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

Introduction 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. Methods 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 (OD 600 ), and nitrate concentration (KNO 3 ) using a four-factor, five-level orthogonal experimental design under controlled laboratory conditions. Results 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 OD 600 increased from 0.05 to 0.25, gas production first improved and then declined, with the optimum performance observed at OD 600 = 0.10. Among the investigated factors, KNO 3 concentration was identified as the most influential variable controlling gas production by Pseudomonas stutzeri . Discussion These findings provide an experimental basis for optimizing the application of MIDP in the anti-liquefaction treatment of coastal liquefiable sand.