• Resources Recycling
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• v.33 no.3
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• pp.48-56
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• 2024

In this study, physical property evaluation and physical separation of the target product were performed to investigate the possibility of using sewage sludge gasification solid residue (GSRs) as a circulating resource. Firstly, the GSRs used in this study was supplied by Sudokwon Landfill Management Corporation, and generally the GSRs was in the form of porous pellets with a particle size of several millimetres. In addition, the partially black areas were confirmed to be unburned and ungasified carbon, and the average carbon content was 5%. In addition, the content of silica, alumina and phosphorus oxide was more than 70% of the total content. It was confirmed that the metallic components of the wet grinding product were separated into individual elements. As a physical separation of metallic and non-metallic components was required, it was finally found that flotation screening was suitable. Accordingly, cationic and anionic surfactants were selected to separate metallic components in which a relatively large amount of non-metallic components were concentrated, and the separation characteristics were confirmed. As a result, it is expected that the concentration of non-metallic components such as silica, alumina and phosphorus will be easier than the separation of metallic components. Therefore, since it is possible to physically treat the gasified sludge residue, it is judged to have potential as a circular resource according to the proposed recycling method for the separated product.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.4
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• pp.393-400
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• 2008

1,4-Dioxane($C_4H_8O_2$), which is used as a solvent stabilizer, could make harmful effects on ecosystem because of its higher solubility, toxicity and carcinogenic by US EPA. From 2011, its discharge limit to waterbody will be regulated at 5 mg/L by Ministry of Environment Republic of Korea. It was thus to investigate that the currently operating activated sludge in polyester manufacturing processes in Gumi can properly treat it to meet with the regulation standard. For that purpose, the removal rate of 1,4-dioxane and its microbial properties were assessed for a few companies(i.e. K, H and T). Its removal efficiency was the most highly recorded in H as 98% and then 77% for K, which met with the regulation standard. However, concentration of 1,4-dioxane of T was 23 mg/L in the effluent, which is more than the regulation standard. Aside from, microbial degradation test was done for 100 ppm of 1,4-dioxane in BSM (Basal salt medium) inoculated with each of activated sludge. After 7 days, 1,4-dioxane was completely removed in the test bottle inoculated with H sludge, 67% in T and 52% in K, which could confirm that the given activated sludge might have different biodegradability against the amount of 1,4-dioxane. Therefore, microbial diversity in each company was investigated by 16s rDNA cloning methods where a species, e.g. Methylibium petroleiphilum PM1, was the greatest observed from H and in lesser from K, but it was not detected from T. Methylibium petroleiphilum PM1 is known to efficiently degrade ether like methyl tertiary-butyl ether(MTBE). It is concluded that the activated sludge in H can be most effectively adopted for a biodegradation of 1,4-dioxane in the concern of industrial sector.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.565-570
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• 2001

Annually, Taiwan generates approximately 2 million tons of inorganic wastes in the form of sludge, fly ash and slug. To increase the added value of waste and maintain the increasingly insufficient supply of natural gravel, large public construction projects account for this large demand each year. future architectural trends are leading towards high-rise buildings. In light of the above, Center for Environmental, Safety and Health Technology Development, Industrial Technology Research Institute has developed the technology of manufacturing cold-bonding, sintering and bloating types of lightweight aggregates with a specific gravity ranging between 0.7~1.7, water absorption rate < 30%. The lightweight aggregate verified by physical property tests can be used as a substitute for the natural aggregate, which generally appears in replacing gravel in concrete, soundproofing and heat insulation materials. Doing so would not only moderate waste disposal problems, but also achieve the goal of resource recovery.

• The Plant Pathology Journal
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• v.16 no.5
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• pp.283-285
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• 2000

Two field tests were conducted in 1995 to examine the effects of composts and soil amendments on physicochemical properties of soil in relation to Phytophthora root and crown rot of bell pepper. Chitosan, crab shell waste, humate, sewage sludge-yard trimmings, and wood chips were applied to test plots, some of which affected the levels of P, K, Mg, pH, and H. Physicochemical properties were not related with disease incidence, but percent organic matter, estimated nitrogen release, K, and Mg were correlated with total microbial activity. The elements K and Mg were especially responsible for the increased soil microbial activity that could affect development of root and crown rot of pepper.

