• Journal of Korean Society on Water Environment
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• v.16 no.4
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• pp.501-512
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• 2000

This study was carried out to develop the new process for RBC process which is capable of nutrient removal and to obtain its design parameters for Sludge Settling Type Rotating Biological Contactors by comparing RBC with RBC combined with HBR (Hanmee Bio-Reactor). To achieve more than 90% of organic removal efficiency, organic loading rate less than $6.0g\;BOD/m^2/d$ is recommended. Nitrification rate was about 90% at $6.0g\;BOD/m^2/d$. TN removal efficiency of RBC+HBR was higher than those of RBC1 and RBC2. TN removal efficiency at condition of $5.0g\;BOD/m^2/d$ was about 60% in RBC1. When BOD loading rate was $6.0g\;BOD/m^2/d$. TN removal efficiencies in RBC2 and RBC+HBR were about 70%, 80%, respectively. TP removal efficiency was more than about 67% for RBC1, about 63% for RBC2 and about 71 % for RBC+HBR at the same loading rate. From the blank experiment to observe removal efficiency in the first stage, it can be known that COD removal efficiency was about 30% and suspend solids settling rate was about 45%. It was proved that RBC+HBR is much better in sludge dewatering than RBC.

• Journal of Wetlands Research
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• v.15 no.4
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• pp.471-476
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• 2013

The operating conditions of sludge disposal for sanitary paper manufacturing wastewater treatment plant were monitored on the basis of daily check sheets during the 3 years of operation. Generated wastes were mainly composed of 79% of sludge, 14% of ash, 5% of waste synthetic resin and 2% of etc. Maximum sludge was produced to 233 ton and the average was 113 ton daily, where the primary sludge occupied 85% and 15% for the secondary sludge. The concentration of coagulant for sludge dewatering was extremely exceeded and the additional experiment such as jar-test was required for the establishment of proper dosage. Presently, the generated sludges were partially treated outside and were also partly handled inside. In the future, most sludges will be expected to be treated to recycling material for the iron industry.

• Journal of Environmental Science International
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• v.7 no.6
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• pp.867-873
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• 1998

Laboratory study was conducted to provide basic data for operating anaerobic sequencing batch reactor(ASBR) process for treatment of nightsoil. The experiments were concerned with digestion characteristics, settleabiltity and dewaterability of digested sludge in ASBR system. Completely-mixed dally-fed control reactor without solid-liquid separation step was also operated to evaluate the baseline performance since the nature of nightsoil was changed with time. In all case, gas production from the ASBR shows 1.3 to 1.44 times higher than that from control, in spite of almost similar trend in organics removal. During thickening period, remarkable decrease in surface settling velocity was observed at the ASBRs compared with the control. In case of the ASBR run, flotation of mixed digested sludge was not occurred. Also, ultimate thickened volume of ASBRs increased 1.2~1.5 times compared with control. Dewaterability of digested sludge without conditioning decreased when the completely-mixed daily-fed reactor for ASBR run was converted to the ASBR. However, improvement of dewaterability of digested sludge from the ASBRs was observed as a result of addition of FeCl$_3$ to digested sludge for conditioning.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.9 no.3
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• pp.149-159
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• 2011

Nuclear power utilities should establish a site-specific groundwater monitoring program for early detection of unplanned radioactive material's releases which can occur due to degradation of systems, structures and components of the nuclear power plants in order to keep the impact of the unplanned releases on the environment and the residents as low as reasonably achievable. For this end, groundwater flow on site should be evaluated based on characterization of the hydrogeology of a site of concern. This paper aims to provide data necessary for establishing groundwater monitoring program which is currently considered at Kori nuclear power plant 1 by characterizing groundwater flow system on the site based on the existing hydrogeological studies and related documents, and by modeling tritium transport. The results showed that the major groundwater flow direction was south-west and that most of groundwater entered a southern and eastern seas. Although the tritium plume also released into the sea, its rate was delayed by dewatering sump.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.1
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• pp.82-88
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• 2007

The objective of this study is to examine the effect of the waste oyster shell powder as the addition agent in bulking sludge thickening of paper manufacturing plant using DAF(Dissolved Air Flotation) and gravitational sedimentation. The effect of parameters such as dosage and size distribution of oyster shell were examined. The results showed that the optimum dosage of mixed oyster shell(size range : $\sim250{\mu}m$) was 0.8 g/L. The oyster shell addition of 5.0 g/L in sedimentation process was increased thickening concentration of 3.25 times. When 5.0 g/L of oyster shell was added in DAF process, water content of sludge was decreased from 95.5% to 82.7% in dewatering process using Buchner funnel test device. When size of oyster shell was divided four ranges($\sim53{\mu}m$, $53\sim106{\mu}m$, $106\sim150{\mu}m$, $150\sim250{\mu}m$), optimum size range for the flotation and dewatering was $53\sim106{\mu}m$.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.8
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• pp.775-780
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• 2008

Sludge conditioning is widely used to improve aggregation and dewaterability of waste sludge in sludge treatment processes. The study aims to examine quantitative correlations between coagulant dosage and sludge cake dewaterability using three kinds of coagulants, such as an aluminum sulfate, a ferric chloride, and a poly aluminum chloride(PAC). When an aluminum sulfate, a ferric chloride, and a PAC were injected with 0.79$\sim$1.19 mmol/g, 0.61$\sim$1.25 mmol/g TSS, and 0.21$\sim$0.39 mmol/g TSS, respectively, specific resistances to filtration of the sludge were decreased at 95.0% or more. This study shows that the correlation between coagulant dosage per g sludge(D) and normalized specific resistance to filtration(R) could be expressed by the exponential functions.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.2
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• pp.239-246
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• 2020

In this paper, an automatic dewatering system for drying water from umbrellas is proposed. In the past, there were problems that users had to put on plastic for removing the water from umbrella by covering it with a plastic or using a water dryer that removes water by manually touching the umbrella to the water surface. But this method was hard to expect. To solve these problems, an air compressor was used to develop a system to remove water from the umbrella by detecting the weight of the umbrella with pressure sensor when the user puts the umbrella into the dewatering machine and driving the motor. It is expected that this invention will have economic and environmental effects by eliminating the use of waste vinyl.

