계형산 Hyoung San Kye , 신경철 Kyung Chul Shin

DOI:

Abstract

The virgin and recycled polyethylene composites with various ratio of fly ash were manufactured by using a fully intermeshing co-rotating twin screw extruder for the reuse of fly ash from power plant and polyethylene recyclates. In this investigation, fly ash were blended with virgin HDPE and recycled polyethylene in the weight fraction of 0 to 40 wt.%. Mechanical properties such as yield strength, elongation at break, flexural strength and impact strength were measured by ASTM standard. The experimental results for the various composites showed that the elongation at break and the yield stress of composites decreases with increasing fly ash contents. On the other hand, the impact strength of JRPE has highest among the three kinds of polyethylene, however, impact strength of JRPE composites shows decreasing tendency with fly ash contents. It was found that the value of flexural strength of recycled polyethylene composites showed up to 80% of virgin PE composite and it is applicable to the filled structured wall polyethylene sewer pipe and pipe support. Co-continuous phase were found from the morphology of the fly ash composite fracture surface.

Key Words

HDPE, Recycled polyethylene, Mechanical property, Impact strength, Flexural strength

김희진 Hee Jin Kim , 김동수 Dong Su Kim

DOI:

Abstract

Cadmium is one of the widely used metals for an industrial purpose. However, use of the metal has been restricted due to its toxic impacts on the environment. The typical method of treat cadmium would be to remove cadmium ion from water and wastewater in the form of hydroxide compound. The efficiency of Cd(OH)2 recovery depends on not only pH of the water system, but also temperature as an environmental factor. The impact can be theoretically analysed by potential-pH diagrams according to a certain temperature. In this study, thermodynamic data based on 298 K was applied to obtain potential-pH diagrams with increasing thermal conditions. As temperature rises, the dominant change in the diagrams was that there were decreases in the levels of pH at which cadmium ion (Cd2+) and hypocadminate (HCdO2 -) are converted into cadmium hydroxide. It was revealed these patterns follow linear relationships between temperature and the variation of pH (%) compared with value at 298 K. Although both of the Cd2+-Cd(OH)2 and HCdO2 --Cd(OH)2 equilibriums occurred at lowered pH different from each initial condition, the concentration of the two types of ions had an opposite influence on the changing patterns by heating. It showed that as the concentration of cadmium ion increases or the concentration of hypocadminate decreases in wastewater, the impacts become stronger on the rate of variation in pH.

Key Words

Cadmium, Eh-pH diagram, Temperature, pH, Cadmium hydroxide

이은영 Eun Young Lee , 오민환 Min Hwan Oh

DOI:

Abstract

The volatile fatty acids are presented as the major odor of the pig manure, and this 4 kinds materials(propionic acid, nbutyric acid, i-valeric acid, n-valeric acid) are included in 22 legal malodorous compounds in Korea. This research analyzed the emission characteristics of VFAs produced from first time weaner`s manure and effect of the food additives on the emission of VFAs for the efficacy assessment of the additives which is used in order to solve the malodor problem of the piggery. The analysis of the 5 kinds of VFAs (propionic acid, n-butyric acid, i-valeric acid, n-valeric acid, and i-butyric acid)using alkali beads method was performed for seven experimental weeks with triplicate. Each of manures (3 kg) produced from six experimental groups (one kind of control and five kinds of experiments) were collected every week and were put in each the odor generating chamber. Malodorous compounds generated for 6 hours in the chambers were sampled with the absorption tube packed with glass beads from the headspace. The concentration of total volatile fatty acids (TVFAs) in control group was 797.7 ppbv, and all experimental groups fed with environmental improving agents were reduced 13.8 ~ 49.0% as compared to the control group. The concentration of propionic acid, i-butyric acid, n-butyric acid, i-valeric acid, and n-valeric acid of control group were 233.5, 74.4, 291.6, 69.6, and 128.7 ppbv, respectively. Maximumreduction rates of each compound in the experimental groups showed 91.6, 92.3, 94.2, 94.5, and 81.8%, respectively.

Key Words

Volatile fatty acids, Odor, Livestock, Pig

김정대 Joung Dae Kim , 김대근 Dae Keun Kim , 남상철 Sang Cheol Nam

DOI:

Abstract

This study provides an overall assessment of the air environmental effects of co-incineration of waste plastics and coal on field-scale cement plants. Two different types of waste plastics, i. e., densified refuse plastic fuel (RPF) and fluff refuse plastic fuel (fluff RPF), were fed into cement kilns to evaluate the emission characteristics of odor, particle and gas phase air pollutants, and dioxin in exhaust gas. The observed results revealed that the emissions of air pollutants were not significantly influenced by the presence of waste plastics in cement kilns, whereas the emission of dioxin seems to increase by feeding wastes to the kiln. The concentrations were however lower than 0.1 ng-TEQ/Sm3 of emission standard for cement kiln. Feeding types of waste plastics made little difference of the emissions of air pollutants in kilns.

