The most common chemical technology for phosphate recovery from municipal wastewater is chemical precipitation which is used after anaerobic treatment. The formation of struvite has been commercialized as a treatment process for phosphorus and ammonia recovery from wastewater sludge dewatering. 145 Ca 2+ and Mg 2+ ions are often used as phosphate precipitators to form Ca5(OH)(PO4)3 (hydroxyapatite) and NH4MgPO4.6H2O (struvite). Aluminum salts such as alum (aluminum sulfate or polyaluminum chloride), iron salts, and lime (calcium hydroxide) are used to chemically precipitate phosphate during the primary sedimentation phase of wastewater treatment. Phosphate is commonly precipitated from wastewater using FeCl3 and AlCl3 as precipitating agents. The phosphate precipitates are removed in the separation unit using sedimentation and flotation tanks. Magnesiumbased precipitation using other precipitating agents or sorbents such as fly ash may be used to recover nutrients in the form of struvite (ammonium magnesium phosphate). Chemical precipitation combined with adsorption was applied to recover phosphate from sewage sludge using zinc-aluminum layered double hydroxides as adsorbents. The pH value is one of the important parameters for chemical precipitation since pH affects the nutrient concentrations and solubility of precipitates. A recent thermodynamic modeling study by Garret Pindine and collaborators demonstrated that phosphoruscontaining precipitates could be profitable when optimally recovered from several high nitrogen to phosphorus containing wastewaters. Temperature, pH and MgCl2 addition schemes were modeled extensively in this study to support their findings. The crystallization of calcium phosphate carried out using CaCO3 particles as seeds proved to be a useful method for phosphorus recovery from wastewater. It was found that the applied current, the CaCO3 particle size, and the feed rate affect calcium phosphate precipitation. Microalgae-derived biochar enriched with magnesium has been used for seeding struvite crystallization. In Ion-Exchange Membrane Electrodialysis (ED), extraction of nutrients from wastewater occurs via application of ion-exchange membranes. 157 Over 95-98% of the phosphate and nitrate nutrients were recovered from the wastewater from a membrane bioreactor using ion exchange. Selective electrodialysis using three consecutive ion-exchange membranes demonstrated enhanced nitrate and phosphate recovery from secondary wastewater sludge. Simultaneous anionic and cationic selective ED was applied to recover NH4 + , K + , Ca 2+ , Mg 2+ and PO4 3-from swine wastewater. 160 ED shows high efficiency in concentration and recovery/removal of ammonium from anaerobic swine digestate. Integrating ED with a membrane bioreactor allowed the recovery >97% of ammonium salts and >76% of phosphate from urine wastewater. Integrating bipolar electrodialysis membrane and membrane capacitive deionization techniques allows simultaneous removal of phosphorus (89%) and nitrogen (77%). A solar energypowered decoupled ED system with a separate anode and cathode and an additional cation exchange membrane in the anode unit was designed to collect phosphates at a higher concentration and enhance the recovered struvite. The Comparing concepts used for chemical nutrient recovery from wastewater (Fig. ) and struvite recovery from wastewater (Fig. ), one can conclude that "precipitation wastewater treatment" is a major concept in both cases making up > 90% of all the concepts. In Fig. , it is followed by "coagulation wastewater treatment" -210 publications, "electrochemical wastewater treatment" -180 publications, "oxidative wastewater treatment" -175 publications, "ion-exchange wastewater treatment" -175 publications, "crystallization wastewater treatment" -140 publications. While for struvite production (Fig. ), "crystallization wastewater treatment" occurs more frequently than for general chemical treatment. Both concepts "precipitation wastewater treatment" and "crystallization wastewater treatment" are directly related to struvite recovery processes. "Catalytic wastewater treatment" found in general chemical treatments was not present in the case of struvite production.