박은영 Eun Young Park , 김용진 Yong Jin Kim , 정승미 Seung Mi Jeong , 이동훈 Dong Hoon Lee

DOI:10.9786/kswm.2014.31.7.707

Abstract

This study investigated the optimal sequential hydrolysis conditions by comparing with reducing sugar yield of sequential hydrolysis of Laminaria japonica processing residue. After acid-catalyzed hydrothermal hydrolysis, sequential enzymatic hydrolysis was performed with single enzymes such as Celluclast® 1.5 L, Saczyme, and Alginate Lyase, and their mixture. As a result, the yield of reducing sugar by sequential hydrolysis with the mixed enzymes was the highest, but there would be an economical problem with excessive enzyme loading. Therefore, considering the reducing sugaryield and economics, it is thought that hydrolysis by the mixed enzymes has no advantage, thus, using the Celluclast® 1.5 L in the sequential hydrolysis was practically more appropriate. The optimal sequential hydrolysis conditions of Laminaria japonica processing residue were determined to be 8% v/w of enzyme injection, 42.6oC of reaction temperature, pH 4.1, and 26 hours of reaction time after acid-catalyzed hydrothermal hydrolysis (0.108 N-HCl, 144oC of reaction temperature, and 22 minute of reaction time).

Key Words

Sequential hydrolysis, Laminaria japonica processing residue, Acid-catalyzed hydrothermal hydrolysis

김종현 Chong Hyun Kim , 박정화 Zheung Hwa Piao , 이종근 Jong Keun Lee , 김재영 Jae Young Kim

DOI:10.9786/kswm.2014.31.7.713

Abstract

Anaerobic digestion is getting attention by its ability to degrade organic materials and produce energy at the same time. Even though most full-scale anaerobic digesters are operated as continuously fed reactors, laboratory-scale tests for design parameters would be conducted using batch or semi-batch reactors. The objective of this study was to investigate the effect of different feeding patterns with an identical organic loading rate on the performance of laboratory-scale batch anaerobic digestion reactors. Laminaria japonica was applied as a substrate with 1.5 g-VS/L.day of loading rate. Three different types of feeding periods, i.e, 12, 24, and 48 hours, were applied. The reactors were operated at HRT 26.7 days, 35 ± 1oC mesophilic anaerobic condition. The methane production rates were 165.10 ± 16.92, 120.74 ± 40.25, and 57.81 ± 20.06 mLCH4/gVS for feeding periods of 12, 24, and 48 hours, respectively. Reactors fed more frequently produced more methane gas and the coefficient of variation was lower. As substrate feeding period increased, concentrations of total volatile fatty acids (VFAs) increased and pH decreased. Finally, the reactor with 48 hours of feeding period was failed after 22 days of operation. Consequently, it was shown that feeding pattern may significantly affect performances of laboratory-scale batch anaerobic digestion reactors and the results from laboratory tests may mislead the design of full-scale digesters.

Key Words

Anaerobic batch reactor, Laminaria japonica, Mesophilic anaerobic digestion, Substrate feeding periods, Volatile fatty acids

민달기 Dal Ki Min

DOI:10.9786/kswm.2014.31.7.720

Abstract

Waste deposit & refund system was performed in order to recycle the waste since 1992, and this system developed into the EPR (Extended Producer Responsibility) system since 2003 in Korea. Many products and packaging materials are recycled by this system, and government published the ‘EPR Practical Manual (2007)’ to estimate the actual recycling rate. According to styrofoam-buoy (SB) included EPR item in 2010, SB does not practical to estimate the recycling rate, EPS (Expanded Poly-Styrene) was recycled only. So in this study, SB recycling rate also includes ‘EPS + parts’ was to estimate through the field investigation. As a results, parts portion of SB are 3.49% when manufactured, and 2.03% when recycled. And process loss, contaminant content, parts portion and yield of EPS ingot are 0.00%, 64.28%, 0.71% and 35.01% in SB recycling, respectively. In the future SB recycling rate is calculated by adding the EPS ingot production and parts recovered.

