Journal of Korean Society of Environmental Engineers (대한환경공학회지)

Korean Society of Environmental Engineers (대한환경공학회)
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Evaluation of Coagulation-UF Process Considering Residual Aluminuim Concentration as Seawater Desalination Pretreatment

해수담수화 전처리 공정으로써 잔류 알루미늄 농도를 고려한 응집-UF 공정 연구

  • Son, Dong-Min (Department of Environmental Engineering, Pukyong National University) ;
  • Kang, Lim-Seok (Department of Environmental Engineering, Pukyong National University)
  • Received : 2013.05.10
  • Accepted : 2013.07.10
  • Published : 2013.07.30
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Abstract

This work was performed to investigate proper condition of coagulation treatment as UF process pretreatment that consider UF permeate flux and residual Al concentration. The coagulant used an alum as $Al_2(SO_4)_3{\cdot}16H_2O$ and PACl (r = 1.5) made this study. The experiment was tested in adjusting conditions such as alum dose, flocculation time and coagulation pH of seawater. Consequently, higher coagulant dose lead to elevation of UF permeate flux while residual aluminium also increased in condition of pH 8.0. The most suitable condition which has a good permeate flux and low residual aluminium, in this works, was coagulant dose of 0.7 mg/L (as Al, alum) and 1.2 mg/L (as Al, PACl) and coagulation pH 6.5. In addition, applying the flocculation time with 1.2 mg/L of PACI reduced. The flocculation time reduced UF permeate flux in using alum.

본 연구는 UF공정의 전처리로써 Al(III)계 응집제인 alum과 PACl을 사용한 응집공정 적용 시 두 응집제의 효율 비교 및 잔류 알루미늄 농도를 고려한 최적 운전 조건을 알아보기 위해 응집제 주입농도, 완속교반의 적용 그리고 해수 원수의 pH를 변화하여 UF막 flux 및 잔류 알루미늄 이온 농도를 조사했다. 그 결과 pH 8.0 조건에서 alum의 주입농도가 증가할수록 flux 또한 증가하였으며 완속교반은 UF막 flux를 오히려 감소시킨 것으로 조사된 반면 PACl의 경우 주입농도가 증가할수록 flux는 일부 감소하는 경향을 보였으며 alum과는 반대로 완속교반 적용시 flux 또한 증가하였다. 반면에 pH 6.5 조건에서 alum 주입량이 0.7 mg/L (as Al)일 때 UF막 flux의 효율이 가장 좋았고 잔류 알루미늄 농도는 0.05 mg/L (as Al) 이하로 측정되었다. PACl의 경우 UF막 flux 측면에서는 최적 조건은 pH 8.0, 주입농도 1.2 mg/L (as Al) 그리고 완속교반 시간을 적용하였을 때였으며 잔류 알루미늄 농도를 고려한 최적 주입조건은 pH 6.5 조건에서 주입농도를 1.2 mg/L (as Al)일 때로 조사되었다.

Keywords

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