Journal of Korean Society of Environmental Engineers (대한환경공학회지)

Korean Society of Environmental Engineers (대한환경공학회)
권호 표지
DOI QR코드

DOI QR Code

Production of Alternative Coagulant Using Waste Activated Alumina and Evaluation of Coagulation Activity

폐촉매 부산물로부터 대체 응집제 제조 및 응집성능 평가

  • Received : 2014.06.18
  • Accepted : 2014.07.31
  • Published : 2014.07.31
Download PDF
⟨ Previous Next ⟩

Abstract

In this study, the production potential of alternative coagulant ($Al_2(SO_4)_3$ solution) having the identical coagulation activity with respect to the commercial coagulant was investigated. The raw material of alternative coagulant was a spent catalyst including aluminium (waste activated alumina) generated in the manufacturing process of the polymer. The alternative coagulant was produced through a series of processes: 1) intense heat and grinding, 2) chemical polymerization and substitution with $H_2SO_4$ solution, 3) dissolution and dilution and 4) settling and separation. To determine the optimal operating conditions in the lab-scale autoclave and dissolver, the content of $Al_2O_3$ in alternative coagulant was analyzed according to changes of the purity of sulfuric acid, reaction temperature, injection ratio of sulfuric acid and water in the dissolver. The results showed that the alternative coagulant having the $Al_2O_3$ content of 7~8% was produced under the optimal conditions such as $H_2SO_4$ purity of 50%, reaction temperature of $120^{\circ}C$, injection ratio of $H_2SO_4$ of 5 times and injection ratio of water of 2.3 times in dissolver. In order to evaluate the coagulation activity of the alternative coagulant, the Jar-test was conducted to the effluent in aerobic reactor. As a result, in both cases of Al/P mole of 1.5 and 2.0, the coagulation activity of the alternative coagulant was higher than that of the existing commercial coagulant. When the production costs were compared between the alternative and commercial coagulant through economic analysis, the production cost reduction of about 50% was available in the case of the alternative coagulant. In addition, it was identified that the alternative coagulant could be applied at field wastewater treatment plant without environmental problem through ecological toxicity testing.

본 연구에서는 상용 응집제와 동일한 응집 성능을 확보할 수 있는 대체 응집제(황산알루미늄 용액)의 제조 가능성을 평가하였다. 사용된 대체 응집제 원료는 폴리머 제조 공정에서 발생하는 폐촉매 부산물(Waste activated alumina)이며, 대체 응집제는 1) 강열 및 분쇄, 2) 황산과의 화학적 중합 및 치환 반응, 3) 용해 및 희석, 4) 침전 및 분리과정을 거쳐 제조되었다. 실험실 규모의 autoclave 및 용해조에서의 최적 운전 조건을 도출하기 위해 황산 순도, 반응 온도, 황산 주입비 및 용해조에서의 물 주입비의 변화 등에 따른 대체 응집제 내 $Al_2O_3$ 함량이 분석되었다. 연구 결과, 황산 순도 50%, 반응 온도 $120^{\circ}C$, 황산 주입비 5배 및 용해조 물 주입비 2.5배의 조건하에서, 7~8% 범위의 $Al_2O_3$ 함량을 가지는 대체 응집제가 제조된다는 것이 확인되었다. 대체 응집제의 응집 성능을 평가하기 위해 호기조 유출수를 대상으로 Jar-test를 수행한 결과, Al/P의 몰비를 1.5 및 2.0으로 주입한 두 가지 경우 모두에서 기존 응집제의 인 제거 성능과 유사하거나 더 높은 제거 성능이 확인되었다. 추가적으로 경제성 평가를 통해 상용 응집제와 비교했을 때 50% 이상의 생산 단가 절감이 가능하였고, 생태독성 평가를 통해 환경적 문제없이 대체 응집제가 실제 하수처리장 또는 폐수처리장에 적용될 수 있는 것이 확인되었다.

Keywords

References

  1. Kim, H. S., Kim, Y. J., Hoang, T. Q., Baek, G. D., Kim, S. S. and Kim, C. W., "Application of real-time feedback control strategies based on effluent $NH_{4}-N$ and $NH_{x}-N$ concentrations in an $A^{2}/O$ process," Kor. J. Chem. Eng., 30(8), 1578-1587(2013). https://doi.org/10.1007/s11814-013-0084-x
  2. Lim, E.-T., Jeong, G.-T., Bhang, S.-H., Park, S.-H. and Park, D.-H., "Evaluation of pilot-scale modified $A_{2}O$ processes for the removal of nitrogen compounds from sewage," Bioresour. Technol., 100, 6149-6154(2009). https://doi.org/10.1016/j.biortech.2009.06.072
  3. Kim, D. G., Park, D. W. and Jang, W. S., "The Study of a Novel Coagulation Technology Using the Atomized Molten Slag as Weighted Coagulation Additives," J. Kor. Soc. Water Qual., 19(6), 655-661(2003).
  4. Lee, S.-H., "Optimization of ASM3 including simultaneous denitrification and phosphorus uptaked," Ph.D. thesis, Pusan National University, 2006.
  5. Kim, J. B., Park, H.-J., Lee, K. W., Jo, A R., Kim, M. W., Lee, Y. J., Park, S. M., Lee, K. Y., Shon, H. K. and Kim, J.-H., "Application of Ti-salt Coagulant and Sludge Recycling for Phosphorus Removal in Biologically Treated Sewage Effluent," Korean Chem. Eng. Res., 51(2), 257-262(2013). https://doi.org/10.9713/kcer.2013.51.2.257
  6. 최의소, 상하수도공학, 청문각, 2005.
  7. Yu, E. S. and Yun, I. M., "The Study of Si-Al Coagulant Development and Characteristics for Wastewater Treatment of Tire Recycling Industry," J. Kor. Soc. Environ. Eng., 26(2), 1-6(2004).
  8. Han, S. W. and Kang, L. S., "Comparison of PACl with Al (3) Coagulants in Water Treatment and Its Characterization," J. Kor. Soc. Water Qual., 15(3), 345-352(1999).
  9. Lee, K.-Y., "총인처리시설 추진현황 및 대책," Magazine Kor. Water Resour. Assoc., 43(6), 56-59(2010).
  10. Lee, J.-I., "(A) production of aluminium sulfate from waste alumina," Master thesis, Chonnam National University, 1997.
  11. Jeong, M.-K., "A study on the improvement of fiber filter using in-line coagulants injection method," Master thesis, Pusan National University, 1997.