• Proceedings of the KIEE Conference
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• 1999.11b
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• pp.291-293
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• 1999

This paper proposed the optimal operational scheduling of cogeneration system for paper mill connected with several auxiliary devices. Auxiliary devices that include auxiliary boilers, waste heat boilers and sludge incinerators operate with multi-cogeneration systems. Especially environment element was considered in objective function to solve the environment problem. And GAs(Genetic Algorithms) was applied to optimize and to analyse nonlinear operational property of cogeneration system of paper mill connected with several auxiliary devices. C-language was used to GAs computation. Electricity can be purchased through power system from utility. The proposed operational strategy on cogeneration system for paper mill to increase energy efficiency can be applied to the similar cogeneration system of industrial field.

• Journal of the Korea Organic Resources Recycling Association
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• v.15 no.3
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• pp.106-112
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• 2007

The purpose of this study is to derive the mixing ratio with stable heating value to be used as fuel and secondary fuel by mixing sewage sludge cake, tar, peat moss, and verify the combustion property of produced solid fuel and the applicability of RDF as alternative fuel. Tar shows the highest heating value with 7,000kcal/kg and the heating value of sewage sludge cake and peat moss ranges from 4,000 to 4,500kcal/kg. Also, the solid fuel with length 1.6cm, diameter 1.3cm and weight 2.3g was produced using the heating value of over 6,000kcal/kg and proper mixing ratio (sewage sludge cake: tar: peat moss) from 1 : 4 : 1 to 1 : 7 : 1. Upon the analysis of the RDF applicability of produced solid fuel, the exhaust gas analysis finds that the composition concentration of exhaust gas occurred according to the mixing ratio did not change significantly and the flame lasting time was found to be around 5 minutes, similar to the lasting time of the same mass (2.3g) of general anthracite burned. Therefore, it can be concluded that solid fuel produced in this study can be used as fuel and secondary fuel.

• Applied Chemistry for Engineering
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• v.17 no.1
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• pp.22-27
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• 2006

Thermal treatment and ozone oxidation methods were examined to reuse waste activated sludge (WAS) produced from a livestock wastewater treatment plant. Analysis of WAS property was made to study usefulness of the recycled waste as fertilizer. From the results of quantitative analysis, WAS particles were found to be composed of 44.25 wt% carbon, 8.43 wt% nitrogen, and 1.35 wt% phosphorus. It was confirmed that the inactivation of pathogenic microorganism was required from the quantitative analysis of microbes. From the results of TSS, COD, SCOD, and pathogenic microorganism measurement, the optimal operating conditions of thermal treatment and ozone oxidation were determined to be 70, 10 min and $0.6L\;O_3/L\;solution{\cdot}min$, 60 min, respectively. The optimized thermal treatment and ozone oxidation represented the efficient pathogen inactivation and particle dissolution, respectively. However, the two methods examined were not themselves sufficient but they need to combine with another treatment for the effective reuse of wastes.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.1
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• pp.111-119
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• 2011

Recently, urban redevelopment programs and expansion of social infrastructure have caused massive amounts of construction waste in construction fields, and the mounds of it keep increasing every year. The disposal of construction waste is emerging as a national and social issue and the recycled powder generated by the treatment process of waste concrete is all being abolished or buried. Therefore, the purpose of this study is to utilize waste sludge generated by the wet-type treatment process of waste concrete as materials(binder, filler) for cement composite. This study evaluates physical and mechanical properties of mortar using recycled powder according to heating temperature, contents and applications. As a result of the chemical analysis, recycled powder is composed mainly of CaO and $SiO_2$, and that it is even lower in the content of CaO than OPC. The charateristics of mortar using recycled powder, according to drying and heating temperature, shows that as the heating temperature increases, flow decreases. Also, compressive strength and porosity of mortar using recycled powder was superior when heating temperature was $600^{\circ}C$. Thus, it is revealed that an effective development of recycled powder is possible since the binder by cement composite recovers a hydraulic property during heating at $600^{\circ}C$.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.251-251
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• 2016

