민달기 Dal Ki Min , 정성우 Sung Woo Chung

DOI:

Abstract

This paper is a research on the material flow analysis (MFA) of the food waste in treatment facility in order to enhance the proper management of food waste. In Korea, food waste is separated from the source compulsorily and treated on the feed plant, compost plant and mechanical plant, etc. In this study the present operation condition of food waste treatment facility, such as quantity of food waste, process water and additives as an input value and vapor release, generation of product, trash and wastewater as an output value, is investigated. All data are expressed as the relative value of the food waste quantity. According to the MFA, an excess process water ratio (0.15~1.16) and low yield coefficient of product (0.13~0.16) are disclosed and considered as urgent and serious problems of the food waste treatment. Therefore the waste policy on food waste leaves much room for improvement, and recent technique such as waste to energy or bio-reactor type of landfill are need to applied the food waste in order to manage the food waste properly and to restrict the ocean dumping.

Key Words

Food Waste & Treatment Facility, Material Flow Analysis, MFA, Process Water, Yield

박진규 Jin Kyu Park , 이남훈 Nam Hoon Lee , 윤석표 Seok Pyo Yoon

DOI:

Abstract

Samples taken from a field-scale aerobic landfill operation site were analysed to evaluate biodegradability of treated landfilled municipal solid waste(MSW). After 5 months and 1 year aerobic operation, samples were taken, and then AT4 and GB21 experiments were conducted to evaluate biodegradability of treated landfilled MSW. AT4 value of untreated landfill waste was 1.9 times greater than AT4 value of 5 months aerobically treated landfill waste, and 2.9 times greater than AT4 value of 1 year aerobically treated landfill waste. GB21 value showed similar trends. But 1 year treated waste by aerobic landfill operation was not enough to satisfy the German allowable entrance criteria for MSW landfill. Therefore considering Korean situation, we suggest 6 months as a period of aerobic landfill operation for recycling the existing MSW landfill based on biological degradability of landfill waste and settlement velocity of MSW landfill surface.

Key Words

Biodegradability, Aerobic Landfill, Field-scale, AT4, GB21

안세웅 Se Woong Ahn , 이희선 Hi Sun Lee

DOI:

Abstract

The aim of this study is to propose the basic direction for the policy of waste resources energy by estimating the available potential volumes of the waste resources energy in Korea. The estimated volumes were taken by reflecting the generation trend of wastes and the various waste management policies until year 2008. Based on these materials, the available potential volumes of waste resources energy are estimated to 9,550 thousands/year in year 2008, and to 9,890 thousand ton/year in year 2013, respectively. The available potential volumes of combustible wastes are expected to decrease because of the policies on reduction, activation of recycling and landfill decrease, etc. However, the available potential volumes of organic wastes are expected to increase due to increase of food waste, increase of food waste leachate generated from the recycling of food waste and increase of organic sludge, etc. The governmental target for waste resources energy in year 2013 is to get 81.2% of combustible waste and 28.2% of organic waste, respectively. For these reasons, the future strategy for waste resources energy should be focused to expand the organic wastes. This policy direction is very urgent and important to achieve the target of the "master plan of new and renewable energy" in considering the difficulty of increase of renewable energy.

Key Words

Waste resources, Combustible waste, Organic waste, Renewable energy, Available potential volume

이기배 Ki Bae Lee , 조성진 Sung Jin Cho , 이장수 Jang Soo Lee , 김정훈 Jeong Hun Kim , 정승재 Seung Jae Jung , 정해영 Hae Young Jung , 윤영식 Young Sik Yoon , 서용칠 Yong Chil Seo , 구자건 Ja Kon Koo

DOI:

Abstract

Key Words

최보람 Bo Ram Choi , 이태윤 Tae Yoon Lee

DOI:

Abstract

In this study, we tried to determine physico-chemical properties and heavy metal contents of sediments collected from Busan harbor. From the elemental analyses, XRD, and XRF analyses, all samples had similar elements. oxides, and minerals. In general, moderately high concentrations of Cu and Zn were found in the samples. Heavy metal contents of sediments were compared with USEPA sediment quality standards and ontario sediment quality guidelines. Seven samples were classified as heavily polluted and the remaining samples were classified as non polluted and moderately polluted. However, all samples could be classified as heavily polluted when ignition loss was considered.

