박소이 So-yee Park , 이재영 Jai-young Lee

DOI:10.9786/kswm.2023.40.4.319

Abstract

This study investigated international standardization trends for waste management, without being limited to specific materials or fields to identify the main direction and issues of sustainable waste management in the international community. The study focused on two types of international standards related to the Sustainable Development Goals (SDGs): the Global Reporting Initiative (GRI) waste sustainability reporting standard and the International Organization for Standardization (ISO) ICS 13.030 waste group standards. The GRI’s reporting standard on waste, updated in 2020, especially, requires organizations to report on the causes of waste generation and waste-related impacts in their activities and value chain, along with actions taken to prevent waste generation and management of waste-related impacts. Six out of the twenty ISO ICS 13.030 waste group standards analyzed in the study are under development. Most recently, the ISO standard on waste reduction and treatment in aquaculture has begun to be developed. It is noteworthy that there are ISO standards classified under both ICS 13.030.30 (Special wastes), a sub-group related to hazardous waste, and ICS 13.030.50 (Recycling). The main common issues addressed in the GRI waste standard and ISO ICS 13.030 waste group standards can be categorized into four categories: waste reduction, recycling, hazardous waste (i.e., three core SDGs indicators suggested by the United Nations Conference on Trade and Development for company reporting regarding waste management), and waste impact management.

Key Words

Climate change mitigation, Carbon removal, Carbon sequestration, Certification

전다희 Dahee Jeon , 강현국 Hyun-kook Kahng

DOI:10.9786/kswm.2023.40.4.336

Abstract

This study investigated international standardization trends for waste management, without being limited to specific materials or fields to identify the main direction and issues of sustainable waste management in the international community. The study focused on two types of international standards related to the Sustainable Development Goals (SDGs): the Global Reporting Initiative (GRI) waste sustainability reporting standard and the International Organization for Standardization (ISO) ICS 13.030 waste group standards. The GRI’s reporting standard on waste, updated in 2020, especially, requires organizations to report on the causes of waste generation and waste-related impacts in their activities and value chain, along with actions taken to prevent waste generation and management of waste-related impacts. Six out of the twenty ISO ICS 13.030 waste group standards analyzed in the study are under development. Most recently, the ISO standard on waste reduction and treatment in aquaculture has begun to be developed. It is noteworthy that there are ISO standards classified under both ICS 13.030.30 (Special wastes), a sub-group related to hazardous waste, and ICS 13.030.50 (Recycling). The main common issues addressed in the GRI waste standard and ISO ICS 13.030 waste group standards can be categorized into four categories: waste reduction, recycling, hazardous waste (i.e., three core SDGs indicators suggested by the United Nations Conference on Trade and Development for company reporting regarding waste management), and waste impact management.

Key Words

Waste management, Sustainability, SDGs, GRI, ISO

홍인기 In-gi Hong , 이종수 Jong-soo Lee , 배재근 Chae-gun Phae

DOI:10.9786/kswm.2023.40.4.349

Abstract

In accordance with the implementation of the ‘Framework Act on Resource Circulation’ in 2018, local governments are required to establish a basic plan for resource circulation and calculate resource circulation indicators to establish a basic resource circulation plan. However, among the resource circulation indicators, the ‘circulation utilization rate’ refers to the ratio of the actual recycling capacity to the amount of waste generated. Therefore, the status of the residues generated in the recycling process of waste should be taken into account. However, the currently announced ‘national waste generation and treatment status’ does not include the data on the residues generated during the selection process, making it difficult to calculate the actual recycling rate. In this study, each result value was derived using a material flow chart divided into five stages and a two-stage recycling process to calculate an appropriate actual recycling rate. As a result, the actual recycling rate of plastic waste among domestic waste was calculated as 71.70, and the final disposal rate was 15.25. As a result, it is judged that realistic figures were calculated compared to the actual recycling rate (100%) and final disposal rate (0%) calculated based on the national waste generation and treatment status used in most local governments and municipalities.

