Life Cycle Assessment of Biocemented Sands using Enzyme Induced Carbonate Precipitation (EICP) for Ground Improvement Applications

Abstract

Integrating sustainability goals into the selection of suitable ground improvement techniques is a global trend. Several bio-inspired and bio-mediated ground improvement techniques have been recently investigated as sustainable alternatives for traditional ground improvement techniques known for their high carbon footprint. Enzyme Induced Carbonate Precipitation (EICP) is an emerging bio-inspired soil improvement technique that is based on the hydrolysis of urea to precipitate carbonates that cement sand particles. Life cycle assessment (LCA) study was conducted to compare the use of traditional ground improvement using Portland cement with bio-cementation via EICP over a range of environmental impacts. The LCA results revealed that EICP soil treatment has nearly 90% less abiotic depletion potential and 3% less global warming potential compared to cement. Compared to cement, EICP has higher acidification and eutrophication potentials due to byproducts during the hydrolysis process. The sensitivity analysis of EICP emissions showed that reducing and controlling the EICP process emissions and using waste non-fate milk has resulted in significantly fewer impacts compared to the EICP baseline scenario.

Evaluation of life cycle assessment (LCA) use in geotechnical engineering

“…Of the seven studies included in this review, six of them clearly defined a functional unit, two published LCI data, and seven reported multiple impact categories. Most publications reviewed focused on ground improvement techniques, including enzyme induced carbonate precipitation (EICP), microbially induced carbonate precipitation (MICP) and bio-grouting (Suer et al 2009, Alotaibi et al 2021, Deng et al 2021. Though Raymond et al (2020) also studied EICP, they did so in the context of fugitive dust control.…”

“…Three of the studies compared bio-geotechnical alternatives with their business as usual counterparts (Suer et al 2009, Raymond et al 2020, Alotaibi et al 2021, Huntoon et al 2023, while the others reported results of a single technology (Martin et al 2020). Alotaibi et al (2021) and Raymond et al (2020) established that although bio-geotechnical solutions can be more sustainable in some respects, they can also be more environmentally intensive in others, highlighting the tradeoff between applied methods. Storesund et al (2012), conversely, found that bioengineered solutions for slope stabilization had less impact on the environment than conventional retaining walls in all measured environmental aspects.…”