title: An exploratory study on seawater-catalysed urine phosphorus recovery (SUPR).
abstract: Phosphorus (P) is a crucial and non-renewable resource, while it is excessively discharged via sewage, significant amounts originating from human urine. Recovery of P from source-separated urine presents an opportunity not only to recover this precious resource but also to improve downstream sewage treatment works. This paper proposes a simple and economic method to recover urine derived P by using seawater as a low-cost precipitant to form struvite, as Hong Kong has practised seawater toilet flushing as an alternative water resource since 1958. Chemical reactions, process conditions and precipitate composition for P precipitation in urine have been investigated to develop this new urine P recovery approach. This study concluded that ureolysis extent in a urine-seawater mixture determines the reaction pH that in turn influences the P recovery efficiency significantly; 98% of urine P can precipitate with seawater within 10 min when 40-75% of the urea in urine is ureolysed; the urine to seawater ratio alters the composition of the precipitates. The P content in the precipitates was found to be more than 9% when the urine fraction was 40% or higher. Magnesium ammonium phosphate (MAP) was confirmed to be the predominant component of the precipitates.
authors.affiliation: Department of Civil and Environmental Engineering, The Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong, China. Electronic address: cedj@ust.hk.
authors.forename: Ji
authors.initials: J
authors.lastname: Dai
authors.affiliation: Department of Civil and Environmental Engineering, The Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong, China.
authors.forename: Wen-Tao
authors.initials: WT
authors.lastname: Tang
authors.affiliation: Department of Civil and Environmental Engineering, The Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong, China.
authors.forename: Yi-Se
authors.initials: YS
authors.lastname: Zheng
authors.affiliation: Department of Civil and Environmental Engineering, The Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong, China.
authors.forename: Hamish R
authors.initials: HR
authors.lastname: Mackey
authors.affiliation: Department of Civil and Environmental Engineering, The Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong, China.
authors.forename: Ho Kwong
authors.initials: HK
authors.lastname: Chui
authors.affiliation: Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands.
authors.forename: Mark C M
authors.initials: MCM
authors.lastname: van Loosdrecht
authors.affiliation: Department of Civil and Environmental Engineering, The Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong, China; SYSU-HKUST Research Centre for Innovative Environmental Technology, Sun Yat-sen University, Guangzhou, China. Electronic address: ceghchen@ust.hk.
authors.forename: Guang-Hao
authors.initials: GH
authors.lastname: Chen
mesh_terms: D006801:Humans; D010758:Phosphorus / Q000032:analysis* / Q000652:urine*; D012623:Seawater / Q000032:analysis*
chemical_list: D010758:Phosphorus
keywords: Phosphorus recovery; Precipitation; Seawater; Ureolysis; Urine