Conditions and effects of microbial soil remediation in solid-state bioreactors

摘要

Transport limitations cause problems like a lack of oxygen which are possible reasons for slow microbial degradation of hydrocarbons in native soils. Mixing the soil can enable sufficient oxygen and nutrient supply of microorganisms causing a higher microbial activity. To avoid an agglomeration of the moist soil a mechanical stress for deagglomeration has to be applied, leading to further increasing of microbial soil activity if the moisture content is above the plastic limit. Even a short soil treatment shows effects lasting longer than the treatment itself. The degradation of hydrocarbons can be positivity influenced by both single and periodic application of mechanical stress. Possible types of solid-state bioreactors are rotary drums and siloreactors. To justify the use of solid-state bioreactors the soil has to be treated at a moisture content with maximum microbial activity. But at this moisture content the physical properties like agglomerate strength, gas permeability and flowability are worst. In spite of that the reactors can be operated without trouble by knowing and considering these properties.