• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.4
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• pp.477-482
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• 2016

This study investigates the expressions characteristics of compression strength depending on the condition of fresh concrete and cured concrete by producing Non-cement mortar and concrete only with solidified sludge in the dehydrated cake form, recycled concrete and premixed materials(BS, FA) in order to actively use remicon recycling water as resources, rather than as construction waste material. After treating wastewater of pH 12.5 or more with alkali activator and after promoting BS hydration reaction, the amount of BS inflow was found to be increased and compression strength was increased accordingly: these results coincide with the analysis results of TG-DTA and SEM.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.11a
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• pp.105-106
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• 2015

With an increase of concrete buildings as result of rapid industrialization, Remicon sludge, which is a strong alkaline construction waste, should be neutralized to prevent damage to a natural environment, and the cost of the neutralization processing is increasing as well. Accordingly, this study investigates the mechanical properties of cementless concrete which is processed with recycled water and industrial byproducts in order to determine the possibility of re-using sludge, recycled sand, and gravel which are contained in recycled water.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.437-442
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• 2001

In an integrated steel mill, zinc (Zn) inputs from raw materials and steel scrap are enriched in the dusts and sludges collected from gas and water cleaning systems. The reuse of these dusts and sludges must be controlled within certain limit to avoid Zn accumulation and related operational problems in blast furnace. An integrated system has been established at China Steel Corporation (CSC) to enhance the internal reuse of Zn-containing dust/sludge while keeping Zn input within control lim it. However. the performance of this system has not been very satisfactory until one and half years ago when a rationalization process was initiated. The essence of this rationalization process, the recent improvements in Zn control and dust and sludge reuse are reported and discussed.

• 한국지구물리탐사학회:학술대회논문집
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• 2003.11a
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• pp.637-641
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• 2003

Abrasive powders were recovered from electrical industry sludge by simple physical separation for their recycling. The raw electrical industry sludge was filter pressed, dried, dispersed and then classified by air classifier at various conditions. The three kinds of particles with different particle size distribution were classified by controlling rotor speed and air volumes of the classifier. The recovered abrasive powders, which are classified at 5,000,9000 and 13,000 rpm of rotor speed, are almost same properties to raw pumice, garnet and rouge powders, respectively. The results of particle size analysis, X-ray diffraction and SEM observation show that the recovered powders can be reused as an abrasive powders.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.201-204
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• 2004

The purpose of this study is recycling of sewage sludge and fly-ash. In this experiment, green aggregates, which is a mixture of sewage sludge and clay and fly-ash, with different content of sewage sludge (up to $80wt\%$). Then they were burned in different soak temperatures from $1190^{\circ}C\;to\;1290^{\circ}C$ with changed soak time and heating rate at 5, 7, 10 minutes and $20^{\circ}C/min$, $30^{\circ}C/min$ respectively in order to produce lightweight aggregate (LWA). Data of both experiment series were generated to evaluate the quality of LWA as well as the relationship between burning condition and product's quality.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2004.11a
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• pp.121-126
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• 2004

• Journal of the Korea Organic Resources Recycling Association
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• v.22 no.1
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• pp.27-34
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• 2014

demand for a low-cost treatment technology is high because the sewage sludge has an 80% or higher water content and a high energy consumption cost. This study apply the thermal hydrolysis reaction that consumes a small amount of energy for sludge treatment. The purpose of this study is to quantify the viscosity of sewage sludge according to reaction temperature. we measured continuously the torque of dewatered sludge by the reaction temperature. As the reaction temperature increased, the dewatered sludge is thermal hydrolysis under a high temperature and pressure. Therefore, the bond water in the sludge cells comes out as free water, which changes the dewatered sludge from a solid phase to slurry of a liquid phase. The results of the viscosity measurements according to the reaction temperature showed that the viscosity was very high at $270,180kg/m{\cdot}sec$ at a temperature of 293K, but rapidly decreased with increases in the reaction temperature to $12kg/m{\cdot}sec$ at a temperature of 400K and to $4kg/m{\cdot}sec$ at a temperature of 460K or higher, similar to the changes in the viscosity of water. And we was obtained the viscosity function of boundary condition for the optimal design of thermal hydrolysis reactor by numerical modeling based on the this results.

