Experimental investigation of factors affecting microbial liquefaction mitigation in coastal liquefied sand

Microbially induced desaturation and precipitation (MIDP) is a promising environmentally friendly technique for improving liquefiable coastal sands; however, the key factors governing microbial gas-production efficiency and their governing patterns remain insufficiently understood.

To clarify the gas-production characteristics of Pseudomonas stutzeri for potential MIDP application in coastal liquefied sand treatment, this study systematically investigated the effects of temperature, pH, bacterial concentration (OD₆₀₀), and nitrate concentration (KNO₃) using a four-factor, five-level orthogonal experimental design under controlled laboratory conditions.

The results show that gas-production efficiency increases markedly with temperature from 10 to 30 °C. Increasing pH from 5 to 9 enhanced the gas-production rate by 2.3-fold. As OD₆₀₀ increased from 0.05 to 0.25, gas production first improved and then declined, with the optimum performance observed at OD₆₀₀ = 0.10. Among the investigated factors, KNO₃ concentration was identified as the most influential variable controlling gas production by Pseudomonas stutzeri.

These findings provide an experimental basis for optimizing the application of MIDP in the anti-liquefaction treatment of coastal liquefiable sand.