• Membrane and Water Treatment
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• v.10 no.1
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• pp.99-104
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• 2019

In Korea, nonpoint pollutants have a significant effect on rivers' water quality, and they are discharged in very different ways depending on rainfall events. Therefore, preparing an optimal countermeasure against nonpoint pollutants requires much monitoring. The present study was conducted to help prepare a method for installing an automatic nonpoint pollutant measurement system for the cost-effective monitoring of the effect of nonpoint pollutants on rivers. In the present study, monitoring was performed at six sites of a river passing through an urban area with a basin area of $454.3km^2$. The results showed that monitoring could be performed for a relatively long time interval in the upstream and downstream regions, which are mainly comprised of forests, regardless of the rainfall amount. On the contrary, in the urban region, the monitoring had to be performed at a relatively short time interval each time when the rainfall intensity changed. This was because the flow rate was significantly dependent on the rainfall's intensity. The appropriate sites for installing an automatic measurement system were found to be a site before entering the urban region, a site after passing through the urban region, and the end of a river where the effects of nonpoint pollutant sources can be well-decided. The analysis also showed that the monitoring time should be longer for the rainfall events of a higher rainfall class and for the sites closer to the river end. This is because the rainfall runoff has a longer effect on the river. However, the effect of nonpoint pollutant sources was not significantly different between the upstream and the downstream in the cases of rainfall events over 100 mm.

• Journal of Korean Society on Water Environment
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• v.23 no.4
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• pp.429-433
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• 2007

Many researchers have made a study of NPS unit-loads and the scientific evaluation method which need for formulating and enforcing a Total Maximum Daily Load (TMDL) management system and modifying a pollutant discharge loadings function. Some showed the event mean concentration (EMC) on single land-use. For the most parts, as the results showed on multiple land-uses, those cannot be used for NPS unit-loads calculation. NPS runoff shows various phenomena depending on rainfall monitoring data, therefore sampling methods and frequency for NPS monitoring must be different from the general monitoring for water quality trend assessment.

• Journal of Korean Society on Water Environment
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• v.23 no.6
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• pp.985-992
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• 2007

There are about 40,000 chemicals used in Korea and 300 new types of chemicals are added to the list every year, influencing quality of air, soil and water. Water quality standards that serve as the basis for water quality management have been proved inefficient and insufficient compared to those of advanced countries. This study aims to improve the existing water quality standards. Most importantly, the water quality standards need to take into account not only protection of human health but also aquatic resources. To that end, water quality criteria need to be set by monitoring each watershed every year and conducting risk assessment. Criteria for human health are set at $10^{-6}$ cancer risk level, and for aquatic life at conservative level, adopting the methodology of the U.S. and Australia, respectively. After carrying out technical and economic feasibility studies, more conservative criteria will be used to decide final water quality standards. The development of this system to establish integrated water quality standards for both human health and aquatic resources protection is urgently needed.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.1
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• pp.36-41
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• 2008

Cooling tower is an important equipment of the cooling systems for large buildings like factory and department store. Water used for cooling in cooling tower is reused continuously. If the water is polluted, corrosion and scale can happen at equipments and pipes. In order to prevent this problem, it is necessary to control the water quality using chemicals. To control the water quality, an automatic control system is designed, fabricated, and experimented. The control system is based on an imbedded microcontroller. Relays are used for power driving, an LCD and LED for display, and RS485 for remote data acquisition. Monitoring program is also developed for easy man-machine interface and extraction of data stored in the imbedded processor and EEPROM. The control system calculates amounts of chemicals necessary using sensor data and injects the chemicals into the cooling tower on proper time. The developed water quality control system is expected to reduce cost of maintenance and extend the lifetime of the cooling systems with low cost.

