Microwave Irradiation as a Way to Reutilize the Recovered Struvite Slurry and to Enhance System Performance

회수된 MAP 슬러리의 재이용과 공정효율 향상을 위한 도구로서의 극초단파 조사

  • Cho, Joon-Hee (Department of Animal Life System, Kangwon National University) ;
  • Lee, Jin-Eui (Department of Animal Life System, Kangwon National University) ;
  • Ra, Chang-Six (Department of Animal Life System, Kangwon National University)
  • 조준희 (강원대학교 동물생명과학대학, 동물생명시스템학과) ;
  • 이진의 (강원대학교 동물생명과학대학, 동물생명시스템학과) ;
  • 라창식 (강원대학교 동물생명과학대학, 동물생명시스템학과)
  • Received : 2009.07.13
  • Accepted : 2009.08.14
  • Published : 2009.08.01


The feasibility of reutilization of magnesium ammonium phosphate (MAP) or struvite slurry recovered from the process through microwave irradiation was studied in this experiment. For this purpose, 4 different operations were performed with or without Mg source addition and different levels of MAP recycled in a batch reactor. Dissolution rate of MAP, ${NH_4}^+$ elimination pattern and physicochemical changes of MAP during microwave irradiation were also studied. The result showed that only 33% orthophosphate ($PO_4-P$) and 27% $NH_4-N$ removal occurred without adding any external Mg source (run A), whereas 87% $PO_4-P$ and 40% $NH_4-N$ removed when 1.0 M ratio of $MgCl_2$ (run B) was added based on $PO_4-P$ in influent. Although the addition of 1.0 molar ratio of microwave irradiated MAP (Run C) removed lower $PO_4-P$ and $NH_4-N$ than 1.0 M $MgCl_2$ (run B), $PO_4-P$ removal was double when compared with no Mg addition (run A). Addition of half MAP and half $MgCl_2$ (run D) showed the similar removal efficiency (88% $PO_4-P$ and 35% $NH_4-N$) with sole $MgCl_2$ addition (run B). Based on these results, the reutilization of MAP irradiated by microwave would be a feasible way to enhance the removal efficiencies of N and P, as well as curtail the Mg chemical usage. Track study showed that $NH_4-N$ gradually increased at initial stage of microwave irradiation of MAP, and then started eliminating from liquor as temperature increased over $45^{\circ}C$. Dissolution rate of ${PO_4}^{-3}$ during microwave irradiation was proportional to the initial MAP concentration, having $0.0091x^{0.6373}$ mg/sec. It was found from the scanning electron microscope (SEM) study that physical structure of MAP crystal started breaking down into small cube granules within very short time by electromagnetic vibration force during microwave irradiation and then gradually melted down into solution.


