How to Clean Oil Contamination from Soil Safely
Oil spills and diesel leaks can happen anywhere — a burst pipe on a farm, a leaking fuel tank near a garage, a construction site mishap, or even a simple accident involving stored equipment. When this happens, the soil underneath absorbs the hydrocarbons, and over time, the contamination becomes a stubborn, long-term problem. For many property owners, the thought of cleaning it up can be daunting — expensive, disruptive, and complicated.
Fortunately, there is now a safe, effective, and environmentally responsible way to deal with contaminated soil without tearing up the ground or using harsh chemicals. Enzyme-based bioremediation is changing the way we think about soil clean-up. This article will explain, step by step, what happens when oil contamination occurs, why leaving it untreated is risky, and how an organic enzyme solution, like the one developed by Bioglobe, can solve the problem naturally.
Understanding the Problem
Oil, diesel, and other petroleum products are made of hydrocarbons — long chains of hydrogen and carbon atoms. These compounds power our cars, machinery, and heating systems, but when they spill into the soil, they behave in a very different way. Instead of burning off as fuel, they seep into the earth, coating soil particles and filling the tiny pores that normally hold water and air.
How Contamination Occurs
Oil contamination can result from:
- Leaking tanks — old fuel storage tanks, whether above or below ground, are common sources of diesel leakage.
- Spills during refuelling — farm equipment, generators, or vehicles can spill fuel while being filled.
- Industrial accidents — during construction or maintenance work, hydraulic fluid or oil can spill onto bare soil.
- Accidental discharge — damaged pipelines, hoses, or drums can release oil slowly over time.
Once spilled, oil does not simply stay on the surface. It sinks downwards with gravity and spreads laterally, forming a plume of contamination. Rain or irrigation water can push the oil deeper, making the clean-up more challenging.
The Consequences of Leaving Oil in the Soil
Many people assume that if the oil is left alone, it will eventually “disappear” on its own. While natural breakdown does occur, it is slow — sometimes taking decades — and meanwhile, the contamination continues to have harmful effects.
Soil Health
Hydrocarbons disrupt the natural balance of soil. They block the spaces between soil particles, reducing aeration and making it harder for water to penetrate. This reduces the amount of oxygen available for beneficial microorganisms. The soil becomes anaerobic, meaning very little life can thrive. Over time, this causes:
- Loss of soil fertility
- Reduced microbial diversity
- Poor structure and compaction
Essentially, the soil becomes lifeless and unsuitable for healthy plant growth.
Harm to Plants and Crops
Oil contamination is toxic to many plants. Roots struggle to absorb water and nutrients, and in some cases, the hydrocarbons themselves interfere with plant metabolism. Farmers may see poor germination rates, stunted growth, yellowing leaves, and drastically reduced yields. In gardens, lawns and ornamental plants may die back or fail to thrive.
Risk to Groundwater
Perhaps the most serious concern is the risk to groundwater. As oil seeps deeper, it can eventually reach the water table. This is a major problem because hydrocarbons can dissolve partially in water or form a floating layer on top of groundwater. If this contaminated water flows into a well, stream, or river, it can cause widespread pollution, killing aquatic life and making the water unsafe for human use.
Human and Animal Health
Oil-contaminated soil can release harmful vapours, especially on hot days. Some hydrocarbons are carcinogenic, and others can irritate the skin, eyes, or lungs. Animals may ingest contaminated soil or plants. People, especially children, are at risk of exposure if the contaminated area is near a home, farmyard, or playground.
Long-Term Persistence
The biggest issue with leaving oil spills untreated is that they simply don’t go away. Unlike organic waste, which decomposes quickly, many hydrocarbons are extremely stable. Some of the heavier fractions can remain locked in the soil for decades, especially if the environment is lacking oxygen or microbial activity.
Traditional Clean-Up Methods and Their Limitations
Historically, the main way to deal with contaminated soil was to dig it up and transport it to a landfill or an incinerator. This is called “dig and dump”. While it removes the immediate problem from the site, it is far from ideal:
- It is disruptive — removing soil means heavy machinery, noise, and disturbance to the surrounding area.
- It is expensive — disposal fees, transport costs, and site reinstatement can add up quickly.
- It is not truly sustainable — the contamination is simply moved elsewhere, not neutralised.
Chemical treatments are another option. They involve applying oxidising agents or solvents to break down hydrocarbons. But chemicals can themselves be harmful to the environment, sometimes killing soil life and leaving behind residues.
This is why many homeowners, farmers, and contractors are turning to biological solutions — and why enzyme-based remediation is becoming the preferred choice.
The Solution: Enzyme-Based Bioremediation
Bioremediation is the process of using living organisms — usually microbes — to clean up pollutants. Enzyme-based bioremediation takes this a step further by introducing specific enzymes that break down hydrocarbons into harmless by-products like water and carbon dioxide.
What Are Enzymes?
Enzymes are natural proteins that act as catalysts — speeding up chemical reactions without being consumed in the process. They are found in all living things and are responsible for everything from digestion to energy production.
In the context of soil remediation, certain enzymes can target hydrocarbon molecules. They cut them apart into smaller, more manageable pieces that microbes can easily digest. This dramatically accelerates the natural clean-up process.
