A technology for phosphate recovery was developed using waste oyster shell as a raw material in a fluidized bed reactor (FBR). Raw oyster shell that causes a major disposal problem in coastal aquaculture regions was converted to activated oyster shell (AOS) by pyrolysis under defined conditions. A prototype of precipitates collection ports was devised relating to AOS particle size and flow velocity. The optimum conditions determined were applied to wastewater for phosphate recovery with the knowledge of mass balance in the FBR system.