박영수 Yeong Su Park , 전병준 Byung Joon Chon , 구재회 Jae Hoi Gu , Poudel Jeeban

DOI:10.9786/kswm.2014.31.5.469

Abstract

A RPS (Renewable Portfolio Standard) for South Korea became effective in 2012 with a beginning renewable electricity quota of 2% of total generation of capacities exceeding 500 MW, increasing to 10% by 2022. However, almost of all the coal-fired power plant are not designed to co-firing large amount of biomass with coal. In practice, the biomass cofiring rate is commonly 5 -10% of total heat input. In the case of biomass import, it will cost a great deal on the transshipment, transportation and storage of biomass. Therefore new research and development on the biomass fuel with high energy density in needed to reduce logistics cost on transportation of the biomass fuel. Torrefaction is a thermochemical treatment process of biomass at temperatures ranging between 200 and 300oC. During this process, 70% of the mass is retained as a solid product, and retain 90% of the initial energy content. The physical and chemical properties of torrefied biomass are similar to those of coal. Therefore co-firing torrefied biomass could increase the co-firing percentages much further to even 40%. This review paper looks into the torrefaction technologies of biomass, the technical characteristic of torrefaction reactors, the overview of torrefaction project and the future prospects of torrefaction.

Key Words

Torrefaction, Carbonization, Biomass, Torrefaction technologies, Torrefaction reactor, Torrefiers

손준익 Jun Ik Son , 김기헌 Ki Heon Kim , 홍용희 Yong Hee Hong

DOI:10.9786/kswm.2014.31.5.480

Abstract

In this study those currently operating SRF (Solid Refuse Fuel) combustion plant were selected for the investigation. The SRF component analysis, and the reaction time to collect contaminants collected and analyzed. As the result, the average caloric value of the SRF was about 8,114 kcal/kg and the result of the analysis was satisfied with the Fuel standard. The SRF could be used as an alternative Coal fuel. However CO, NOx and Dust analysis result was exceeded the emission standard. In case of Hydrogen chloride, high concentration of emission from the facilities was observed. Although normal operation was performed, ineffective the operational management causedt, incomplete blockage of drug injection facilities and personnel management system. To prevent such problems, a regular maintenance of facilities is need to be installed. At the moment applied to the monitoring system (TMS) are installed in waste incinerators with the medium to large capacities, However such as a periodically monitoring system is needed to manage a small solid fuel boliers as well.

Key Words

SRF, Combustion, Solid fuel

나춘기 Choon Ki Na , 송명기 Myung Ki Song

DOI:10.9786/kswm.2014.31.5.487

Abstract

This research investigated the feasibility of rice husk as a biosorbent for removal of ammonium ion from aqueous solutions. To improve the sorption functionality of rice husk, the carboxyl groups were chemically bound to the surface of the rice husk by graft polymerization of acrylic acid using potassium peroxydisulphate as a redox initiator. The removal of ammonium ion by rice husk grafted with acrylic acid (RH-g-AA) was studied in a batch mode and fixed bed columns. The kinetic and equilibrium data obtained from batch experiments follow the second-order kinetics and fit well with the Langmuir isotherm model. The sorption energy determined from D-R model was 8.61 kJ/mol indicating an ion-exchange process as the primary sorption mechanism. To determine the characteristic parameters of the column useful for process design, four mathematical models; Bed Depth Service Time (BDST), Bohart-Adams, Clark and Wolborska models were applied to experimental data obtained from the fixed bed columns with varying bed heights. All models were found to be suitable for simulating the whole or a definite part of breakthrough curves, but the Wolborska model was the best. The fixed bed sorption capacity determined from the Wolborska model was in the range 33.3 ~ 40.5 mg/g close to the value determined in the batch process. The thickness of mass-transfer zone was calculated to be approximately 40 mm from DBST model. The RH-g-AA sorbent could be regenerated by a simple acid washing process without a serious lowering the sorption capacity or physical durability.

Key Words

Biosorbent, Ammonia, Sorption equilibrium, Fixed bed column, Modelling

정승미 Seung Mi Jeong , 황다혜 Da Hye Hwang , 노혜경 Hye Gyoung Nho , 이현우 Hyun Woo Lee , 김용진 Yong Jin Kim , 이동훈 Dong Hoon Lee

DOI:10.9786/kswm.2014.31.5.498

Abstract

This study focused on immobilization of Saccharomyces coreanus to support materials and ethanol fermentation by the immobilized yeast. Three porous media as support material were surveyed; synthetic zeolite, aluminum silicate and granular activated carbon. Amount of yeast (determined by organic matter content) immobilized into/on support materials was lowest in fermentation using aluminum silicate as supports. Glucose as substrate of ethanol fermentation was easily sorbed more than ethanol into/on 3 types of support materials. Of these, absorbed amount of glucose and ethanol into/ on activated carbon was highest. The ethanol was actively produced for 16 hours in fermentation processes by yeast immobilized into/on aluminum silicate and activated carbon, produced after 16 hours by yeast immobilized into/on zeolite. The produced ethanol concentration after 24 h was as follows; 24.2 g/L by using aluminum silicate, 19.3 g/L by activated carbon and 16.1 g/L by zeolite.