Key Words

Plastic waste, Material flow, Actual recycling rate, Recycling, Residue

이종효 Jong Hyo Lee , 황용우 Yong Woo Hwang , 김다연 Da Yeon Kim , 노형주 Hyung Joo Roh , 박종필 Jong Pil Park

DOI:10.9786/kswm.2023.40.4.363

Abstract

This study aims to quantify the environmental benefits derived from producing compost and dried larvae of black soldier fly (BSF), as well as decomposing 1 ton of food waste using BSF larvae. This analysis is compared with the production of aerobic compost and dry single ingredient feedstock through conventional food waste recycling methods, employing life cycle assessment methodology. The findings reveal that the environmental impact of food waste decomposition using BSF larvae is reduced by 88.4% compared to the production of dry single ingredient feedstock and aerobic compost. The emissions of C₂H₄, trifluoromethyl bromide, SO₂, CO₂, phosphate, and antimony were reduced by 99.6%, 95.5%, 88.5%, 88.4%, 86.0%, and 80.6%, respectively. In the case of CO₂, assuming the national food waste discharge, the reduction effect amounted to 1.87 million tons of CO₂-eq. This is equivalent to the amount of greenhouse gases absorbed annually by 800 million pine trees and 530 million oak trees. Although this study has certain limitations as it relied on estimated figures obtained through the allocation of utilities for optimal BSF breeding, the findings of this study can serve as valuable data for management and policy support data in related industries. The production of compost and dried BSF's larvae through BSF treatment offers a quantified reduction in environmental impacts caused by replacing aerobic compost and dry single ingredient feedstock with common food waste recycling treatment. This suggests the possibility of derivative research through a more sophisticated data collection process in the future.

Key Words

Black soldier fly, BSF, Food waste, Life cycle assessment, LCA, Environmental impact reduction effect, Food waste treatment

김상채 Sang-chae Kim , 송주현 Ju Hyun Song , 김웅찬 Woong Chan Kim , 여종빈 Jong-bin Yeo

DOI:10.9786/kswm.2023.40.4.372

Abstract

In this paper, we investigated the properties of volume reduction ingot for the recycling of flame-resistant expanded polystyrene (EPS) waste. The experimental method consisted of a composite process involving EPS reduction, grinding, crushing, and degreasing. Through our study we determined that the optimum process for achieving the desired results involved a combination of multi-grinding and degreasing methods. Furthermore, we identified the optimal heat condition for the degreasing process to maintain flame retardant properties as 600℃ for a duration of 2 h. In addition, we provide evidence to support the feasibility of using this process in EPS recycling for flame retardant materials.

Key Words

Recycle, Flame resistant EPS, Waste EPS, Multi-grinding

김나원 Nawon Kim , 이가영 Gayeong Lee , 김용진 Yong-jin Kim

DOI:10.9786/kswm.2023.40.4.378

Abstract

Plastic waste is a widespread byproduct of industrial development. Once released into the environment, it degrades into microplastics, due to physical breakdown, photodegradation, chemical deposition, and biological degradation. These materials are found in various ecosystems, including rivers, lakes, beaches, estuaries, sediments, and waste incineration residues. Waste landfills are the main storage of plastic waste, and about 79% of the wasted plastics are accumulated alongside landfills and the natural environment. In addition, microplastics formed within landfills are mixed with landfill leachate and evacuated for a variety of factors. Various pretreatment methods have been proposed to separate and extract microplastics from landfill leachate. However, researchers’ methodologies significantly differ in the type of reagent for the density solution and the filter paper; consequently, there is no standardized method. Hence, this study aims to compare and classify various techniques suggested in previous studies that separated and extracted microplastics from leachate to find efficient methods that can be applied in the future. Furthermore, analytical items showing a correlation with the concentration of microplastics among environmental media were also considered and presented.

Key Words

Landfill, Leachate, Microplastics, Separation, Density solution

범봉수 Bongsu Bum

DOI:10.9786/kswm.2023.40.4.391

Abstract

Organic wastewater, enriched with nutrients such as nitrogen and/or phosphorus, is commonly treated utilizing an A²/ O process. However, technological and cost barriers pose challenges for the extra processing of excess sludge. This study aims to analyze the effects of employing a co-treatment of microwave-irradiated (MWI) excess sludge with wastewater via an A²/O process on subsequent excess sludge production. A comparative experiment was performed, wherein two reactors implementing the A2/O process were deployed. The process included anaerobic (An), anoxic (Ao), aeration (Ox), and settling tanks, along with an internal recycle rate of 2Q, and a sludge return rate of 1Q. Initially, primary effluent and returned sludge from the S Sewage Treatment Plant were utilized. The reactors' hydraulic retention time (HRT) was gradually decreased from 10 hr to 4 hr. All excess sludge was wasted in one reactor (R-C), operating as a control. In contrast, in the other reactor (R-M), 250 mL of excess sludge was microwave-irradiated for 3 minutes and then channeled to an anaerobic tank with primary effluent. Results indicated that the Reagent-Volume to Microorganism-Weight (F/M) ratio in R-M was slightly higher than in R-C. Excess sludge production in R-M was 34% less than in R-C, corresponding to the average microbial growth coefficients for R-C and R-M were 0.352 mg SS/mg COD_rem. and 0.234 mg SS/mg COD_rem, respectively. Although l influent concentrations of Chemical Oxygen Demand (COD), Total Nitrogen (T-N), and Total Phosphorus (T-P) were higher for R-M, their removal efficiencies proved superior. However, a shortened HRT of 4 hr resulted in a drop in treatment efficiencies across all reactors.

