Petroleum hydrocarbon remediation requires technologies to address specific site conditions within a contaminated aquifer. Petroleum Hydrocarbon treatment technologies are designed to break the carbon – hydrogen bonds which make up the contaminate. Petroleum hydrocarbons can have a single carbon with multiple hydrogens bond (methane, CH4) to more complex hydrocarbons such as benzene (C6H6).
The more complex the hydrocarbon compound the more difficult it is to fully remediate. Petroleum Hydrocarbon remediation technologies provided by Hepure are primarily in-situ. Is-Situ remediation occurs within an aquifer and/or soil matrix without the need for the water or soil to be removed. In-Situ treatment has been shown to be very effective and reduce the overall time and cost of Petroleum Hydrocarbon remediation.
The in-situ treatment of Petroleum Hydrocarbon contaminated soil requires saturation of the soil with water. This is due to chemical and biological reaction only taking place with the contaminate in solution. In-Situ treatment can be accomplished with injection of the chemical substrate with water or soil mixing. Site conditions are important when selecting a Petroleum Hydrocarbon remediation technology. Some of the specific site conditions important to concern when designing an in-situ approach are:
Type of aquifer, perched, non-drinking groundwater, drinking water.
Type of Geology. Clay, Silt, Sand, Fractured Bedrock
Type of Contaminate; BTEX, Gasoline, Diesel, Oils
Concentration of Contaminates; PPM or PPB
Remedial Goals; Polishing, Drinking Water Standards
Groundwater Chemistry; pH, Redox, Minerals, Hardness
The factors discussed above are typically collected and documented in a detailed site assessment. Site assessments will address soil and groundwater conditions as well as document the types of contaminates and potential sources of the release.
Typical applications would include a long lasting oxygen source (Calcium Peroxide) and a strain of hydrocarbon degrading bacteria. Although many In-Situ applications rely on natural occurring bacteria, addition of a bacteria strain will help establish a hydrocarbon degrading population faster and is advisable given the limited release life of Calcium Peroxide.
Soil mixing can be effective in treatment of hydrocarbon contaminated soils with bio-augmentation and chemical oxidation if the soils are shallow enough to be mixed (up to 20’ bgs) and adequate water can be added to saturate the soil. Mixing can be performed with an excavator bucket (not considered completely effective mixing) or with a rotary tool attached to an excavator. Mixing needs to be more complete for chemical oxidation than biological treatment since the effectiveness is dependent on full contact.
Biological treatment can be considered for soil mixing applications. Once again, the soils will need to be saturated. Bio-Argumentation is more forgiving since the chemical will have time to diffuse within the saturate soil matrix.
Injection treatment is performed with drilling or direct push equipment where a casing or hollow rod is inserted into the contaminated area. Treatment chemicals and water are injected under pressure to insure full contact and saturation with the soils.