원저(原著) : Struvite 생성반응에 의한 축산폐수내 질소-인 회수 및 마그네슘과 인의 재활용 효율

As an approach based on resource recovery is preferable, the control over the point sources of N and P recently shifted from removal to recovery, with a particular emphasis on improving the sustainability of wastewater treatments as well as agricultural activities. Struvite precipitation may be an effective method for this purpose. In this study, swine wastewater was treated by chemical coagulation with cationic polymer flocculant and subsequent struvite precipitation. PO4-P was effectively removed from swine wastewater accompanied with SS coagulation and NH4-N was effectively recovered by subsequent struvite precipitation. The NH4-N recovery was effective in the struvite formation with equimolar concentrations of Mg2+, NH4+ and PO4(3-) at pH 10.5, and was more enhanced with seeding the struvite precipitant dried at about 100℃ due to vaporization of NH3 from precipitant during dry which leads the disintegration of struvite into NH4, Mg and PO4. It also indicates that the dried struvite precipitant can be reused as a Mg and P sources for NH4-N recovery with forming struvite precipitation. In a five-step recycle process, NH4-N recovery was initially 81% and progressively decreased to 26% in the fifth stage due to increasing inactiveness of recycled magnesium phosphate. In spite of that, NH4-N recovery based on the recycling of struvite looks attractive in a viewpoint of cost reduction.