Conversion of municipal wastewater-derived waste to an adsorbent for phosphorus recovery from secondary effluent

• Published in: The Science of the total environment Vol. 705; p. 135959
• Main Authors: Xia, Wen-Jing, Xu, Lian-Zeng-Ji, Yu, Lin-Qian, Zhang, Quan, Zhao, Yi-Heng, Xiong, Jin-Rui, Zhu, Xiao-Yan, Fan, Nian-Si, Huang, Bao-Cheng, Jin, Ren-Cun
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 25.02.2020
• Subjects: Alkali-treatment; Iron sludge; Municipal wastewater; Phosphate adsorption; Secondary effluent; Iron sludge; Phosphate adsorption; Secondary effluent; Alkali-treatment; Municipal wastewater
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2019.135959

The sustainable management and recirculation of phosphorus resources are essential to our human lives. In this work, phosphorus removal and recovery from secondary effluent were achieved using municipal wastewater-derived materials as adsorbents. Through modification with 0.5 M NaOH for 30 min, iron containing sludge that originated from the coagulation pretreatment of municipal wastewater was successfully converted to phosphorus adsorbent. The maximal adsorption capacity of the prepared adsorbent was estimated to be 22 mg-P/g, and the adsorption performance remained stable in the pH range of 5–8. FeO(OH) was identified as the key adsorption site, and the ligand exchange mediated chemical adsorption was the main mechanism for phosphorus removal by the prepared material. Moreover, a laboratory-scale continuous-flow adsorption column experiment showed that the surplus phosphorus in secondary effluent could be readily reduced to <0.1 mg/L. By pyrolysis of P-laden alkali-treated iron sludge under oxygen limited conditions, the phosphorus was recovered and successfully applied to support wheat growth. This work provides valuable information for both the sustainable management of phosphorus streams in wastewater and cyclic utilization of waste sludge. [Display omitted] •Iron enriched sludge was successfully converted into phosphorus absorbent.•Phosphorus in secondary biological effluent was readily reduced to <0.1 mg/L.•The potential of reusing adsorbed phosphorus as fertilizer was evaluated.