Key Words

EPR, Resource circulation, Styrofoam-buoy, EPS ingot, Aquaculture

나춘기 Choon Ki Na

DOI:10.9786/kswm.2014.31.7.725

Abstract

This research investigated the feasibility of rice husk (RH) as a biosorbent for the removal of anions from aqueous solution. RH-g-GMA-Am biosorbent, which possesses anionic exchangeable function, was prepared through graft polymerization of glycidyl methacrylate (GMA) in the presence of N,N``-methylene-bis-acrylamide as a cross-linker using potassium peroxydisulphate as a redox initiator and subsequent amination reaction using ethylenediamine (EDA), diethylenetriamine (DETA), dimethylamine (DMA) and trimethylamine (TMA) as a amine source. Fourier transform infrared (FTIR) and scanning electron microscopy (SEM) analysis as well as the sorption capacity for anions verified the presence of grafted GMA polymers and amine groups on the RH surface. The zero point of surface potential of aminated RH-g-GMA-Am sorbent was 6.4, which facilitated the sorption of anions on the positively charged sorbent at pH < 6.4. The sorption capacity of RH-g-GMA-Am depending on the amination chemicals increased in the order: DETA ≥ EDA > DMA > TMA, i.e., primary amine > secondary amine > tertiary amine. The sorption selectivity of RHg- GMA-Am sorbent aminated with DETA and EDA in the presence of equimolar anions and at pH 4.7 increased in the order: SO4> PO4> NO3 > F. Furthermore, their sorption capacities for PO4 were much higher than those of commercial anion-exchange resins. The results obtained suggest that the RH-g-GMA-Am biosorbent prepared by the GMA graftcopolymerization and subsequent amination can be used as an effective anion-exchanger comparable to commercial anionexchange resins.

Key Words

Rice husk, Graft polymerization, Amination, Anion, Sorption selectivity

류우신 Yu Chen Liu , 안종화 Johng Hwa Ahn

DOI:10.9786/kswm.2014.31.7.734

Abstract

The objective of this study was to find optimum pretreatment conditions of ozone and microwave for solubilization of thickened waste activated sludge (TWAS). Response surface analysis was applied to determine the combination of ozone concentration (0.03 to 0.1 g O3/g total solid (TS)) and microwave temperature (100 ~ 170oC). The temperature significantly affected the solubilization degree of sludge (p < 0.01). Within the design boundaries, the conditions predicted to maximize the solubilization degree of 41.6% were determined to be 0.065 g O3/g TS and 170oC. On the other hand, the solubilization degree with the ozone pretreatment alone was 2.7 to 12.2% at 0.03 ~ 0.1 g O3/g TS. The results show that the combination of ozone and microwave pretreatments is effective in solubilization of TWAS.

Key Words

Sludge, Ozone, Microwave, Solubilization

김영진 Young Chin Kim

DOI:10.9786/kswm.2014.31.7.740

Abstract

Wheel tracking test and ice pull-out test were performed in laboratory on dense grade asphalt mixture and asphalt mixture including 2.5% of 19 mm PE aggregates. Meanwhile, temperature change, thermal conductivity, and snow melting speed were measured for both dense grade asphalt and PE aggregate mixed asphalt pavement via field testing on a test road. Laboratory test results show that dynamic stability was improved and ice was removed easily by mixing PE aggregates in an asphalt mixture. Moreover, the existence of PE aggregates enhances heat insulation and snow melting speed due to the lower thermal conductivity compared to ordinary dense grade asphalt mixtures.

Key Words

PE aggragate, Asphalt concrete, Dynamic stability, Ice pull-out strength, Thermal conductivity, Snow melting effect

민달기 Dal Ki Min

DOI:10.9786/kswm.2014.31.7.748

Abstract

At present red mud didn``t recognized as recyclable resources because of large generation and some problems such asimpermeability, high pH value, aluminium leachate, and causing red water in Korea. In order to recognized as recyclable resources, therefore, we suggest the policy proposals were suggested by reducing the above mentioned problems. In ``Waste Management Act`` similar inorganic sludge which has similar characteristics with red mud is regulated land treatment by mixing with general soil, so red mud should be treated in the same method in order to promote the permeability. Red mud should be neutralized because its pH is very high. It should be careful in neutralized operation because of red water generated from red mud. It may be suspected that the red water is contaminated un aesthetic point. To reduce the strength of red water, red mud is treated to a magnetic process in order to recover the magnetic ferrous material. Through thismagnetic process, ferrous material could be recovered 20 thousand ton per year, and the color intensity reduced to 77.3%.