Key Words

Refuse plastic fuel, Waste plastic fluff, Cement kiln, Air pollution

강준구 Jun Gu Kang , 전아현 Ah Hyeon Jeon , 이성수 Sung Su Rhee , 차준석 Jun Seok Cha , 오길종 Gil Jong Oh , 김규연 Kyu Yeon Kim

DOI:

Abstract

In this study, municipal wastes were divided into household wastes and nonhousehold wastes, and household wastes were classified as waste in the standard plastic garbage bag, food waste and recycling waste. Units of household wastes with city size and dwelling type were estimated to manage the effective disposal of municipal waste and to improve a waste managing system. Results showed that a unit of the special city (Type A) was 341.1 g/day/person, 364.7 g/day/ person for the metropolitan city (Type B), 421.8 g/day/person for the small and medium sized city (Type C), and 366.5 g/day/person for the agriculture and fishery village (Type D). In the cases of household wastes with dwelling type, a unit of the apartment was 373.6 g/day/person, the row house was 395.4 g/day/person, the multiplex house was 415.8 g/day/person, the house in the non-residental building was 348.2 g/day/person, and the detached house was 389.9 g/day/person.

Key Words

Municipal waste, Household waste, City size, Dwelling type, A unit

정다위 David Chung , 강영렬 Young Yeul Kang , 연진모 Jin Mo Yeon , 박호연 Ho Yeun Park , 김용준 Yong Jun Kim , 유혜영 Hae Young Yoo , 윤철우 Cheol Woo Yoon , 김민선 Min Sun Kim , 신선경 Sun Kyoung Shin

DOI:

Abstract

Organic hazardous compounds were analyzed and investigated the leaching possibilities for environmentally sound recycling of coal ash. Coal ash generated by power plant of coal would be remained of hazardous substances as Dioxins in ash from incinerator. 33 samples (8 coal and 25 coal ash) were collected and analyed dioxins, PCBs, HCB, PAHs and phenols as hazardous substances by GC/HRMS, GC/ECD, and GC/MSD. In coal ash samples, Dioxins were detected in the range of 0.002 to 0.019 ng/g and co-PCBs detected in the range of 0.005 to 0.042 ng/g but HCB, PAHs, phenols was were not detected. Therefore recycling of coal ash would not affect environmental pollution. In coal samples, Dioxins were detected in the range of 0.016 to 0.090 ng/g, co-PCBs in the range of 0.056 to 0.173 ng/g and PAHs detected in the range of 0.00 to 9.27 ng/g but HCB and phenols were not detected. In the case of PAHs, the concentration in bituminous coal was higher than anthracite coal. Comparing to waste and soil, the concentration of Dioxins and co-PCBs in coal ash was very low. No significant environmental risk is expected from the use of coal ash as filling materials to soil by the substances.

Key Words

Coal ash, Coal, Dioxins, PCDDs/DFs, co-PCBs, HCB, PAHs, phenols

정진도 Jin Do Chung , 임병욱 Byoung Uk Im , 김진완 Jin Wan Kim

DOI:

Abstract

In this study, we investigated medium/long-term physical/chemical characteristics of domestic waste in small and medium cities of Chungcheongnam-do, C city, A city and D gun. Apparent density, physical composition, three ingredients, elementary composition and caloric value of domestic waste of each area in summer season were analyzed in accordance with the waste process test method, the basic unit generation of domestic waste was calculated and future production was predicted. In the result of analysis, no difference in apparent density was shown by district and, as to physical composition, food in C city and A city and paper in D gun showed the highest percentages. The result of analyzing elementary composition showed that carbon content and oxygen content in D gun were lower than those of C city and A city. Also, in the analysis of caloric values, D gun was the lowest showing a value of 2188kcal/kg in comparison to those of C city and A city which were 2,634 kcal/kg and 2,231 kcal/kg respectively. As to the basic unit generation, while there was no big difference between C city and A city which were 1.11 kg/dayperson and 1.02 kg/day person respectively, D gun was 0.63 kg/dayperson showing a big difference.

