• Journal of environmental and Sanitary engineering
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• v.14 no.4
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• pp.110-116
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• 1999

This study was conducted to investigate the contaminants removal efficiency and the optimal operating parameters by the internal recycle rate (IRR) in the combining A2/O process with fixed film. The average removal efficiency of BOD and COD was 92.5%~94.6%, 73.9%~87.0% in RUN 1 and 91.9%~94.7%, 77.7%~89.0% in RUN 2, respectively. Organic removal efficiency, at two different hydraulic retention time of 10 and 14hr, was similar. At 50% of the internal recycle rate, organic removal efficiency was somewhat higher than the other. Total nitrogen (T-N) and total phosphorus (T-P) were removed, highly, at 50% of internal recycle rate. It could be suggested by this study that the optimum internal recycle rate is 50% and hydraulic retention time is 14hr.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2003.10a
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• pp.639-642
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• 2003

Characteristics of concentration of pollutants such as total nitrogen(T-N), total phosphorus(T-P) and chemical oxygen demand(COD) during dry days of $2002{\sim}2003$ were investigated for streamwater from a rural watershed. Water was sampled and discharge was measured at 5-days intervals at outlet of study area. The mean concentrations of pollutants in non-irrigation and irrigation period not significantly different. For increasing discharge in 2002, TN concentration increased but COD concentrations decreases.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.604-609
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• 2005

Runoff characteristics of organic matters and nutrients from greenhouse site in paddy field area were investigated during the irrigation period in 2004. The greenhouse selected which situated near the Nam river, Jinju, Korea used the ground water as the irrigation purpose. And, the rotating system of paddy field to upland was adapted as a cropping system which is a typical practice in this area. Various items such as total phosphorus(T-P), total nitrogen(T-N), dissolved oxygen(DO), BOD, etc. were observed to figure out the seasonal and spatial variation in the study sites. it was found that the risk of water pollution due to the contamination of nutrients in canals in green house sites, and their neighbouring small sized streams are much higher than those in ordinary paddy field areas. Further surveys and investigations are required to find out the counter measures to reduce water pollution occurred in greenhouse sites.

• Journal of Animal Environmental Science
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• v.7 no.2
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• pp.77-82
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• 2001

This research was carried out to investigate the daily amount and characteristics of wastewater produced from bucket milkers, pipeline, tandem ad herringbone milking system for washing operations after milking included 28 dairy farms. The average amount of wastewater produced from milking system was 9.8l/head/day. The amount of wastewater varied from a low of 8.2 litters/head/day(pipeline milking system) to 13.4 litter/head/day(herringbone milking system). The moisture content, Biochemical Oxygen Demand($BOD_5$), Chemical Oxygen Demand($COD_{Mn}$), Suspended Solids(SS), Total Nitrogen(T-N) and Total Phosphorus(T-P) concentration of wastewater were 99.9%, 394mg/l, 417.3mg/l, 1,201.3mg/l, 3.78mg/l, 0.51mg/l.

• Membrane and Water Treatment
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• v.9 no.6
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• pp.455-462
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• 2018

The measurement and monitoring of the biochemical oxygen demand (BOD) play an important role in the planning and operation of wastewater treatment plants. The most basic method for determining biochemical oxygen demand is direct measurement. However, this method is both expensive and takes a long time. A five-day period is required to determine the biochemical oxygen demand. This study has been carried out in a wastewater treatment plant in Turkey (Hurma WWTP) in order to estimate the biochemical oxygen demand a shorter time and with a lower cost. Estimation was performed using artificial neural network (ANN) method. There are three different methods in the training of artificial neural networks, respectively, multi-layered (ML-ANN), teaching learning based algorithm (TLBO-ANN) and artificial bee colony algorithm (ABC-ANN). The input flow (Q), wastewater temperature (t), pH, chemical oxygen demand (COD), suspended sediment (SS), total phosphorus (tP), total nitrogen (tN), and electrical conductivity of wastewater (EC) are used as the input parameters to estimate the BOD. The root mean squared error (RMSE) and the mean absolute error (MAE) values were used in evaluating performance criteria for each model. As a result of the general evaluation, the ML-ANN method provided the best estimation results both training and test series with 0.8924 and 0.8442 determination coefficient, respectively.

• The Korean Journal of Mycology
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• v.26 no.4 s.87
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• pp.562-573
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• 1998

The symbiotic activities of arbuscular mycorrhizal fungi (AMF) by analyzing spore density, symbiosis intensity and vertical distribution of AMF spores, phytomasses of higher plants such as Calamagrostis epigeios, Imperata cylindrica, Artemisia scoparia, Aster tripolium and Sonchus brachyotus, and physico-chemical properties of soil were determined in the rhizospheres of higher plants in abandoned two coastal reclaimed lands, which were constructed in 12 and 30 years ago, respectively. Vertical distribution of the AMF spores in the rhizospheres of higher plants was restricted within 20 cm depth from soil surface, which would be closely related with vertical distribution of root system, water table and soil aeration. Of vertical distribution of soil properties, W.C., A-P and K concentrations were increased as soil depth was lowered. In the coastal reclaimed lands, symbiotic activities of the AMF such as spore density and symbiotic intensity, were conspicuously stimulated by the increase of soil pH value, organic matter and total nitrogen concentrations, but inhibited by the increase of moisture, available phosphorus and sodium concentrations in the rhizosphere soil. Phosphorus absorption by higher plants growing in the reclaimed lands increased by the rise of symbiotic activities of AMF. Since symbiotic activities of AMF were stimulated with decreasing soil phosphorus concentrations, higher plants associated with AMF absorbed a large amount of phosphorus from the soil is low phosphorus concentrations.

