노연희 Yeon Hee Ro , 정우진 Woo Jin Chung , 바라스브라마니라빈드란 Ravincran Balasubramani , 장순웅 Soon Woong Chang , 김현욱 Hyunook Kim , 신중두 Joung Du Shin

DOI:10.9786/kswm.2020.37.7.443

Abstract

The aerobic digestion for the composting process of livestock manure is the most widely used recycling method. Accordingly, research for efficient and high-quality compost production has been actively conducted. During the composting process, the addition of activated biochar can maintain a higher temperature and a water holding capacity with having the good quality compost. Therefore, the objective of this experiment was to evaluate the changes of physicochemical properties for the aerobic composting process of poultry and cattle manure according to the mixing ratio of activated rive hull biochar. For the production of manure compost, the treatments of activated rice hull biochar were set at 0%, 5%, 10%, and 15%, respectively, during composting the poultry and cattle manure. Assessment of maturity for producing the manure composts was evaluated through changes of temperature, water holding capacity, pH, and C/ N ratio. For producing the good quality compost, an optimum mixing rate was 10% of activated rice hull biochar during composting, considering the physicochemical properties of composts.

Key Words

Compost, Livestock manure, Activated rice hull biochar, Physicochemical properites

정연우 Yeonwoo Jeong , 최연석 Yeonseok Choi , 최상규 Sangkyu Choi , 한소영 Soyoung Han , 응웬반꾸잉 Quynhvan Nguyen

DOI:10.9786/kswm.2020.37.7.451

Abstract

The drying process is essential to remove the water content of waste to enhance the calorific value of the produced fuel. Even with the development and enhancement of the waste-to-heat technology highly encouraged, the current domestic dryer development capability is still insufficient not only in the design but also in the operation. Therefore, research or investment in the development of highly efficient dryers is required. In this study, a multi-stage rotary dryer was used to dry coffee ground waste, which is supplied at a rate of 110kg/ hr. Various operation parameters were tested such as drum speed, recirculation rate of exhaust gas, and temperature of exhaust gas. Results suggest that a drum speed of 0.4 rpm, an exhaust gas recirculation rate of 73%, and an exhaust gas temperature of 128℃ were the optimum conditions to minimize the water content in coffee ground waste.

Key Words

Multi-stage rotary dryer, Drum speed, Recirculating rate of exhaust gas, Temperature of exhaust gas, Coffee ground waste

정석현 Suckhyun Jeong

DOI:10.9786/kswm.2020.37.7.459

Abstract

Domestic heavy oil power plants are trying to change the fuel from B-C heavy oil to bio-heavy oil in consideration of environmental concerns. By strategically replacing bio-heavy oil fuels in B-C heavy oil-fired power plants, governments can effectively respond to the implementation of the U.N framework convention of climate change. In 2018, gross domestic power was 593,406,797 MWh, about 1% of which came from heavy oil fuels. B-C heavy oil thermal power plants are attempting to mix or replace bio-heavy oil with B-C heavy oil. B-C heavy oil and bio-heavy oil have different viscosity, composition and combustion characteristics. In this study comparing the fouling elements on the heat transfer tubes equipped on the bio heavy oil boiler, difference of composition was affected by the temperature of gas but not by the temperature of heat transfer tubes. Fly ash of heavy oil and bio-heavy oil as a boiler fuel was compared by the method of ICP and SEM.

Key Words

Fine dust, Fouling, Fly ash, B-C heavy oil, Bio-heavy oil

김영신 Yeong-shin Kim , 배재근 Chae-gun Phae

DOI:10.9786/kswm.2020.37.7.468

Abstract

The amount of fruit and vegetable byproducts produced from their production to consumption by consumers was characterized by focusing on the distribution route. The considered fruits and vegetables were divided into five groups: leafy vegetables, root vegetables, fruit vegetables, condiment vegetables, and fruits. The amount of their distribution was calculated at each distribution stage of the overall distribution process. Byproducts of each group produced at individual distribution channel was calculated using the basic unit obtained through field and literature surveys. It was also considered that the byproducts can be recovered. The byproducts produced for distributing leafy vegetables, root vegetables, fruit vegetables, condiment vegetables, and fruits were 509,379; 68,844; 151,189; 479,936; and 282,897 tons per year (t/y), respectively. The total recovery for the five groups was 1,492,245 t/d, corresponding to 13.48% of the total production of the fruits and vegetables (11,067,638 t/d).

