• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.240-241
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• 2014

The environmental pollution problem the globally related to global warming arises. In the construction industry the cement mostly use material, generates the great quantity of CO₂ among the fired process and the global warming is more aggravated. In addition, the polysilicon that is the main raw material used in the solar power generation, produces 1 ton and the industrial by-product of 2 tons is generated. In this way, the arising sludge there is not method recycling and it is all discarded. Therefore, in this research, try to present as the fundamental research material for using the polysilicon sludge as the admixture of the cement in order to reduce the amount of the cement. The based on 'KS L ISO 679' was progressed mortar test. the liquidity, air flow rate, setting time, water absorption ratio, flexural and compression strength was measured. According to, appropriate replacement ratio of the polysilicon sludge tries to analyze.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.4
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• pp.2043-2048
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• 2013

OPR-1000 CE Steam Generator, of which tube material is composed of Alloy-600 HTMA in nuclear power plant, secondary side is generated ODSCC(Outside Diameter Stress Corrosion Cracking) due to the accumulated sludge. ODSCC is centered around the tube sheet and is being affected depending on the height of the sludge. Chemical cleaning was carried out for a top-of-the-tube sheet(TTS) of Steam Generator in order to decrease corrosive condition of the secondary side of Steam Generator tubes and suppress the occurrence of stress corrosion cracking. The amount of sludge removal was 259.2kg. The height of the accumulated sludge was reduced from 0.71 to 0.34 inches. Corrosion rate as the maximum 2.34 mils was satisfied to within EPRI (Electric Power Research Institute) recommendation(10 mils).

• Korean Journal of Materials Research
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• v.29 no.10
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• pp.592-602
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• 2019

Feasibility is investigated for reduction of chromium ore by Si sludge with mixed silicothermic and carbothermic reaction. The reduction behavior of chromium ore using Si sludge is investigated precisely to determine the effects of carbon addition, reaction time, and reaction temperature. The pellets are dropped into the furnace after temperature stabilized. As the amount of C addition increases, the amounts of CO and $CO_2$ gas generation increase. After the dropping of the pellets, the pellets are heated and the reaction starts at about 1,573 K or higher. The pellets maintain their shape until 10 min after the drop, and then melted. As the holding time increased, the size of the reduced metal particles increased. The chromium ore is rapidly reduced by the Si sludge, and the slag penetrated into the chromium ore and reduction progressed inside. As the reduction temperature increased, the reaction initiation time is shortened and the reaction fraction of the reduction reaction increased. As the reaction temperature increased, agglomeration of reduced ferrochrome metal is promoted.

• Journal of Electrochemical Science and Technology
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• v.13 no.2
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• pp.186-198
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• 2022

Heavy metals recovery from Printed Circuit Boards industrial wastewater is crucial because of its cost effectiveness and environmental friendliness. In this study, a copper recovery route combining the sequential processes of acid leaching and LIX 984N extracting with an electrowinning technique from Printed Circuit Boards production's sludge was performed. The used residual sludge was originated from Hanoi Urban Environment One Member Limited Company (URENCO). The extracted solution from the printed circuit boards waste sludge containing a high copper concentration of 19.2 g/L and a small amount of iron (0.575 ppm) was used as electrolyte for the subsequent electrolysis process. By using a simulation model for multi-step current electrolysis, the reasonable current densities for an electrolysis time interval of 30 minutes were determined, to optimize the specific consumption energy for the copper recovery. The mathematical simulation model was built to calculate the important parameters of this process.

• Korean Journal of Environmental Agriculture
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• v.9 no.2
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• pp.121-131
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• 1990

Four crop plants, such as green onion(Allium ascalonicum L.), radish(Raphanus sativus L.), potato(Solanum tubersum L.) and chinese cabbage(Brassica pekinensis Rupr), were grown in greenhouses to determine the accumulations of Cd and Zn absorbed by the plants grown on soils treated with municipal sewage sludge of different levels of 0, 22.5, 45.0 and 90.0 ton $ha^{-1}$ as soil dry weight. The result was analyzed to be comparable to the heavy metal content in the plant tissues among the crop species and the statistical characteristics were investigated to determin a possible relationship between causes of increased contents of Cd and Zn in plants and in soils. The results were as follows : 1. The Cd and Zn content in experimental crop plants increased with increase in quantity of treatment sludge. 2. The Cd and Zn content in roots of all experimental plants increased with sludge treatment amount in soil, in the following order : green onion>potato>chinese cabbage>radish. 3. The Cd content in leaves of crop plants were high in this order : green onion>radish>potato>chinese cabbage, and the Zn content in leaves of crop plants was high in this order. : potato>radish>chinese cabbage>green onion. 4. Concentrations of Cd in potato tubers, radish roots and chinese cabbage leaves ranged from 0.03 to 0.12 ppm. 5. Concentrations of Cd and Zn in plant tissues grown in sludge treated soil of 90.0 ton $ha^{-1}$ were 1.2 to 10 times and 0.4 to 2.3 times higher as compared with those absorbed from sludge-free soil, respectively. 6. The accumulation rates of Cd and Zn in sludge-treated plant tissue were almost constant except for green onion roots.

