• Journal of Korean Society of Environmental Engineers
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• v.35 no.1
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• pp.23-30
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• 2013

The sludge disposal is a major economic factor in the sewage treatment facility operation. Moreover, since the ocean dumping will be prohibited by Korean environmental law from 2013, sludge should be eliminated or sludge volumetric reduction should be performed urgently. In this study, improvement of the sewage sludge dewaterability was investigated by ultrasound and electric field treatment. Sludge was treated by a single or in combination of either the electric field or ultrasound on a pilot pretreatment facility, then it was dewatered by lab-scale filter press. The operating input energy of ultrasound device was varied from 225~1,200 kJ/L and electric field device was varied from 4.5~24 kJ/L. The water contents of dewatered sludge cake treated with ultrasound (1,200 kJ/L) and combination of ultrasound/electric field (1,224 kJ/L) were decreased 10~12% by comparing non-treated sludge. At that time, water contents were 65~66%. The combination treatment of ultrasound/electric field was effective to reduce water content of dewatered sludge cake, however, water content was not changed by a single treatment of electric field because of low energy density.

• Journal of Industrial Technology
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• v.36
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• pp.83-88
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• 2016

In this study, a series of experiment was carried to improve dewaterability of the sludge produced in a treatment plant, located in Hongcheon, Gangwondo, which has been treating municipal wastewater and livestock wastewater. Optimum sludge mixing ratio and the amount of sludge conditioner were determined. As sludge conditioners, alum and ferric salt were selected and tested. For the measurement of sludge dewaterability, capillary suction time(CST) and the specific resistance were measured, The specific resistance was detemined by running a series of Buchner Funnel Test. Mixing the two sludges at a 50:50 ratio with the addition of 20 mL alum gave the best results in terms of dewaterability. The moisture content decreased by 2% at this condition.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 1999.04a
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• pp.27-27
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• 1999

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 1999.11a
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• pp.141-146
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• 1999

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 1999.11a
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• pp.215-219
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• 1999

• Journal of Korean Society of Water and Wastewater
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• v.18 no.4
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• pp.508-514
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• 2004

Industrial and municipal wastewater treatment plants produce large amounts of sludge cakes for final disposal. This problem is an inevitable drawback inherent to the activated sludge process. Both the reduction of the amount of sludge produced and improvement of its dewaterability are presently very important issue also in Korea. So many pre-treatment processes have been developed in order to improve sludge dewatering efficiency. In this study the effects of hydrogen peroxide and paper sludge mixing processes were considered as reasonable alternatives to enhance sludge dewaterability. The CST of sludge was significantly decreased, and dewaterability improved by hydrogen peroxide oxidation treatment. The optimum dosage of hydrogen peroxide was proved to be 10mg/g-TS (when TS of sludge was 2%) with the conditions of pH 4 and only 1~2 minutes of reaction time. The mixing of paper sludge with sewage sludge was turned out to be very effective in reduction of sludge cake; 30% of sludge cake reduction was accomplished. Optimum mixing ratio of paper sludge was about 30%(v/v). This process also could save 25% of polymer to be required. These two alternatives are somewhat realistic, but it was concluded that paper sludge mixing process will be the best choice.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.5
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• pp.608-618
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• 2004

Since polyelectrolytes have been used as conditioners, conventionally only a single polyelectrolyte has been added for sludge conditioning. However, the amount of polyelectrolyte needed for optimal conditioning of sludge is very critical. Overdosing reduces the sludge dewaterbility. In this experimental study, sludge conditioning with single or dual polyelectrolyte was conducted to avoid problems associated with overdosing. Single polyelectrolyte conditioning was conducted by one of cationic, nonionic, and anionic polyelectrolytes. The dual polyelectrolyte conditioning was performed by adding one polyelectrolyte and another one in sequence. The dewaterbility of sludges were measured by SRF(specific resistance to filtration), TTF(time to filter), CST(capillary suction time) respectively. Additionally, parameters such as turbidity, zeta potential, viscosity of conditioned sludges or supematant were measured to evaluate the changed characteristics of sludge by addition of polyelectrolytes. From the experiment results, it was concluded that single polyelectrolyte conditioning had a high probability of overdosing, whereas dual polyelectrolyte conditioning resulted in a better dewaterbility and less chance of overdosing. But, it was also found that dosing sequence in dual conditioning was very important according to the characteristics of sludge. Parameters such as viscosity, turbidity, zeta potential were found to be useful as a means of evaluating sludge dewaterbility.

• Korean Journal of Construction Engineering and Management
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• v.4 no.4 s.16
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• pp.88-95
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• 2003

Dewatering mold form get many holes on the surface to drain excessive water from combine concrete. While fiber is adhered to the forms inter surface, that makes it possible to improve concrete workability by draining excess water through the holes. We can expect the outer layer to solidify and to compact and get improvement of concretes durability. Maybe, it is valuable enough that dewatering mold form is put to practical use. On this study, the purpose is to obtain fundamental data for effective dewatering mold and properties of exposed concrete with the form, and ultimately, is to propose practical theory.

• Applied Chemistry for Engineering
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• v.27 no.2
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• pp.128-134
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• 2016

Due to the great development made in converting the shale gas into the more valuable products, research and commercialization for production technology of olefins like propylene, butenes, butadiene from light alkanes have been intensively investigated. Especially the technology using oxygen like oxidative dehydrogenation or selective hydrogen combustion to overcome thermodynamic limit of direct dehydrogenation conversion has been extensively studied and some cases of applying this technology to the plant scale was reported. In this review, we have categorized the technology into two parts; gas phase oxygen utilization technology and lattice oxygen utilization technology. The trends, results and future direction of the technology are discussed.

• 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.