• Journal of Animal Environmental Science
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• v.7 no.3
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• pp.169-172
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• 2001

This research was carried out to investigate the quantity of Holstein milking cow manure excreted and their characteristics. The average body weight of the Holstein milking cow during experiment was 550.0kg, and fried intake(DM basis), water consumption, milk yield was 16.7, 85.4, 24.4k7/day/head, repectively. The average manure production of Holstein milking cow was 63.5kg/day/head(feces 42.3, urine 10.2kg). The average moisture content of feces and urine was 83.9%, 96.9%, respectively. Wastewater pollutant concentration of $BOD_5$(Biochemical Oxygen demand). $COD_{Mn}$ (Chemical Oxygen demand), SS(Suspended Solids), T-N(Total Nitrogen) and T-P(Total Phosphorus), excreted from Holstein milking cow was 16,560, 40,329, 78,500, 2,854, 577mg/ l in feces and 4,580, 7,575, 370, 4,164, 7mg/ l in urine, repectively.

• Journal of Korean Society of Water and Wastewater
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• v.34 no.6
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• pp.411-423
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• 2020

To remove phosphorus from the effluent of public wastewater treatment facilities, hundreds of enhanced phosphorus treatment processes have been introduced nationwide. However, these processes have a few problems including excessive maintenance cost and sludge production caused by inappropriate coagulant injection. Therefore, the optimal decision of coagulant dosage and automatic control of coagulant injection are essential. To overcome the drawbacks of conventional phosphorus removal processes, the integrated sedimentation and dissolved air flotation(SeDAF) process has been developed and a demonstration plant(capacity: 100 ㎥/d) has also been installed. In this study, various jar-tests(sedimentation and / or sedimentation·flotation) and multiple regression analyses have been performed. Particularly, we have highlighted the decision-making algorithms of optimal coagulant dosage to improve the applicability of the SeDAF process. As a result, the sedimentation jar-test could be a simple and reliable method for the decision of appropriate coagulant dosage in field condition of the SeDAF process. And, we have found that the SeDAF process can save 30 - 40% of coagulant dosage compared with conventional sedimentation processes to achieve total phosphorus (T-P) concentration below 0.2 mg/L of treated water, and it can also reduce same portion of sludge production.

• Journal of Korean Society on Water Environment
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• v.33 no.1
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• pp.90-96
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• 2017

Many sewage treatment plants have applied the advanced technology of chemical coagulant system to remove phosporus in Korea. However there are some problems for the injection of optimum coagulant dosage. In order to solve these problems, the research related to the more cost-effective automatic total phosphorus coagulation control system using an EC(Electrical Conductivity) have been in progress. This study was conducted by the same process and operation method as the Lab-scale for public small town sewage treatment plant. First, it confirmed the correlation among the EC, PO4-P and coagulant dosage in the Lab-scale MSBR(Membrane Sequencing Batch Reactor) process. Next, it analyzed that correlation coefficient of EC and the coagulant dosage was 0.92 in the Full-scale MSBR process. As a result, not only T-P removal efficiency was doubled but also it satisfied the effluent water quality standard in a stable manner. In addition, by applying the automatic control system using the EC, compared to the fixed coagulant injection system the coagulant dosage could be reduced by 28%.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.1
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• pp.18-24
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• 2007

Paddy fields are apparently nonpoint source pollution and influence water environment. In order to improve water quality in rivers or lakes, to low nutrient load from paddy fields are required. To establish comprehensive plan to control agricultural non-point source pollution, it is imperative to get a quantitative evaluation on pollutants and pollution load from paddy fields. A field monitoring study was carried out to investigate the water balance and losses of nutrients from fields in Sumjin river basin. The size of paddy fields was 115 ha and the fields were irrigated from a pumping station. The observed total nitrogen loads from paddy fields were larger than those of the unit loads determined by Ministry of Environment data (MOE). It is because the nitrogen fertilization level at the studied field was higher than the recommended rate and the high irrigation and subsequent drainage amount. On the contrary, total phosphorus loads were less than those addressed by MOE since phosphorus fertilization level was lower than that of standard level. Therefore, it was found that fertilization, irrigation, and drainage management are key factors to determine nutrient losses from paddy fields. When the runoff losses of nutrients were compared to applied chemical fertilizer, it was found that 42 to 60% of nitrogen lost via runoff while runoff losses of phosphorus account for 1.3 to 7.6% of the total applied amount during the entire year.