이재호 Jae-ho Lee , 이종수 Jong-soo Lee , 김도완 Do-wan Kim , 배재근 Chae-gun Phae

DOI:10.9786/kswm.2022.39.1.1

Abstract

To improve recyclable waste collection system, this study conducted a survey of 123 apartments complexes and 229 local governments and suggested the measures to improve the current collection system based on the results of the survey. The survey revealed that respondents preferred public intervention collection. Currently, 80% of apartment complexes input the results of recyclable resources into the circular resource information center, but private collection companies are required to directly input them to simplify the administrative system of local governments. Most apartment complexes choose private collection companies based on down payment, which is likely to result in excessive competition. 97% of apartment complexes that implement the price linkage system set a one-year cycle, indicating that the effectiveness of the price linkage system is poor and measures to improve it are necessary. The public collection ratio of local governments was found to be 100% for detached houses, 48% for obligatory apartment, and 83% for non-obligatory apartment. The mixed collection ratio of detached houses and multi-use facilities is 50%, which is higher than the mixed collection ratio of apartment houses (38%), which is expected to reduce the effectiveness of the recycling system. Hence, it is necessary to establish a collection system based on the source. To establish public responsibility collection, it is necessary to strengthen the standards and the price linkage system for collection companies. To reduce the administrative burden of local governments, it is necessary to manage apartment at a regional level or to entrust local government work.

Key Words

Recycling, Apartment, Collection type, Collection system

최주섭 Joo-sub Choi , 서병륜 Byong-yoon Suh , 김덕열 Deok-yeol Kim , 민달기 Dal-ki Min

DOI:10.9786/kswm.2022.39.1.10

Abstract

A legislative notice was announced in 2021 that 17 plastic products managed through a voluntary agreement system for more than five years would be transferred to the extended producer responsibility (EPR) system. Accordingly, related industries have been thinking about whether to transfer to the EPR system and to form a producer responsibility organization (PRO). This study investigated how the PROs should be established, including the existing five plastic packaging materials and products. It was also studied that it is desirable for product groups to be incorporated into an integrated PRO rather than a single PRO. Furthermore, the integrated PRO plan is the [3rd alternative], which is to design the PRO as the existing ① household goods (existing packaging material + add 1 new item), ② agricultural and fishery goods (existing 4 items + add 3 new items), and the newly established ③ industrial goods (6 new items), and ④ construction goods (7 new items). In addition, considering the product’s characteristics, it is suggested that the industry establishes a separate autonomous management system for ⑤ products with a long life cycle such as construction items and ⑥ returnable products such as plastic pallets.

Key Words

Voluntary Agreement (VA), Extended Producer Responsibility (EPR), Producer Responsibility Organizations (PROs), 17 items of plastic product

조은해 Eun-hae Cho , 김경 Kyung Kim , 김도완 Do-wan Kim , 배재근 Chae-gun Phae

DOI:10.9786/kswm.2022.39.1.17

Abstract

Beverage cartons are made of natural pulp and, if recycled, can be used as high-quality resources that generate high economic profits and low carbon emissions. However, as of 2020, the recycling rate for beverage cartons was 16.1%, the lowest level since the extended producer responsibility system was introduced in 2003. This study diagnosed a problem with the beverage carton recycling system and proposed a plan for improvement. Through a nationwide on-site survey (n=41), this study identified the discharge ratio of used beverage cartons by region (metropolitan city), housing type (sale, lease), discharge method (separate, mixed), collection type (daily, regular), and the current status of beverage carton-related collection and recycling companies. According to an analysis of the discharge characteristics of used beverage cartons, the proportion of aseptic cartons in densely populated areas in Seoul and other metropolitan regions was high (37.1% to 40.4%). Furthermore, the disposal rate of aseptic cartons was high in the following order : lease > sale > lease + sale. The difference in the aseptic carton waste generation rate by collection method was not statistically significant. Still, the difference in discharge type was 4.8 percent point higher than that of mixed discharge when disposed separately. According to an on-site survey of carton pack-related collection and recycling companies, the poor collection rate, low collection quality, and lack of market for recycled sanitary paper were recognized as significant challenges. Following the prospect of delivered and imported ratio of aseptic cartons raise to 50% in 2024 and 80% in 2035, this study proposed to split the separate discharge system for gable-top cartons and aseptic cartons to diversify recycled products like other foreign countries.

