PHOSPHORUS RECOVERY FROM WASTE AS STRUVITE

Abstract

The paper gives information on the depletion of phosphorus (P) as an important element for all forms of life and its pollution impact on the environment in case of intensive discharge of phosphorus compounds into water bodies. Two secondary waste sources of Phosphorus are under consideration, namely the domestic wastewater and sludge and animal manure. The characteristics of these two fluids regarding organic matter and nutrient content are summarized. Discussing the techniques for P extraction mostly attention is given to phosphorus precipitation as ammonium magnesium phosphate (struvite). Examples of effectiveness of P precipitation as struvite in Municipal Wastewater Treatment Plants (MWWTPs) with chemical and biological P removal are presented. The examples of struvite production from sewage and manure waste show evidently the great potential of utilization of such a waste as a source of phosphorus. The recovered product is valuable both as it is a slow release fertilizer and with its low content of heavy metals compared to the mineral fertilizers. In respect of the diminishing amount of natural P rocks, the sewagec wastewater and sludge and the animal manure can be regarded as an important secondary source of Phosphorus.