title: Recovery of phosphorus from sewage sludge in combination with the supercritical water process.
abstract: In this paper, the fraction transformation and recovering of phosphorus (P) from sewage sludge (SS) residues, derived from supercritical water process, was investigated by extraction and precipitation processes. In addition, the form of heavy metals existing during the recovery process is also discussed. First, P in the solid residues was recovered by acid leaching with HCl, and then the derived P was adsorbed by activated alumina (Al(2)O(3)). Finally, the Al2O3 was desorbed with low concentration of NaOH. Results showed that 80% organic P was converted into HCl-P. The total P (the chief ingredient of HCl-P) in solid residue increased from 86.1 to 95.6% as temperature increased from 350 to 400 °C. The amount of P in the solid residue that was dissolved by 1 M HCl was 97.8%, and over 95% of P in the leaching solution (15 mg/L for P concentration) was adsorbed after 5.0 g of Al(2)O(3) powder was added. The amount of P desorbed from Al(2)O(3) with 0.1 M NaOH was 98.7%. Ultimately, over 85% of TP in SS was recovered. Moreover, the proportion of Cu, Zn and Pb in the extracted P products was lower than 5%.
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, China and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China E-mail: ybzhai@hnu.edu.cn; ybzhai@163.com.
authors.forename: Yunbo
authors.initials: Y
authors.lastname: Zhai
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, China and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China E-mail: ybzhai@hnu.edu.cn; ybzhai@163.com.
authors.forename: Bobin
authors.initials: B
authors.lastname: Xiang
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, China and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China E-mail: ybzhai@hnu.edu.cn; ybzhai@163.com.
authors.forename: Hongmei
authors.initials: H
authors.lastname: Chen
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, China and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China E-mail: ybzhai@hnu.edu.cn; ybzhai@163.com.
authors.forename: Bibo
authors.initials: B
authors.lastname: Xu
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, China and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China E-mail: ybzhai@hnu.edu.cn; ybzhai@163.com.
authors.forename: Lu
authors.initials: L
authors.lastname: Zhu
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, China and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China E-mail: ybzhai@hnu.edu.cn; ybzhai@163.com.
authors.forename: Caiting
authors.initials: C
authors.lastname: Li
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, China and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China E-mail: ybzhai@hnu.edu.cn; ybzhai@163.com.
authors.forename: Guangming
authors.initials: G
authors.lastname: Zeng
mesh_terms: D019216:Metals, Heavy / Q000737:chemistry; D010758:Phosphorus / Q000737:chemistry*; D012722:Sewage / Q000737:chemistry*; D013696:Temperature; D014865:Waste Disposal, Fluid / Q000379:methods; D014867:Water / Q000737:chemistry; D014874:Water Pollutants, Chemical
chemical_list: D019216:Metals, Heavy; D012722:Sewage; D014874:Water Pollutants, Chemical; D014867:Water; D010758:Phosphorus