What Environmental Engineers Say About Managing Contaminated Land

Contaminated land is a site where different types of hazardous substances are present at a detrimental level. A land can be contaminated by industrial waste, asbestos, agricultural chemicals, and oil spills. The land contamination is not visible from above the land. In most cases, soil contamination checks are conducted by analyzing the soil quality underneath the surface. This is how engineers approach managing contaminated land: 

• At first, engineers focus on site assessment of the contaminated land
• The contaminant substance is identified
• Remediation methods are determined, like in situ and ex-situ
• The focus is on mitigating the risks associated with land contamination and plan the land reuse technique.

Environmental engineers and remediation service providers have a greater role in assessing the projects and the level of soil contamination. The approach of engineers to manage and process contaminated land is depicted in this blog, closely following the regulatory and environmental aspects. The process starts with a site assessment.

Site Assessment: The First Critical Step

Engineers focus on site assessment because it is essential to identify the extent of the contamination in the land. Here is how engineers focus on site assessment in different phases: 

Phase I Assessment

In phase I, engineers mainly conduct research in order to review the land. This review includes checking on the historical data of the land to assess potential risks of soil contamination. 

Phase II Assessment

Engineers get an idea from the phase I assessment about potential soil contamination. Therefore, they can plan for the remediation service. To confirm the contamination, soil and groundwater analysis is conducted. 

Regulatory frameworks

Management of the contaminated land is also required to comply with the regulatory authorities. Globally, there are different authorities that impose provisions on contaminated lands. In Australia, governing bodies like the Environmental Protection Authority (EPA) regulate contaminated land under the Contaminated Land Management Act 1997 (CLM), which warrants regulations on lands that are notably contaminated. 

Contamination Identification and Categorization

Remediation experts and engineers are able to identify the type of contamination. Categorization of land contaminants is essential to opt for the remediation service that uses the appropriate technique to manage the level of contamination. 

Here are different types of land-contaminating substances: 

Contaminant Type	Examples	Common Sources	Environmental / Health Impact
Heavy Metals	Lead, mercury, Arsenic, and Cadmium	Industrial sites, batteries, and paints	Toxic to humans
Petroleum Hydrocarbons	Diesel, gasoline, oil	Fuel stations and leaks from underground tanks	Soil and groundwater pollution
Asbestos	Chrysotile, Amosite	Older structure	Lung diseases and long-term environmental persistence
Pesticides	DDT and Atrazine	Agriculture and Pest Control	Groundwater leaching and harm to biodiversity
Sewage and pathogens	Bacteria, viruses	Septic tanks and leaking sewer lines	Waterborne disease
Construction Waste	Concrete dust, treated wood, and adhesives	Demolition sites, landfills	Leaching in soil, chemical imbalance in the soil

Table 1: Types of Soil Contaminants causing damage to the environment and health

Remediation Techniques Recommended by Engineers

Considering the site-specific soil contamination, the engineers can determine the remediation methods. Factors like the chemical composition of soil, contaminant type, planning and budget constraints are some key things that are essential to consider different types of remediation. 

Common land remediation processes include: 

In-Situ Methods

Following the in-situ soil remediation method, the contaminated land is treated directly at its primary location. Engineers use strategies like bioremediation, where microorganisms or plants are used to deactivate the contaminant. 

Ex-Situ Methods

Ex-situ methods involve treating the contaminated soil in a different place. Some key ex-situ methods include using bioreactors and soil washing. Using bioreactors, engineers can treat the contaminated material by using microorganisms in a contained place. On the other hand, soil washing is another method where the contaminated soil is mixed with liquid to segregate the contaminants from it. 

Capping

In the context of soil contamination, capping refers to a method of covering contaminated portions of land with specific materials like concrete, asphalt, or synthetic materials. Remediation service providers apply capping to reduce the exposure and spread of contaminants. 

Risk Mitigation and Land Reuse Planning

Engineers also approach to manage land contamination management by planning to mitigate the human and ecological risks from it.

Managing Human and Ecological Risks

Land contaminants like heavy metals, asbestos, sewage water, and construction waste can impact humans and biodiversity. Opting for in-situ solutions will contain the spread of harmful chemicals, which can be key to reducing the impact of contaminants on humans and the ecosystem. 

Incorporating Sustainable Land Remediation Practice

Sustainable ways of land remediation include soil erosion control and bioremediation, where plants and bioorganisms are used to prevent soil erosion and remove contaminants. 

In Summary

Environmental engineers and remediation service providers play an important role in recognizing and evaluating contaminated land. Turning the contaminated land into a safe and usable space will help to improve the life-cycle of people and biodiversity located around the area. 

Consult with Professional Remediation Service Providers!

Thinking of remediating your old contaminated site? Consider taking the opinions of expert remediation service providers and experienced engineers to ensure safety and sustainability in the process.