Pilot-scale field studies on activated microbial remediation of petroleum contaminated soil

Abstract

A simple and cost-effective microbial remediation process has been developed for the treatment of petroleum contaminated soil by adding microbial activators to active the native microorganisms for enhancing the degradation of petroleum hydrocarbon. The microbial activator is formulated to provide nitrogen sources, phosphorus sources, trace elements, growth factors, biosurfactants, and soil pH regulators. The field trials, involving two 500 m3 oily soil samples with initial oil content of 5.01% and 2.15%, respectively, show that the petroleum hydrocarbon content can be reduced to 0.41% and 0.02%, respectively, in 50 days, reaching the national standard of cultivated land category II. The treatment period is significantly shorter than the commonly used composting and bioaugmentation methods. The remediation effect of microbial activator on oily soil was investigated through the germination experiment of rye seeds. The results showed that the activator itself could not only activate the functional microorganisms in the soil, but also reduce the biological toxicity of oily soil. After 40 days of treatment, the germination rate of rye seeds increased from 20–90%, indicating that the microbial activator could be effectively used for rapid in-situ remediation of oil contaminated soil.