Recovery of phosphate from dewatered anaerobic sludge and wastewater by thermally treated P.oceanica residues and its potential application as a fertilizer

A process for the valorization of seagrass residues has been developed, aiming to investigate its potential as a phosphate adsorbent and production added-value products, which can be assessed in agricultural applications. Posidonia oceanica were thermally treated (500 °C, 1 h) tested an from real wastewater. Chemical leaching experiments dewatered anaerobic sludge (DWAS) conducted, evaluating sonication inorganic acids (sulfuric acid (SA), thermal-sulfuric (TSA), nitric (NA)) extraction methods. ?he efficiency each method demonstrated that most suitable medium leach out SA TSA processes with 84.9 93.2% removal efficiency, respectively. Moreover, saturation capacity P. was assessed, results confirmed high adsorption (179.1 mg g?1). Adsorption batch wastes (anaerobic effluent wastewater leached solution DWAS), could have selectivity towards phosphate. After adsorption, solid mixed compost different ratio then fertilizer substitutes on plant growth. The residue after produced or synthetic solutions imposed positive effect growth germination index (GI) values 96.7–111.14%, all types seeds (Solanum Lycopersicum, Lepidium sativum, Sinapis alba), while DWAS negatively affected plants, probably due potentially refractory compounds contained DWAS.