• 한국상하수도협회지
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• s.10
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• pp.52-55
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• 2005

• Environmental engineer
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• v.19 s.205
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• pp.88-89
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• 2003

• Korean Journal of Construction Engineering and Management
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• v.7 no.6
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• pp.175-184
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• 2006

This study focused on developing Life Cycle Cost(LCC) analysis model for selecting sludge collectors in wastewater treatment system and applying the model to a case study. Cost items are examined through literature review and historical data of a facility. Analysis period, discount rate, energy cost escalation ratio are assumed to reasonable level. Monetary evaluation is performed using historical data and estimations from vendors. Sensitive analysis is executed using Monte Carlo Simulation for assumed factors. Interviews with operators, vendors, constructors, managers are conducted to define factors which indicates ease of maintenance, ease of delivery, technical performance, efficiency, environmental friendship. Factors are representing technical and social factors. Results from LCC analysis and qualitative analysis are evaluate together with Weighted Matrix Evaluation Methods for optimum alternative of sludge collectors.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1034-1039
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• 2008

Recently, the sludge suction collector is preferred rather than the scraper type sludge collector due to enhancement of the clarifier efficiency. The sludge suction collector is usually operated by the user's experience without any scientific and technical consideration. There are many factors that should be considered for higher quality of discharged water and stabilized flow in the rectangular sludge suction collector but, the optimal design on the inflow channel and orifices connecting with the inflow channel is needed for similar flow rates at the orifices. The 4 cases of channel geometry are considered and mass flow rates of each case at the orifices are evaluated using Computational Fluid Dynamics applied VOF(Volume of Fraction) model.

• The KSFM Journal of Fluid Machinery
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• v.9 no.5 s.38
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• pp.22-27
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• 2006

Sedimentation phenomenon of suspended solids occurs by the gravitational force. Pollution particles are separated from slowly flowing waste water in clarifier. Recently, the sludge suction collector is Preferred rather than the scraper type sludge collector due to the enhancement of the clarifier efficiency. The sludge suction collector is usually operated by the user's experiences without any scientific and/or technical consideration. To evaluate the performance of sludge suction collector, the three dimensional numerical simulation was conducted by the finite volume method. To analyze the performance, the velocity vectors and the suction flow rates of the orifices were investigated. The result showed that each suction flow rate through out the collector was equivalent in the sludge suction collector and the efficiency of suction collector was good to remove high concentrated sludge in clarifier.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1851-1856
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• 2004

Sedimentation phenomenon of suspended solids occurs by the gravitational force. Pollution particles are separated from slowly flowing wastewater in clarifier. Recently, the sludge suction collector is preferred rather than the scraper type sludge collector due to enhancement of the clarifier efficiency. The sludge suction collector is usually operated by the user's experiences without any scientific and/or technical consideration. To evaluate the performance of sludge suction collector, the three dimensional computer simulation was conducted by the finite volume method. To analyze the performance, the velocity vectors and the suction flow rates of the orifices were investigated. The result showed that each suction flow rate through out the collector was equivalent in the sludge suction collector and the efficiency of suction collector was good to remove high concentrated sludge in clarifier.

• 유체기계공업학회:학술대회논문집
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• 2003.12a
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• pp.415-420
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• 2003

Sedimentation phenomenon of suspended solids occurs by the gravitational force. Pollution particles are separated from slowly flowing wastewater in clarifier. Recently, the sludge suction collector is preferred rather than the scraper type sludge collector due to enhancement of the clarifier efficiency. The sludge suction collector is usually operated by the user's experiences without any scientific and/or technical consideration. To evaluate the performance of sludge suction collector, the three dimensional computer simulation was conducted by the finite volume method. To analyze the performance, the velocity vectors and the suction flow rates of the orifices were investigated. The result showed that each suction flow rate through out the collector was equivalent in the sludge suction collector and the efficiency of suction collector was good to remove high concentrated sludge in clarifier.

• Ecology and Resilient Infrastructure
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• v.8 no.4
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• pp.194-203
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• 2021

With the recent increase in maintenance works on water and sewer pipes as well as district heating supply pipes, pavement cutting work using pavement cutter is on the rise. The pavement cutting operation generates considerable dust (cutting sludge) as well as noise; therefore, it is necessary to apply eco-friendly technologies that have low noise and dust recovery capability. Thus far, various equipment for recovering dust have been developed; however, there is a limitation in that the environmental friendliness is not quantified. Therefore, in this study, we developed a low-noise, dust-recovery type pavement cutter that can fundamentally remove the causes of environmental hazards such as noise and dust and evaluated the eco-friendliness of the pavement cutting process performed by this cutter. To this end, an integrated water cooling-sludge recovery system composed of a vacuum device and a sludge suction unit was developed, and the developed system was applied to a pavement cutter. Subsequently, the developed equipment was applied to the test bed, and data related to its eco-friendliness were collected and evaluated. The results showed that the cutting sludge recovery rate of the developed equipment was greater than 83%, the noise level was approximately 82 - 83 dB, and the sound power level was 115 dB. The results of this study will be used as basic data to develop improved pavement cutters in the future with improved cutting sludge recovery performance and lower noise.

• Korean Journal of Construction Engineering and Management
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• v.24 no.4
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• pp.3-13
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• 2023

The purpose of this study is to compare and analyze the performance and work productivity of wet type pavement cutters and sludge suction type pavement cutters (hereinafter referred to as automatic pavement cutters) developed to reduce scattering dust. We first investigated the development status of wet type manual pavement cutters that are mainly used in Korea and automatic pavement cutters, and analyzed the pavement cutting work in detail. And the standard cutting performance was derived by measuring the cutting time by depth by applying the two equipment to the test bed under the same conditions. However, there is a limitation that the data measured in the test bed does not reflect the various variables of the actual pavement cutting site. Therefore, in this study, data was collected through field surveys, and the correlation between cutting distance and time was analyzed, and then a model for calculating the productivity of pavement cutters was presented through simple regression analysis. As a result of comparative analysis of the values derived from the regression equation with the standard cutting performance derived from the test bed, the cutting performance derived through the regression equation showed a similar trend to the standard cutting performance. Finally, we verified the usability of the automated pavement cutter developed by qualitatively analyzing three tasks that are difficult to measure quantitatively but affect productivity.

• Resources Recycling
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• v.22 no.3
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• pp.73-80
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• 2013

Metal prices are rapidly rising due to increasing demand of metals and limited available resources according to the industrial requirement. As a result, securing a stable supply of these metal resources has been recognized as a core element of national competitiveness and sustained economic growth. In the case of magnesium and its alloys which are entirely depending on import, low-grade magnesium scraps from end-of-life vehicles and 3C(Camera, Computer, Communication) parts and magnesium wastes such as sludge and dross generated during melting process are hardly recycled. Accordingly, the development and commercialization of recycling technology of low-grade magnesium scrap is desperately needed to improve efficiency of resource circulation and to establish the required proprietary of resource metal supply and demand. In this study, papers and patents on recycling technologies of waste magnesium were analyzed. The range of search was limited in the open patents of USA (US), European Union (EP), Japan (JP), Korea (KR) and SCI journals from 1974 to 2012. Patents and journals were collected using key-words searching and filtered by filtering criteria. The trends of the patents and journals was analyzed by the years, countries, companies, and technologies.