Enzyme-induced carbonate mineral precipitation for fugitive dust control

TLDR

Fugitive dust is a major problem in arid regions, and conventional control methods are limited; enzyme‑induced carbonate precipitation (EICP) shows promise for mitigation, with urease—a common enzyme—catalyzing calcium carbonate formation. The study evaluated a topically applied EICP solution containing plant‑derived urease to stabilize soil against fugitive dust emission. The approach used urea hydrolysis to precipitate calcium carbonate and was tested on three soil types: Arizona silty sand, medium‑grained silica sand, and mine tailings. Wind tunnel tests showed that EICP at specific concentrations outperformed wetting or salt‑urea treatments in reducing fugitive dust, demonstrating its potential for dust mitigation.

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 (CaCO 3 ) 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.