How It Works in Practice
Bioglobe has developed a range of organic enzyme solutions specifically for remediating oil and diesel contamination. Here is how the process typically works:
- Site Assessment
- Soil samples are taken from the contaminated area.
- The type and concentration of hydrocarbons are identified.
- Soil conditions are analysed — including pH, moisture, and microbial activity.
- Bespoke Enzyme Formulation
- Based on the analysis, a tailored blend of enzymes is created.
- This ensures that the solution is optimised for the specific contaminants present on the site.
- Application
- The enzyme solution is applied to the affected soil, usually by spraying or mixing it into the ground.
- Sometimes additional nutrients or aeration are provided to create the ideal conditions for microbial growth.
- Biodegradation
- The enzymes immediately begin breaking down hydrocarbons.
- Microbes in the soil (or sometimes added microbes) consume the resulting smaller molecules, turning them into harmless end-products.
- Monitoring and Follow-Up
- The progress is monitored over several weeks or months.
- Additional treatments can be applied if necessary until hydrocarbon levels are reduced to safe standards.
Why This Approach Is Safe
Because the solution is based on natural biological processes, there is no risk of introducing toxic chemicals. Once the hydrocarbons are degraded, the enzymes themselves break down into amino acids — the building blocks of life — and simply become part of the soil’s natural nutrient cycle.
There is no residue, no need to dispose of hazardous waste, and no damage to the soil structure. In fact, as the microbial community recovers, the soil often becomes healthier and more fertile than before.
Benefits of Enzyme Bioremediation
For homeowners, farmers, and contractors, enzyme-based remediation offers clear advantages:
- Non-disruptive: No need to excavate or transport soil.
- Cost-effective: Typically less expensive than traditional dig-and-dump.
- Safe for the environment: No secondary pollution or chemical residues.
- Restores soil health: Supports microbial recovery and future plant growth.
- Scalable: Can be used for small garden spills or large agricultural sites.
Bioglobe’s laboratory expertise ensures that each solution is tailored for maximum effectiveness, giving you confidence that the contamination will be properly treated.
Real-World Applications
Enzyme-based remediation is suitable for a wide range of situations:
- Residential properties: Cleaning up after a heating oil tank leak.
- Farms: Treating diesel spills near tractors, generators, or storage tanks.
- Construction sites: Dealing with hydraulic oil or fuel leaks during works.
- Industrial yards: Remediating long-term contamination under machinery bays.
Because it is a flexible, customisable approach, it can be applied almost anywhere where hydrocarbon contamination has occurred.
The Ecosystem-Friendly Option
Traditional remediation methods often sacrifice soil quality for the sake of removing contamination quickly. Enzyme solutions, on the other hand, work with nature. They use natural processes to restore balance, allowing soil life to recover.
The goal is not just to remove the contamination, but to leave behind healthy, living soil. This makes enzyme remediation the sustainable choice — protecting groundwater, supporting biodiversity, and allowing the land to be used productively again.
FAQs
Is it possible to clean oil spills without digging up the soil?
Yes. In most cases, enzyme-based bioremediation allows you to treat the contaminated area in place (this is known as in situ remediation). By applying the enzyme solution directly to the soil, the hydrocarbons are broken down over time without any need for excavation. This means less disruption to your property, no need to transport contaminated soil, and a lower overall cost.
How long does bioremediation take?
The time required depends on several factors:
- The type and concentration of hydrocarbons
- Soil temperature and moisture levels
- Oxygen availability
- The specific enzyme blend used
Under good conditions, significant reduction in contamination can often be achieved within a few weeks. For heavier contamination or colder conditions, it may take several months. The key advantage is that the process is continuous — the enzymes and microbes keep working until the hydrocarbons are gone.
Are enzyme solutions safe for crops or gardens?
Yes. The enzymes used in bioremediation are biodegradable and non-toxic. Once they have finished breaking down hydrocarbons, they simply decompose into amino acids and other harmless substances. This means the soil is safe for planting again, and in many cases, the improved microbial activity leads to healthier plants in the future.
Can enzymes clean up old oil contamination?
Yes, although older contamination can be more challenging because the hydrocarbons may have become weathered and tightly bound to the soil particles. In these cases, the solution may need to be applied more than once, or combined with additional techniques like aeration or nutrient amendment to boost microbial activity.
How do I know if my soil is safe after treatment?
The best way is to have the soil tested before and after remediation. Laboratory analysis can measure the concentration of hydrocarbons and confirm when they have dropped to safe levels. In addition to chemical tests, visual signs like healthy plant growth and normal soil smell can indicate successful treatment.
Bioglobe offer Organic Enzyme pollution remediation for major oil-spills, oceans and coastal waters, marinas and inland water, sewage and nitrate remediation and agriculture and brown-field sites, throughout the UK and Europe.
We have created our own Enzyme based bioremediation in our own laboratory in Cyprus and we are able to create bespoke variants for maximum efficacy.
Our team are able to identify the pollution, we then assess the problem, conduct site tests and send samples to our lab where we can create a bespoke variant, we then conduct a pilot test and proceed from there.
Our Enzyme solutions are available around the world, remediation pollution organically without any harm to the ecosystem.
For further information:
BioGlobe LTD (UK),
Phone: +44(0) 116 4736303| Email: info@bioglobe.co.uk