In this study, the fate and removal of 15 pharmaceuticals (including stimulants, non-steroidal anti-inflammatory drugs, antibiotics, etc.) in unit processes of a sewage treatment plant (STP) were investigated. Mass loads of pharmaceuticals were 2,598 g/d in the influent, 2,745 g/d in the primary effluent, 143 g/d in the secondary effluent, and 134 g/d in the effluent. The mass loads were reduced by 95% in the biological treatment process, but total phosphorous treatment did not show a significant effect on the removal of most pharmaceuticals. Also, mass balance analysis was performed to evaluate removal characteristics of pharmaceuticals in the biological treatment process. Acetaminophen, caffeine, acetylsalicylic acid, cefradine, and naproxen were efficiently removed in the biological treatment process mainly due to biodegradation. Removal efficiencies of gemfibrozil, ofloxacin, and ciprofloxacin were not high, but their removal was related to sorption onto sludge. This study provides useful information on understanding removal characteristics of pharmaceuticals in unit processes in the STP.

수은은 인체독성과 생물농축성 그리고 대기를 통한 장거리 이동성이 크기 때문에 국제적으로 관리가 필요한 화학물질로 인식되어 왔다. 이에 따라 유엔환경계획(UNEP) 집행이사회에서는 2013년 “수은에 관한 미나마타협약”을 채택하였다. 미나마타협약은 국제적으로 수은사용 및 배출을 저감하는 것이며, 이를 위해 모니터링, 배출원 관리, 원자재 및 제품관리, 폐기물 처리, 노출저감, 기술개발 등 6개 주요 분야별 관리방안을 마련하도록 요구하고 있다. 본 연구에서는 국내 폐형광등 재활용처리시설에 처리방식에 따라 처리공정별 수은 농도변화를 측정하여 공정단계별 수은 물질수지를 분석하였다. 처리방식으로 건식과 습식시설을 각각 선정하여 현장에서 공정단계별 입자상과 기체상 수은 농도, 유량을 측정하거나 시료를 일정시간 동안 3회 채취하여 분석하였다. 또한 직관형 형광등 무게 당 투입 갯수를 확인하였다. 형광등 투입구, 파쇄장치, 건식 및 습식 수은 처리공정, 대기방지시설 등에서 분진, 유리, 비철, 활성탄 등 26개 시료를 채취하고, 수은농도를 측정하여 물질수지를 계산하였다. 연구 결과, 폐형광등 재활용시설로 입고되는 직관형 폐형광등은 박스 당 무게는 약 40-45 kg이고, 형광등 개수는 약 240개 정도이었다. 일부 환형, 일체형 형광등이 처리시설 투입구로 투입되지 않도록 미리 제거하였고, 처리과정에서 발생한 폐기물 중 수은 함량농도를 측정한 결과, 분진, 슬러지, 폐활성탄 및 폐수에서 높게 검출되었다.

This paper presents the actual recycling rates and recycling processes of waste plastic recycling facilities using material flow analysis. Determination of actual recycling rates through the processes of waste plastics is a very important subject not only from the point of plastic recycling efficiency energy conversion but also from the perspective of the recycling technology level. In this study, the recycling processes and recycling rates of waste plastic recycling facilities were evaluated by the MFA analysis based on 14 site visits and 25 questionnaires. The MFA methodology based on mass balance approach applied to identify the inputs and outputs of recyclable plastic materials in the recycling processes at recycling facilities. It is necessary to determine the composition and flows of the input materials to be recycled in a recycling facility. A complete understanding of the waste flows in the processes along with the site visit and data surveys for the recycling facilities was required to develop a material flow for the processes and determine the actual recycling rate. The results show that the average actual recycling rates for the recycling facilities by the site visit and the questionnaire was found to be approximately 87.5 ± 7.1% and 84.3 ± 14.5%, respectively. The recycling rates depended upon several factors including the quality of incoming waste plastics, the type and operating conditions of recycling processes, and the type of final products. According to the national statistics, the recycling rate of waste plastics was about 53.7%, while the actual recycling rate at national level was estimated to be approximately 45.1% by considering the recycling performance evaluated as well as the type of recycling process applied. The results of MFA for the recycling processes served as a tool to evaluate the performance of recycling efficiency with regard to the composition of the products during recycling. They may also support the development of the strategy of improvement of recycling processes to maximize resource recovery out of the waste plastic materials.