Key Words

Excess sludge production, Microwave-irradiated, MWI, Excess sludge, A^{2, O process}

김효수 Hyo-su Kim , 김도완 Dowan Kim , 배재근 Chaegun Phae

DOI:10.9786/kswm.2023.40.4.400

Abstract

Recently, the conversion and integrated bio gasification of food waste have been aggressively explored in the waste management sector to reduce greenhouse gas emissions and promote the production of renewable energy. However, diverse constraints limit the transfer of all facilities to integrated bio gasification, resulting occasional use of stand-alone bio gasification. Methods of bio gasification of food waste include utilizing the raw material itself as a raw material or using discharged food wastewater from various resource facilities as a substrate. This study employs operating data from two types of food waste bio gasification facilities to calculate parameters such as sludge reduction, energy consumption, wastewater treatment, and biogas emission and reduction effects, culminating in the computation of net greenhouse gas emissions. The study shows that while the Food waste-Based Biogasification Process (FBP) excellent in biogas production, it generates more greenhouse gases in terms of energy usage and wastewater treatment than the Food Wastewater-Based Biogasification Process (FWBP). Notably, this study's results differ from previous research by considering wastewater treatment, thereby providing data that is crucial for technology developers and policymakers.

Key Words

Food waste, Food wastewater, Biogas, Energy, Greenhousegas

권안규 Ankyu Kwon , 정진도 Jindo Chung

DOI:10.9786/kswm.2023.40.4.408

Abstract

Renewable energy is becoming a competitive resource in numerous countries, leading to continuous expansion in electricity generation. Burning biomass in Circulating Fluidized Bed Combustion (CFBC) systems presents a method for reducing CO₂ emissions and necessitates further technological advancements. After a comprehensive computational analysis of the ejector, parameters were established in which the air blower flowrate is 2.4 kg/s, the fuel input is between 8.3 to 10 tons per hour, and the fuel is stably injected at 180 mm of ejector nozzle diameter (Dnoz) and 300 mm of throat diameter (Dth). Additionally, we analyzed the benefits of using domestic, unused forest biomass fuel - a form of carbonneutral energy. The results show that it is possible to secure 11.2 million tons of Renewable Energy Certificates (RECs) per year as a Renewable Portfolio Standard (RPS) mandatory supplier without relying on imported wood pellets, thus reducing greenhouse gas CO₂ emissions by 120,000 tons annually.

Key Words

Biomass, Ejector, CFBC, Booster chamber, Air Blower

윤상일 Sangil Yun , 송상훈 Sang-hoon Song , 이남훈 Nam-hoon Lee , 박진규 Jin-kyu Park

DOI:10.9786/kswm.2023.40.4.417

Abstract

The aim of this study is to introduce criteria for categorizing semi-aerobic landfills in Korea. To fulfill the requirements for the establishment and management of semi-aerobic landfills, the landfill design must be tailored to this specific type. The key components of semi-aerobic landfills include leachate collection pipes situated beneath the landfill, along with vertical gas vent pipes. To adhere to design standards, a leachate collection pipe with a minimum diameter of 0.4 m must be installed. However, this study suggests increasing the diameter of the leachate collection pipe to ensure the leachate level does not reach one-third, thereby enhancing its air introduction efficiency. Vertical gas vent pipes should be positioned at intervals of 20 to 40 m, with precautions taken to prevent damage during landfill operation. Monitoring aspects encompass air temperature, landfill’s internal temperature, leachate level, air inflow rate into the leachate collection pipe, and landfill gas composition. In conclusion, it is crucial to consider the design criteria and monitoring aspects outlined in this study to ascertain whether a landfill qualifies as a semi-aerobic landfill.

Key Words

Greenhouse gas, IPCC guidelines, Semi-aerobic landfill, Methane correction factor