• Proceedings of the KIEE Conference
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• 대한전기학회 2001년도 하계학술대회 논문집 C
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• pp.1777-1779
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• 2001

In this experiment, an attempt to use the sludge pellets as catalyst for NO removal from simulated gas is experimentally investigated by using cylinder type reactor. An experimental investigation has been conducted for NO concentration of 50[ppm], 100[ppm], 200[ppm] balanced with air. a gas flow rate of 5[1/min]. Cylinder type reactor is at upstream of system for corona discharge and packed bed type reactor filled with sludge pellets ate put at downstream of Cylinder type reactor for catalystic effect. And AC voltage to discharge the gases was supplied. In the result, NO removal with magnetic field is higher than that without magnetic field, when packed-bed reactor with sludge pellet is installed at downstream of cylinder reactor NO, $NO_2$ removal rate increased and $O_3$ is not generated.

• Clean Technology
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• 제23권3호
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• pp.331-342
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• 2017

To estimate the combustion characteristics of sewage sludge and wood pellet, thermogravimetric analysis (TGA) was conducted. As TGA results, combustion characteristics of sewage sludge was worse than wood pellet. In ash fusion temperature (AFT) analysis, slagging tendency of sewage sludge is very high compared to wood pellet. And also, the bubbling fluidized bed reactor with a inner diameter 400 mm and a height of 4300 mm was used for experimental study of combustion characteristics fueled by sewage sludge and wood pellet. The facility consists of a fluidized bed reactor, preheater, screw feeder, cyclone, ash capture equipment and gas analyzer. The thermal input of sewage sludge cases were $54.5{\sim}96.5kW_{th}$, in case of wood pellet experiment, it was $96.1kW_{th}$. As experiment results, the $NO_x$ emission of sewage sludge was averagely about 10 times the $NO_x$ emission of wood pellet. And also CO emission of sewage sludge is about 3.5 times of wood pellet. Lastly as a result of analysis of captured ash in cyclone, the combustion efficiency of all cases were over 99%, but the potential for slagging/fouling was high at all cases by component analysis of ash.

• Journal of Korean Society of Water and Wastewater
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• 제13권4호
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• pp.35-44
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• 1999

In this study, it was attempted to remove nitrate and carbon in a single-stage reactor using acetate as substrate. Hybrid type upflow sludge baffled filter reactor was adopted using anaerobic sludge. Sludge bed in the bottom of reactor was intended to remove carbon and nitrate by denitrification and methanogenesis. And floating media in the upper part of reactor were intended to remove remaining carbon which was not removed due to the inhibition of nitrogen oxide on methane producing bacteria. The reactor removed over 96% of COD and most of nitrate with volumetric loading rate of $4.0kgCOD/m^3{\cdot}day$, hydraulic retention time of 24hr, 4,000mgCOD/L, and $266mgNO_3-N/L$. Nitrate in anaerobic sludge was converted to nitrogen gas(denitrification) or ammonia (ammonification) according to pH of influent, COD removal efficiency was easily affected by the change of volumetric loading rates and nitrate concentration. And when influent pH was about 4.7, most nitrate changed to ammonia while when influent pH was about 6.8~7.0, most nitrate denitrified independent of $COD/NO_3-N$ ratio. Most granules were gray and a few were black. In gray-colored granule, black inner side was covered with gray substance and SEM illustrated Methanoccoci type microorganisms which were compact spherical shape. Anaerobic filter removed residual COD effectively which was left in sludge bed due to the inhibition of nitrogen oxide.

• Journal of the Korean Society of Combustion
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• 제1권1호
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• pp.1-10
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• 1996

An effective scale-up methodology of fluidized bed incinerators for low calorific value industrial wastes such as paper sludge and sewage sludge has been developed based on the similarity rules. Conventional scale-up theories are briefly reviewed and a new simple theory defining the diffusion Fourier number is established taking account of the lateral mixing of fuels in the fluidized bed. From the design and the operating conditions of the pilot FBC plant at Inchon, important design data for the full-scale incinerators are calculated and discussed.