Key Words

Immobilization, Yeast, Aluminum silicate, Zeolite, Activated carbon, Bioethanol

이윤희 Yun Hee Lee , 민경남 Kyoung Nam Min , 이재원 Jae Won Lee , 이중관 Jung Gwan Lee , 어성욱 Seong Wook Oa

DOI:10.9786/kswm.2014.31.5.505

Abstract

Asbestos contaminated soil remediation was performed depending on wind velocity and water content using a wind remediation treatment device. The soil samples were collected from upland and paddy soil near inactive asbestos mine and 8% wollastonite was applied instead of asbestos due to health hazard. The wollastonite in soil was analyzed by scanning electron microscopy (SEM) combined with energy dispersive spectrometer (EDS). With 8 m/s of wind velocity, 86% and 92.8% of wollastonite in upland soil and paddy soil were releasable, respectively. When distance from air blast module in the device was 1 ~ 1.5 m, the removal efficiency was highly significant. The removal efficiency decreased as increased as the distance. The releasable wollastonite was significantly affected by water content rather than wind velocity, and this tendency was pronounced with paddy soil. With 0% water content, the correlation between distance and residual amount of wollastonite was low, while the removal efficiency of wollastonite was the highest. Consequently, the removal efficiency of wollastonite was increased with high wind velocity and low water content. For the effective asbestos contaminated soil remediation based on this study, controlling equipment for wind velocity and water content requires in pilot-scale plant and additionally enough air injection and sufficient volume of dust collection module are necessary.

Key Words

Releasable asbestos, Soil contamination, Water content, Wind velocity, Wind remediation treatment device

김병일 Byoung Il Kim , 이문환 Mun Hwan Lee , 이세현 Sea Hyun Lee , 김규현 Gue Hyun Kim

DOI:10.9786/kswm.2014.31.5.514

Abstract

This study introduces physical property of biodegradable construction materials and their possible methods of performance evaluation. The used biodegradable polymer was Polycarporlactone and additionally Starch and pMDI was also mixed to accelerate biodegradation of composites as well as reduce the cost of composites. Tensile strength, modulus and elongation was measured as to Starch and pMDI mixing ratio to PCL. Test results showed that the addition of Starch resulted in the reduction of tensile strength, modulus and elongation due to the weakness of PCL-Starch interfaces. On the other hand, the addition of pMDI to composites improved physical property and the best effect was revealed when the composites were PCL/Starch (80/20) resulting reinforcement of PCL-Starch interfaces. The performance evaluation of possible biodegradable construction materials was summarized by systematical methods. The requirement conditions for complex-type vegegation unit was first arranged and then transferred to requirement performance. The test performance was classified based on KS ISO standards from non-biodegradable plastics test methods. Finally, environmental performance was proposed by evaluating life cycle assessment of biodegradable construction materials from production of raw materials to decomposition of composites-type vegetation unit.

Key Words

Biodegradable polymer, Polycarprolactone, Starch, Vegetation mat, Life cycle assessment, LCA

최효현 Hyo Hyun Choi , 강영렬 Young Yeul Kang , 김우일 Woo Il Kim , 오길종 Gil Jong Oh

DOI:10.9786/kswm.2014.31.5.526

Abstract

This study was performed to prediction of generation and estimation of recycling value on waste artificial turf. The artificial turf consist of a different components by playground type, and combined of plastic, silica, and rubber materials. The weight per unit area of artificial turf is about 67.5% of the silica that is the highest, and infill rubber powder, pile, backing in order. As the result of investigation on artificial turf installation area from 2003 to 2012, the school playground is the largest portion because the development business plan of variety school grounds by government. And installed artificial turf will be discharge as the end of lifespan from 2011 to 2020. As the results of generation prediction by trend analysis, logarithmic function was estimated the most optimum method among the trend analysis. If 86.9% is recycled by Case II, the valuable materials of waste artificial turf was estimated that an annual average of about 2,990 tons of pile, about 2,177 tons of backing, about 52,803 tons of quartz sand, and about 20,241 tons of infill rubber powder in 2021 ~ 2040, respectively. It was evaluated to efficient recycling method of waste artificial turf that separated into the fabric and infill materials through first screening, and then infill materials separated into the silica and rubber powder through second screening.

