이승희 Seung Whee Rhee , 조영훈 Young Hun Cho

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Abstract

Characterization of ceramic support manufactured by the mixture of spent foundry sands (SFSs) and loess is examined to obtain the optimal conditions of calcination process which is the most important process in manufacturing ceramic supports. SFSs used in this study are furan sand, green sand, and CO2 sand. Ceramic support with SFSs is formed by a extruder. Characterization of ceramic support is estimated by bulk density, porosity, compressive strength, and chemical resistance. From particle size analysis, the order of particle size for SFSs is furan sand>green sand>CO2 sand. As increasing elevating temperature time and calcination temperature, porosity in ceramic support with furan sand is almost similar to that with green sand. As increasing elevating temperature time, compressive strength of ceramic support is in order of furan sand>CO2 sand>green sand. As increasing calcination temperature, compressive strength and durability of ceramic support are improved. As increasing calcination temperature, compressive strength and durability of ceramic support are improved to 9hrs. Porosity of ceramic support is high at 900℃ Hence, it is confirmed that calcination temperature and calcination time can be decided by 900℃ and 9 hrs, respectively.

Key Words

Spent foundry sand, Ceramic support, Recycling, Calcination condition, Compressive strength, Porosity

김신조 Shin Jo Kim , 전태완 Tae Wan Jeon , 신선경 Sun Kyoung Shin , 오길종 Gil Jong Oh , 강영렬 Young Yeul Kang , 황동건 Dong Gun Hwang

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Abstract

This study has been carried out to manage effectively 3 unregulated hazardous organic chemicals (PCBs, PAHs, HCB) in Korea. Total content characteristics of the organic chemicals have been investigated from 16 major hazardous industrial categories such as sludges, waste and mechanical oils, etc. The ranges of concentration of 7 PCBs isomers (IUPAC No.28, 52, 101, 118, 138, 153, 180) and 7 PAHs substances in sludges, which can be dumped into a marine, are N.D~0.429 mg/kg (dry base) and N.D~82.75 mg/kg (dry base), respectively. Among PAHs, naphthalene concentration is detected the highest at coke/petrochemical industry and phenanthrene concentration exceeded 5 times on the 1st standard of Korean Ocean Dumping Act at primary metal industry. The range of HCB concentration, which is regulated in Stockholm Convention, is N.D~0.274 mg/kg (dry base) and detected at chemical manufacturing industry, primary metal industry and the others equipment manufacturing industry.

Key Words

Unregulated organic substance, PCBs, PAHs, HCB, Hazardous waste

김병환 Byung Hwan Kim , 김정헌 Jeong Heon Kim

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Abstract

Activated carbon (AC) is a cheap and effective adsorbent to remove nitrogen oxides (NOx) from flue gas. Experimental study was carried out to remove NOx and dioxins using impregnated activated carbon and catalyst with alumina, manganese (adsorbents/catalysts). The results from the tests demonstrated that adsorbent/catalyst technology with impregnated AC injection is more effective for simultaneous removal of NOx and dioxins emissions from as 100ppm NOx and about 50ng-TEQ/Nm3. For the simultaneous adsorption of NOx and dioxins showed applicable possibility in real plant of this study. Improved ACs and catalysts were injected to the pilot plant, adsorption capacity of NO increased. As a result, it was shown that AC is contributed to simultaneous removal of NOx and dioxins. Additional tests will be performed using the pilot plant for circulation ratio and injection rate.