For several decades, industrial processes consume a huge amount of raw water for various objects that consequently results in the generation of large amounts of wastewater. Wastewaters are consisting of complex mixture of different inorganic and organic compounds and some of them can be toxic, hazardous and hard to degrade. These effluents are mainly treated by conventional technologies such are aerobic and anaerobic treatment and chemical coagulation. But, these processes are not suitable for eliminating all hazardous chemical compounds form wastewater and generate a large amount of toxic sludge. Therefore, other processes have been studied and applied together with these techniques to enhance purification results. These include photocatalysis, absorption, advanced oxidation processes, and ozonation, but also have their own drawbacks. In recent years, electrochemical techniques have received attention as wastewater treatment process that could be show higher purification results. Among them, boron doped diamond (BDD) attract attention as electrochemical electrode due to good chemical and electrochemical stability, long lifetime and wide potential window that necessary properties for anode electrode. So, there are many researches about high quality BDD on Nb, Ta, W and Si substrates, but, their application in effluents treatment is not suitable due to high cost of metal and low conductivity of Si. To solve these problems, Ti has been candidate as substrate in consideration of cost and property. But there are adhesion issues that must be overcome to apply Ti as BDD substrate. Al, Cu, Ti and Nb thin films were deposited on Ti substrate to improve adhesion between substrate and BDD thin film. In this paper, BDD films were deposited by hot filament chemical vapor deposition (HF-CVD) method. Prior to deposition, cleaning processes were conducted in acetone, ethanol, and isopropyl alcohol (IPA) using sonification machine for 7 min, respectively. And metal layer with the thickness of 200 nm were deposited by DC magnetron sputtering (DCMS). To analyze microstructure X-ray diffraction (XRD, Bruker gads) and field emission scanning electron microscopy (FE-SEM, Hitachi) were used. It is confirmed that metal layer was effective to adhesion property and improved electrode property. Electrochemical measurements were carried out in a three electrode electrochemical cell containing a 0.5 % H2SO4 in deionized water. As a result, it is confirmed that metal inter layer heavily effect on BDD property by improving adhesion property due to suppressing formation of titanium carbide.

• Journal of the Mineralogical Society of Korea
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• v.20 no.4
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• pp.303-311
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• 2007

The consumption of artificially crushed sands exceeds more than 30 percent of the domestic sand supply in South Korea, and its rate is still increasing. For the manufacture of crushed sand granites and granitic gneisses are preferred, fine fractions (i.e. sludge, particles finer than 63 microns) are removed by use of flocculation agents, and its amount occupy about 15 wt%. The sludges consist of quartz, feldspars, micas, chlorite/vermiculite, kaolinites, smectites and occasionally calcite. Among the clay minerals micas are usually predominant, and $14{\AA}$ minerals, kaolinites and smectites are rather scarce. Jurassic granites usually contain more kaolinites and smectites than those of Cretaceous to Tertiary granites, probably due to longer geologic ages. On the other hand, sludge from Precambrian gneiss does not contain kaolinites and smectites. Chemical analyses for the granites and their sludges show rather clear differences in most of major chemical components. Except for $SiO_2,\;Na_2O\;and\;K_2O$, all other components represent rather clear increase. Decrease of $SiO_2$ content is attributed to the relative decrease of quartz in the sludges. And the $Na_2O decrease is caused by a relatively stronger weathering property of albite compared to Ca plagioclase. The $K_2O$ content shows rather small differences throughout the whole samples. The increases of $Al_2O_3$ and other major components resulted from weathering processes and most of colored components are also concentrated in the sludges. Particle size analyses reveal that the sludges are categorized as sandy loams in a sand-silt-clay triangular diagram. The sludge is now classified as industrial waste because of its impermeability, and this result was also confirmed by rather higher hydraulic conductivities. For the environmental problems, and accomplishing effective sand manufacture, more fresh rocks with little weathering products must be chosen.