Key Words

Waste artificial turf, Prediction of generation, Estimation of recycling, Logarithmic function, Trend analysis

유흥민 Heung Min Yoo , 김기헌 Ki Heon Kim , 서용칠 Yong Chil Seo , 박세원 Se Won Park

DOI:10.9786/kswm.2014.31.5.535

Abstract

Since the volume based tipping system was adopted for municipal solid wastes in Korea, the system has been well implied with the positive participation of households. Therefor local governments have started to apply the system to food wastes as well in recent years and each household has put an effort to reduce the generation of food wastes consequently. Another big movement on the management of municipal solid waste has been made, which was intending to utilize wastes to energy resources by converting to solid refuse fuel (SRF). In the meantime the conversion of biomass to energy became an issue to argument national renewable energy. Such motivation made an attempt to utilize fruit husks as SRFs since they has been used to dispose of as food wastes with the payment of tipping fee by households. Thus, in this study, five fruits (mandarine, apple, pear, sweet persimmon and grape) of 6 main consuming fruits in Korea were chosen as tested materials to check out any potentials of biomass SRFs. The basic characteristics of 5 fruit husks after drying naturally were analyzed. Heating values, proximate analysis results were reported and thermo-gravimetric tests were made for suggesting them to combustible wastes or bio-SRFs. The higher heating values of all fruit husks with natural drying showed above 3,000 kcal/kg which is the criterium of SRF and the lower heating values were less than SRF standard due to higher content of moisture. Proximate analysis and thermo-gravimetric data were similar to other biomass fuels like wood and municipal solid waste. It is concluded that such fruit husks could be used as SRFs by adopting an effective drying method in advance.

Key Words

Fruit husk, Volume based tipping system, Combustible waste, Food waste, Bio-SRF

윤용수 Yong Soo Yoon , 김사동 Sa Dong Kim

DOI:10.9786/kswm.2014.31.5.542

Abstract

The aim of this paper is to compare the characteristics of the T-P removal from synthesized municipal wastewater by electro-coagulation using cylindrical Al and Fe electrode as anode. For this purpose, a concentric circle type electrolysis reactor was used and the operating conditions for T-P removal from synthesized wastewater are as follows; potential 10 V, electrolyte 0.03% NaCl, initial T-P concentration 1.0 ~ 6.0 mg/L and flow rate 1.0 ~ 5.0 L/min. From the experimental results, T-P concentration of treated wastewater was decreased to less than 0.2 mg/L enough to discharge standard and Al electrode showed performance than Fe electrode for T-P removal by electro-coagulation. Optimal conditions for T-P removal to less than 0.15 mg/L which is 75% of discharge standard for large scale municipal wastewater plant (capacity higher than 500 m3/day) were obtained as follows; flow rate 2.503 L/min, and 2.337 L/min, HRT 1.059 min, 1.134 min, for Al and Fe electrode, respectively. Consumed mass of Al and Fe were of 3.76 times and 8.90 times respectively, were obtained to removed T-P at optimal conditions with potential 10 V, and 0.03% NaCl as electrolyte.

Key Words

T-P removal, Electro-coagulation, Al electrode, Fe electrode

노다지 Da Ji Noh , 강대엽 Dae Yeop Kang , 김미란 Mi Ran Kim , 이제근 Jea Keun Lee

DOI:10.9786/kswm.2014.31.5.549

Abstract

From the results of GC-FPD and GC-MS analysis, the major odorous compounds emitted from a sewage sludge dryer were identified as sulfur compounds, aldehydes, fatty acids and amine compounds, which accounted for 99.99% of the total calculated odor concentration. Three kinds of wet packed beds, such as an alkali wet packed bed, an electrolytic wet packed bed and an alkali-electrolytic dual wet packed bed, were used to investigate the removal characteristics of the odorous compounds from the dryer. The results obtained were; in an alkali wet packed bed, isovaleric acid and trimethylamine were removed over 99% under NaOH/S mass ratio of 0.5. However, sulfur compounds were removed at much higher NaOH/S mass ratio of 20. In an electrolytic wet packed bed, the removal efficiencies of sulfur compounds showed 99% under a HOCl/S mass ratio of 10. When an alkali-electrolytic wet dual packed bed was used, however, higher removal efficiencies for most of the odorous compounds were obtained under the lower NaOH/S and HOCl/S mass ratioscompared to those in each single alkali wet packed bed or electrolytic wet packed bed.