Key Words

Used beverage cartons, Recycling, Gable top carton, Aseptic carton, Apartment

박명선 Myoung Sun Park , 황용우 Young Woo Hwang , 문진영 Jin Young Moon , 이성유 Seong You Lee

DOI:10.9786/kswm.2022.39.1.28

Abstract

To change from a linear economy to a circular economy, the necessity of recycling scarce resources through recycling waste is emerging. In South Korea, the concept of landfill mining has been introduced as a way to convert landfills into resources, and recycling-type landfills are being created. In this study, the operation status of domestic municipal waste landfills was identified, and the amount of resource recovery according to the renovation of a circular landfill was calculated. Of 215 public landfill sites, 67 landfill sites that have been used or have a residual landfill rate of less than 40% were investigated, and the total amount of waste landfills here was confirmed to be 68,509 thousand m3. Among landfill wastes, the energy production potential from combustible wastes was calculated to be 55,835,540 Gcal when energy was recovered through stocker-type incineration. The amount of recovered valuable resources among landfill wastes was estimated to be 1,065 thousand tons. As a result of evaluating the potential for recycling of major metals, trace metals, and rare earth elements contained in incineration ash, the content of Fe among major metals such as Fe, Al, Cu, and Zn was in the range of 27,280 to 245,517 tons, which is the national integrated resource management system. The possibility of circular use was confirmed as the range of the mass flow analysis statistic was similar. In the case of trace metals, the content ranges of Cr, Pb, and Co were 162 to 1,716 tons, 99 to 875 tons, and 35 to 64 tons, respectively, similar to the statistics. In the case of rare earth elements with high potential value as future resources, national statistics were absent or recent data were insufficient, but in the case of Dy, a similar content could be confirmed. 70% of the total landfill capacity can be used for the recycling landfill capacity according to the composition of the recycling landfill, and when the municipal waste is finally disposed of after resource recovery in the recycling landfill, the lifespan of the existing landfill can be extended by more than 5.4 times.

Key Words

Circular Landfill, Resources recovery, Metals, REE

이동희 Dong-hee Lee , 신준호 Junho Shin , 류태공 Taegong Ryu , 김민길 Min-gil Kim

DOI:10.9786/kswm.2022.39.1.36

Abstract

Water treatment sludge (WTS), hydrothermally synthesized powder (HSP) using the WTS, and CuO added HSP (CuHSP) after heat treatment at 500℃ were prepared and its hydrogen sulfide (H₂S) removal properties were investigated. The physicochemical properties of adsorbents were studied by N₂ adsorption-desorption, scanning electron microscope, x-ray diffraction, and thermogravimetric-differential thermal analysis. The specific surface area for the WTS was 42.7㎡/g and was increased by 78.1㎡/g after the hydrothermal reaction and was maximized by 168.7㎡/g after the heat treatment at 500℃ for 1 h. The breakthrough time of the WTS, HSP, and CuHSP for H₂S removal at 25℃ was measured for 10 min, 20 min, and 170 min, respectively, thus demonstrating an effective application of WTS as the catalytic carrier for low temperature H₂S removal.

Key Words

Water treatment sludge, CuO, Adsorbent, H_{2S removal}

김민정 Min-jung Kim , 조나현 Na-hyeon Cho , 최자형 Ja-hyung Choi , 전태완 Tae-wan Jeon , 정미정 Mi-jeong Jeong

DOI:10.9786/kswm.2022.39.1.43

Abstract

In this study, waste with the environmental potential for medium-contact type waste recycling was evaluated. Target samples were collected from ten waste foundry sand sources. The samples were selected by considering seven hazardous heavy metals, ecological toxicity, and polycyclic aromatic hydrocarbons that may cause problems during the recycling processes in contact with nature. The upstream permeation method was used to analyze the ecological toxicity. Toxic effects were identified by analyzing ecotoxicity influencing factors. Ecotoxicity was tested in two ways after mixing the sample and artificial soil in consideration of the actual recycling situation. To this end, waste foundry sand was subjected to either clay caking or chemical caking when molding it. Because the caking agent used is different, the characteristics of each sample are different. The main causes of ecological toxicity at the waste foundry were pH and ammonia.

Key Words

Waste foundry sand, Environmental Assessment of Recycling, Ecotoxicity

최자형 Ja-hyung Choi , 박윤수 Yoon-su Park , 조나현 Na-hyun Jo , 전태완 Tae-wan Jeon , 강영렬 Young-yeul Kang , 엄남일 Nam-il Um

DOI:10.9786/kswm.2022.39.1.50

Abstract

To prevent inappropriate waste management such as abandoning or illegally dumping exported and imported waste, it is important to establish a monitoring system through using advanced waste management technology. Recent investigations into the illegal disposal of exported and imported waste have resulted in false income and waste disposal reports. Therefore, the intention of this study is to examine the effect of monitoring the entire waste treatment process by using a waste tire management system (WTMS). From the results of drawing technical elements and examining the effect of monitoring, it is considered appropriate to establish a WTMS based on radio-frequency identification (RFID) and global navigation satellite system (GNSS). To minimize of the weaknesses of RFID and GNSS systems in the monitoring, elements such as video recording devices, load cells, and indicators can be combined in a multitude of different ways. Finally, the effect of the introduction is reviewed through evaluation according to the combination of WTMS equipment, and a strategy for WTMS is proposed in consideration of the interworking capability.