• Journal of Environmental Health Sciences
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• 제33권6호
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• pp.488-492
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• 2007

The influence of additive materials including saw dust and cow manure in the ripening of leather sludge for the efficient vermisabilization was studied. The ripening characteristics of the leather sludge, the growth of earthworms in the growth bed and the by-products like cast were observed according to the mixing ratio of additive materials. When the mixed leather sludge of which the additive materials contents were over 20% were ripened for 50 days, the values of ORP and alkalinity were changed to the favorable ranges for earthworms, the positive (+) and below 1,000 mg/l as $CaCO_3$, respectively. The velocity of ripening improving the characteristics of the leather sludge was faster in the sludge mixed with cow manure than saw dust. This results could also be verified from the monitoring of the states of earthworm growth using the survival rate, the increase rate of lifeweight and the hatching rate of earthworm cocoon in the their growth bed packed with the ripened sludge. The values of CEC in cast, the vermi-stabilized sludge, were increased with the mixing ratio of additive materials, but the content of heavy metals was drcreased by the dilution effect and accumulation in the earthworm body. Above results show that the leather sludge might be efficiently stabilized by earthworms through the ripening for 50 days using additive materials. Cow manure can be used as a good additive materials for leather sludge as much as saw dust, and the optimum content of additive materials in the well-ripened leather sludge was about 30%.

• Journal of the Korea Organic Resources Recycling Association
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• 제20권3호
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• pp.27-33
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• 2012

According to the statistics of the Ministry of Environment, the emission of sewage sludge is increased by 7~9% yearly. In the future, it will be increased continuously because of extension of sewage disposal plants, high class treatment for removing nitrogen and phosphorus. Until now, we have depended on reclamation for lots of quantity and some part has been treated by ocean emission. But, direct reclamation of organic waste will be prohibited and even ocean emission will be prohibited now, so the treatment of sludge is put on emergency alert. Bio-gas can be produced by applying anaerobic digestion method for the recycling or refuse derived fuel can be conducted by applying carbonization method. However, the process is difficult, causes bad smell and makes it the second waste, so it cannot be practical method in fact. This study applied a fluidized bed combustor for sewage sludge treatment technologies that can actually take advantage of key technologies in order to verify its purpose is to demonstrate selected. If applying the fluidized bed combustor, it can be easily utilized as the replaced resource of energy(fuel) in the countries whose energy resources are insufficient, like our country. Especially, if applying only original strengths of the fluidized bed combustor sufficiently, the sewage sludge can be treated simply, eco-friendly, sanitarily and economically. Particularly, it is verified as the energy technology suitable for government's green growth policy.

• Journal of Ocean Engineering and Technology
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• 제17권2호
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• pp.8-13
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• 2003

Soil, ground water, and sea bed are exposed to a continuous accumulation of polluted materials, causing serious environmental damage. It has been reported that such pollution causes a massive mortality of fish stock in rivers due to the resuspension of toxic chemicals, occurring during strong wind conditions. Therefore, it becomes apparent that there is an immediate demand for the restoration treatment of polluted river bed (or sea bed) sediment layers. Pollution levels of major rivers and ports, such as Paldang, Kyungan rivers, and Masan port, are becoming of great public concern, and are posing a serious environmental threat. In particular, the pollution of the Shi-hwa river has become a nation wide issue for the last few years. In spite of such public concern, the pollution levels of such rivers or ports are worsening everyday. In this study, an environmentally sound engineering package is introduced that helps to restore the polluted river bed or sea bed sediments. This engineering package consists of a suction facility, followed by a series of mechanical, chemical, and biological treatment units. The suction facility is designed to minimize secondary pollution that occurs from the resuspension of toxic materials during suction. The sea bed cleaning engineering package is designed to be installed on the top of a floating barge. Such a combination of environmental plant and shipbuilding technology provides a cost-effective solution, minimizing the transportation between suction and treatment facilities.

