Environmental Geology

, Volume 38, Issue 3, pp 199–203

Tentative nitrogen budget for pit latrines – eastern Botswana

  • G. Jacks
  • F. Sefe
  • M. Carling
  • M. Hammar
  • P. Letsamao
Research articles

DOI: 10.1007/s002540050415

Cite this article as:
Jacks, G., Sefe, F., Carling, M. et al. Environmental Geology (1999) 38: 199. doi:10.1007/s002540050415

Abstract

 A major problem with on-site sanitation is nitrate pollution of the groundwater. A tentative nitrogen budget is established for pit latrines in eastern Botswana. The ammonia volatilisation was found to be negligible while leaching varied largely from about 1 to 50%. Leaching of nitrate was assessed by using chloride as tracer, assuming two sources of chloride, atmospheric deposition and the use of common salt in food. The initial content of nitrogen in excreta was assessed from nutritional data. The residual nitrogen in abandoned latrines as found by analysis, was 15–20%. The remainder should be denitrification which would then be in the order of 30–70%. That denitrification is important is supported by an elevated N-isotope ratio in groundwater and in deep-rooted non-N-fixing trees. The varying leaching rate provides a possibility of checking it by sealing the latrines. Since about 95% of the nitrogen in human excreta is present in the urine, an even more attractive solution would be urine-separating latrines with surface near percolation of the urine in the root zone of the vegetation, utilising it for crop growth. Since such latrines are used elsewhere in the world the problem is not technical but social acceptability.

Key words Nitrate pollutionSanitationGroundwaterBotswana

Copyright information

© Springer-Verlag Berlin Heidelberg 1999

Authors and Affiliations

  • G. Jacks
    • 1
  • F. Sefe
    • 2
  • M. Carling
    • 3
  • M. Hammar
    • 3
  • P. Letsamao
    • 4
  1. 1.Dept. of Civil and Environ Eng Royal Inst of Technology, S-100 44 Stockholm, Sweden, e-mail: Gunnjack@aom.KTH.SESE
  2. 2.Dept. of Environments Sciences, University of Botswana, Gaborone, BotswanaBW
  3. 3.Luleå University of Technology, S-971 87 Luleå, SwedenSE
  4. 4.Central District Council, Private Bag 001, Serowe, BotswanaBW