Abstract

Alkaline dehydration is a promising technology for producing organo-mineral fertiliser from source-separated human urine, but potential risks to users from handling alkaline earth hydroxides at source and carbonation of hydroxides during dehydration limit its implementation in real-life settings. These issues could be addressed by enclosing chemicals in bio-derived polymers. In this study, we investigated degradation and erosion of poly-L-lactic acid (PLLA) biopolymer films of different thicknesses (0.05, 0.1 and 0.25 mm) in Ca(OH)2-dosed fresh urine and Milli-Q water at two temperatures (20 degrees C and 45 degrees C). Evaluation of degraded films by XRD, GPC and SEM showed changes in crystallinity, reduction in molecular weights and change in surface morphology, respectively. SEM/EDX, FTIR and ICP-OES data indicated that L-CaL2, L-lactides and lactic acid were formed in urine. Overall, we found that thinner films, higher temperature and higher pH accelerated PLLA degradation in urine.

Keywords

Polymer; Decentralised sanitation; Nutrient recovery; Source separation; Wastewater treatment

Published in

Resources, Conservation and Recycling
2023, Volume: 198, article number: 107202
Publisher: ELSEVIER

SLU Authors

• Deka, Anuron

  • Department of Energy and Technology, Swedish University of Agricultural Sciences
    
  • Tezpur University

• Simha, Prithvi

  • Department of Energy and Technology, Swedish University of Agricultural Sciences
    

• Vinnerås, Björn

  • Department of Energy and Technology, Swedish University of Agricultural Sciences
    

Sustainable Development Goals

SDG6 Ensure availability and sustainable management of water and sanitation for all


UKÄ Subject classification

Polymer Chemistry
Water Treatment


Publication identifier

DOI: https://doi.org/10.1016/j.resconrec.2023.107202

Permanent link to this page (URI)

https://res.slu.se/id/publ/127496