Journal of the Korea Academia-Industrial cooperation Society (한국산학기술학회논문지)

The Korea Academia-Industrial cooperation Society (한국산학기술학회)
권호 표지
DOI QR코드

DOI QR Code

Dewaterability Improvement and Volume Reduction of Bio-Solid using Ultrasonic Treatment

Bio-Solid의 탈수성 개선 및 감량화를 위한 초음파 적용

  • Park, Cheol (Greentech Environmental Consulting Co.) ;
  • Ha, Jun Soo (School of Civil, Environmental and Architectural Engineering, Korea University) ;
  • Kim, Young Uk (Department of Civil and Environmental Engineering, Myongji University)
  • 박철 ((주)그린텍환경컨설팅) ;
  • 하준수 (고려대학교 건축사회환경공학과 환경정책연구소) ;
  • 김영욱 (명지대학교 토목환경공학과)
  • Received : 2014.03.28
  • Accepted : 2014.06.12
  • Published : 2014.06.30
Download PDF
⟨ Previous Next ⟩

Abstract

This study examined the effectiveness of ultrasound on enhancing the dewaterability and volume reduction of bio solids from a waste treatment plant. The test specimen was obtained from a storage tank immediately before the dewatering process at a local treatment plant. The test conditions included the energy levels of ultrasonic waves and treatment time. The tests were undertaken using three types of different treatment processors (7 liter, 1 ton, 7 ton container). The capillary suction time (CST) and the viscosity of sludge, which is one of the influencing factors for dewaterbility, were obtained under various test conditions. The results showed that ultrasound increases the CST of the raw specimens, whereas a significant reduction (20 % of the maximum value) of CST occurred in the sample with ultrasound and flocculent. The decrease in viscosity reached 40 % of the maximum value. A centrifugal test was performed to examine the characteristics of the sludge settlement. The settling rate and time required to reach the final values were both enhanced by the ultrasonic energy. An ultrasonic treatment is potentially useful tool for reducing the amount of released sludge. To examine the possible use of field application, the real scale sonic processor was designed and operated. The results were similar (50 % of the maximum value) to those of laboratory experiments.

이 연구에서는 하수 처리 시 발생하는 잉여슬러지의 탈수성을 증대시켜 탈수 후 최종슬러지 케이크를 감소시키기 위해 초음파 적용 가능성을 검토하였다. 이번 연구에서 사용된 슬러지는 하수처리장에서 직접 채취한 탈수 전 잉여슬러지이며 여기에 초음파 조사시간과 조사강도를 달리 가하여 탈수성 변형특성을 고찰하였다. 실내외 실험을 동시에 수행하였으며 각각 용량이 다른 세 개(7리터, 1톤, 7톤)의 처리조를 제작 활용하였다. 초음파 처리 시간과 처리강도에 따라 탈수성 및 감량화 판단 인자로 사용되는 CST와 점도의 변화를 측정하였다. 연구결과 초음파 조사시간이 길어질수록 원 시료의 CST가 증가하는 경향을 보였으나 조사한 슬러지에 응집제를 첨가할 경우 도리어 초음파 강도와 조사시간에 따른 CST가 아주 낮게 최고점의 20%까지 측정되었다. 초음파에 의한 점도 변화는 최고점의 40%까지 감소하였다. 또한 원심력에 따른 슬러지의 침하를 분석하였는데 초음파를 가하고 응집제를 첨가한 슬러지의 초기 침하속도가 더 빠르며, 최종침하량에도 더 빨리 도달한 것으로 나타났다. 연구결과 초음파 조사시간과 초음파 강도가 탈수성에 큰 영향을 주는 것으로 나타났으며 연구결과를 현장에 도입할 경우 잉여슬러지의 탈수능 향상과 최종 탈수케이크 감량화에 유용하게 사용될 수 있을 것으로 기대된다. 가능성 평가를 위하여 대형 처리조를 처리장에 설치 운영하여 탈수케이크의 CST 및 함수율 변화를 고찰하였으며 실험실과 유사한 결과(최고 50% 감소)를 도출하였다.