Key Words

Odorous compounds, Sewage sludge dryer, Removal characteristics, Calculated odor concentration, Alkalielectrolytic wet dual packed bed

Zheng Hua Piao , Xin Zhao , 이종근 Jong Keun Lee , 김재영 Jae Young Kim

DOI:10.9786/kswm.2014.31.5.561

Abstract

Seaweeds are received high attending as one of new and renewable energy sources. In this study, the effects of organic loading rate (OLR) and hydraulic retention time (HRT) on anaerobic digestion with Laminaria japonica were investigated using labrotory-scale semi-continuous stirred type reactors. The results demonstrated that anaerobic digestion of Laminaria japonica performed stably with OLRs in the range of 1.00 ~ 1.50 g-VS/L.d and HRTs in the range of 27 ~ 40 days. The maximum methane production obtained was 251.33 mL-CH4/L.d, which was achieved for an OLR of 1.50 g-VS/L.d and a HRT of 27 days. However, an OLR of 1.75 g-VS/L.d and a HRT of 23 days brought about a decrease in the pH and volatile fatty acids (VFAs) accumulation, causing the destabilization of the reactor and process failure. The reactors operated at a constant influent substrate concentration, i.e., 40 g-VS/L, thus OLR and HRT could not be treated separately and independently. According to the limited results of this study, it seems that the suitable OLR of anaerobic digestion of Laminaria japonica was lower than 1.50 g-VS/L.d and suitable HRT was higher than 27 days.

Key Words

Laminaria japonica, Anaerobic digestion, Organic loading rate, Hydraulic retention time

김형진 Hyung Jin Kim , 이갑수 Kab Soo Lee , 김상식 Sang Sik Kim , 조진규 Jin Kyu Cho , 강형석 Hyung Seok Kang , 박경북 Kyung Buk Park

DOI:10.9786/kswm.2014.31.5.567

Abstract

The mock-up test was carried out to evaluate applicability of unmanned coating method to prevent asbestos scattering from fiber insulation board in same vibration condition of school. Fiber insulation boards were cut into uniform size and attached in checker figure. Bang machine and rubber hammer were used to scatter asbestos sufficiently. Sodium silicate was used as a asbestos scattering inhibitor. The asbestos concentration was counted by PCM (Phase Contrast Microscope) and TEM (Transmission Electron Microscope). Asbestos concentration was 0.014 (1st day) and 0.021 (14th day) f/cm3, respectively in case of without coating. Asbestos concentration was 0.006 (1st day) and 0.008 (14th day) f/cm3, respectively in case of unmanned coating method. It was satisfied the standard of asbestos concentration in indoor air quality management law. So unmanned coating method was applicable to prevent asbestos scattering from fiber insulation board in buildings

Key Words

Mock-up test, Unmanned coating method, Asbestos, Fiber insulation board, PCM

백선재 Seon Jai Baik , 한인섭 In Sup Han , 홍성민 Seoung Min Hong , 강성효 Sung Hyo Kang

DOI:10.9786/kswm.2014.31.5.574

Abstract

The amount of sewage treatment has been increasing year by year as the small and medium sized cities grow in Korea. Besides, the treatment of sludge has been more significant owing to the total ban on disposal of organic sludge in a landfill since April 2004 and ocean dumping of organic waste since December 2013. In this research, we studied the drying characteristics of sewage sludge by indirect heating device using thermal oil. The indirect heating device operated in a batch for 16 hours according to the variation of drying temperature between 100 and 200oC and the initial input weight of each type of sewage sludge was equally 60 kg. As a result, the moisture content in raw, excess and mixed sludge became lower than 10% under 14 hours at 160oC. The average water loss rate of raw, excess and mixed sludge is 0.436 g-wet/ min, 0.362 g-wet/min and 0.367 g-wet/min respectively at this stage. Therefore, the raw sludge can be dried well, using indirect heating device in sewage treatment plant. Also, it is better to dry raw sludge or excess sludge alone than mixed sludge because each type of sludge does not make synergistic effect but counter effect when they are together.

Key Words

Sewage sludge, Dry, Thermal oil, Indirect heating

조현대 Hyun Dae Cho , 도재범 Jae Beom Do , 김보수 Bo Soo Kim , 정재동 Jae Dong Jaung

DOI:10.9786/kswm.2014.31.5.581

Abstract

In this study, the vibratory crusher was developed to develop the high quality recycled coarse aggregate for concrete. The vibratory crusher was installed on the production line of recycled aggregate and the produced recycled aggregate was compared with that from conventional crusher for evaluation of the performance of vibratory crusher and the quality of the produced recycled aggregate. The results showed that the performance of the recycled aggregate was better than conventional aggregate by 39% in water absorption ratio, 10% in absolute dry density, 31% in resistance to wearing, 14% in satisfactory particle size distribution, 41% in volume of clay ball and 32% in safety, thus showing that the quality of the recycled coarse aggregate is much improved. The microscopic observation showed that a lot of mortar, minute cracks and segregation have been removed.

Key Words

Vibratory crusher, Recycled coarse aggregate, Cone crusher