An Introduction to Groundwater Remediation Options: Physical, Biological and Chemical Treatments

Ground remediation is essential for contaminated sites. Groundwater plays an integral role in the health of our soil, crops and ecosystems. It sits just below the ground surface which makes it particularly susceptible to spills and leaks but processing polluted groundwater can be a costly and lengthy process, particularly when harmful chemicals from industrial sites are involved.

If you own an industrial site, keeping your soil and groundwater safe from negative environmental impacts is your responsibility. Today, there are many different techniques and treatments for groundwater remediation to suit every type of contamination.

The process of groundwater treatment

The first step to ensuring healthy groundwater is to perform an environmental site assessment which includes researching the site’s history and creating a hydrogeology model of the site and surroundings to identify risks to the quality of the groundwater. After the groundwater has been tested and if a contaminant has been identified, remediation may be deemed necessary.

Groundwater can be contaminated by many different pollutants and depending on the degree and type of pollutant, there are many different methods to clean the contaminated water. The methods used by environmental consultants are often combined for increased effectiveness, but the treatment processes mainly fall into three different categories: physical, biological and chemical.

In-situ treatment vs ex-situ treatment

Groundwater remediation processes can be performed in-situ or ex-situ. The in-situ remediation process involves cleaning the water through biological or chemical means on-site. It is the less expensive method of groundwater remediation. Ex-situ treatment is typically a more expensive and time-consuming process as it involves the excavation and transport of the contaminated groundwater for treatment. It does have the advantage of immediately preventing the groundwater from suffering from further pollution and it can be necessary if the damage is too difficult to be treated by on-site remediation methods.

Physical treatments

A common type of remediation practice, typically referred to as ‘pump and treat’ involves pumping the groundwater from the subsurface to physically remove the water from the contaminated site and treat it through biological or chemical means before returning it to the original position.

Another physical remediation tactic is air sparging or air stripping. This involves injecting pressurised air into the contaminated groundwater, causing bubbles to rise and the pollutants to dissolve into a vapour state. The contaminant vapours are then extracted by vacuum systems, leaving behind the treated groundwater.

Biological treatments

Biological treatment of domestic wastewater has been practised since the mid-1800s. In the 1980s, Bioremediation was adapted for the treatment of groundwater that was polluted by oil or other petroleum wastes. Biological treatments for groundwater are still widely used today due to their cost efficiency and adaptability to different contaminants.

Biological remediation technologies involve encouraging indigenous bacteria or introducing biological material and matter to target the contaminants and speed up the breakdown of chemical waste in the groundwater. This includes bioaugmentation, bioventing and biosparging.

Bioaugmentation involves introducing strains capable of degrading contaminants to the groundwater to speed up the degradation rate, bioventing adds microorganisms to biodegrade organic contaminants and biosparging involves pumping air and nutrients to increase the biological activity of helpful microorganisms in the groundwater. Biological treatments are useful for both inorganic and organic contaminants with numerous methods and implementation options for each site’s unique requirements.

Chemical treatments

Chemical remediation is necessary if there are no biological options for removing the pollution from the groundwater. Some methods of chemical treatment include carbon absorption, ion exchange and oxidation. In the carbon absorption method, the activated carbon absorbs volatile organic compounds. These compounds attach to the surface of the activated carbon which is then removed leaving behind clean groundwater.

The ion exchange process cleans the groundwater of pollutants by pushing the water through a granular medium while the chemical oxidation process delivers liquid or gas oxidants into the subsurface to destroy organic molecules. Any combination of these methods may be necessary to improve the quality of your industrial site’s groundwater.

Worried about your groundwater quality?

Sites that have a history of industrial processes including waste or chemical storage need to have a site assessment due to their risk of poor groundwater quality. Alpha Environmental is here to provide comprehensive groundwater assessment, water sampling treatment and quality management plans. There is plenty your business can do to mitigate the risk of polluting your groundwater, but a site assessment is a great way to begin doing your part for the environment.

If you’d like to know more about our groundwater remediation services, contact us today via the enquiry form on our site or by calling 1300 039 181.