Key Words

Resource circulation, Red mud, Alkali waste, Red leachate

조재범 Jae Beom Cho , 최한나 Han Na Choi , 조은하 Eun Ha Cho , 김병수 Byung Soo Kim , 최미영 Mi Young Choi

DOI:10.9786/kswm.2014.31.7.754

Abstract

The objectives of this research was to evaluate the anaerobic digestibility of waste activated sludge (herein after WAS) and waste beverages (herein after WB) in beverages manufacturing industry using actual plant under various conditions. In this study, anaerobic digestion with WAS and WB were evaluated according to different operating conditions. As the basis operating conditions for anaerobic digestion, the reaction temperature was controlled at 35 and hydraulic retention time 30 days. WAS and WB were mixed at the ratio of 1 : 0, 9 : 1, 8 : 2, 7 : 3, 5 : 5, Respectively. The organic loading rate (herein after OLR) was maintained less than 0.5 kgVS/m3·day. Biogas productivity in accordance with VS was fed at the each mixing ratio with WAS and WB was increased from 0.92 Nm3/kg VSfeed to 1.28 Nm3/kg VSfeed, except mixing ratio 5 : 5 (0.19 Nm3/kg VSfeed). Also Biogas productivity in accordance with VS was removed at the each mixing ratio with WAS and WB was increased from 1.13 Nm3/kg VSrem to 1.81 Nm3/kg VSrem, except mixing ratio 5 : 5 (0.35 Nm3/ kg VSrem). It was judged that pH was reduced with WB addition. From the results, it was judged that anaerobic digestion using WAS and WB could be feasible.

Key Words

Biogas, Anaerobic digestion, Waste activated sludge, Waste beverages

이동진 Dong Jin Lee , 이수영 Su Young Lee , 강준구 Jun Gu Kang , 이성수 Seong Soo Lee , 김영란 Young Lan Kim , 황동건 Dong Gun Hwang , 김기헌 Ki Heon Kim , 정진 Jin Chung

DOI:10.9786/kswm.2014.31.7.763

Abstract

In this study the effects of co-digestion of sewage sludge and food waste leachate on the anaerobic digestion efficiency from sewage treatment facilities in S. Korea were investigated. For this study 15 facilities were selected including 9facilities treating sewage sludge only (S-Only) and 6 facilities treating sewage sludge and food waste leachate (S-MIX). The average volatile solid (VS) removal rate of S-Only was 30.7% and that of S-MIX was 45.2%. The COD removal rate of S-MIX (61.3%) was higher than that of S-Only (48.6%). It has been observed that the anaerobic digestion efficiency of S-MIX was superior to that of S-Only because S-MIX contained more sufficient nutrient with higher VS contents and total solid (TS) contents emerging from food waste leachate. Therefore food waste leachate addition in sewage sludge anaerobic digestion would be the preferred option to treat only sewage sludge.

Key Words

Food waste leachate, Sewage sludge, Anaerobic digestion, Sewage treatment, Anaerobic digestion efficiency

김하석 Ha Seog Kim , 이세현 Sea Hyun Lee

DOI:10.9786/kswm.2014.31.7.772

Abstract

Carbon dioxide generated from construction materials and construction material industry among the fields of construction is approximately 67 million tons. It is about 30% of the carbon dioxide generated in the fields of construction. In order to reduce carbon dioxide in the fields of construction, it is necessary to control the use of fossil fuel consumed and decrease carbon emission by reducing the secondary and tertiary curing generating carbon dioxide in construction material industry. Therefore, this study produced an extrusion panel by using cement as the base materials and substituting binding materials up to 40% to analyze strength characteristics. According to the results of strength characteristics by the replacement binder (Low energy curing Admixture) showed an apparent active strength improvement. In particular, specimens substituting binder as 45% indicated the greatest strength improvement. When binding materials was used with substitution, it showed strength characteristics similar or higher than specimens made from tertiary autoclave curing as secondary steam curing.

