Soil engineering in vivo : harnessing natural biogeochemical systems for sustainable, multi-functional engineering solutions

Abstract

Carbon sequestration, infrastructure rehabilitation, brownfields clean-up, hazardous waste disposal, water resources protection and global warming—these twenty-first century challenges can neither be solved by the high-energy consumptive practices that hallmark industry today, nor by minor tweaking or optimization of these processes. A more radical, holistic approach is required to develop the sustainable solutions society needs. Most of the above challenges occur within, are supported on, are enabled by or grown from soil. Soil, contrary to conventional civil engineering thought, is a living system host to multiple simultaneous processes. It is proposed herein that ‘soil engineering in vivo ’, wherein the natural capacity of soil as a living ecosystem is used to provide multiple solutions simultaneously, may provide new, innovative, sustainable solutions to some of these great challenges of the twenty-first century. This requires a multi-disciplinary perspective that embraces the science of biology, chemistry and physics and applies this knowledge to provide multi-functional civil and environmental engineering designs for the soil environment. For example, can native soil bacterial species moderate the carbonate cycle in soils to simultaneously solidify liquefiable soil, immobilize reactive heavy metals and sequester carbon—effectively providing civil engineering functionality while clarifying the ground water and removing carbon from the atmosphere? Exploration of these ideas has begun in earnest in recent years. This paper explores the potential, challenges and opportunities of this new field, and highlights one biogeochemical function of soil that has shown promise and is developing rapidly as a new technology. The example is used to propose a generalized approach in which the potential of this new field can be fully realized.

Biogeochemical processes and geotechnical applications: progress, opportunities and challenges

“…The first international workshop on biogeotechnical engineering in 2007 facilitated interdisciplinary discussions and prioritisation of research topics in this emerging field (DeJong et al, 2007). Research advanced quickly, with a bio-geo-civil-engineering conference in 2008, and several dedicated sessions at national and international conferences, additional papers assessing the potential of the field (Ivanov & Chu, 2008;Ivanov, 2010;Seagren & Aydilek, 2010;DeJong et al, 2011;Hata et al, 2011), and more than 100 technical conference and journal papers dedicated to this topic since. Research programmes on biogeotechnical engineering are currently active in more than 15 countries around the world.…”

Biomineralization Mediated by Ureolytic Bacteria Applied to Water Treatment: A Review

“…Carballa et al [78] describe a method to remove phosphate from wastewater from anaerobic effluents by ureolytic precipitation. This study applied phosphate precipitation mediated by ureolytic bacteria when the concentration of this ion in wastewater from a vegetable processing industry was below <30 mg PO 4 3− -P levels by liter. MgO (preferably Mg(OH) 2 ) and urea were added to facilitate precipitation, decreasing its concentration to approximately 5−7 mg PO 4 3− -P per liter.…”

“…Sporosarcina pasteurii ATCC11859, formally Bacillus pasteurii [35], is the terrestrial ureolytic bacterium most used as an example of MICP and presents an active intracellular urease [4,11].…”

“…Such is the case of biomineralization, a process that is mediated by bacteria and other organisms for the formation of minerals from ions present in the surrounding environment. A particular form of biomineralization is microbiological carbonates precipitation (MICP), and is defined as the process involving the formation of minerals mediated by living organisms as a result of the cellular activity that promotes the physicochemical conditions required to carry out the formation and growth of the biominerals [4]. There is a great variety of structures and, in nature, more than 60 types of biological minerals have been described [5].…”

“…Within this point, biological processes that increase the pH of the medium and create the oversaturated conditions necessary for its precipitation have been identified [4,18]. Different bacteria with varied metabolisms are able to precipitate biominerals from carbonates [19][20][21][22][23], oxides [24,25], sulfates [26,27] and phosphates [28,29].…”