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SLU:s publikationsdatabas (SLUpub) (stage, solr2:8983)

Sammanfattning

We evaluated a novel closed-loop evaporative system designed to concentrate alkalised human urine while simultaneously recovering water using regenerable superabsorbent polymers (SAPs). This architecture recirculates air and physically isolates urine from atmospheric CO2, thereby maintaining high alkalinity and preventing enzymatic urea hydrolysis. The system was operated at similar to 30 degrees C using sodium polyacrylate, potassium polyacrylate, or a 1:1 (w/w) blend of both SAPs across eight absorption-desorption cycles. All treatments exhibited high initial water uptake (>1.4 kg m(-2) day(-1)) and gravimetric absorption (>0.8 g g(-1)), with performance declining due to polymer fatigue after repeated use. FT-IR spectra revealed the depolymerisation of the acrylate backbone leading to the formation of acrylic acid residues, confirming chemical deterioration during the thermal regeneration of the SAPs. Notably, the closed-loop design eliminated the need for supersaturating urine with Ca(OH)(2), which is required in open evaporative systems to buffer against CO2-induced acidification. Colorimetric and targeted metabolomic analyses confirmed complete nitrogen retention and > 99 % recovery of the 30 most abundant endogenous organic solutes in urine, including urea, creatinine, and hippuric acid. These results demonstrate that low-temperature evaporation can preserve the full biochemical complexity of urine, producing a dry, sanitised fertiliser as well as water with extremely low organic content.

Nyckelord

Water reuse; Safe nutrient recycling; Decentralised sanitation; Source separation; Wastewater treatment; Fertiliser production

Publicerad i

Desalination
2026, volym: 622, artikelnummer: 119786

SLU författare

UKÄ forskningsämne

Miljöteknik och miljöledning
Jordbruksvetenskap

Publikationens identifierare

  • DOI: https://doi.org/10.1016/j.desal.2025.119786

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/145375