Key Words

Carbon dioxide, Steam curing, Ground granulated blast-furnace slag, Electric arc furnace slag

김정은 Jeong Eun Kim , 김상우 Sang Woo Kim , 정재칠 Jae Chil Jung , 육종묵 Jong Mook Yuk , 문정모 Jeong Mo Moon , 장성민 Seong Min Jang , 노영석 Young Seok Roh

DOI:10.9786/kswm.2014.31.7.780

Abstract

In this research, chemical vapor deposition equipment built in the semiconductor·CVD (Chemical Vapor Deposition) process was introduced. Through polysulfone hollow fiber membranes under similar conditions to those of the actual process, conditions such as flow and pressure were used to observe the influence in order to separate and collect the SF6 and CF4 substances. Results showed that as the retentate flow rate of the discharge unit increased and the residence time to penetrate the membrane decreased, the emission concentration increased. As the pressure of the discharge unit increased and the exhaust flow decreased, when the retentate flow rate was 10 L/min, CF4 was shown to have a density of 4,963ppm, and it was 4,028 ppm for SF6 the gas mixture had a concentration effect of three to four ratio. In addition, through the separation factor of fluorinated gases that arise in the actual process, the collection and concentration of SF6 and CF4 were possible each gas’s recovery rate was higher than 99%.

Key Words

Permeance, Membrane, Separation, Electronics industry, Perfluorocompound gas

이남훈 Nam Hoon Lee , 윤석표 Seok Pyo Yoon

DOI:10.9786/kswm.2014.31.7.787

Abstract

Generator’s direct weighing method was applied for investigation of household waste generation. At least 28 days, each household member measured and recorded the weight of garbage discharged with plastic garbage bag, food waste, and recyclable waste. Collected garbage record books were used as input data in Microsoft Excel, and statistical analysis were done with Minitab 16 software. By generator’s direct weighing method for household waste generation, garbage discharged by plastic bag, food waste, and recyclable waste were 130.5, 98.2, and 187.9 g/capita/day, respectively. Difference in averages of per capita garbage discharge between Seoul, Gyeonggi, Incheon, and Chungbuk were no statistically significant. And as the number of house member decrease, per capita garbage discharge increase numerically, but there was no statistically significant.

Key Words

Household waste, Generator, Direct weighing, Per capita generation, Garbage record book

윤상혁 Sang Hyuck Yoon , 송태협 Tae Hyeob Song , 이세현 Sea Hyun Lee

DOI:10.9786/kswm.2014.31.7.794

Abstract

Hydrochlorofluorocarbon (HCFC) is an ozone-depleting substance that is subject to environmental regulations based on the Montreal Protocol, and in Republic of Korea, which is regarded as a developing country, its use will be restricted in phase starting in 2013 until finally being prohibited in 2030. HCFC is regulated Based on the Tokyo Protocol, HCFC is a regulated construction material for carbon dioxide reduction with GWP of 1,700 ~ 2,400 times that of CO2, with a GWP of 1. Using the CO2 in the heat insulating material in the extrusion process conditions are the first extruder, the polystyrene resin (melting point) and the blowing agent (CO2 : Ethanol : HCFC) as interval (Mixing zone) which is the combined pressure 11.0 MPa, temperature 200oC, second within the extruder discharge pressure 6.5 MPa, and determines that it is desirable to set the temperature of 115oC, the blowing agent mixing ratio (CO2 : Ethanol : HCFC), taking into account the stability of the thermal conductivity of 30 : 20 : 50%, 25 : 25 : 50% is expected to be utilized in the foaming agent.

Key Words

Lowing agent, CO2, Ethanol, XPS, Global warming, ODP

임성수 Sung Soo Lim

DOI:10.9786/kswm.2014.31.7.800

Abstract

Agriculture is not only sources, but also sinks of GHGs through removal or sequestration of carbon and methane. There have been many efforts around the world to improve agriculture’s ability to sequester GHGs and to seek ways for economic benefits through the emissions reduction project. Specially, animal waste management system and biogas plants have been useful to environmental policies in agriculture sector. The objectives of this study were to analyze the CDM project current situation in agriculture sector and draw a implications from its analysis. As a result of the investigation, strategies and procedures are suggested to link agricultural policies to the CDM projects to create economics opportunities for the korean agriculture. So it will be useful, a strategy to raise the economic feasibility of a rural area’s animal waste management system and biogas plant project should consider to develop domestic technologies of biogas digester. Also, local government, local college, rural communities should agree to closely work together to resolve the national’s greenhouse gas reduction issue.

Key Words

Agriculture, Animal Waste management system, Biogas plants, CDM project