• Resources Recycling
• /
• v.22 no.5
• /
• pp.20-28
• /
• 2013

This study was carried out to evaluate the possibility of resource recovery for municipal solid waste(MSW) that sorted by a MBT system. First, physical property of MSW was similar to wastes carried into Sudokown landfill site. However, moisture of MSW was little higher than that. As a result of BMP test using organic fraction of MSW(OFMSWs), approximately 60 ~ 80 mL $CH_4/g$-VS of methane was occurred. Compared to the other studies, the value of methane is lower. It seems to be caused that high ratio of vinyl/plastic in OFMSWs. The other BMP test using sample of MBT system located in Sudokwon landfill was conducted each physical properties. According to the result of experiment, food waste makes 193 mL $CH_4/g$-VS, and paper is 102 mL $CH_4/g$-VS. However, there was not methane production in vinyl and rubber. Additionally, others that can't sort no more show 30 m $CH_4L/g$-VS of methane production. From the result of experimental data OFMSWs has high fraction of vinyl, rubber and other substance that difficult for biodegradation. Therefore it is need to sort of them.

• Resources Recycling
• /
• v.26 no.2
• /
• pp.11-17
• /
• 2017

Many problems are occurred by using industrial by-product and municipal solid waste in the cement manufacturing process. The main components of chlorine by-pass dust generated by the use of the wastes are $K^+$, $Cl^-$, and a slight amount of heavy metals is also contained. In terms of waste recycling, it is necessary to eliminate the heavy metals. Therefore, in this study, the experiments for the removal of heavy metals from KCl which was produced by chlorine by-pass dust were conducted. In order to find optimum conditions for the removal of heavy metals, we have controlled the amount of water and precipitator. The type and concentration of heavy metals in KCl were analyzed. The concentration of heavy metals decreased as amount of precipitator increased. The heavy metals such as Pb, Cd, and As were not detected in dust A and B, when the mixing ratios between dust A(B) and water were controlled to be 1:2 (1:2, 1:3.5) with the addition of 3% precipitator (NaOCl).

• Korean Journal of Environmental Agriculture
• /
• v.23 no.4
• /
• pp.258-263
• /
• 2004

Bioassay was employed to assess toxicity of soil which had been treated with sewage sludges for seven years. The $Microtox^{(R)}$ and root elongation test of lettuce (Lactuca Sativa.) elucidated that the intensity of soil toxicity was closely related with the types and amount of sewage sludges applied. Both bioassay methods proved to be useful in an assessment of soil toxicity and were consistent to some extent with the conventional chemical analysis methods. $EC_{50}$ values resulted from $Microtox^{(R)}$ were highly correlated with concentration of heavy metals in soils amended with sewage sludges : Cu ($r^2=\;0.86^{**}$), Cr ($r^2\;=\;0.84^{**}$), Ni ($r^2\;=\;0.83^{**}$), and Zn ($r^2\;=\;0.69^{**}$). This demonstrated that both bioassay techniques could be employed as tools for soil toxicity assessment when the soil was exposed to solid wastes such as sewage sludge.

• Resources Recycling
• /
• v.25 no.3
• /
• pp.29-36
• /
• 2016

The characteristics analysis and pH neutralization test were carried out to use of slurry generated from recycling processes of construction wastes. D (5.0) of raw sludge was $42.4{\mu}m$ and over 60 % of sludge distribute under 45 um (-325 mesh). Muscovite and carbonate minerals were main minerals of fine particles, and the portion of carbonate minerals increased as particle size decreased. Although the more heavy metals were observed in the finer particle size, the contents was found to be less than Korean contaminated soil regulation (area 2). The effects of flocculants addition for accelerating solid-liquid separation were negligible because the slurry already contains excess of coagulant added in the waste concrete recycling process. It was difficult to neutralize the sludge supernatant due to high pH (about 12) by adding acids, but the introduction of $CO_2$ decreased the pH to 8.5, The precipitate recovered during $CO_2$ introduction was determined to be $CaCO_3$ with XRD, and it indicates that high pure $CaCO_3$ could be obtained during the process.

• Resources Recycling
• /
• v.7 no.3
• /
• pp.52-57
• /
• 1998

The objective of this study was to investigate the effect of cow manure as additive material on the ripening of sewage s sludge for vermistabiJization. The changes of the waste properties by ripening for 50days were observed as a function of the v various mixture ratios of sewage sludge ‘and cow manure. The pH values of the mixture wastes decreased from 7.5-7.67 to 6_ 9~7.2 by the ripening for 50days, and the mixture ratio made dIfferent pH values. The initial value of oxidation-reduction p potential (Eh) of the mixture waste was a negative (-) value indicating an unfavorable condition for earthworm after, but the v values of Eh increased with the opening time. The Increase rate at Eh value was prop$\alpha$rtional to the mixture ratio of cow m manure. The value of alkalinity was also changed into the favorable range for earthworm after 50days except for non-use of 1 the cow manure When the mixture ratio of the cow manure increased from 10% to 30%, the growth of earthworms increased h from 63.7% to 88.3 % tor the survival rate, 265% to 321% for the liveweight increasing rate and 66.7_7% to 91% for hatching f rate of the cocoons. It can be concluded that the proper content of tbe cow manure in the sewage sludge to ensure effective v vermistabilization was over 20%, when the mixture was ripened during 50 days. The quantity of ingestion and 며ectian at 20%-30% was found to be O.15--i.L18g sludge and 0 1l--O.14g solid per capacity earthworm per day, respectively.

