Enzyme-induced carbonate mineral precipitation for fugitive dust control

Abstract

Wind tunnel tests show that enzyme-induced carbonate precipitation (EICP) holds promise as a method for mitigation of fugitive dust emissions. Fugitive dust (wind-blown fine-grained soil) is a significant environmental problem in semi-arid and arid environments. Conventional methods for fugitive dust control, including the application of water, salt, or synthetic polymers, are either ineffective in arid climates, limited to short-term stabilisation, or very expensive. EICP employs hydrolysis of urea (ureolysis), a process catalysed by the urease enzyme, to precipitate calcium carbonate (CaCO3) in the presence of calcium ions. Urease is a widely occurring enzyme found in many plants and microorganisms. Wind tunnel experiments were conducted to evaluate the use of a topically applied EICP solution containing plant-derived urease to stabilise soil against fugitive dust emission. Three different soils were tested: a native Arizona silty sand, a uniform medium-grained silica sand and fine sand-sized mine tailings from southern Arizona. The wind tunnel tests established the treatment concentrations at which EICP was more effective in suppressing fugitive dust than specimens prepared by either thoroughly wetting the soil or treatment with a salt–urea solution. These tests demonstrate the potential of EICP treatment as a means of mitigating fugitive dust emissions.

Soil Stabilization using Calcium Carbonate Precipitation via Urea Hydrolysis

“…The SEM images shown in Fig. 3 confirm the carbonate precipitation around sand particles with calcite concentration at particle/particle contacts even in the absence of bacteria comparable to the results in MICP [15].…”

“…Moreover, in EICP there is no need to provide nutrients for bacterial activity [10]. Hamadan and Kavazanjian [15] showed the results of SEM scanning for treated sand using EICP solution. In their research, Hamadan and Kavazanjian [15] used EICP solution that have enzymes derived from (Jack Bean) and organic material as stabilizing agent (dry milk).…”

“…Hamadan and Kavazanjian [15] conducted wind tunnel experiments to evaluate the use of EICP solution containing plant-derived urease to stabilize soil against fugitive dust emission. In their study, three different soils were tested: a native Arizona silty sand, a uniform medium-grained silica sand and fine sand-sized mine tailings from southern Arizona.…”

One Phase Soil Bio-Cementation with EICP-Soil Mixing

“…Hamadan and Kavazanjian [6] summarized EICP urea hydrolysis summery process in the following reaction steps: Ureolysis is catalyzed by the urease enzyme which hydrolyses urea (CO(NH2)2) into carbon dioxide (CO2) and ammonia (NH3). In aqueous systems, ammonia may undergo speciation reactions forming ammonium (NH4 + ) and thereby increasing the pH of the solution (creating conditions favourable to carbonate precipitation).…”

Effect of maize and peanut crops on Ivory Coast northern soil biological activities and their response to arbuscular mycorrhizal fungi inoculation

“…The occurrence of microorganisms depends on the presence of allopathic compounds secreted by roots as well as mutual interactions between different groups of microorganisms in the soil (Bowles, 2014). Plant-induced differences in microbial communities due to the rhizosphere effect are well established (Hamdan and Kavazanjian, 2016). Thus, plant cover and consequently soil moisture can be an important driver of a soil microbial community (Lange et al, 2014).…”