KSCE Journal of Civil and Environmental Engineering Research (대한토목학회논문집)

Korean Society of Civil Engeneers (대한토목학회)
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A Study of the Regeneration of Spent GAC using an Electrochemical Method

전기화학적 방법을 이용한 Spent Granular Activated Carbon (GAC)의 재생 연구

  • 이상민 (국립공주대학교 환경공학과) ;
  • 주수빈 (국립공주대학교 환경공학과) ;
  • 조영수 (국립공주대학교 환경공학과) ;
  • 오예지 (국립공주대학교 환경공학과) ;
  • 김형준 ((주)피앤아이휴먼코리아 기업부설연구소) ;
  • 심인태 ((주)피앤아이휴먼코리아 기업부설연구소)
  • Received : 2021.11.24
  • Accepted : 2022.05.06
  • Published : 2022.08.01
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Abstract

This study investigates the characteristics of the GAC adsorption behavior during the operation of a multi-stage cross-flow filtration and GAC adsorption process for the purpose of devising an advanced treatment of combined sewer overflows (CSOs) and evaluates the regeneration efficiency of spent GAC that has reached the design breakpoint. During the filtration process, suspended substances are easily removed, but dissolved organic substances are not removed, necessitating a process capable of removing dissolved organic substances for the advanced treatment of CSOs. In general, GAC adsorption has been applied under low-concentration organic conditions, such as for water purification and tertiary treatments of sewage, and has rarely been applied under conditions with high organic concentrations, such as with sewage or CSOs. Accordingly, this study will provide a new and interesting experience. Also in this study, the continuous operation and breakthrough characteristics of GAC according to the strength of the inflow organic matter were investigated, electrochemical regeneration was applied to the used GAC, and the regeneration efficiency was evaluated through desorption and re-adsorption tests. The results showed that the breakthrough period was 21 days under high concentration conditions, 28 days at medium concentrations, and 32 days under low concentration conditions. The desorption of adsorbed organic matter through electrolysis occurred in the range of 188 to 609 mgCOD/L depending on the electrolysis conditions, and the effect of the electrolyte type led to the finding that NaOH was slightly higher than H2O2.

본 연구는 CSOs의 고도처리를 목적으로 다단 횡류식 여과와 GAC 흡착조의 융합공정의 운영에서 GAC 흡착조의 유기물 처리 특성을 조사하고 설계 파과점에 도달한 GAC를 전기화학적 방법을 통한 재생효율을 평가하는 것이다. 여과공정은 부유물질은 용이하게 제거되지만 용존 유기물이 제거되지 않아 CSOs의 고도처리를 위해서는 용존유기물질의 제거능이 추가로 필요하다. 일반적으로 GAC 흡착은 정수처리 공정이나 하수의 3차 처리공정과 같은 저농도 유기물 조건에서 적용되어왔고 하수나 CSOs와 같이 유기물 농도가 높은 조건에서는 거의 적용이 되지 않았기에 본 연구에서 GAC를 이용한 CSOs 처리는 흥미로운 경험을 제공할 것이다. 본 연구는 유입 유기물 강도에 따른 GAC의 연속 운전 및 파과 특성을 조사하고 사용된 GAC를 전기화학적 재생을 적용하였으며, 이때 전압강도 및 전해액이 종류에 따른 흡착 유기물의 탈착 특성을 조사하였고 재생 후 GAC의 재흡착실험을 통해서 재생효율을 평가하였다. GAC 연속 운전결과 파과기간은 고농도 조건에서 21일, 중농도에서 28일 그리고 저농도에서 32일을 나타내었다. 전기분해를 통한 흡착 유기물의 탈착은 전기 분해 조건에 따라 188~609 mgCOD/L까지 발생하였고 전해액 종류의 영향은 NaOH가 H2O2보다 조금 우수한 탈착 특성을 나타냈다.

Keywords

Acknowledgement

본 결과물은 환경부의 재원으로 한국환경산업기술원의 유망 녹색기업 기술혁신개발 사업으로 지원을 받아 연구되었습니다 (2020003160012). 본 논문은 2021 CONVENTION 논문을 수정·보완하여 작성되었습니다.

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