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Biocement production from microbially induced calcium carbonate precipitation (MICP) is an environmentally friendly approach for construction works, but the use of calcium chloride (CaCl 2 ) in the conventional MICP process is a cost-limiting factor. The aim of this work is to develop a method for producing soluble calcium ions through two waste sources, limestone powder derived from aggregate quarries and acetic acid derived from fast pyrolysis of lignocellulosic biomass, as a replacement for the reagent grade CaCl 2 in the MICP process. The ratio of limestone powder to acetic acid solution was optimized for a desirable calcium concentration with an appropriate pH. Procedures for applying the urease-producing bacteria, urea, and calcium solutions were developed for a successful MICP process and were treated for sand column test. The engineering properties of the biocemented sand, including water permeability, unconfined compressive strength, and tensile strength, were evaluated as a function of the calcium carbonate content of the product. It was found that the properties of the sand treated using the limestone/acetic acid derived calcium solution were comparable to those of sand treated using reagent grade CaCl 2 . Collectively, the results indicate that the new MICP process is effective, more sustainable, and cheaper compared with the conventional MICP method.
Choi et al. (Tue,) studied this question.