using collimated beam batch experiments in the laboratory. The experiment results by turbidity or SS concentration presented that the increased concentration of them lowered MS2 inactivation. At the turbidity (below 4.27 NTU) and SS (below 1.47 mg/L) of the low level range, the inactivation of 60 UV dose is higher than 30 UV dose. However, at the turbidity and SS of the high level, the increasing UV dose did not show apparent increasing the MS2 inactivation. In quantitative microbial risk assessment (QMRA), it can confirm the trend that $P_D$ and turbidity concentrations have positive correlationship at the low concentration, which was also observed in SS. The QMRA can be helpful in communication with public for safe wastewater reuse and be recommended.

• 한국환경과학회지
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• 제7권1호
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• pp.81-88
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• 1998

This study was conducted to assess the characteristics of plgment wastewater and the removal rates of appropriate treatment by physical, chemical and biological Process, and the possibility of reuse for effluent. Based on the results, the wastewater qualities of pigment were pH 5.1$\pm$3.4, temperature 43.0$\pm$ 15.$0^{\circ}C$, BOD 1,431.4$\pm$589.6mg/l, COD 2,282.8$\pm$466.5mg/l, turbidity 1,340$\pm$820NTU, color 243.0$\pm$147.0unit, Pb 36.5$\pm$9.5mg/l and $Cr^+6$ 10.3$\pm$ 1.3mg/l, respectively. The removal rates of adsorption by activated carbon and filter process were BOD 40.6% , COD 57.0% , turbidity 89.6%, color 87.2%, Pb 86.0% and $Cr^+6$ 10.6%, respectively. And the removal rates of reduction, neutralization, coagulation and aP floatation process were BOD 18.2%, COD 24.3%, turbidity 74.3%, color 56.7%, Pb 68.6% and $Cr^+6$ 97.8%, respectively. The removal rates of activated sludge process were BOD 95.9%, COD 86.0%, turbidity 27.8%, color 25. 2%. Pb 26.9% and $Cr^+6$ 50.0% , respectively. The total removal rates of treatment by physical, chemical and biological process were BOD 98.0% , COD 95.4%, turbidity 98.1%, color 95.8%, Pb 97.0% and $Cr^+6$ 99.0%, respectively. According to the test results for possibility of reuse with coagulation-adsorption by activated carbon process of effluent, COD was higher than that of raw water and others were similar to that of raw water thus, it Is considered to be reused.

• 한국환경과학회지
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• 제25권7호
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• pp.999-1005
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• 2016

The H water treatment plant has been operating since 1982 and has had no renovation. It is assumed that the filters have been operated for more than 30 years and therefore are deteriorated. Many of the filters show an unequal state of air scouring during backwashing. For this study one filter, which was presumed most deteriorated among eighteen filters, was selected as a model filter for renovation. Some of the effects seen after renovation of the underdrain system were a lower average filtrated turbidity by approximately 0.02 NTU and an equal backwash state throughout the filter bed. Sand wash efficiencies by backwash before renovation of the underdrain system were 28%, 8%, and 5% at the surface, 50 cm depth, and 100 cm depth, respectively, and after renovation of the underdrain system were 94%, 26%, and 15%, respectively. The standard deviation of the effective sand size was 0.025-0.033 mm before renovation of the underdrain system and 0.002-0.011 mm after renovation of the underdrain system, meanings there was equal backwash pressure throughout the filter. Filtration time after renovation was approximately 2 times longer than before renovation.

• 한국농공학회지
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• 제45권5호
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• pp.160-170
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• 2003

A pilot study was performed to examine the feasibility of intermittent slow sand filtration for agricultural reuse of reclaimed water. The effluent of biofilter for 16-unit apartment was used as influent to the slow sand filtration system at 0.6 $m^3$/day loading rate using 15 seconds spray in every 10 minutes on the about 1 $m^2$ surface area and 0.5 m depth. The influent concentrations of total coliform (TC), fecal coliform (FC) and E. coli were in the range of 10.000 MPN/100 mL. and they were reduced to less than 1,000 MPN/100 mL after filtration with average of 320, 270, and 154 MPN/100 mL, respectively, showing over 95 % removal. Turbidity and SS were improved effectively and their average concentration was reduced to 0.8 NTU and 1.7 mg/L, respectively, and removal rate was about 50 %. Average BOD and COD concentrations were also reduced substantially to 2.6 and 25.8 mg/L with about 55 and 21 % removal rate, respectively. Nutrients removal was relatively low and removal rate for T-N and T-P was low however, remaining nutrients might be beneficial and less concerned in case of agricultural reuse. The concentration of biofilter effluent used in this experiment was in the range of secondary treatment effluent but slightly stronger than the one from existing wastewater treatment plants (WWTPs). Therefore, intermittent slow sand filtration might be also applicable to the effluent from WWTPs as long as its agricultural reuse is available. Considering stable performance and effective removal of bacterial indicators as well as other water quality parameters, low maintenance, and cost-effectiveness, the intermittent slow sand filtration was thought to be an effective and feasible alternative for agricultural reuse of reclaimed water. This paper is a preliminary result from pilot study and further investigations are recommended on the optimum design parameters before full scale application.

