ORIGINAL ARTICLE Pilot-Scale Phosphate Recovery from Secondary Wastewater Effluents Kyriaki Kalaitzidou 1 & Manassis Mitrakas 1 & Christina Raptopoulou 2 & Athanasia Tolkou 2 & Panagiota-Aikaterini Palasantza 3 & Anastasios Zouboulis 2 Received: 7 December 2015 /Accepted: 16 February 2016 # Springer International Publishing Switzerland 2016 Abstract Earth’ s phosphorus resources are being depleted at an alarming rate, while at the same time eutrophication caused by its uncontrolled disposal in surface waters is considered as a significant environmental problem. In order to achieve phosphate recovery from the second- ary effluents of an urban wastewater (biological) treatment plant, the adsorption onto single iron (GFH, Bayoxide and FeOOH) and onto binary iron-manganese (AquAsZero) oxy- hydroxides, as well as the ion exchange by using Purolite A200EMBCL resin, were investi- gated as post-treatment methods. Among them, laboratory batch experiments and dynamic Rapid Small Scale Column Tests (RSSCTs) evaluated AquAsZero, as the relatively better qualified material, presenting the higher efficiency. Based on these experimental results a pilot- plant, utilizing AquAsZero, was constructed and operated, treating 200 L/h. The breakthrough curves of RSSCTs for AquAsZero showed an adsorption capacity of 33.6 mg PO 4 3- /g ads at the equilibrium concentration of 3 mg PO 4 3- /L, whereas at pilot-scale application the respective breakthrough curve indicated a similar adsorption capacity (31.5 mg PO 4 3- /g ads ). The regen- eration process, by applying a NaOH solution at pH range 12.6–13, resulted in the efficient (>80 wt.%) phosphate desorption, which in turn allows the multiple reuse of adsorbent media. Subsequently, phosphate was recovered from the alkaline regeneration (concentrate) solution by precipitation with the appropriate Ca 2+ addition, as the respective calcium salt (hydroxy- apatite, HAP). Phosphate concentration in the finally collected amorphous (precipitated) solids from the laboratory scale experiments was around 51 wt.% and that of calcium was around Environ. Process. DOI 10.1007/s40710-016-0139-1 Electronic supplementary material The online version of this article (doi:10.1007/s40710-016-0139-1) contains supplementary material, which is available to authorized users. * Anastasios Zouboulis zoubouli@chem.auth.gr 1 Department of Chemical Engineering, Aristotle University of Thessaloniki, Thessaloniki, Greece 2 Department of Chemistry, Aristotle University of Thessaloniki, Thessaloniki, Greece 3 AKTOR S.A., Wastewater Treatment Plant of Touristic Area of Thessaloniki BAINEIA^, N. Michaniona, Thessaloniki, Greece