• Journal of the Korea Organic Resources Recycling Association
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• v.12 no.4
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• pp.121-129
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• 2004

Anaerobic digestion is the most common process for sewage sludge stabilization and has benefits of VS reduction and biogas production. Many pretreatment methods have been studied to improve hydrolysis rate because the rate of sewage sludge degradation is slow in anaerobic digestion. This study mainly focused upon the effects on disintegration of sewage sludge by ultrasonic pretreatment according to the variation of acoustic density and duration of sonication time. In this study, acoustic density has been changed as follows : 33W/L, 70W/L, 88W/L, 139W/L in case of 40 kHz with the test time changes of 10min, 20min, 25min, 30min and 40min. In the comparison of $SCOD_{Cr}/TCOD_{Cr}$ variation for excess sludge and mixed sludge disintegration, the rates of $SCOD_{Cr}/TCOD_{Cr}$ have been increased in the condition of denser acoustic density and longer sonication time with acoustic frequency of 40kHz. The pH of the excess sewage sludge and mixed sewage sludge has been decreased in the condition of denser acoustic density and longer sonication time with acoustic frequency of 40kHz.

• Journal of the Korea Organic Resources Recycling Association
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• v.4 no.2
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• pp.77-85
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• 1996

The study on the ripening of leather waste sludge was performed to vemistabilize the sludge effectively using a laboratory scale darkened wood box reactor ($10{\times}10{\times}20cm$). The acceptable feed conditions for earthworm of Eh, alkalinity were obtained in the 30th and 35th days, respectively. The value of pH was gradually decreased from 7.8 to 7.1 through the ripening time. The contents of heavy metals of the ripened sludge were estimated as lower levels compared to the other regulatory standards for compost. After the ripening time for 50days, the physico-chemical properties of the sludge were estimated as pH 7.1, water content 72%, redox potential 85mV, electrolytic conductivity $2,620{\mu}mhos/cm$ and alkalinity 450 ppm as $CaCO_3$, respectively. In the ripened sludge, survival rate of the earthworms for 50 days was about 75%, and the live weight increase rate was about 230% at the temperature range of $20{\sim}25^{\circ}C$. Moreover, hatching rate of the earthworm cocoons was about 87% and the highest value was obtained in the 20~30th days. From the above results, it was evaluated that leather waste sludge could be vermistabilized effectively by earthworms, when the sludge was ripened during 50 days.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.3
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• pp.217-222
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• 2009

This study was conducted to search possibilities of the use of sludge from waterworks industry in the manufacturing of red clay bricks. Different compositions of the sludge were added into the raw materials of the bricks and required engineering characteristics of the manufactured bricks were examined. Compressive strength, plasticity, and surface absorption of the recycled bricks were analyzed and were compared with the bricks quality standard rules and regulation for quality assurance of the product. Compressive strength of the bricks made in a ratio 75% clay, 5% sludge and 20% silica was found 261.3 $kg_f/cm^3$ and that was comparable with first grade bricks standard. Compressive strength of the bricks made in a ratio 70% clay, 10% sludge, and 20% silica was found 249.9 $kg_f/cm^3$ while it was decreased to 217.3 $kg_f/cm^3$ when bricks were made in a ratio 65% clay, 15% sludge and 20% silica. However, these values of compressive strength were in agreement with the bricks quality standard. Surface absorption of the bricks made by the mixing of 20% silica with varying amount of sludge, i.e., 5%, 10%, and 20% was found 10%, 9.65% and 10.92% respectively. These values satisfied the quality standard of bricks of grade 1 and 2. Recycling of proper amount of sludge in bricks making could produce bricks of high engineering characteristics.