International Journal of
Water Resources and Environmental Engineering

  • Abbreviation: Int. J. Water Res. Environ. Eng.
  • Language: English
  • ISSN: 2141-6613
  • DOI: 10.5897/IJWREE
  • Start Year: 2009
  • Published Articles: 342

Full Length Research Paper

Lactic acid from food waste enhances pathogen inactivation and urea stabilization in human urine

Zerihun Getaneh
  • Zerihun Getaneh
  • School of Civil and Environmental Engineering, Addis Ababa Institute of Technology, Addis Ababa University, Ethiopia.
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Nancy G. Love
  • Nancy G. Love
  • Department of Civil and Environmental Engineering, University of Michigan, 1351 Beal Avenue, EWRE, ANN Arbor, MI 48109, United States.
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Adey Desta
  • Adey Desta
  • Institute of Biotechnology, College of Natural and Computational Science, Addis Ababa University, Ethiopia.
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Agizew Nigussie
  • Agizew Nigussie
  • School of Civil and Environmental Engineering, Addis Ababa Institute of Technology, Addis Ababa University, Ethiopia.
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  •  Received: 09 August 2021
  •  Accepted: 13 September 2021
  •  Published: 30 September 2021

Abstract

In areas where conventional sewer systems are not possible, innovative and low-cost methods are needed to get rid of pathogens in human urine. Treatment through acidification is a reliable method. In this study, the effect of fresh cabbage waste, potato peel, and teff flour water as substrate for lactic acid treatment of source-separated urine was investigated. Laboratory scale batch experiments were conducted to compare the substrates for pH 4 and high distribution of lactic acid bacteria (LAB), important for urine hygienization and urea stabilization. It was found that with the addition of 10% molasses as a sugar supplement, fermentation of fresh cabbage waste could establish the desired effect for lactic acid treatment of source-separated urine. The final pH in the urine mixed with lactic acid in the ratio of 1:1 and 1:2 (lactic acid: urine) was 4.12 and 4.26, respectively. While the final pH in the 1:4 and control reactors was 8.3 and 9.2, respectively. Escherichia coli count was below the detection limit in both 1:1 and 1:2 reactors after 5 days, whereas the number of E. coli in the samples collected from 1:4 and control reactors showed only slight reduction until the final day of the treatment process. Urea decomposition improved in 1:1 and 1:2 reactors, while it kept increasing in 1:4 and control reactors. The results revealed that food waste produced lactic acid enhances pathogen inactivation, urea stabilization and reduce odors in human urine.

Key words: Lactic acid, odor control, pathogen inactivation, urea stabilization