Microwave;Struvite;MAP ($MgNH_4PO_46H_2O$);Swine wastewater


Supported by : Korea Research Foundation


  1. Ahn, P. B., Kim, J. H. and Hwang, J. S. 2004. Use of microwave pretreatment for enhanced anaerobiosis of secondary sludge. Water Sci. Technol. 50(9):17-23.
  2. Bi, X. Y., Wang, P., Jiang, I. H., Xu, H. Y., Shi, S. J. and Huang, J. L. 2007. Treatment of phenol wastewater by microwave-induced $ClO_2-CuOx/Al_2O_3$ catalytic oxidation process. J. Environ. Sci. 19:1510-1515.
  3. Bonmati, A. and Flotats, X. 2003. Air stripping of ammonia from pig slurry: characterization and feasibility as a pre-of post-treatment to mesophilic anaerobic digestion. Waste Manag. 23:261-272.
  4. Chan, W. I., Wong, W. T., Liao, P. H. and Lo, K. V. 2007. Sewage sludge nutrient solubilization using a single-stage microwave treatment. J. Environ. Sci. Heal., Part-A. 42(1): 59-63.
  5. Chirmuley, D. G. 1994. Struvite precipitation in WWTPs: Causes and solutions. Water (J. Austr. Water Assoc.) December. 21-23.
  6. Eskicioglu, C., Terzian, N., Kennedy, K. J., Drostea, R. L. and Hamoda, M. 2007. A thermal microwave effects for enhancing digestibility of waste activated sludge. Water Res. 41:2457-2466.
  7. Jaffer, Y., Clark, T. A., Pearce, P. and Parsons, S. A. 2002. Potential phosphorus recovery by struvite formation. Water Res. 36(7):1834-1842.
  8. Jeong, B. Y., Song, S. H., Baek, K. W., Cho, I. H. and Hwang, T. S. 2006. Preparation and properties of heterogeneous cation exchange membrane for recovery of ammonium ion from waste water. Polymer (Korea). 30:486-491.
  9. Kim, K. W., Kim, Y. J., Kim, I. T., Park, G. I. and Lee, E. H. 2006. Electrochemical conversion characteristics of ammonia to nitrogen. Water Res. 40:1431-1441.
  10. Lee, S. I., Weon, S. Y., Lee, C. W. and Koopman, B. 2003. Removal of nitrogen and phosphate from wastewater by addition of bittern. Chemosphere. 51:265-271.
  11. Li, X. Z., Zhao, Q. L. and Hao, X. D. 1999. Ammonium removal from landfill leachate by chemical precipitation. Waste Manag. 19:409-415.
  12. Liao, P. H., Wong, W. T. and Lo, K. V. 2005. Advanced oxidation process using hydrogen peroxide/microwave system for solubilization of phosphate. J. Environ. Sci. Heal., Part-A. 40(9):1753-1761.
  13. Lin, L, Yuan, S., Chen, J., Xu, Z. and Lu, X. 2009. Removal of ammonia nitrogen in wastewater by microwave radiation. J. hazard. Mater. 161 (2-3):1063-1068.
  14. Martin, D. I., Margaritescu, I., Cirstea, E., Togoe, I., Ighigeanu, D., Nemtanu, M. R., Oproiu, C. and Iacob, N. 2005. Application of accelerated electron beam and microwave irradiation to biological waste treatment. Vacuum. 77(4):501-506.
  15. Menendez, J. A., Inguanzo, M. and Pis, J. J. 2002. Microwave induced pyrolysis of sewage sludge. Water Res. 36:3261-3264.
  16. Munch, E. V. and Barr, K. 2001. Controlled struvite crystallisation for removing phosphorus from anaerobic digester sidestreams. Water Res. 35(1):151-159.
  17. Ponne, C. T. and Bartels, P. V. 1995. Interaction of electromagnetic energy with biological material-relation to food processing. Radiation Phys. Chem. 45(4):591-607.
  18. Qureshi, A., Lo, K. V. and Liao, P. H. 2008. Microwave treatment and struvite recovery potential of dairy manure. J. Environ. Sci. Heal., Part-B, 43(4):350-357.
  19. Saillard, R., Poux, M., Berlan, J., Audhuy-Peaudecerf, M. 1995. Microwave heating of organic solvents: thermal effects and field modelling. Tetrahedron 51(14):4033-4042.
  20. Sanz, J., Lombrana, J. I., Luis, A. M. D., Ortueta, M. and Varona, F. 2003. Microwave and Fenton’s reagent oxidation of wastewater. Environ. Chem. Lett. 1:45-50.
  21. Suzuki, K., Tanaka, Y., Kuroda, K., Hanajima, D. and Fukumoto, Y. 2005. Recovery of phosphorous from swine wastewater through crystallization. Bioresour. Technol. 96(14): 1544-1550.
  22. Welander, U., Henrysson, T. and Welander, T. 1998. Biological nitrogen removal from municipal landfill leachate in a pilot scale suspended carrier biofilm process. Water Res. 32:1564-1570.
  23. Wojciechowska, E. 2005. Application of microwaves for sewage sludge conditioning. Water Res. 39(19):4749-4754.
  24. Wong, W. T., Chan, W. I., Liao, P. H. and Lo, K. V. 2006. A hydrogen peroxide / microwave advanced oxidation process for sewage sludge treatment. J. Environ. Sci. Heal., Part-A. 41 (11):2623-2633.
  25. Yetilmezsoy, K. and Zengin, Z. S. 2009. Recovery of ammonium nitrogen from the effluent of UASB treating poultry manure wastewater by MAP precipitation as a slow release fertilizer. J. Hazard. Mater. 166:260-269.
  26. Zhang, T., Lili, Ding, L. and Ren, H. 2009. Pretreatment of ammonium removal from landfill leachate by chemical precipitation. J. Hazard. Mater. 166:911-915.

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