• Korean Journal of Environmental Agriculture
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• v.7 no.1
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• pp.26-33
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• 1988

To investigate the effects of paper sludge on the growth response of paddy rice, paper sludge was applied to pots at the rate of either 300, 600, 900 or 1,200 kg/l0a which was either preadjusted at a C/N ratio of 30 : 1 or not adjusted. The effects were compared with those of the control. 1. Plant heights, number of tillers and dry weight were significantly reduced with the increasing application of paper sludge in the early stages of rice growth, whereas opposite results were observed after the heading stage when treated with C/N ratio preadjusted paper sludge. 2. The uptake of $N,P_2O_5,K_2O$ and $SiO_2$ by rice plants grown in paper sludge treated soil was significantly reduced in the early stages of rice growth. Conversely, uptake was enhanced in the C/N ratio preadjusted plot in the young panicle formation stage. 3. Zn, Cu and Cd content in rice straw was in the range of $39{\sim}101$, $0{\sim}0.11$ and $0.03{\sim}0.14ppm$, respectively, and Pb and Cr in rice straw were not detected at all. However, there was no difference in the content of all these heavy metals in rice straw irrespective of treatment.

• Journal of the Korean Applied Science and Technology
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• v.25 no.3
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• pp.363-369
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• 2008

In the present work, the choice of the nano carbon black and optimum mixed ratio and effectiveness of the mixed carbon black to get a raw data for a manufacturing method of conductive complex board. Optimum mixed ratio of paper sludge & water was 1 : 2.5 for reformations. HB-41-Y was cheaper than Super-P with the single carbon black. Also electric conductivity of HB-41-Y($6.406{\times}10^{-2}\;{\Omega}cm^{-1}$) was about 6.5 times higher than Super-P($9.741{\times}10^{-3}\;{\Omega}cm^{-1}$) at 20 wt% carbon black. This time optimum mixture ratio of the paper sludge and the carbon black to be about 15 wt%, optimum mixed ratio HB-41Y and Graphite about 3:1 and its electric conductivity was $5.824{\times}10^{-2}\;{\Omega}cm^{-1}$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.10
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• pp.861-867
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• 2001

In this paper, in order to investigate the catalytic effect of the sludge exhausted from waterworks on NO$_{x}$ removal, we measure NO removal characteristics with and without sludge pellets in BaTiO$_3$-sludge packed-bed reactor of plate-plate geometry. NO initial concentration is 50 ppm balanced with air and a gas flow rate is 5ι/min. Gas temperature is changed from 25 to 10$0^{\circ}C$ to investigate the role of sludge pellet on removing active oxygen species and NO$_2$. BaTiO$_3$pellets is filled for coronal discharge at upstream of reactor and sludge pellets is filled for catalytic effect at downstream of reactor. The volume percent of sludge pellets to BaTiO$_3$pellets is changed from 0% to 100% and AC voltage is supplied to the reactor for discharging simulated gases. In the results, when sludge pellets is put at the downstream of plasma reactor, NO removal rate is slightly increased. However, NO$_2$and $O_3$ as by-products during NO removal is significantly decreased from 51ppm without sludge pellets to 5 ppm with sludge pellets and from 50 ppm without sludge pellets to 0.004ppm with sludge pellets, respectively. Therefore, NO$_{x}$(NO+NO$_2$) removal rate is increased up to 93%. It is thought that sludge pellet maybe react with active oxygen species and NO$_2$ generated by corona discharge in surface of BaTiO$_3$pellets, the then NO$_2$O$_3$as by-products are considerably decreased. When we increase gas temperature from room temperature to 10$0^{\circ}C$, NO removal rate is decreased, while NO$_2$ concentration is independent on gas temperature. These result suggest that the removal mechanism of active oxygen species and NO$_2$in sludge pellet is not absorption, but chemical reaction. Therefore we expect that sludge pellets exhausted for waterworks could be used as catalyst for NO$_{x}$ removal with high removal rate and low by-product.oduct.

• Journal of the Korea Concrete Institute
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• v.13 no.6
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• pp.561-567
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• 2001

It is reported that a lot of sludge powder is produced during the process of manufacturing crushed fine aggregate in mines. However, there is a limitation on the its use that most of them are disposed and wasted, which cause environmental pollution. Therefore, in this paper, tests are carried out in order to recycle sludge powder as filler for cement mortar products. Kinds of aggregates and mix proportion of mortar are varied under various contents of sludge powder. According to test results, it is found that cement mortar products using sludge powder as substitution of fine aggregate about 10% have better qualities than those without sludge powder.