Key Words

Busan harbor, Elemental analyses, Ignition Loss, Sediments, Heavy metals

박상신 Sang Shin Park , 박재홍 Jae Hong Park , 현준호 Jun Ho Hyun , 황정호 Jung Ho Hwang

DOI:

Abstract

A plate-type dielectric barrier discharge (DBD) reactor was designed and tested for removal of aerosol particles of toluene. The DBD reactor consisted of 9 parallel plate electrodes. The frequency, voltage, and current of the reactor were applied to 1kHz, 10kV, and 6mA, respectively. The aerosol particles of toluene passed through the DBD reactor and their concentrations at the inlet and outlet were measured by an aerodynamic particle size (APS). The carbon monoxide (CO), hydrogen (H2), and total hydro carbon (THC) which were produced by decomposition of toluene in the DBD reactor, were sampled and analyzed by a real-time gas analyzer and a micro gas chromatography. The physical removal efficiency of toluene aerosol particle was about 73%. The cold gas efficiency (CGE) of syngas was very low as 0.28%. However, the efficiency was enhanced to 3% and 1.5% utilizing with catalysts of activated carbon and dolomite, respectively.

Key Words

Dielectric barrier discharge, Toluene, Catalyst, Tar removal

이채홍 Chae Hong Lee , 전영남 Young Nam Chun

DOI:

Abstract

Perfluorocompounds (PFCs) have been extensively used for plasma etching and chemical vapor deposition (CVD) gases for semiconductor manufacturing processes. PFCs have significant effects on the global warming and have very long atmospheric lifetimes. Also, the wastewater including the fluorine would caused by of the ground water pollution. Long-term consumption of water containing excessive fluoride can lead to fluorosis of the teeth and bones. The CF4 decomposed by the waterjet plasma produces the HF. And it is dissolved in the waterjet. The present system in the work utilized electrocoagulation and calcium hydroxide, which is very effective to get rid of hydrogen fluoride from waste water. The operating condition such as reaction pH, Ca(OH)2 feed amount, reaction time and mixer speed were investigated experimentally using a calcium hydroxide. Through the parametric studies, the highest hydrogen fluoride destruction of 95% was achieved at 11pH, 250 g/L Ca(OH)2 feed amount, 60 min reaction time and 250 rpm mixing speed.

Key Words

Tetrafluoromethane, Waterjet plasma, Hydrogen fluoride, Electrocoagulation, Calcium hydroxide

강화영 Hwa Young Kang , 박성봉 Sung Bong Park , 박상숙 Sang Sook Park

DOI:

Abstract

It was studied to utilize wasted gypsum and blast furnace slag as raw materials to produce new cementious materials. The strength and microstructure of alkali-activated gypsum/slag-cement (AGS-cement) were examined. The parameters of the process studied were: activator concentration (NaOH 1M~7M), activation temperature (25˚C, 55˚C and 85˚C), gypsum/slag ratios (0/100, 10/90, 20/80, 30/70, 40/60, and 50/50), and activator/gypsum+slag ratios (0.35~0.50/1.0). XRD, SEM and porosimetry were used to observe the reaction products and microstructure of the AGS-cement pastes. At 28 days of reaction, the mixture of 30% gypsum and 70% slag activated with 5 M NaOH and activated at 25˚C and 55˚C, develop compressive strength of 24.8 MPa (25˚C) and 27.6 MPa (55˚C). The higher strength of AGS-cement paste was attributed to a more compact and continuous gelatinous matrix due to restructuring of reaction products.

Key Words

Cement materials, Alkali activation, Strength, Gypsum, Blast furnace slag

이승희 Seung Whee Rhee , 최효현 Hyo Hyun Choi , 박헌수 Hun Su Park

DOI:

Abstract

Carbonization process with rice husk is carried out to estimate the validity of carbonization residue as a renewable energy source. From the basic characteristics of rice husk, combustible content and heating value on the wet basis are estimated by 72.2% and 3,143 kcal/kg, respectively. In the carbonization process with rice husk, the optimal conditions of the reaction are decided by temperature of 300˚C and reaction time of 20 min. After the carbonization process, the carbonization residue is examined by the energy characteristics such as heating value and fuel ratio (fixed carbon/volatile combustible). However, heating value and fuel ratio of the residue at the optimal conditions are not satisfied with the 2nd grade standard of solid fuel product. Since sulfur in the residue is not detected and chloride in the residue is much less than the 1st grade standard of solid fuel product, the residue could be approved as a clean fuel. From the results of the energy characteristics of the residue, it is desirable that rice husk should be carbonized with other biomass to use as a renewable energy source.

Key Words

Rice husk, Heating value, Fuel ratio, Renewable energy, Carbonization

선용호 Yong Ho Seon , 이용현 Yong Hyun Lee , 김동진 Dong Jin Kim

DOI:

Abstract

This study proposed and investigated the feasibility of a modified 2 phase anaerobic digestion for the treatment of food wastewater which consists of an alkaline treatment of particulate solid residue after acidogenic fermentation followed by methane fermentation. Particulate solid residue of the food wastewater was treated by alkaline (NaOH) after 3 days of acidogenic fermentation to increase solubility and to reduce the solid volume to be treated. The SCOD/COD ratio increased from 0.55 to 0.79 after alkaline treatment. COD removal efficiency and methane production of the proposed M2AD and conventional 2 phase anaerobic digestion (control) were compared. COD and SCOD removal efficiencies of the proposed process were 63.8% and 51.2% while the control process had 61.0% and 44.5%, respectively. Methane production was 1,570 mL and it was higher than that of the control (1,180 mL). The proposed food wastewater treatment process, alkaline treatment after acidogenic fermentation, showed better performance in organics removal and methane production and it also showed the possibility of pretreatment cost reduction.