Key Words

Adsorption, Activated carbon, Nitric oxides, Simultaneous removal, Dioxins

나춘기 Choon Ki Na , 송명기 Myoung Ki Song

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Abstract

As an approach based on resource recovery is preferable, the control over the point sources of N and P recently shifted from removal to recovery, with a particular emphasis on improving the sustainability of wastewater treatments as well as agricultural activities. Struvite precipitation may be an effective method for this purpose. In this study, swine wastewater was treated by chemical coagulation with cationic polymer flocculant and subsequent struvite precipitation. PO4-P was effectively removed from swine wastewater accompanied with SS coagulation and NH4-N was effectively recovered by subsequent struvite precipitation. The NH4-N recovery was effective in the struvite formation with equimolar concentrations of Mg2+, NH4+ and PO4(3-) at pH 10.5, and was more enhanced with seeding the struvite precipitant dried at about 100℃ due to vaporization of NH3 from precipitant during dry which leads the disintegration of struvite into NH4, Mg and PO4. It also indicates that the dried struvite precipitant can be reused as a Mg and P sources for NH4-N recovery with forming struvite precipitation. In a five-step recycle process, NH4-N recovery was initially 81% and progressively decreased to 26% in the fifth stage due to increasing inactiveness of recycled magnesium phosphate. In spite of that, NH4-N recovery based on the recycling of struvite looks attractive in a viewpoint of cost reduction.

Key Words

Swine wastewater, Struvite, Ammonia, Phosphate, Recycling

원철희 Chul Hee Won , 윤선영 Seon Young Yoon , 이현주 Hyun Joo Lee , 임재명 Jay Myoung Rim

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Abstract

This paper shows the experimental results during seven months operation from an anaerobic system treating swine waste. The system was composed of an upflow anaerobic sludge blanket (UASB) and the equipment for its denitrification of nitrate nitrogen which is injected into UASB. To induce the denitrification reaction in UASB reactor, nitrate stock solution (KNO3) with the same flow rate as the swine wastes was fed to the separated feed line with the swine wastes. Nitrate was injected ranged from 50mg/L to 1,000mg/L. C/Nitrate ratio was operated at a rate from 6.7 to 79. The UASB reactor was operated at an organic volumetric loading rate (VLR) of from 1.12kg to 2.28kg TCOD(cr)/m3/day and the removal rate of TCOD(cr) was from 61.6% to 68.8%. As the C/Nitrate ratio decreased, the removal rate of SCOD(cr) gradually increased and was more than 80% at the C/Nitrate ratio was below 12.4. The nitrate removal efficiency was higher than 95% at C/Nitrate ratio above 12.4. It means that short chain fatty acids generated by the acid former and the volatile fatty acids (VFAs) in influent wastewater were easily available for an electron donor in denitrificaiton. Methane production bacteria (MPB) was severe inhibited and methane generation was not happened at C/Nitrate ratio was 6.7. It means that organics removal was possible only by denitrifiers. Consequently, simultaneous denitrification and methanogenesis of the swine wastes containing high concentration of nitrate was performed successfully in UASB reactor.

Key Words

UASB, Denitrification, C/Nitrate ratio, Methanogenesis, Swine waste

권보연 Bo Youn Kweon , 최명찬 Ming Can Cui , 임정현 Jung Hyun Lim , 장민 Min Jang , 심연식 Yon Sik Shim , 김지형 Jee Hyeong Khim

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Abstract

This study investigates low-cost sorbent as replacements for current costly methods of removing heavy metals from AMD (acid mine drainage). This investigation explores the coal mine drain sludge, which is a by-product of AMD of Na-Jeon Mine. The coal drain sludge, which contains 64.7% ferric oxide (Fe2O3) as mainly component, was utilized as an adsorption forCu(II) removal from aqueous solution. The equilibrium and kinetics adsorption was investigated during series of batch adsorption experiments. Langmuir and Freundlich models were used to fit the equilibrium data and Langmuir isotherm was fitted better. The removal efficiency was affected by pH, temperature, initial ion concentration, quantity of adsorbent and contact time. Two simple kinetic model, pseudo-first-and second-order, were used to investigate the adsorption mechanism. The pseudo-first-order reaction kinetics provides the best correlation with the experimental data. As the activation energy was 51.0kJ mol-1 at pH 5.9, the adsorption of Cu(II) onto coal mine drainage sludge was by chemisorption.

