Patent ID: 7005072

Claim:
A method for removing phosphorus from a wastewater effluent stream comprising the steps of: (a) introducing wastewater effluent including a phosphorous content to the bottom of a continuous crystallizer comprising a fluidized bed of struvite therein and a struvite crystal collection chamber therebeneath, said crystallizer being formed such that the cross sectional area thereof generally increases from a relatively smaller cross sectional area at the bottom thereof to a relatively larger cross sectional area at the top thereof; (b) introducing an effective amount of ammonia to the wastewater effluent at the bottom of the crystallizer to elevate the wastewater stream effluent pH range a predetermined amount; (c) introducing an effective amount of magnesium to the wastewater effluent at the bottom of the crystallizer; (d) continuously passing the wastewater effluent including ammonia and magnesium upwardly through the fluidized bed of struvite to reduce the total phosphorus content of the wastewater effluent a predetermined amount; (e) removing the treated wastewater effluent from the top of the crystallizer; and (f) periodically removing struvite crystals that grow large enough to sink from the bottom of the crystallizer into the collection chamber.