강슬기 Seul-gi Kang , 김동수 Dong-su Kim

DOI:10.9786/kswm.2020.37.5.301

Abstract

In this study, It was investigated that the adsorption mechanism of methylene blue on the NaOH modified coffee waste based on the isotherm, kinetics and thermodynamics using the various experiment factor like pH, ionic strength and temperature. When the amount of adsorbent was 20 mg, maximum adsorption amount per unit mass was observed as 13.25 mg/g. Adsorption efficiency was shown to be over 90.6% except under the range of pH 4. In isotherm experiment results, it followed Langmuir isotherm equation more than Freundlich isotherm equation. In kinetic study, it was observed to be pseudo second order equation more than pseudo first order. Adsorption efficiency was decreased as increasing the ionic strength. In the thermodynamics estimation, the adsorption of methylene blue on coffee waste was examined to be physical adsorption since ΔGo was calculated in the range of -20 to 0 kJ/mol. Also, ΔGo values were calculated to increase according to temperature. ΔHo and ΔSo values were calculated to be -12.554 kJ/mol and -0.010 J/mol K, respectively.

Key Words

Adsorption, Coffee waste, Dye, Modification, Waste water treatment

김한수 Han-soo Kim , 김대봉 Dae-bong Kim

DOI:10.9786/kswm.2020.37.5.310

Abstract

The use of electrical equipment produces large quantities of waste. We investigated the difference in quantity performance of recycling and mandatory recycling quantities and analyzed the product families and specific products that have not achieved a long-term recycling target. It was suggested a method to promote the recycling of waste electrical equipment. Although the delivery volume of medium and small household appliances was increased, the long-term recycling target was still not achieved. To increase the performance of recycling, apartments and houses should be equipped with small recycling bins, and retail stores over a certain capacity should be equipped with free recycling points. Novel product families could be introduced as “products that exceed the recycling target” and “products that do not meet the quantity for mandatory collection”. Large manufacturers and producers should step down these rates. This study may contribute to improving existing infrastructure and promoting recycling of waste electrical equipment.

Key Words

Long-term recycling target, Waste electrical and electronic equipment, Recycling, Mandatory collection

장용철 Yong-chul Jang , 김홍경 Hongkyoung Kim , 이가인 Gain Lee , 이승훈 Seunghun Lee , 홍용석 Yongseok Hong

DOI:10.9786/kswm.2020.37.5.315

Abstract

Mercury is one of toxic heavy metals and a persistent pollutant of global concern that is regulated by the Minamata Convention in 2017 August. There is a need for carefully identify mercury levels in waste streams and properly treat and manage the waste, if significant amount of the metal exists. In this study, mercury in waste materials and byproducts (112 samples) from treatment processes from a fluorescent lamp recycling facility as well as industrial and medical incineration facilities was measured. Substance flow analysis (SFA) of mercury was performed on the recycling and incineration facilities. Other relevant data such as sludge generation, chemical addition, and wastewater treatment rates were obtained through the field investigations, literature review from available reports and statistics. Data reconciliation with material flow analysis Software STAN 2.5 was employed for mercury flow in each process by decreasing data error and by adopting least square method and error propagation theory. Based on the results of SFA, it was found that major flow of mercury at wastewater treatment facilities is attributed to the sludge during the treatment processes. As a result of this study, it was found that mercury flow from the fluorescent lamp recycling facility was estimated to be approximately 499 g/day (equivalent to 175 kg/yr), mainly from adsorption treatment (activated carbon filter) process as well as the condensate and phosphor powder. In the industrial incineration facility, air emission of mercury was estimated to be 21.4 g/day (equivalent to 7.8 kg/yr), followed by bottom ash (8.7 g/day) and sludge (5.9 g/day), while the medical waste incineration process mainly generated mercury in fly ash (22.8 g/day) and wastewater (25.3 g/day). Detailed examination of more diverse waste treatment facilities is still needed to eliminate unidentified mercury streams from the waste treatment facilities.

Key Words

Mercury, SFA, Medical waste, Florescent lamp, Material flow

Md Akhte Khirul , Beom-geun Kim , Daechul Cho , Sung-hyun Kwon

DOI:10.9786/kswm.2020.37.5.327

Abstract

Eutrophication is a serious environmental issue in coastal areas, caused by increased nutrient concentration from external sources. Nutrients could augment in the bottom sediment and be released into overlying water, acting as an internal nutrient source. Converted oyster shell powders were used to evaluate the suppression of nutrients release from bottom sediments. Two kinds of oyster shell powder were applied into the sediment in the individual column with the control column. The natural oyster shell powder (NOSP) was composed of calcium carbonate and the functional oyster shell powder (FOSP) was composed of calcium peroxide. In the column where FOSP was applied, pH was increased due to hydrolysis of calcium peroxide in the overlying water. The concentration of dissolved oxygen in the FOSP-treated columns was higher than that of the control column. The FOSP could suppress the release of ammonia nitrogen and phosphates from the sediment into the overlying water. It was proven that FOSP can effectively adsorb phosphates from organically enriched sediments. Overall, the application of FOSP could effectively control nutrient release from the sediment to overlying water and help reduce the eutrophication in the coastal areas.