Key Words

Export & Import waste, Waste tracking management system, GNSS, RFID

김호남 Ho Nam Kim , 이창민 Changmin Lee , 김재영 Jae Young Kim

DOI:10.9786/kswm.2022.39.1.60

Abstract

In Republic of Korea, waste disposer-treated food waste can be recovered from the waste disposer wastewater before it is discharged into the sewer system. The solid phase in the waste disposer-treated food waste can be subjected to anaerobic digestion. However, it contains kitchen detergent that can inhibit the anaerobic digestion process. The objectives of this study were to evaluate the degradation and phase distribution of kitchen detergent and the effect of the detergent on the anaerobic degradation of the solid phase in the waste disposer-treated food waste. 47-58% (w/w) of detergent existed in the recovered solid phase. According to biochemical methane potential tests, 70% (w/w) of the detergent had been anaerobically degraded and 4-5% and 26-30% (w/w) of the liquid and solid phases remained, respectively. In the range of 0-300 mg/L of kitchen detergent, the maximum methane generation rate slowed as the concentration increased and the maximum methane production was statistically the same. When the detergent concentration was 450 mg/L, the maximum methane production of the recovered food waste decreased by 22.8% (v/v). These indicate that the inhibition on the methane potential would not happen due to degradation of the detergent for an estimated probable concentration of 101.4 mg/L. When considering the expected detergent concentration in the disposer wastewater, the recovered food waste can be used as an anaerobic digestion substrate without inhibiting methane recovery.

Key Words

Anaereobic digestion, Detergent, Fate and effect, Food waste disposer, Sulfactant

최예덕 Yeduk Choi , 이준연 Junyeon Lee , 하현주 Hyunju Ha , 김민철 Mincheol Kim , 장주호 Jooho Chang , 유종영 Jongyoung Yoo , 조승희 Seunghui Cho , 임찬섭 Chansub Lim , 오석률 Seokryul Oh , 이목영 Mokyoung Lee

DOI:10.9786/kswm.2022.39.1.69

Abstract

Sewage treatment plants produce large amounts of sewage sludge yearly in Korea. In this study, a Membrane-Filter Press System (MFPS) using ultrasonic waves was developed to treat sewage sludge at the Seonam sewage treatment plant in Seoul. The MFPS consists of an ultrasonic extractor, a polymer injection tank, a membrane-filter press, and a centrate tank for improving sludge dewatering and phosphorus recovery. Two types of sewage sludge were used: digested raw sludge and digested excess sludge. In lab-scale experiments with an ultrasonic extractor, the concentration of phosphorus was 214.9 mg/L at 50 rpm after sonication at 500 W for 20 min, which was around 4.9 times higher than non-treated sludge. In the pilot-scale experiment, dewaterability of the digested raw and excess sewage sludge was investigated in the MFPS under three sets of operating conditions involving modifier injection, ultrasonication, and polymer injection. it was found that the moisture content of the dewatered digested raw and excess sewage sludge cakes was reduced to 50.5% and 54.3%, respectively. Lowering the moisture content reduced the total volume of the sludge by approximately 40% compared to a conventional centrifugal dehydrator. It is expected that the MFPS will reduce the disposal cost of sludge and offers a sustainable solution for recycling resources.

Key Words

Ultrasonic waves, Membrane, Sludge, Moisture, Phosphorus

임동순 Dongsoon Lim , 김현철 Hyuncheol Kim

DOI:10.9786/kswm.2022.39.1.78

Abstract

However the food waste problem has been well characterized by the local government, finding the best solution is a difficult and daunting task. Although much attentionhasbeenpaid to analyze the effect of food waste treatment facilities, there have been few sophisticated comparisons of the costs and potential effects of food waste reduction equipment subsidized. In this study, an attempt was made to analyze lump-sum purchase and rental subsidies by comparing the costeffectiveness of food waste reduction equipment distribution by the local government, Jeju Special District. A set of scenarios for two kinds of subsidies were constructed and the data on the cost of financing methods was assembled after upscaling the costs over a 10-year period. The estimated costs are 6,091 million KRW for the purchase subsidies and 6,463 million KRW for the rental subsidies, which indicates that the former is more cost-effectivet hanthelatter. However, cost-effectiveness can vary with assumptions, such as technological progress, interest rate, risk premium, etc. The present approach can be adapted to establish proper food waste policy interventions or a mixture of policies by considering the regional economic conditions and environment.

Key Words

Food waste management, Reduction equipments, Cost effectiveness, Policy mix