Data for - Microbial-Induced Calcite Precipitation in soils: use of alternative raw materials and analysis of environmental implications

Microbial-Induced Calcite Precipitation (MICP) is a biogeochemical process that induces the precipitation of calcium carbonate minerals as a result of microbial activity. In MICP via urea hydrolysis, urea, calcium, and simple carbon and nitrogen chemical compounds are supplied to stimulate degradation of urea by ureolytic microorganisms to produce carbonates and induce precipitation of calcium carbonate minerals. Compared to traditional soil stabilisation techniques, MICP is regarded as ‘environmentally friendly’ however, environmental impact of MICP is not yet fully assessed and reliance on industry end products (e.g., urea, calcium chloride) increases both the environmental impact and treatment costs of MICP.

The associated thesis considered, on the basis of a circular economy, use of available ‘waste’ products as alternatives to the chemical-based treatment used for MICP to increase sustainability and potentially reduce treatment costs. Dolerite fines by-product of the quarrying sector and cow urine derived from the farming sector were investigated as sources of calcium and nutrients to induce urea hydrolysis, respectively. In laboratory experiments, suitability of the proposed products was investigated, on the one hand, in dissolution experiments on dolerite quarry fines to determine their potential to source calcium-rich solutions through chemical weathering and, on the other hand, characterising urea content and stability in urine. The effectiveness of the proposed products was investigated monitoring reactants and products of MICP in soil column experiments and compared to the chemical-based treatment. Soil carbonation and improvement of mechanical properties via MICP with dolerite fines as a source of calcium was investigated. Environmental aspects of MICP investigated included quantification of ammonium and nitrates in soil leachates and a study on the greenhouse gas fluxes of MICP, where dolerite fines were investigated for their capacity to act as a carbon sink.

The dataset contains data obtained in the laboratory corresponding to thesis experimental chapters 3, 4, 5 and 6, which include: chemical analyses of liquid samples (calcium, urea, pH, total organic and inorganic carbon, total nitrogen and inorganic nitrogen, dissolved elements); chemical analyses on dolerite (x-ray fluorescence, thermogravimetric analysis), chemical and physical analyses of soil (total organic and inorganic carbon, isotopic signature of inorganc carbon, unconfined compressive strength), and greenhouse gas fluxes (carbon dioxide, methane and nitrous oxide).

The dataset is currently embargoed due to forthcoming publications.