Key Words

Marine sediment, Eutrophication, Remediation, Phosphate, Oyster shell powder, Nitrification

장유나 Yu Na Jang , 정민웅 Min Woong Jung , 우샘이 Saem Ee Woo , 서시영 Si Young Seo , 조광곤 Gwanggon Jo

DOI:10.9786/kswm.2020.37.5.335

Abstract

This study to collect basic data for odor management in a swine facility, using the characteristics of changes in the manure according to its storage period in the pit. Samples were collected weekly for 12 weeks from manure accumulated in slurry pit. Then, odorous substances, chemical properties, and microbial communities were analyzed. Results showed that the concentration of odorous substances and their physicochemical properties increased during the storage period. A strong positive correlation between physicochemical properties and odorous substances was found, which shows applicability as an indicator for malodor management. In addition, - dominant communities changed according to the storage period. Therefore, it is necessary to consider how characteristics of manure change according to the storage period, in order to manage the odor in the swine facility.

Key Words

Bacterial communities, Odorant, Pit, Storage period, Swine manure

김용준 Yong-jun Kim , 김교근 Kyeo-keun Kim

DOI:10.9786/kswm.2020.37.5.344

Abstract

This study aims to suggest an appropriate management plan for flammable liquid waste discharged at higher rates compared to other designated wastes. GC/MS analysis of waste organic solvents was conducted to confirm the types and contents of solvents. Hazardous properties such as flammability, explosiveness, spontaneous ignition, corrosiveness, and reactivity with water were also investigated. Through GC/MS analysis of 21 samples of organic solvents, six kinds of organic solvents were mainly detected, namely methylethylketone, ethylbenzene, phenol, acetone, 1,4-dioxane, and 1, 2-dichloroethylene. In addition, it was found that nine of the examined samples were flammable, without additional hazardous properties. Therefore, this study calls for the necessity to examine waste organic solvents through GC/MS and assess their flammability and other hazardous characteristics.

Key Words

Waste organic solvents, Hazardous characteristics, Flammability

Jeeban Poudel , 김혁진 Hyeok Jin Kim , 이유민 You Min Lee , 구재회 Jae Hoi Gu , 오세천 Sea Cheon Oh

DOI:10.9786/kswm.2020.37.5.354

Abstract

Waste-to-energy plants based on gasification using municipal solid waste (MSW) as their fuel are highly efficient rather than conventional sources of energy such as coal, oil or natural gas. This study proposes a Computational Fluid Dynamics (CFD) model of MSW gasification with air in a downdraft fixed bed gasifier. 3D commercial code ANSYS was used to predict the CFD analysis results of MSW gasification and to provide process fundamentals with regards to syngas production from MSW gasification. Values for temperature, velocity, and syngas species contours were obtained from the analysis and compared with experimental results. CFD predicted values compliment the trend obtained experimentally, indicating the accuracy of the analysis model followed.

Key Words

Gasification, Downdraft fixed bed, Computational fluid dynamics, CFD, Municipal solid waste, MSW, CFD models

박동규 Dong Kyoo Park , 김동주 Dongju Kim , 구재회 Jae-hoi Gu , 이상필 Sang-feel Lee

DOI:10.9786/kswm.2020.37.5.366

Abstract

Domestic livestock manure is generated at an average of more than 170,000 tons per day, and technologies that effectively exploit manure as an energy source are drawing attention. Co-firing of coal and solid fuel derived from livestock manure is one of the most economical and efficient methods to reduce CO₂ emissions and increase renewable energy supplies. However, the high moisture content, low caloric value, and biodegradability of livestock manure limit the applicability of this process. Torrefaction is a thermochemical process that converts biomass into a coal-like material with increased caloric value, energy density, and hydrophobicity. This study investigated the effects of reaction temperature and time on the torrefaction of three waste biomass samples derived from livestock manure. Torrefaction at 300℃ for 15 min increased the caloric value of the product up to 3,842 kcal/kg, which is eight times greater than that of the raw material. Further comparisons of fuel characteristics including the fuel ratio and combustibility index reveal that the product is suitable for co-firing with coal.

Key Words

Torrefaction, Waste biomass, Livestock manure, Co-firing, Solid fuel