Key Words

Adsorption, Cu(2), Coal mine drainage sludge, Equilibrium Kinetics, AMD

김동훈 Dong Hoon Kim , 신항식 Hang Sik Shin , 오세은 Sae Eun Oh

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Abstract

In this study, troublesome high-strength organic waste, food waste leachate was treated using two-stage anaerobic digestion system, consisting of acidogenic sequencing batch reactor (SBR) and methanogenic upflow anaerobic sludge blanket (UASB) reactor. Successful performance was obtained at 2 d of HRT in acidogenic fermenter, but it dropped significantly with decreased solubilization, organic acids production, and biogas production at 1.5 d of HRT. To improve the methanogenesis efficiency, solid portions in the acidogeneic fermenter effluent were removed using membrane. The filtrate passing the membrane with 40-100㎛ of pore size showed the highest CH4 yield at short reaction time, and thus, only this filtrate was fed to the UASB. At 18h of HRT, 87% of COD removal and 297mL CH4/gCOD(added) of CH4 yield were achieved. However, treatment efficiency dropped at shorter HRT. In sum, by operating two-stage anaerobic digestion system treating food waste leachate, 66.7% of COD removal and 62.5% of biogas recovery were achieved at total HRT of 3 days.

Key Words

Food waste Leachate, Anaerobic fermentation, Acidogenesis, Methanogenesis, Biogas

권철기 Cheol Ki Kwon , 이명호 Myung Ho Lee , 조영관 Young Kwan Cho , 이진수 Jin Soo Lee , 이재영 Jai Young Lee

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Abstract

A number of laboratory batch tests were performed using natural apatite. Five different kinds of chemical compounds were selected and mixed with the apatite in order to treat mine tailings contaminated with arsenic and heavy metals. Prior to the batch experiments, basic material property tests were carried out for the mine tailings. From the laboaratory experiments, domestic apatite with 60~70% of purity would be acceptable for the economical purposes and the mixing ratio to produce the stabilizer was found to be 80% of apatite, 5% of Al2(SO4)3·18H(2)O, 5% of FeSO4·7H(2)O, and 5% of MgO.

Key Words

Mine tailings, Apatite compounds, Stabilization, Heavy metals, Arsenic

김현경 Hyeon Kyeong Kim , 김승도 Seung Do Kim

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Abstract

For the support of analysis and decision making in incineration plant, we propose a knowledge-based system. While many efforts have been made to develop complete quantitative incineration process model, complicated thermodynamic nature of the process has made it difficult to build such a model. We face incomplete knowledge in various respects of incineration process. Aiming at an effective computational support for the tasks of diagnosis and planning, we chose a knowledge-based approach with qualitative representation. We will present the design of the overall system with its implementation. Our system represents concepts taken from terminology and reasoning as applied by domain experts.

Key Words

Incinerator for household solid waste, Artificial intelligence, Qualitative reasoning

김혜진 Hye Jin Kim , 박진규 Jin Kyu Park , 이남훈 Nam Hoon Lee

DOI:

Abstract

The EU Landfill Directive of April (99/31/EC) defined the requirements on landfill design and operation and set targets to reduce the amount of biodegradable MSW going to landfill. So, in many country, residual waste had also to be pretreated prior to landfilling. The purpose of this paper was to review the suitability of some available methods for biodegradability testing of MSW and to show limit values of stability index for pretreated MSW. AT4, GB21, DRI, and GS21 are widely used in Europe to assess the biological activity of wastes. And BMP, SOUR and SRI ect. are used to measure the biodegradable organic matters. AT4, DRI, SOUR and SRI ect. are performed under aerobic conditions. And BMP, GB21 and GS21 are performed under anaerobic conditions. There was a close correlation between results obtained from AT4 and GB21. In different investigations, there shows a good correlation between results obtained from aerobic and anaerobic method. Priority was usually given to the determination of aerobic methods (AT4, DRI), as a period of 4 days because aerobic methods were shorter than anaerobic method (GB21, GS21) in a period of 21 days. In Germany and Austria, methods for the determination of AT4 respiration activity and of GB21 gas formation potential are applied as standardized test methods for the assessment of mechanically-biologically pretreated waste. In Germany, the limit values for AT4 lie below 5mg O2/g DM and below 20Nl/g DM for GB21. And in Italy, a Dynamic Respiration Index (DPI) below 1,000mg O2/g VS/h shall deem that the treated residual municipal waste be not any more degradable waste.

Key Words

Biodegradabilty of waste, Mechanically-biologically pretreated waste, Anaerobic microorganism, Stability index (BMP, GB21, GS21 ect.)