Major factors affecting in situ biodegradation rates of jet-fuel during large-scale biosparging project in sedimentary bedrock

Abstract

Biodegradation of petroleum hydrocarbons (TPH), mainly jet fuel, had taken place at the former Soviet Army air base in the Czech Republic. The remediation of large-scale petroleum contamination of soil and groundwater has provided valuable information about biosparging efficiency in the sandstone sedimentary bedrock. In 1997 petroleum contamination was found to be present in soil and groundwater across an area of 28 hectares, divided for the clean-up purpose into smaller clean-up fields (several hectares). The total estimated quantity of TPH released to the environment was about 7,000 metric tons. Biosparging was applied as an innovative clean-up technology at the site and was operated over a 10-year period (1997-2008). Importance of a variety of factors that affect bacterial activity in unsaturated and saturated zones was widely studied on the site and influence of natural and technological factors on clean-up efficiency in heavily contaminates areas of clean-up fields (initial contaminant mass 111-452 metric ton/ha) was evaluated. Long-term monitoring of the groundwater temperature has shown seasonal rises and falls of temperature which have caused a fluctuation in biodegradation activity during clean-up. By contrast, an overall rise of average groundwater temperature was observed in the clean-up fields, most probably as a result of the biological activity during the clean-up process. The significant rise of biodegradation rates, observed after air sparging intensification, and strong linear correlation between the air injection rates and biodegradation activities have shown that the air injection rate is the principal factor in biodegradation efficiency in heavily contaminated areas. It has a far more important role for achieving a biodegradation activity than the contamination content which appeared to have had only a slight effect after the removal of about 75% of initial contamination.

Biotechnological advances in bioremediation of heavy metals contaminated ecosystems: an overview with special reference to phytoremediation

“…Furthermore, it is a non-invasive technique, leaving the ecosystem intact (Vidali 2001). However, it is not easy to predict the rate of cleanup for a bioremediation exercise as several environmental factors are involved in deciding the fate of bioremediation, and till date, scientists are in search of rules for predicting the rate of degradation of a contaminant in various components of the environment (Machackova et al 2012).…”

“…The optimal dosage of injection of soybased methyl ester (SME) solution effectively treated the cocontaminated aquifer, without increasing the BOD to the point where overly reducing conditions in the aquifer would potentially disturb current decreasing benzene and arsenic concentration trends. The remediation of large-scale petroleum contamination of soil and groundwater has provided valuable information about biosparging efficiency in the sandstone sedimentary bedrock (Machackova et al 2012;Kumar and Mani 2012). The nutrient structures control the biosparging pressure and distribution of oxygen and nutrients in the saturated zone.…”

“…Biosparging was applied as an innovative cleanup technology at the site and was operated over a 10-year period (1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008) at the former Soviet Army air base in the Czech Republic (Machackova et al 2012). An overall rise in average groundwater temperature was observed in the cleanup fields, most probably as a result of the biological activity during the cleanup process.…”

“…An overall rise in average groundwater temperature was observed in the cleanup fields, most probably as a result of the biological activity during the cleanup process. The significant rise in biodegradation rates, observed after air sparging intensification, and strong linear correlation between the air injection rates and biodegradation activities have shown that the air injection rate is the principal factor in biodegradation efficiency in heavily contaminated areas (Machackova et al 2012). …”

In Situ Bioremediation of a Gasoline‐Contaminated Vadose Zone: Implications from Direct Observations

“…Typically, for BTEX, aerobic degradation is the most rapid and complete process and is hence preferred in engineered bioremediation (Yadav and Hassanizadeh, 2011). Bioventing, infiltration, and O 2 -releasing compounds are the most common ways to deliver O 2 to the unsaturated zone (Machackova et al, 2012;Suthersan et al, 2016).Remediation efficiency in the vadose zone is greatly dependent on the ability to implement optimal hydraulic and chemical conditions, which enable the proliferation and activity of specific indigenous pollutant-degrading bacteria Aharoni et al, 2017). These conditions are usually predetermined in laboratory experiments where the parameters, such as the chemical composition of the soil water solution and the redox potential and water content of the sediment, are fully controlled.…”