Keywords

References

  1. Banks, C. J. and Walker, I. (1977), Sonication of Activated Sludge Flocs and the Recovery of their Bacteria on Solid Media, Journal of General Microbiology, Vol.98, pp. 363-368. DOI: http://dx.doi.org/10.1099/00221287-98-2-363
  2. Wang, F., Ji, M. and Lu, S. (2001), Influence of Ultrasonic Disintegration on the Dewaterability of Waste Activated Sludge Environmental Progress, American Institute of Chemical Engineers, Vol.25, No.3, pp. 257-260.
  3. Muller, J. A. (2003), Prospects and problems of sludge pre-treatment processes, Water Science and Technology, Vol. 44, No. 10, pp. 51-67.
  4. Bien, J. B., Kempa, E. S. and Bien, J. D. (1997), Influence of ultrasonic field on structure and parameters of sewage sludge for dewatering process, Water Science and Technology, Vol. 36, No.4, pp. 287-291. DOI: http://dx.doi.org/10.1016/S0273-1223(97)00444-7
  5. Neyens, E. and Baeyens, J. (2003), A review of thermal sludge pre-treatment processes to improve dewaterability, Journal of Hazardous Materials, Vol. 98, No. 1, pp.51-67. DOI: http://dx.doi.org/10.1016/S0304-3894(02)00320-5
  6. Lyons, W. A. (1951), The effect of ultrasonics on suspended matter in sewage, Sewage Indust Waste, Vol. 23, No.9, pp. 1084.
  7. NA, S. M., Park, J., Kim, Y., and Khim, J., (2005), Enhanced Dewaterability and Physico-chemical Characteristics of Digested Sewage Sludge by Ultrasonic Treatment , KSWM, Vol. 22, No.7, pp. 637-634.
  8. SAMSUNG ENGINEERING (1999), Developing the new technology of dewatering sewage sludge, Ministry of Science and Technology, 99-J-CG-01-B-21.
  9. Oh, C., Kim, Y., and Kim, B., (2002), Enhanced Dewaterability of Sewage Sludge by Ultrasonic Treatment, KSWM, Vol. 19, No.8, pp.929-932.
  10. Yoon, Y. S., Kim, K. N., and Choi, S. S. (2002), Release of Organic Matter and Behavior of Nitrogen in the Degradation of Sewage Sludge Using Ultrasound, KORRA, Vol. 10, No. 4, pp. 75-80.
  11. Jung, B. G., Ko, H. W., Song, H. Y., Kim, D. Y., Park, J. H., and Ha, S. A. (2007), A Study on the Pretreatment for Solubilization of Sewage Sludge by Ultrasound and Alkaline, The Korean Society of Water and Wastewater, Vol. 2005, pp. 115-118.
  12. Yoon, Y. S., Jeong, J. Y., Han, D. W., Lee, S. C., and Kim, D. J. (2007), Effect of Heat and Ultrasound on Solubilization of Wastewater Sludge, Korean Society of Water Quality, Vol. 2007, pp. 837-842.
  13. Lee, E. K., Min, B. D., and Han, L. S. (2008), Comparison of Solubilization Efficiency Using Microwave and Ultrasound for Pre-treatment of Sewage Sludge, Journal of Korean solid wastes engineering society, Vol. 25, No. 6, pp. 546-553.
  14. Seo, J. W., Han, J. S., Ahn, C. M., Min, D. H., Yoo, Y. S., Yoon, S. U., Lee, J. G., Lee, J. Y., and Kim, C. G. (2011), Study on Characteristics of Solubilization for Sewage Sludge Using Electronic Field and Ultrasonification, Korean Society Of Environmental Engineers, Vol. 33, No. 9, pp. 636-643. https://doi.org/10.4491/KSEE.2011.33.9.636
  15. Mo, W. J., Han, J. S., Ahn, C. M., Yoon, S. U., Seok, H. J., and Kim, G. (2013), Korean Society Of Environmental Engineers, Vol. 35, No. 1, pp. 23-30. https://doi.org/10.4491/KSEE.2013.35.1.023