Civil Engineering Reference
In-Depth Information
simplified representation of the events occurring during the ureolytic induced
carbonate precipitation.
ramachandran et al. (2001) reported that a high ph hinders the growth
of bacteria. They also state that the optimum ph for the growth of
Bacillus
pasteurii
is around 9. according to arunachalam et al. (2010)
Bacillus
sphaericus
bacteria-induced calcium carbonate precipitation at ph = 8
yields the highest results. Urease-catalyzed ureolysis is also temperature
dependent and the optimum temperature ranges from 20 to 37 °c. in fact,
increasing the temperature from 15 to 20 °c increased the rate of ureolysis,
k
urea
, 5 times and 10 times greater than
k
urea
at 10 °c (okwada and li, 2010).
The same authors reported that
k
urea
is more dependent on the bacterial cell
concentration than initial urea concentration so long as there is enough urea
to sustain the bacteria. at 25 mM ca
2+
concentration, increasing bacterial cell
concentration from 10
6
to 10
8
cells ml
-1
increased the caco
3
precipitated
by over 30%. however, when ca
2+
concentration was increased 10-fold,
the caco
3
precipitated increased by over 100% irrespective of initial urea
concentration.
21.3 Bacterium types
Different bacteria lead to very different calcium carbonate precipitation
results. Table 21.1 summarizes the species used by different authors.
Table 21.1
Bacterium types
References
Bacterium type
De Muynck et al. (2008a, 2008b)
Van Tittelboom et al. (2010)
Arunachalam et al. (2010)
Wang et al. (2012a)
Wang et al. (2012b)
Bacillus sphaericus
LMG 225 57
Ramachandran et al. (2001)
Okwadha and Li (2010)
Okwadha and Li (2011)
Sporosarcina pasteurii
ATCC 11859
Chahal et al. (2012)
Grabiec et al. (2012)
S. pasteurii (formerly Bacillus pasteurii)
Reddy et al. (2010)
Afifudin et al. (2011)
Bacillus subtilis
Achal et al. (2009)
Achal et al. (2011c)
Phenotypic mutant of
S. pasteurii
(Bp M-3)
Ramachandran et al. (2001)
Pseudomonas aeruginosa
ATCC 27853
Jonkers et al. (2010)
Bacillus pseudofirmus
DSM 8715
Ghosh et al. (2005, 2009)
Shewanella
sp.
Achal et al. (2011a)
Bacillus megaterium
ATCC 14581
Achal et al. (2011b)
Bacillus
sp. CT-5
Wiktor and Jonkers (2011)
Bacillus alkalinitrilicus
Woodhead Publishing Limited; proof copy not for publication