• Korean Journal of Environmental Agriculture
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• v.14 no.1
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• pp.72-81
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• 1995

Utilization of municipal sewage sludge(MSS) for agriculture was reviewed in this paper. Sewage sludge applied to rice and corn resulted in higher products of grains which showed lower heavy metal contents at an application rate of 20 to 80 dry ton/ha than the cases without sludge application. Most of heavy metals and nitrogen applied remained in soil. Our MSS could be classified as a high-quality sludge with regards to US 503 sludge rule, but this sludge could not be applied under our current regulations, which must be reviewed at intra-governmental levels.

• Architectural research
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• v.12 no.1
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• pp.49-55
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• 2010

Stone powder sludge is a by-product of the manufacturing process of crushed sand. Most of it is dumped with soil in landfills, and the disposal of stone powder sludge causes a major environmental problem. This paper investigates the applicability of stone powder sludge in fly ashbased geopolymer. For this, stone powder sludge was used to replace fly ash at a replacement ratio of 50% and 100% by weight. The compressive strength of the samples was measured and scanning electron microscopy/ energy dispersive spectroscopy (SEM/EDS) analysis and X-ray diffraction (XRD) were performed. The test results indicated that the optimum level of the alkali activator ratio ($Na_2SiO_3$/NaOH) for fly ash-based geopolymer using stone powder sludge was 1.5. The strength development is closely related to the NaOH solution concentration. In addition, the compressive strength of the sample cured at $25^{\circ}C$ was significantly improved between 7 days and 28 days, even though the strength of the sample showed the lowest value at 7 days. Microscopy results indicated that a higher proportion of unreacted fly ash spheres remained in the sample with 5M NaOH, and some pores on the surface of the sample were observed.

• Journal of the Korean Society of Safety
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• v.19 no.2
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• pp.6-10
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• 2004

The magnetic polishing is the useful method to finish using magnetic power of magnet. This method is one of precision polishing techniques and has an aim of the clean technology using for the pure of gas and inside of the clean pipe for transportation. The magnetic abrasive polishing method is not so common for machine that it tis not spreaded widely. There are rarely researcher in this field because of non-effectiveness of magnetic abrasive. Therefore, in ths paper deals with development of the magnetic abrasive using sludge. In this development, abrasive grain WA and GC used to resin bond fabricated low temperature. And magnetic material was fabricated from the sludge which were crused into 200 mesh and average diameter ${\o}$1.2mm ball type. The XRD analysis result show that only WA and GC abrasive and sludge crystal peaks detected which explains resin bond was not any more chemical reaction. From SEM analysis it tis found that WA and GC abrasive and sludge were stron bonding with each other by bond.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.30 no.1
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• pp.105-114
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• 2007

In this paper, we propose sludge collection strategies which allocate each sewage store of village to sewage treatment plants and decide the schedule of sludge collection in order to collect sludge efficiently. The strategies aim to decrease transportation cost with deciding proposed vehicle routing and scheduling the sludge collection. When we decide route of vehicles, we consider the collection time in sewage store of village, distance between sewage store of villages and vehicle information as average velocity of vehicle, operation time of vehicle driver. We also develop the SCMS (Sludge Collection Management System) based on windows system with real data which is used in certain circumstance. And we experiment to figure out vehicle route and transportation cost throughout changing input data.

• Korean Chemical Engineering Research
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• v.52 no.4
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• pp.413-424
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• 2014

The potential of using the biogas as energy source has long been widely recognised and current techniques are being developed to upgrade the technical quality and to enhance energy efficiency. The objective of this paper is to present efficient and effective pre-treatment methods of increasing the amount of produced biogas in anaerobic digestion of activated sludge treatment process. The paper also presents a review of the effect on biogas production between pre-treated and raw sludge, and also put forward the advantages and disadvantages of each pre-treatment method.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.1 no.1
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• pp.56-61
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• 2001

Activated sludge processes are broadly used in the biological wastewater treatment processes. The activated sludge processes are complex systems because of the many factors such as the variation of influent flowrate and ingredients, the complexity of biological reactions, and the various operation conditions. The main motivation o this research is to develop an intelligent control strategy for activated sludge process (ASP). ASP is a complex and nonlinear dynamic system owing to the characteristic of wastewater, the change in influent flowrate, weather conditions, and so on. The mathematical model of ASP also includes the uncertainty which is a ignored or unconsidered factor from process designers. The ASP model based on Matlabⓡ/Simulinkⓡ is developed in this paper. And the model performance is examined by IWA (International Water Association) and COST (European Cooperation in the filed of Scientific and Technical Research) data. The model tests derive steady-state results of 14 days. In this paper, fuzzy logic control approach is applied to handle DO concentrations. The fuzzy logic controller includes two inputs and one output to adjust air flowrate. The objective function for the optimization, in the implemented evolutionary strategy, is formed with focusing on improving the effluent quality and reducing the operating cost.