• Journal of Chitin and Chitosan
• /
• v.23 no.4
• /
• pp.285-292
• /
• 2018

In this study, for the purpose of decomposing food waste, the strain was screened from traditional fermented food and soils. The enzyme activity (protease, amylase, cellulase, lipase) experiment was carried out using the paper disc method in 212 strains isolated from 5% NaCl media. Among them, only the strains having enzyme activity of more than 2 (soil) or more than 4 (traditional fermented food) with the halozone of enzyme activity of 15 mm or more were selected first, and microorganism identification through 16S rRNA sequencing was performed. Finally, were identified such as Bacillus subtilis, Bacillus amyloliquefaciens, Bacillus siamensis, Bacillus licheniformis, Bacillus aquimaris, Bacillus megaterium, Bacillus koreensis, Bacillus stratoshericus, Bacillus aryabhattai, Bacillus safensis, Marinobacter hydrocarbonoclasticus. 11 species of mixed strains were confirmed that the culture time was 24 hours, the incubation temperature was $30^{\circ}C$ and the optimum pH was 7.0. In order to confirm the degree of decomposition of standard food wastes (100 g) by treating 11 kinds of mixed strains (25%), solid content of more than $2000{\mu}m$ was determined to be 103 g for the sterilized water group and 18 g for the mixed strains group. And the rest was decomposed to a size of less than $2000{\mu}m$.

• Korean Chemical Engineering Research
• /
• v.57 no.4
• /
• pp.539-546
• /
• 2019

Global warming has mentioned as one of the international problems and these researches have conducted. Carbon Capture, Utilization and Storage (CCUS) technology has improved due to increasing importance of reducing emission of carbon dioxide. Among of various CCUS technologies, mineral carbonation can converted $CO_2$ into high-cost materials with low energy. Existing researches has been used ions extracted solid wastes for mineral carbonation but the procedure is complicated. However, the procedure using seawater is simple because it contained high concentration of metal cation. This research is a basic study using seawater-based wastewater for mineral carbonation. 3 M Monoethanolamine (MEA) was used as $CO_2$ absorbent. Making various concentrations of seawater solution, simulated seawater powder was used. Precipitated metal carbonate salts were produced by mixing seawater solutions and $rich-CO_2$ absorbent solution. They were analyzed by X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), and Thermogravimetric Analysis (TGA) and studied characteristic of producing precipitated metal carbonate and possibility of reusing absorbent.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.29 no.1
• /
• pp.29-36
• /
• 2021

In spite of the highest energy potential among all domestic organic solid wastes. the research on biogas production from cattle manure is limited. In particular, effects of organic content degradation and sawdust addition during storage on biomethane potential have never been investigated. In the present work, we investigated the change of organic content during storage of cattle manure under different temperatures (20℃ and 30℃), and its impact on biomethane potential and odor emissions. 90 days of investigation results showed that 10% of organics in terms of VS and COD were degraded at 20℃ during storage, while 30% were degraded at 30℃. This result impacted on biomethane potential, while 10-13% and 24% reduction were observed from beef and dairy cattle manure, respectively. The temperature also affected on CH4 and odor emissions during storage by 3.3-3.8 times and 29 times. The effect of sawdust on lowering down biomethane potential was found to be substantial, reducing 61-75% compared to the control.

• Journal of Appropriate Technology
• /
• v.5 no.2
• /
• pp.106-113
• /
• 2019

In order to respond to the global environmental issues, developed countries have been helped the developing countries as the Official Development Assistance (ODA). It is important to understand technology needs of the developing countries to provide the optimum solutions. In this study, the information of the environmental R&D dealing with appropriate technology were comprehensively collected based on the conducted R&D projects from the ministry of environment in Korea. The technology needs by UNFCCC (United Nations Framework Convention on Climate Change) and Korean government were analyzed named as TNA and CPS according to the target developing countries. In South-East Asia and Africa region, there were technology needs on water, biota, air, solid wastes, infrastructures and resources. And they were related to the issues such as environmental pollution, construction, climate change, biodiversity, energy and water management. The technology needs by UNFCCC and Korean government were also compared. Furthermore, the environmental R&D on appropriate technology should be focused on localization and maintenance to provide sustainable solutions to the developing countries.

• Journal of the Korean Wood Science and Technology
• /
• v.34 no.4
• /
• pp.37-45
• /
• 2006

Recently, wood-framed houses has been built in the Korea for pension. Wood is good material for human healthy, while the construction lumbers are treated with preservative such as CCA (chromated copper arsenate), which contain some toxic elements for human body. However, if the waste woody biomass treated with various heavy metals, which has been collected from house construction or demolition, was fired in the field, and incinerated or landfilled after mass collection, such components will result in the toxic air pollutants in the burning or land fills, and spreaded into other areas. So the careful selection of wood and chemicals are required in advance for house construction, in particular, for environment-friendly housings. Therefore, this study was carried out to determine the content of toxic heavy metals in woody materials such as domestic hinoki and imported hemlock treated with CCA for housing materials, and the post-treated wood components such as organic fertilizer, sludge, dry-distilled charcoal and carbonized charcoal, to be returned finally into soil. The results are as follows. 1) The chemical analysis of toxic trace elements in various solid biomass required accurate control and management of laboratory environment, and reagents and water used, because of the error of data due to various foreign substances added in various processing and transporting steps. So a systematic analyzers was necessary to monitor the toxic pollutants of construction materials. 2) In particular, the biomass treated with industrial biological or thermal conditions such as sludge or charcoals was not fully dissolvable after third addition of $HNO_3$ and HF. 3) The natural woody materials such as organic fertilizer, sludge. and charcoals without any treatment of preservatives or heavy metal components were nontoxic in landfill because of the standard of organic fertilizers, even after thermal or biological treatments. 4) The CC A-treated wood for making the construction wood durable should not be landfilled, because of its higher contents of toxic metals than the criterion of organic fertilizer for agriculture or of natural environment. So the demolished waste should be treated separately from municipal wastes.