Key Words

Landfill, Domestic Waste, Physical/Chemical Characteristics

정다위 David Chung , 윤정인 Jung In Yoon , 임진홍 Jin Hong Im , 류지연 Ji Yeon Ryu , 윤철우 Cheol Woo Yoon , 유혜영 Hye Young Yu , 오길종 Gi Jong Oh , 이재형 Jae Hyung Lee , 장순복 Sun Bok Jang , 김혜태 Hea Tae Kim

DOI:

Abstract

In this study the amounts of asbestos-containing material (ACM) used in a farmhouse have been investigated. Types of asbestos wastes that have been taken from the farmhouse were also determined. For management of ACMs in rural areas, information on usage of the farmhouses, the type of roofing material, the year of construction, and the age of residents were collected and used to establish a preliminary database. According to the results, asbestos substances were detected at 805 farmhouses (i.e., 82%) out of 951 that had been investigated in the study. The majority of farmhouses was used for residential purpose, accounting for 86%, and 9% of them were remained as-unoccupied. In total, 1,665 samples turned out to contain chrysotile asbestos, and in 81 samples was also present amosite asbestos. The amount of asbestos waste was estimated to reach 1.4 tons per house.

Key Words

Asbestos, Waste, Farmhouse, Slate, Roof-material, Chrystotile, Amosite

윤용수 Yong Soo Yoon

DOI:

Abstract

This study was performed to investigate the feasibility of an electrolysis of T-P in practical sewage using cylindrical Fe electrode as an anode in a continuous mode and to determine design parameters. Our result shows that the current increased with increasing of potential, and optimal condition was obtained at 10 V. The current of sewage linearly depended on the potential from 5 V to 10 V, but remained stationary above 10 V. Therefore, we performed experiments at the potential at 10 V. The removal of T-P depended on the initial concentration of T-P and inversely depended on the flowrate of synthesized wastewater. From the results of the sewage treatment, the optimal condition of T-P removal was obtained at 10 V, 0.03% NaCl addition and flowrate of 3 LPM. The T-P concentration of the treated sewage was obtained less than 0.16 mg/L. Therefore, we concluded that the electro chemical treatment of T-P can be applied for advanced treatments of sewage and these results will be useful for the design of Ehsms electrochemical treatment plants.

Key Words

T-P, Electrolysis, Flow rate, NaCl

장산 Shan Zhang , 이윤희 Yun Hee Lee , 김태형 Tae Hyeong Kim , 황선진 Sun Jin Hwang

DOI:

Abstract

The effects of initial pH were evaluated on hydrogen production, glucose consumption by Clostridium bifermentans 3AT-ma, and spore germination and endospore-reforming. The initial pH was examined from 4 to 7. The bacteria were not growing at all at the pH 4 condition, resulted in no hydrogen production. The hydrogen production rate and the cumulative hydrogen production were increased as lower as the initial pH ranged from 5 to 7. While the low initial pH inhibited on glucose consumption and spore germination. After the fermentation, depleted glucose and decreased pH caused to spore-reforming resulted in decreased hydrogen production.

Key Words

Bio-H2, Clostridium bifermentans 3AT-ma, pH, Spore-forming

정호준 Ho Jun Jung , 손세구 Se Gu Son , 박은용 Eun Yong Park , 김미경 Mi Kyoung Kim , 김영도 Young Do Kim

DOI:

Abstract

We examined the effect of shrinkage rate and compressive strength by the addition of refractory aggregate to the geopolymer paste containing waste disc. The metakaolin and blast furnace slag, waste disc and several aggregates as mineral source and activator solution which is 0.65 of the molar ratio K2O/SiO2 were prepared for geopolymer composites. The physical fire resistance properties of the composites such as compressive strength, shrinkage rate and surface transition were observed as a function of heat treatment temperature (RT, 500oC and 1000oC). And the linkage structure, phase transition and microstructure characteristics depending on heat treatment were characterized with XRD, FT-IR and SEM analysis. As a result, addition of waste disc were affected with crack decrement of geopolymer paste. And the compressive strength of the composites tended to decrease as the amount of the addition of waste disc without regard to the heat treatment. The results of refractory aggregate addition for improvement the fire resistance efficiency were shown that the surface crack and shrinkage rate of geopolymer composites were decreased. The compressive strength depending on several refractory aggregate at 1000oC heat treatment were shown in decreasing order of amount, refractory aggregate (23.1 MPa) > chamotte (16.1 MPa) > coal bottom ash (14.8 MPa) > sand (10.4 MPa). In the XRD and FT-IR pattern of geopolymer composites made on room temperature, non-crystalline state halo peak (20 ~ 35°(θ) and Si-O-Al bonding band (1,000 cm-1) were observed. Also, after heat treatment, we confirmed that the major crystalline phase were transformed stable phase at high temperature such as leucite (KAlSi2O6), gehlenite (AlCa2Mg0.5O7Si1.5) and anorthite (Al1.77Ca0.88 O8Si2.23). The SEM images indicate the needle shape on the geopolymer paste and mortar containing waste disc. But the images on the heat treated geopolymer composites did not show needle shape fiber. It suggest that the crystalline phase transformed to stable phase, previously observed in XRD pattern.