• Journal of the Korean Society of Hazard Mitigation
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• v.2 no.4 s.7
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• pp.69-75
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• 2002

In this paper the development of a real time river water quality management system is described. This system can manage a river water quality fluctuation by finding out abnormal conditions quickly and exactly. The GIS based monitoring system collects various properties of river water quality through the wireless real time network. Tanchun, the first branch of the Han River was selected as the target basin of the system development. This system is composed of three parts - wireless real time field measuring system with a GPS receiver, a server computer and a GIS platform. After the first field test in Tanchun basin, the result showed the many possibilities of measuring various water quality properties in real time and storing the data and analyzing them within the GIS environment in real time in very efficient manners. It is expected that the developed system will contribute to the efficient management of a river water quality control and water quality related disaster prevention purposes.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.6
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• pp.472-476
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• 2019

We have proposed a novel planar lightwave circuit (PLC) optical sensor to monitor the contamination in a flow-cell where water is continuously supplied through a water quality measurement system. We designed a PLC chip with a V-shape waveguide and the simulated its function as a sensor for monitoring contamination in a flow-cell using a numerical the FDTD (finite-difference time-domain) analysis. A novel cross type of waveguide was introduced to make the PLC chip of the V-shaped waveguide. The fabricated PLC was cut into the cross waveguide. A change in the optical propagation loss of the PLC sensor was observed after immersing the PLC sensor into city water. It was determined that the propagation loss of the PLC sensor was 3 dB at a wavelength of $1.55{\mu}m$ in the city water for 15 days.

• Journal of Digital Convergence
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• v.17 no.10
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• pp.1-12
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• 2019

In this study, TI(Toxic Index) of Daphnia toximeter corresponded to ecological toxicity standard 1 TU(Toxic Unit) was set up using Daphnia toximeter and when operating NOEC(water quality standards for drinking water) and $EC_{50}$ Daphnia toximeter alarm was issued appropriately, which enables real time ecological toxicity evaluation. I studied to get a good shot and the research was conducted by investigating domestic and international related data and conducting a preliminary study. 6 of 59 hazardous substances (As, Hg, Cr, Diazinon, Dioxane, and Phenol) recommended by the water quality monitoring items for artificial river water were selected and static, dynamic and quality management test, TI was shown to be good in other materials except Diazinon, and as a result of $EC_{50}$ spiking test, TI was matched to TU by distinguishing between 1 TU and 1 TU. in suggesting the complementary point of ecological toxicity management system and the future of research on water Daphnia toximeter.

• Journal of Korean Society on Water Environment
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• v.35 no.1
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• pp.55-63
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• 2019

The Four Major Rivers Restoration Project started in 2009 and completed in early 2013 is a large-scale inter-ministry SOC project investing ₩22.2 $10^{12}$ and one of the Project's objectives was to enhance the water-quality grade through recovering the river eco-system and environment. The average concentration and probability distribution of water-quality constituents at given and selected sampling sites are very significant elements for analyzing and controlling the water-quality of rivers or reservoirs effectively. Average concentration can be estimated by point estimator, distribution function of water-quality constituents or Bootstrap method, in which the distribution function estimated with more data in case of insufficient dataset, is applied. Ipo and Gangcheon water-quality monitoring stations in South Han River were selected to compare and analyze the variation of concentration before and after Ipo and Gangcheon Weirs construction, using the whole 4-year's data, from 2005 to 2008 and from 2014 to 2017. Water-quality constituents such as BOD and COD relating to oxygen demanding wastes and TP and Chlorophyll-a relating to the process of nutrient enrichment called eutrophication were also selected. The guidelines for water-quality control and management after weir construction including evaluation of water-quality constituents' variations can be presented by this paper.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.5
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• pp.930-936
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• 2008

CMOS image monitoring system for optimal measuring the activity of biosensor is developed using genetic algorithm. Most of living organism in water as water flea, fish, etc are frequently used as biological sensor for monitoring the water quality. It is very difficult to measure the activity of biosensor by image sensor because the value of measurement is varied with gathering method of biosensor images. The suggested monitoring system can optimally measures the activity of biosensor by genetic algorithm. The system is implemented with FPGA into the small hardware which is excellent in terms of the price and performance.

• Agribusiness and Information Management
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• v.9 no.1
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• pp.18-22
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• 2017

It takes lots of time and labor if a worker have to measure the water quality at a certain but designated time every day in an un-automated aqua farm. In addition, if the equipment is soaked in the sea water consistently, it will be contaminated by diverse floating matters and barnacles, and it often becomes mal-functional within 2~3 months. Therefore, we need to develop a system with which the sensed data could be checked in real time and operated automatically, while preventing the contamination of the sensor, a crucial component for water quality measuring equipment, as much as possible, and increasing the replacement cycle. We have developed a non-cleaning water quality measuring equipment and its software which are used in the fishery household of offshore aqua farms. By providing the workers with a mobile application which has a function of monitoring the water quality in real time, they can check the situation directly without going to the fishery household.