TY  - JOUR
AV  - none
JF  - Journal of Cleaner Production
KW  - Ammonia; Calcite; Carbonation; Compressive strength; Metabolism; Sand; Surface properties; Sustainable development; Urea
KW  -  Biocementation; Calcite precipitation; Calcium carbonate content; Less is mores; Marine environment; Response surfaces methods; Sand columns; Treatment modeling; Unconfined compressive strength; Ureolytic
KW  -  Calcium carbonate
ID  - scholars14461
UR  - https://www.scopus.com/inward/record.uri?eid=2-s2.0-85109215836&doi=10.1016%2fj.jclepro.2021.128208&partnerID=40&md5=bfe5072f35f22746d6c2d2c95c7f2b8e
PB  - Elsevier Ltd
TI  - Less is more: Optimising the biocementation of coastal sands by reducing influent urea through response surface method
SN  - 09596526
VL  - 315
N1  - cited By 12
Y1  - 2021///
A1  - Ashraf, M.S.
A1  - Hassan Shah, M.U.
A1  - Bokhari, A.
A1  - Hasan, M.
N2  - The excessive effluent ammonia produced during the conventional biocementation of coastal sands by ureolytic Microbially Induced Calcite Precipitation (MICP) poses a looming threat to the marine environment. This research mitigates this threat by employing a brute force deployment of the Response Surface Method (RSM) for optimal minimisation of urea, which is the primary contributor of this effluent ammonia, to develop a sustainable MICP treatment model for the biocementation of coastal sand columns. The unconfined compressive strength (UCS) and calcium carbonate content (CCC) results of these columns, measured during their UCS and gravimetric acid washing testing, were used in this developed model for its validation and further optimisation. The biocementation solution resulting from this finally optimised MICP model used 75 lesser influent urea per gram of sand than its predecessor treatment model and still significantly improved the UCS of biocemented sand columns (from 0 kPa to 111.63 kPa). The structural analyses (XRD, FESEM) of these biocemented columns showed the adsorption of calcium carbonate and nesquehonite crystals on sand grains. This reduction in the consumption of urea significantly lowers the production of effluent ammonia during the biocementation of coastal sands. Therefore, it is suggested that this optimised MICP treatment model offers a sustainable method for strengthening coastal sands with little to no effect on the natural mosaic of their subsurface ecosystems. © 2021 Elsevier Ltd
ER  -