• Journal of Korean Society of Water and Wastewater
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• v.14 no.1
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• pp.62-75
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• 2000

Most of biological treatment to remove contaminants in municipal wastewater have been conducted by activated sludge process. But, the process have several probIems such as enormous site needed for construction of treatment facilities, unstable treatment due to limited ability to control load fluctuation, frequent sludge bulking and appearance of lots of surplus sludge. In this study, the experiments were performed through submerging biofilm of PEPP media in existing aeration tank with raw water from municipal wastewater treatment plant and then submerging PVDC and PEPP media, different from shape and chemical peculiarity in anoxic reactor. Throughout the experience, nutrient removal efficiency according to HRT, nitrogen phosphorous removal efficiency, behavior of nitrogen and dewatering efficiency have been compared and analysed with those of activated sludge process. As the results, BOD removal efficiency according to BOD volumetric load and F/M ratio was not found any differency in two processes, but was decreased below 90% as going along the condition of high load in activated sludge process. Kinetic coefficient was $K_{max}=1.162day^{-1}$, $K_s=53.77mg/L$, $Y=0.166mgVSS/mgBOD_{rem}$. and $K_d=0.019day^{-1}$. It was found that the removal efficiency, even though in aerobic condition, in biofilm process equipped anoxic reactor was higher than the one in activated sludge process within the range of 70~80%, and became better as HRT increased. Phosphorous removal efficiency was not found any differency in two processes. In biofilm process, treament efficiency even in conditions of high load was not decreased, because the biomass concentration could be maintained in high condition compared with activated sludge process. As HRT increased, suspended and attached biomass was increased and the other hand, F/M ratio was decreased as biomass' increasing. Biomass thickness was increased. from $10.43{\mu}m$ to $10.55{\mu}m$ as HRT increased and density of biomass within $40.79{\sim}41.16mg/cm^2$. The results also present that the dewatering efficiency of sludge generated in biofilm process was higher than in activated sludge process, and became better as HRT increased.

• Journal of Environmental Health Sciences
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• v.8 no.2
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• pp.13-31
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• 1982

Factors affecting on dewatering characteristics of anaerobically digested or/and elutriated sludges were examined from 15 January 1982 to 30 April 1982, results obtained were as follows 1. Sludges, either anaerobically digested or/and elutriated sludges, which were produced at the Joong Rang Cheon Sewage Treatment Plant wore found to be compressive in its nature, coefficient of compressibility ranged from 0.83 for unelutriated and 1.10 for elutriated. 2. Dosage of FeC13 for the anaerobically digested sludges were difficult to establish for the most favorable dosage rate, though the filterability indicated linear improvement with increased dosage from dosing rate excess of over 15% in terms of dry solids by weight, under the conditions of this examination. Optimum filterability were obtained with 9~11% of $FeCl_3$ for elutriated sludges, and required CaO, as aids, were appeared to be 2.5~3.5 times that of the $FeCl_3$ at that point by weight. 3. The specific resistances for anaerobically digested sludges showed higher value than the elutriated one, being $11 \times 10^{12} ~ 20 \times 10^{12}$ cm/g with no chemical conditioning, and $2 \times 10^{12} ~ 11 \times 10^{12}$ cm/g with conditioned ($FeCl_3$ + CaO) contrast to $0.5 \times 10^{12} ~ 2.0 \times 10cm/g$ for the elutriated. 4. The strength of the alkalinities before and after elutriation were measured to 10,000 ~ 15,000 mg/l and 1,500 ~ 2,000mg/l respectively. These alkalinities affected greatly on the filterabilities together with concentration of the organic matters in the sludges. 5. The yields with 11% $FeCl_3$, by weight to the DS, on the elutriated sludges averaged to $14.7 kg/m^2.hr$, and $3.2kg/m^2.hr$ for unelutriated sludges. Which was 4.6 times of not elutriated sludges. Elutriated sludges without chemical conditioner added showed much better filterabilities than with 15% of $FeCl_3$ added to the anaerobically digested and unelutriated sludges.

• Journal of the Korean Geosynthetics Society
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• v.4 no.1
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• pp.7-15
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• 2005

In recent years, the geotextile tubes filled with dredged material have been used in dike and breakwater construction for a number of projects around the world, and their use in this field is growing very fast. One of the most attractive advantages of geotextile tube technology is can be use the in-situ filling materials by hydraulic pumping, it can be also established lower costs and fast construction than other technology. Geotextiles form one of the two largest groups of geosynthetics and it is commonly made by two major types of polymer material(Polypropylene, Polyester). The objective of this paper is to examine several issues associated with drainage function and feasibility of geotextile tube structure such as filtering efficiency, dewatering efficiency, and filling process with polymer materials. Based on the laboratory filtering test and in-situ tests, polypropylene goetextile is more effective for drainage function of geotextile tube technology.