Bioremediation offers a promising solution for treating organic waste, particularly oil-contaminated soil. This method harnesses the natural ability of bacteria to break down organic compounds, resulting in harmless byproducts like carbon dioxide, water, ash, and microbial cells.
Project Overview
YWC Midwest, an environmental contractor, successfully implemented a bioremediation project to treat 7,500 cubic yards of oil-contaminated soil at a refinery. Years of leaks and spills around storage tanks and treatment lagoons caused the contamination, posing a risk of groundwater leaching.
Excavation and Processing
The project involved excavating and transporting the contaminated soil to two processing sites. There, workers spread the soil in layers of 12 to 18 inches. To create optimal conditions for bacterial growth, they added lime to adjust pH, provided nitrogen through fertilizer, and supplied moisture with rainwater.
Auger-Aeration Technology
The key to success was using a Brown Bear tractor equipped with a large auger. This machine efficiently turned and aerated the soil, ensuring a consistent supply of oxygen crucial for breaking down hydrocarbons.
Advantages of Bioremediation of Oil-Contaminated Soil Over Traditional Methods
- Enhanced Aeration and Bacterial Distribution: The auger thoroughly mixed the soil, ensuring even distribution of oil-eating bacteria while maximizing oxygen exposure. Consequently, this method resulted in a significantly faster degradation rate compared to older equipment.
- Improved Drainage and Moisture Control: The windrows created by the auger facilitated better rainwater runoff. This improvement prevented waterlogging and maintained optimal conditions for bacterial activity during heavy rainfall.
- Increased Efficiency and Productivity: The auger tractor operated at a faster pace and greater depth than traditional methods. Additionally, it eliminated the need for space-consuming alleyways between windrows.
- All-Weather Performance: Unlike conventional tractors, the Brown Bear tractor operated effectively in wet conditions. This capability allowed the project to start earlier in spring and continue uninterrupted during rainy periods.
Results Achieved
As a result of this innovative approach, YWC Midwest achieved remarkable outcomes:
- Significant Reduction in Contaminants: Total petroleum hydrocarbons (TPH) levels dropped from 59,000 mg/l to under 1,000 mg/l, meeting environmental standards for reuse.
- Cost and Time Savings: The project reduced costs and time requirements by 50% to 75%, leading to savings of up to $200 per ton of hazardous soil.
- On-Site Remediation and Material Reuse: Bioremediation allowed for on-site treatment, eliminating expensive transportation and disposal costs. The treated soil became suitable for reuse in refinery applications.
This case study highlights the effectiveness of auger-aeration technology in bioremediation. By combining natural bacterial processes with efficient soil management techniques, this approach offers a cost-effective and environmentally sound solution for treating oil-contaminated soil.
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- Bioremediation Techniques: This article from Springer discusses various bioremediation techniques, including ex situ methods like composting and their effectiveness in treating contaminated sites. Bioremediation Techniques – Springer.
- Wikipedia – Bioremediation: This page provides a comprehensive overview of bioremediation, including its methods, applications, and the role of microorganisms in the process. Bioremediation – Wikipedia.
- BioCycle – Environmental Remediation by Composting: This article explores how composting can serve as an effective method for environmental remediation, detailing processes and benefits. Environmental Remediation by Composting – BioCycle.
- NCBI – Composting and Bioremediation of Organic Contaminants: This systematic review discusses the application of composting in bioremediation, focusing on its advantages and effectiveness in degrading organic pollutants. Composting and Bioremediation – NCBI.
- EPA – Bioremediation Overview: This page from the EPA provides an overview of bioremediation technologies, including composting, and their environmental benefits. EPA Bioremediation Overview.