Key Words

Geopolymer, Shrinkage rate, Compressive strength, Waste disc, Refractory aggregate

장한성 Han Sung Jang , 조영혁 Young Hyuck Cho , 김태오 Tae Oh Kim

DOI:

Abstract

To this end, three cellular phone manufacturers with the same production process were selected, and cellular phone models that have been produced form January, 2009 to December for one year were subject products. A list analysis of subject products with front cover, rear cover, and battery cover was carried out, and the data was used for the Ministry of Environment, the local government, and the relevant company`s material. In addition, product development and environmental characteristics of the process were established as the application area, considering future environment. In terms of functions, function unit, and standard flow, 1set of cellular phone case was used for the study, and the system boundary was divided from the stage providing raw materials to the stage producing the cellular phone case. The factors influencing environment were quantitatively examined, and the basic data to reduce environmental load caused by the greenhouse gas emissions was suggested.

Key Words

LCA, Life cycle assessment, Greenhouse gas, Front cover, Rear cover, Battery cover, Cellular phone

정소연 So Yeon Jeong , 최현주 Hyun Joo Choi , 김동수 Dong Su Kim , 손정수 Jung Soo Sohn

DOI:

Abstract

The adsorption features of Co2+ ion onto granular activated carbon have been investigated by employing artificial wastewater. Based on the calculation using MINTEQ program, the form of Co2+ ion was examined to change from its free ionic state to Co (OH)+ complex with pH and Co (OH)3 - complex was formed in highly alkaline condition. The stable region of free ionic Co2+ was observed to be enlarged as temperature increases, and the adsorption of Co2+ ion was shown to be a second order reaction. The adsorption behaviour of Co2+ ion at equilibrium was explained well by Freundlich adsorption isotherm with the values of adsorption capacity and adsorption intensity as 14.7 and 7.9, respectively. The activation energy for the adsorption reaction of Co2+ ion was observed to be 9.63 kcal/mol and thermodynamic estimation of the adsorption reaction revealed that it is endothermic and exergonic. Also, the entropy of the system was estimated to increase as the adsorption of Co2+ ion proceeds, which was assumed to be due to the desorption of water molecules from adsorbate. Co-existing Cu2+ ion was shown to affect the adsorbability of Co2+ ion more strongly than co-existing Ni2+ ion and the pre-treatment of absorbent by NaOH solution resulted in an increase of the adsorbed amount of Co2+ ion in the concentration condition of above 0.01 mol/L.

Key Words

Cobalt ion, Granular activated carbon, Adsorption, Kinetics, Thermodynamic estimation

전관수 Kwan Soo Jun , 양봉호 Bong Ho Yang , 안남우 Nam Woo Ahn

DOI:

Abstract

The respective effects of sequential ultrasonication followed by ozonation and ozonation followed by ultrasonication on the characteristics of sewage sludge and its methane fermentation were evaluated in this study. The COD of filtrate and centrifugal supernatant from sludge were determined after sequential ozonation for 10 minutes and ultrasonication for 30 minutes. The concentrations of centrifugal supernatant were higher than filtrate as much as 60 ~ 134% in COD. The COD of centrifugal supernatant from sludge after sequential alkaline ozonation followed by ultrasonication was higher than the control and the other as much as 2,756% and 22%. The methane from the ultrasonicated sludge after alkaline ozonation was more than the control and the other as much as 40% and 35%, respectively. The specific resistances of sludge for dewatering after anaerobic digestion were 1.620 × 1012 to 2.083 × 1012 m/kg, and they were similar to each other in the all cases of sequential ozonation and ultrasonication and none treatment. As a result of this study, sequential alkaline ozonation followed by ultrasonication would be useful for methane fermentation of sewage organic sludge before the anaerobic digestion.

Key Words

Sewage sludge, Methane fermentation, Ozonation, Ultrasonication, Centrifuge, Filtrate