Influence of salinity on bioremediation of oil in soil

Spills from oil production and processing result in soils being contaminated with oil and salt. The effect of NaCl on degradation of oil in a sandy-clay loam and a clay loam soil was determined. Soils were treated with 50 g kg(-1) non-detergent motor oil (30 SAE). Salt treatments included NaCl amendments to adjust the soil solution electrical conductivities to 40, 120, and 200 dS m(-1). Soils were amended with nutrients and incubated at 25 degrees C. Oil degradation was estimated from the quantities of CO(2) evolved and from gravimetric determinations of remaining oil. Salt concentrations of 200 dS m(-1) in oil amended soils resulted in a decrease in oil mineralized by 44% for a clay loam and 20% for a sandy-clay loam soil. A salt concentration of 40 dS m(-1) reduced oil mineralization by about 10% in both soils. Oil mineralized in the oil amended clay-loam soil was 2-3 times greater than for comparable treatments of the sandy-clay loam soil. Amending the sandy-clay loam soil with 5% by weight of the clay-loam soil enhanced oil mineralization by 40%. Removal of salts from oil and salt contaminated soils before undertaking bioremediation may reduce the time required for bioremediation.     

微域培养试验中影响石油降解的几个因素

试验研究微域培养中土壤深度，油水添加次序以及搅拌等因素对石油降解速率的影响，结果表明：微域中随着土壤深度由４ｍｍ增加到３２ｍｍ，ＣＯ２累积释放量下降１６．７Ｔ％，石油碳氢化合物降解量减少１８．２％；先加水后加油可增加ＣＯ２累积释放量达３６．５％，ＴＰＨ降解量提高２１．５％；搅拌可以增加ＣＯ２释放与ＴＰＨ的降解。