|
Operational parameters for struvite crystallization, as a process to recover nitrogen and phosphorus resources from animal wastewater, were studied in this research. Crystallization distinctive of NH_(４)-N and PO_(４)^(３-) in accordance to chemical sources, influent ?, aeration and stirring was examined using 2L of working volume of struvite reactor. Also, to find an effective treatment process combining with electrolysis method, removal characteristics of NH_(４)-N and PO_(４)^(３-) in 6 different processes was tested. As chemical sources for the derivation of struvite formation, MgSO_(４) and MgCl_(２) were superior to CaCO_(３) and CaCl_(２). From experiment which was conducted to know the effects of aeration and stirring on struvite formation, it was revealed that aeration stimulated the crystallization reaction by inducing faster ? increase. While 90％ of P removal was achieved within 1 hour under aeration, 14 hours was consumed under stirring condition. Struvite formation under aeration was affected by influent ?. No crystallization was observed at ? 5 level, but active crystallization reaction was induced over ? 6.0. 95％ of P removal by struvite formation at ? 6, 7 and 9 was achieved within 3h, 2h and 10min, respectively. However, over ? 10, operational problem due to excessive foam formation occurred, and blunting of crystallization reaction was observed at ? 11. When consider the ? range of animal wastewater, ? 7 to 9. efficient struvite formation could be achieved by simple aeration, without andy chemicaa usage for ? adjustment. Among tested processes, the treatment process which electrolyzing the supernatant from struvite reactor, providing air to both reactors, showed best pollutant removal respectively, and 92.4％ of color removal was obtained.
|