title: Effects of environmental factors on microbial induced calcium carbonate precipitation.
abstract: OBJECTIVE
  To gain an understanding of the environmental factors that affect the growth of the bacterium Sporosarcina pasteurii, the metabolism of the bacterium and the calcium carbonate precipitation induced by this bacterium to optimally implement the biological treatment process, microbial induced calcium carbonate precipitation (MICP), in situ.
  
  
  RESULTS
  Soil column and batch tests were used to assess the effect of likely subsurface environmental factors on the MICP treatment process. Microbial growth and mineral precipitation were evaluated in freshwater and seawater. Environmental conditions that may influence the ureolytic activity of the bacteria, such as ammonium concentration and oxygen availability, as well as the ureolytic activities of viable and lysed cells were assessed. Treatment formulation and injection rate, as well as soil particle characteristics are other factors that were evaluated for impact on uniform induction of cementation within the soils.
  
  
  CONCLUSIONS
  The results of the study presented herein indicate that the biological treatment process is equally robust over a wide range of soil types, concentrations of ammonium chloride and salinities ranging from distilled water to full seawater; on the time scale of an hour, it is not diminished by the absence of oxygen or lysis of cells containing the urease enzyme.
  
  
  CONCLUSIONS
  This study advances the biological treatment process MICP towards field implementation by addressing key environmental hurdles faced with during the upscaling process.
authors.affiliation: Department of Civil and Environmental Engineering, University of California, Davis, CA 95616, USA. bmmortensen@ucdavis.edu
authors.forename: B M
authors.initials: BM
authors.lastname: Mortensen
authors.forename: M J
authors.initials: MJ
authors.lastname: Haber
authors.forename: J T
authors.initials: JT
authors.lastname: DeJong
authors.forename: L F
authors.initials: LF
authors.lastname: Caslake
authors.forename: D C
authors.initials: DC
authors.lastname: Nelson
mesh_terms: D002119:Calcium Carbonate / Q000737:chemistry*; D011232:Chemical Precipitation; D003470:Culture Media / Q000737:chemistry; D005618:Fresh Water / Q000737:chemistry / Q000382:microbiology; D012623:Seawater / Q000737:chemistry / Q000382:microbiology; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology; D058644:Sporosarcina / Q000254:growth & development* / Q000378:metabolism; D014508:Urea / Q000032:analysis; D014510:Urease / Q000378:metabolism
chemical_list: D003470:Culture Media; D012987:Soil; D014508:Urea; D014510:Urease; D002119:Calcium Carbonate