• Environmental Engineering Research
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• 제11권4호
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• pp.173-180
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• 2006

Autotrophic nitrogen removal and its microbial community from a laboratory scale upflow anaerobic sludge bed reactor were characterized with dynamic behavior of nitrogen removal and sequencing result of molecular technique (DNA extraction, PCR and amplification of 16S rDNA), respectively. In the experiment treating inorganic wastewater, the anaerobic granular sludge from a full-scale UASB reactor treating industrial wastewater was inoculated as seed biomass. The operating results revealed that an addition of hydroxylamine would result in lithoautotrophic ammonium oxidation to nitrite/nitrate, and also hydrazine would play an important role for the success of sustainable nitrogen removal process. Total N and ammonium removal of 48% and 92% was observed, corresponding to nitrogen conversion of 0.023 g N/L-d. The reddish brown-colored granular sludge with a diameter of $1{\sim}2\;mm$ was observed at the lower part of sludge bed. The microbial characterization suggests that an anoxic ammonium oxidizer and an anoxic denitrifying autotrophic nitrifier contribute mainly to the nitrogen removal in the reactor. The results revealed the feasibility on development of high performance lithoautotrophic nitrogen removal process with its microbial granulation.

• Proceedings of the KIEE Conference
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• 대한전기학회 2001년도 하계학술대회 논문집 C
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• pp.1780-1782
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• 2001

In this experiment, an attempt to use the sludge pellets as catalyst for NO removal from simulated gas is experimentally investigated by using $BaTiO_3$-sludge packed-bed reactor of plate-plate geometry. An experimental investigation has been conducted for NO concentration of 50[ppm] balanced with air, a gas flow rate of 5[1/min]. $BaTiO_3$ pellets are filled at upstream of reactor for corona discharge and sludge pellets are put at downstream of reactor for catalystic effect. The volume rate of sludge pellets to $BaTiO_3$ pellets is 50[%] and AC voltage to dischare the gases was supplied. In the result, when sludge pellets is seperated to $BaTiO_3$ by other reactor and AC voltage is supplied to $BaTiO_3$ and sludge pellets NO, $NO_2$ removal rate is higher. When gas temperature increase from room temperature to 100[$^{\circ}C$], NO removal is decreased while $NO_2$ concentration is independent on gas temperature. This result suggest that the removal mechanism of active oxyzen species and $NO_2$ in sludge is not absorption, but chemical reaction. Temperature of heating treatment is on sludge pellets increased, $NO_x$ removal rate is decrease. It is thought that organic compound is removed by heating treatment.

• Journal of environmental and Sanitary engineering
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• 제13권1호
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• pp.16-25
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• 1998

Laboratory-scale experiment using anaerobic fluidized bed reactor was carried out to investigate the prehydrolysis step with caustic soda on the treatment efficiency of anaerobic sludge treatment, since the overall rate-limiting step for the complete anaerobic digestion of sludge was the hydrolysis step by extracellular bacterial enzymes of insoluble polymeric molecules. Reactors received a sludge which had not been pretreated, a 50-50 mixture of pretreated and untreated sludge, and the fully pretreated sludge. Hydraulic retention time of 10, 5, 2.5 days and 1 day were applied with an respective equivalent organic loading rate of 1.17, 2.23, 4.17, 11.24 gCOD/L/d. Reactor with the untreated sludge did not archieve adequate digestion even at the HRT of 5 days, and reactor, which received the 50-50 mixture, operated well at the HRT of 5 days, but began to show signs of unstable digestion at the HRT of 2.5 days. While, reactor, which was fed the hydrolyzed sludge, operated reasonably well at the 2.5 days, but was showing somewhat decrease in removal efficiencies. Results, therefore, have substantiated that the limiting reaction in the anaerobic treatment process is hydrolysis. The soluble COD did not significantly accumulate in the reactor as organic acid form, even when they were highly stressed. It was believed that this resistance to a build-up of organic acids and soluble COD behavior was mainly due to the maintenance of the methane bacteria in the fixed-film system which prevents washout as the organic loading increased. The anaerobic fluidized bed reactor was therefore effective for the digestion of waste activated sludge at short HRT.