Abstract
Activated microbial induction of CaCO3 precipitation
(AMICP) is a niche with innovative approaches that involves the
exploration of bacterial attacks towards the alteration/transformation
of the physical properties of soils. A handful have been documented
on this technology in developed countries however, much is yet to be
understood in developing African countries like South Africa, just as
vermicomposting and waste water treatment technologies are gaining
grounds. It is widely known that AMICP by urea hydrolysis in
natural soils is possibly affected by contacts between ureolytic and
non-ureolytic bacteria, the study explored a designed and
experimental assessment of the relations between ureolytic and nonureolytic
bacteria and their interactive effects on AMICP. Through
existing studies an artificial leveled groundwater medium was
injected with model species of bacteria i.e., ureolytic species
Sporosarcina pasteurii and the non-ureolytic species Bacillus
subtilis. The control treatment was inoculated with a pure culture of
S. pasteurii under measurements of pH, optical density (OD),
development of NH4-N, dissolved calcium (DC) and dissolved
inorganic carbon (DIC). Outcomes revealed DC precipitated as
CaCO3 slower in the control mixture than in the mixed culture
irrespective of unfavorable conditions in the mixed culture, i.e., lower
concentrations of pH and CO32−. Higher density of bacterial cells in
the mixed culture resulted from B. subtilis showing significant higher
growth rate than S. pasteurii. Previous authors indicate that the
presence of the non-ureolytic bacterial species, B. subtilis, stimulate
AMICP process through supply of nucleation sites in the form of
non-ureolytic bacterial cells.