Efficient option of industrial wastewater resources in cement mortar application with river-sand by microbial induced calcium carbonate precipitation.

The industrial wastewater disposal has been growing attention for environmental protection and resource substitution, current decades. Similarly, the durability enhancement of concrete has increased attention by microbial induced CaCO3 precipitation (MICP) process (biocalcification). However, ecofriendly utilization of industrial wastewater in concrete formation is unstudied so far. The present study was carried out to evaluate the effect of industrial wastewater on the formation of cement mortar, compressive strength and water absorption. The biocement mortar strength (y) increased (y = 0.5295×2 + 1.6019×+251.05; R2 = 0.9825) with increasing percentage of organic wastewater (x) (BM0 - BM100) by MICP, where highest strength (280.75 kgf/cm2) was observed on BM100 (100% wastewater), compared to control (252.05 kgf/cm2). The water absorption (y) of biocement mortar decreases (y = -0.0251×2-0.103× + 15.965; R2 = 0.9594) with increment of wastewater (x) (%) (BM0 - BM100), where a minimum-water-absorption (14.42%) observed on BM100, compared to control (15.89%). SEM micrograph and XRD shows the formation of most-distinctive CaCO3 crystallization (aragonite/calcite) (acicular, brick shape, massive and stacked structure) inside biocement mortar (BM100), which fills the pores within cement mortar to form a denser structure, by microbial organic wastewater. Thus, present findings implied a cost-effective of MICP technology to improve the concrete properties along with the mitigation of industrial wastewater pollution, which goes some way towards solving the problem of industrial wastewater pollution.