Key Words

Fruits, Vegetables, Byproduct, Distribution stage, Entire process

안정원 Jeong-won An , 오민아 Minah Oh , 오승진 Seungjin Oh , 이재영 Jai-young Lee

DOI:10.9786/kswm.2020.37.7.481

Abstract

Thanks to energy transition policy, the production and use of solid refused fuels (SRFs) using organic waste attracts a great deal of attention. In this study, bio-drying was applied to improving the economic feasibility of drying sewage sludge. Due to sewage sludge characteristics such as high moisture and viscosity, a bulking agent is required during the drying process. Therefore, this studyused food waste compost as a bulking agent and suggested the optimal compost mixing ratio and airflow conditions for bio-drying.

Key Words

Sewage sludge, Food waste compost, Bio-drying, Solid refused fuel, Organic waste

최재민 Jae-min Choi , 이채영 Chae-young Lee

DOI:10.9786/kswm.2020.37.7.487

Abstract

This work investigates the characteristics of methane production from food waste (FW) that is collected from different sources such as apartments, military camps, government offices, and correctional facilities. It was evaluated the relationship between chemical compositions of FW (e.g., carbohydrates, proteins, and lipids) and the methane yield. The highest methane yield was achieved with the FW collected from correctional facilities, ascribed to a high lipid content. The FW collected from military camps showed the highest rate of methane production, attributed to a high carbohydrate content. The methane production rate was positively correlated with the lipid content (R²=0.9933) and the carbohydrates content (R²=0.9361), while the protein content exhibited no significant correlation with the methane production from FW.

Key Words

Carbohydrates, Food waste, Lipids, Methane production, Proteins, Sources

윤상혁 Sang-hyuck Yoon , 이세현 Sea-hyun Lee

DOI:10.9786/kswm.2020.37.7.495

Abstract

The density based on the mixing ratio of recycled coarse aggregate and crushed coarse aggregate decreased as the mixing ratio increased, and the absorption rate increased. Based on the mixed coarse aggregate’s quality characteristics showed the highest performance at the mixing ratio of 20 to 80. exhibited. Furthermore, the recycled coarse aggregate satisfying the KS F 2527 standard can be used for ready-mixed concrete production up to 80%. The particles resulting from the increase in the mixing ratio of recycled coarse aggregate is applicable as mixed coarse aggregate for ready-mixed concrete production.

Key Words

Recycled coarse aggregate, Crushed coarse aggregate, Mixed aggregate, Density, Absorption rate

오화수 Hwa-soo Oh , 김형수 Hyung-soo Kim , 이재영 Jai-young Lee , 노연희 Yeon-hee Ro , 정우진 Woo-jin Chung

DOI:10.9786/kswm.2020.37.7.502

Abstract

In this study, the feasibility of using waste concrete as a cover material to remove hydrogen sulfide (H₂S) from landfill gas was evaluated. The waste concrete composed of alkaline earth metal-based compounds was applied as a H₂S adsorbent owing to its high ion exchange capacity. The H₂S adsorption amount and breakthrough characteristics with relation to the temperature of the waste concrete and the flow rate of H₂S were examined by applying the Adam-Bohart, Tomas, and Yoon-Nelson models. The highest adsorption amount of H₂S per unit mass of waste concrete was achieved at 40℃ with a flow rate of H₂S of 100 mL/min. The Tomas and Yoon-Nelson models showed an R² of 0.9601. A basic study was conducted on the H₂S adsorption by waste concrete as the cover material.

Key Words

Adsorption, H_{2S, Landfill gas, Waste concrete}