Adaptation of urine source separation in tropical cities: Process optimization and odor mitigation

Jiefeng Zhang, Apostolos Giannis, Victor W.C. Chang, Bernard J.H. Ng, Jing-Yuan Wang

Research output: Contribution to journalArticleResearchpeer-review

27 Citations (Scopus)


Source-separating urine from other domestic wastewaters promotes a more sustainable municipal wastewater treatment system. This study investigated the feasibility and potential issues of applying a urine source-separation system in tropical urban settings. The results showed that source-separated urine underwent rapid urea-hydrolysis (ureolysis) at temperatures between 34-40oC, stale/fresh urine ratios greater than 40%, and/or with slight fecal cross-contamination. Undiluted (or low-diluted) urine favored ureolysis; this can be monitored by measuring conductivity as a reliable and efficient indicator. The optimized parameters demonstrated that an effective urine source-separation system is achievable in tropical urban areas. On the other hand, the initial release of CO2 and NH3 led to an elevated pressure in the headspace of the collection reservoir, which then dropped to a negative value, primarily due to oxygen depletion by the microbial activity in the gradually alkalized urine. Another potential odor source during the ureolysis process was derived from the high production of volatile fatty acids (VFA), which were mainly acetic, propanoic, and butyric acids. Health concerns related to odor issues might limit the application of source separation systems in urban areas; it is therefore vital to systematically monitor and control the odor emissions from a source separation system. As such, an enhanced ureolysis process can attenuate the odor emissions.Urine source separation is promising to improve the management of domestic wastewater in a more sustainable way. The work demonstrates the achievability of an effective urine source-separation system in tropical urban areas. The installation of urine-stabilization tanks beneath high-rise buildings lowers the risk of pipe clogging. Conductivity measurement can be utilized as a reliable process indicator for an automated system. However, urine hydrolysis raises a strong potential of odor emission (both inorganic and organic), which might limit the application of source separation systems in urban areas. An enhanced ureolysis process could shorten and attenuate the odor emissions. © 2013 Copyright 2013 A&WMA.
Original languageEnglish
Pages (from-to)472-481
Number of pages10
JournalJournal of the Air and Waste Management Association
Issue number4
Publication statusPublished - 2013
Externally publishedYes


  • Automation
  • Body fluids
  • Carbon dioxide
  • Hydrolysis
  • Odor control
  • Optimization
  • Separation
  • Tall buildings
  • Tropics
  • Urea
  • Volatile fatty acids
  • Wastewater treatment, Conductivity measurements
  • Cross contamination
  • Domestic wastewater
  • Microbial activities
  • Monitor and control
  • Municipal wastewater treatment
  • Optimized parameter
  • Source-separation systems, Source separation, acetic acid
  • ammonia
  • butyric acid derivative
  • carbon dioxide
  • propionic acid
  • urea, article
  • bacterium contamination
  • conductance
  • feasibility study
  • hydrolysis
  • microbial activity
  • monitoring
  • odor control
  • pressure
  • priority journal
  • process optimization
  • reservoir
  • separation technique
  • temperature
  • tropics
  • urban area
  • urine source separation
  • waste water management

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