• Membrane and Water Treatment
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• 제7권4호
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• pp.313-325
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• 2016

South Africa recognises piped water as the main source of safe drinking water supply. Remote areas do not have access to this resource and they rely solely on surface water for survival, which exposes them to waterborne diseases. Interim point of use solutions are not practiced due to their laboriousness and alteration of the taste. Bio-ultra low pressure driven membrane system has been noted to be able to produce stable fluxes after one week of operation; however, there is limited literature on South African waters. This study was conducted on three rivers namely; Umgeni, Umbilo and Tugela. Three laboratory systems were setup to evaluate the performance of the technology in terms of producing stable fluxes and water that is compliant with the WHO 2008 drinking water guideline with regards to turbidity, total coliforms and E.coli. The obtained flux rate trends were similar to those noted in literature where they are referred to as stable fluxes. However, when further comparing the obtained fluxes to the normal dead-end filtration curve, it was noted that both the Umbilo and Tugela Rivers responded similarly to a normal dead-end filtration curve. The Umgeni River was noted to produce flux rates which were higher than those obtainable under normal dead-end. It can be concluded that there was no stabilisation of flux noted. However, feed water with low E.coli and turbidity concentrations enhances the flux rates. The technology was noted to produce water of less than 1 NTU and 100% removal efficiency for E.coli and total coliforms.

• 한국농공학회지
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• 제45권6호
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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.

• Environmental Engineering Research
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• 제21권3호
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• pp.311-317
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• 2016

A new type of biofilter packed with composite carriers was designed for tertiary denitrification of the secondary effluent with removal of both oxidized nitrogen and suspended solids (SS). At the empty bed residence time of 15 min and organic carbon to nitrate nitrogen ($C/NO_3-N$) ratios of 2, 1.5 and 1 g/g, the removal percentage of $NO_3-N$ was 67%, 58% and 36% in the ethanol biofilter, and was 61%, 43% and 26% in the acetate biofilter, respectively. The biofilters packed with composite carriers removed SS effectively, with the effluent turbidity in both biofilters of less than 3 NTU. During the operating cycle between the biofilter backwashings, the $NO_3-N$ removal percentage decreased initially after backwashing, and then gradually increased. Under $C/NO_3-N$ ratios of 2, 1.5 and 1 g/g, the $NO_3-N$ reduction rate was 1.75, 1.04 and $0.68g/m^2/d$ in the ethanol biofilter, and was 1.56, 1.07 and $0.76g/m^2/d$ in the acetate biofilter, respectively. In addition, during denitrification, the ratio of the consumed chemical oxygen demand to the removed $NO_3-N$ was 5.06-8.23 g/g in the ethanol biofilter, and was 4.26-8.6 g/g in the acetate biofilter.

• 한국산학기술학회논문지
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• 제18권5호
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• pp.330-335
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• 2017

본 논문은 수중 초음파 시스템을 교각 수중부의 손상 진단 및 점검에 적용하기 위한 기초 연구로써, 수중 초음파와 광학 영상의 하이브리드 시스템을 이용하여 교각의 수중부 점검 실험을 수행하였다. 수중 초음파 시스템을 이용하여 교각 수중부 촬영 시 현장실험에 영향을 미치는 환경변수를 파악하기 위하여 촬영 방향이나 촬영 방법 등을 변화 시키면서 결과영상을 획득 하였다. 교각 주위의 탁도는 10 NTU이었고, 물살과 파고에 의하여 수중 초음파영상에 잡음이 발생하였으나, 이를 최소화 할 수 있는 최적의 촬영 방향과 방법을 제안하였다. 수중 초음파시스템을 이용하여 교각 수중부의 손상 의심부위를 선정하였고, 광학 영상시스템을 이용하여 손상상태를 확인할 수 있었다. 또한 수중 초음파영상과 광학 영상의 정량적인 분석을 위하여 도트게이지를 활용하는 방안을 제안하였다. 본 논문의 결과는 수중 초음파와 광학 영상의 하이브리드 시스템을 이용한 교각 수중부 점검 기법 연구로, 이와 관련된 기술개발을 위하여 기초자료로 활용할 수 있을 것이라 판단된다.

• 환경위생공학
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• 제13권2호
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• pp.1-13
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• 1998

Seasonal variation of algae distribution were studied in the Chuam reservoir from August 1996 to July 1997. As a result, 127 taxa were observed, representing 6 classes, 14 orders, 5 suborders, 29 families, 2 subfamilies, 54 genus, 118 species, 7 variaties and 2 formula. The majors of them are Chlorophyceae (59 taxa), Bacillariophyceae(39 taxa) and Cyanophyceae(20 taxa). The number of species was that 35 and 31 taxa were occurred in August 1996 and April 1997, 11 and 17 taxa in July 1997 and October 1996 respectively at Dam station, 53 taxa were occurred in September, 18 taxa in November at Munduck station. The biomass composition of occurrence species were as fallowes; Cyanophyceae are 80%, Bacillariophyceae 14% and Chlorophyceae 5% at Dam station and Cyanophyceae are 90%, Bacillariophyceae 1.3% and Chlorophyceae 0.4% at Munduck at Munduk station. At Munduk station, water bloom occurred by Cyanophyceae(99.9%, 3.7 $\times$ 10$^{7}$ cells/L) in November 1996 and the major causing algae was Microcrystis aeruginosa. Microcystis aeruginosa was dominant species (dominant index : 0.72 - 0.99) during summer and autumn, Fragilaria crotonensis and Asterionella formasa (DI : 0.33 - 0.74) during winter and spring. The water quality factors of the Chuam reservoir were that the values of water temperature ranged of 3.6 - 31.4$\circ$C, pH 6.7 - 9.0, conductivity 69.6-118.2 $\mu $s/cm, and turbidity 1.0-22.5 NTU, and the proper temperature of water for algae growth was 15 and 16.7$\circ $C in April and November. Also the concentration of dissolved oxygen(DO) ranged of 6.8-15.5mg/L, total nitrogen(T-N) 0.54-1.78 mg/L, total phosphrous (T-P) 0.003-0.034 mg/L, and chlorophyll-a 0.9-23.2mg/m$^{3}$. The concentration of Chlorophyll-a was in inverse proportion T-N/T-P ratio.