Key Words

2 phase anaerobic digestion, Acidogenic fermentation, Methanogenic fermentation, Alkaline treatment, Food wastewater, Hydrolysis

남성남 Seong Nam Nam , 임호주 Ho Joo Lim , 이동진 Dong Jin Lee , 전태완 Tae Wan Jeon , 신선경 Sun Kyoung Shin , 오길종 Gil Jong Oh

DOI:

Abstract

Since asbestos is known as carcinogenic and toxic material, the safe management and disposal of asbestos wastes have become a global health issue. Currently, asbestos-cement sheets (ACS, often called roofing slates), which constitute the majority of asbestos-containing waste discharged in South Korea, are treated mostly by a melting technique at high temperatures above 1,400˚C or by solidification/stabilization of ACS followed by disposal in a controlled landfill. These treatment techniques are very cost-intensive and energy-demanding. Thus, this study has been performed to evaluate the treatability of ACS by means of chemical digestion using various acids (phosphoric acid, hydrofluoric acid and sulfuric acid), and to understand removal mechanisms via reactants and products tracking. As results of this study, it turned out that ACS has contained ~17% of chrysotile asbestos (Mg3Si2O5(OH)4) mingled within cement constituents, and final products of ACS digested by phosphoric acid, hydrofluoric acid and sulfuric acid were brushite (CaHPO4), fluorite (CaF2), and calcium sulfate (CaSO4), respectively. Overall, the acid-only digestion showed a limitation on chrysotile removal below the detoxification criterion of South Korea (i.e., less than 1% wt.). Regarding asbestos destruction, magnesium in the brucite layer, Mg(OH)2, was preferentially removed from the structure, and the silicon-oxide sheet was found to be more stable against an acid attack. This study is meaningful as the first report, so far, on chemical treatability of asbestos wastes in South Korea, and provides reactional understanding on acid digestion with raw chrysotile and ACS.

Key Words

Asbestos, Chemical digestion, Chrysotile, Hydrofluoric acid, Slate, Sulfuric acid

이선기 Sun Ki Lee , 김나랑 Na Rang Kim , 구재회 Jae Hoi Gu

DOI:

Abstract

Biomass is ``carbon neutral`` fuel, so biomass gasification technology gain spotlight as environment-friend technology. In gasification reactor, gasification efficiency is effected by reactor shape, flow characteristics. In this paper, numerical analysis of fixed bed gasification reactor is performed for gasification efficiency prediction. We calculated various air/fuel ratios, feed rates, so we predicted flow characteristics, temperature distribution, syngas composition in fixed bed reactor by using commercial CFD(computational fluid dynamics) code FLUENT 6.3 The results of calculation show that gasifier outlet temperature is 700~800˚C, heating value of syngas is most high at air/fuel ratio=0.5, compositions of CO & H2 are most high at air/fuel ratio=0.75.

Key Words

Biomass, Gasification, CFD, Chemical reaction, Air/fuel ratio

Byeong Kyu Lee , Seung Hyeok Byeon

DOI:

Abstract

This study analyzed the feasibility of using industrial combustible solid waste (ICSW) generated from the largest industrial city in Korea (Ulsan) as a potential energy resource. Based on pre-existing data, solid waste generated from two national industrial complexes (NICs), including non-ferrous metal (NFM), mechanical and shipbuilding (MS), petrochemical (PC), and miscellaneous (MC) industries, were first categorized as industrial combustible solid waste (ICSW) or non-combustible waste. We then analyzed the physicochemical and thermo-chemical properties for each component of the ICSW via proximate analysis, elemental analysis, heating value, and trace analysis of heavy metals. The most prominent component of the ICSW in the two NICs was sludge produced primarily by wastewater plants (46.9 wt%), followed by other CSWs (29.8 wt%) and synthetic resin (16.1 wt%). Other CSWs (mostly plastic waste), the synthetic resin, and the wastewater sludge accounted for 51.4%, 30.2%, and 11.5%, respectively, of the total potential energy obtainable from utilization of ICSWs. Finally, the feasibility of using ICSWs as alternative fuel resources was evaluated by testing the standards specified in the government regulations concerning refuse-derived fuel (RDF). These standards are mainly related to heating value, chlorine content, and ash content of single or combined ICSWs.

Key Words

Energy resource, Combustible waste, Industry, Heating value, Alternative fuel