• 한국연소학회:학술대회논문집
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• 2014.11a
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• pp.267-270
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• 2014

Since contaminants of syngas obtained from the biomass gasification are removed, the syngas is clean fuel. In this study a high-efficiency energy production system is developed. The system produces electricity using a waste pressure and feeds a low-pressure steam to Dyeing industrial complex. Also, iron oxide derived from dyeing sludge is utilized as a self-catalyst to reform a tar and reduce a tar emission from gasifier. This system increases the amount of syngas and finally achieves a highly efficient gasification.

• Journal of the Korean Wood Science and Technology
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• v.48 no.3
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• pp.271-282
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• 2020

Sewage treatment plants are social infrastructure of cities. The sewage distribution rate in Korea is reaching 94% based on the sewage statistics based in the year of 2017. In Korean sewage treatment plants, use of PAC (Poly Aluminum Chloride) accounts for 58%. It contains a large amount of impurities (heavy metal) according to the quality standards, however, there have been insufficient efforts to reinforce the standards or technically improve the quality, which resulted in secondary pollution problems from injecting excessive coagulant. Also, the increase in the use of chemicals is leading to the increases in the annual amount of sewage sludge generated in 2017 and the need to reuse sludge. As such, this study aims to verify the possibility of reusing sludge by evaluating the stability of heavy metals based on the injection of coagulant mixture during water treatment which uses the torrefield wood powder and natural materials, and evaluating the sedimentation and heating value of sewage sludge. As a result of analyzing heavy metals (Cr, Fe, Zn, Cu, Cd, As, Pb, and Ni) from the coagulant mixture and PAC (10%), Cr, Cd, Pb, Ni, and Hg were not detected. As for Zn, while its concentration notified in the quality standards for drinking water is 3 mg/L, only a small amount of 0.007 mg/L was detected in the coagulant mixture. Maximum amounts of over double amounts of Fe, Cu, and As were found with PAC (10%) compared to the coagulant mixture. Also, an analysis of sludge sedimentation found that the coagulant mixture showed a better performance of up to double the speed of the conventional coagulant, PAC (10%). The dry-basis lower heating value of sewage sludge produced by injecting the coagulant mixture was 3,378 kcal/kg, while that of sewage sludge generated due to PAC (10%) was 3,171 kcal/kg; although both coagulants met the requirements to be used as auxiliary fuel at thermal power plants, the coagulant mixture developed in this study could secure heating values 200 kal/kg higher than the counterpart. Therefore, utilization of the coagulant mixture for water treatment rather than PAC (10%) is expected to be more environmentally stable and effective, as it helps generating sludge with better stability against heavy metals, having a faster sludge sedimentation, and higher heating value.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.2
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• pp.161-170
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• 2014

It is essential to decrease energy consumption and excess sludge to economically operate sewage treatment plant. This becomes more important along with a ban on sea dumping and exhaustion of resource. Therefore, many researchers have been study on energy consumption reduction and strategies for minimization of excess sludge production from the activated sludge process. The aeration cost account for a high proportion of maintenance cost because sufficient air is necessary to keep nitrifying bacteria activity of which the oxygen affinity is inferior to that of heterotrophic bacteria. Also, additional costs are incurred to stabilize excess sludge and decrease the volume of sludge. There were anoxic, aerobic, membrane, deairation and concentration zone in this MBR process. Continuous aeration was provided to prevent membrane fouling in membrane zone and intermittent aeration was provided in aerobic zone through ammonia sensor. So, there was the minimum oxygen to remove $NH_4-N$ below limited quantity that could be eliminated in membrane zone. As the result of this control, energy consumption of aeration system declined by between 10.4 % and 19.1 %. Besides, we could maintain high MLSS concentration in concentration zone and this induced the microorganisms to be in starved condition. Consequentially, the amount of excess sludge decrease by about 15 %.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.39 no.4
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• pp.61-67
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• 2007

Paper sludges collected from three different paper mills were physico-chemically analyzed in order to use them as raw materials for making bed soils and seedling pots. The sludge from a fine paper mill contained lots of inorganic pigment particles used for coating, as those from a newsprint mill and a tissue mill had not. It was clearly through XRD analysis confirmed that all sludges included calcium carbonate. The paper sludge from the tissue mill contained the greatest amount of particles, which would contribute to water absorption and nutrient storage. The sludge from the fine paper mill had the highest density due to many inorganic elements. While the ash content and the total nitrogen content were the highest in the sludge from the fine paper mill, the C/N ratio was the lowest in the fine paper mill sludge. All sludges seemed to have insufficient contents of potassium. The sludges from the newsprint mill and the tissue mill showed more silicon contents than that from the fine paper mill. It was concluded that the sludge from the fine paper mill would be able to be the most efficient raw materials for making bed soils and seedling pots and the other two sludges would be more efficient for intensive culture for crops such as rice and grain with additional supplement of nitrogen and other nutrients.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.777-780
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• 2008

There were some attempt to reuse water with sludge combinative water for ready mixed concrete. But recycling water consist of cement, aggregate and chemical admixture. So it caused deterioration of concrete. The object of this study was to search for recycling method of the recycling water sludge as mineral admixture. This experiment dealed with the effect of $2.5{\sim}12.5$% range of the recycling sludge which can be used for admixture binder(BFS, FA, BFS+FA) on properties of activated recycling water sludge for admixture of concrete. As a result, Although the slump levels reduced and air contents increased as sludge replacement levels increased, it didn't change highly. The compression strength of concrete slightly increased with an increasing amount of recycling water sludge replacement.