A demonstration crystallization reactor and struvite accumulation device for the removal and recovery of phosphorous was constructed
and their performance was evaluated using actual swine wastewater for 3.5 years. The wastewater pH was increased by aeration,
and the concentrations of total P and soluble PO4–P were reduced by a struvite crystallization reaction induced under a high pH condition.
A 30% MgCl2 addition was eVective in enhancing the struvite crystallization reaction. The concentrations of suspended solids, total
Zn and total Cu, were also decreased by the settling function of the reactor. On removing the eYciencies of these components, no noticeable
seasonal Xuctuation in performance was observed during the 3.5-year operation. In terms of maximum yield, 171 g struvite was
obtained from 1m3 swine wastewater by the demonstration accumulation device for struvite recovery. The recovered struvite needed only
air-drying before use since it was approximately 95% pure even without washing.
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