Research and Application of Crystallization Technology in Treating Phosphorus Wastewater

Abstract

At present, the crystallization method has become a hotspot in the field of wastewater treatment. The crystallization method not only remove phosphorus effectively in wastewater, but the phosphorus also can be recycled. The crystallization method includes ammonium magnesium phosphate crystallization method, calcium hydroxy calcium phosphate crystallization method, vivianite crystallization method and so on. The study introduced the principle of phosphorus removal and the influencing factors of the three crystallization methods, and discussed the effects of pH, ion concentration and stirring conditions on the crystallization. pH has the greatest influence on crystallization among of them. The best pH of the vivianite crystallization is between 7 and 9, and it is easier to form crystals in the general wastewater than MAP and HAP. In a certain concentration range, the phosphorus removal rate increased with the increase of ion concentration. In the case of air stirring or cyclical stirring, crystallization can be instantly formed, effectively increasing the crystallization rate. Finally, the application prospect of crystallization method in the treatment of phosphorus wastewater is prospected, which provides technical and theoretical support for the removal and recovery of phosphorus in wastewater.

Optimum phosphate ion removal from aqueous solutions using roller kiln industrial solid waste

“…Many natural and synthetic adsorbents can be used for phosphate ions removal from wastewater such as coal fly ash, polymer hydrogels and industrial solid wastes like Fume Dust from Electric Arc Furnace (FD-EAF) 13 . In the crystallization process calcium reacts with hydroxide ions that exist in the aqueous alkaline solution to remove phosphate ions in the form of hydroxyapatite 10 , 14 . Due to the hydrophilic and three-dimensional polymeric network of polymer hydrogel, it is observed that polymer hydrogel is effective to be used as an adsorbent for phosphate ion removal from wastewater 9 , 14 – 16 .…”

“…In the crystallization process calcium reacts with hydroxide ions that exist in the aqueous alkaline solution to remove phosphate ions in the form of hydroxyapatite 10 , 14 . Due to the hydrophilic and three-dimensional polymeric network of polymer hydrogel, it is observed that polymer hydrogel is effective to be used as an adsorbent for phosphate ion removal from wastewater 9 , 14 – 16 . Because, nanomaterials/nanoparticles, snail shell dust and, carbon-based materials (activated carbon and biochar) have exceptionally high surface areas and phosphate adsorption properties, they are widely used for phosphate removal from wastewater 11 , 17 – 23 .…”