Air sparging and biosparging

Air sparging involves injecting air into contaminated groundwater to volatilize and remove contaminants, while biosparging enhances biodegradation by supplying oxygen to microorganisms.

Targeted problems

Source and pathway management for:

• Petroleum hydrocarbons
• Chlorinated solvents
• VOCs
• Organic contaminants

Performance gains

• Accelerates degradation of contaminants
• Increases removal efficiency of VOCs
• Low-cost compared to traditional excavation
• Effective for both dissolved and adsorbed contaminants

Bioelectrochemical Remediation (BER)

Bioelectrochemical enhanced degradation of reduced and oxidized compounds. Enhanced redox through electrode participation in microbial metabolism of environmental pollution.

Targeted problems

Source and pathway management for:

• Petroleum hydrocarbons
• Chlorinated solvents
• Heavy metals

Performance gains

• Petroleum hydrocarbons
• Chlorinated solvents
• Heavy metals
• Long term solution over an operational site's lifetime
• Cheap: simple installation, and maintenance, and zero / low energy demand
• Tolerates high contaminant concentrations
• Treats mixed contamination

Capping and cover systems

Capping and cover systems involve placing an impermeable layer over contaminated materials to isolate them from the environment, preventing exposure and limiting the infiltration of water that could spread contaminants.

Targeted problems

Effective for containing:

• Landfill waste
• Heavy metals
• Organic contaminants
• Radionuclides

Performance gains

• Cost-effective containment solution
• Reduces exposure risk and environmental impact
• Minimizes leachate production
• Applicable to large contaminated areas

Electro-nanobioremediation (ENB)

In situ bioremediation integrated sequentially or in parallel with nanoscale zero-valent iron (nZVI) applications in combination with electrokinetic inputs

Targeted problems

Source and pathway management for:

• Complex and persistent halogenated organic compounds
• Pesticides
• Metalloids
• PFAS

Performance gains

• Broader range of treatable aquifers
• Reduced resource use (less bio-substrate, ZVI)
• Reduced energy demand / renewable energy supply
• Tolerance of high contaminant concentrations

Electro-remediation

Electro-remediation utilizes electric fields to mobilize and remove contaminants from soil or groundwater. Electrodes are placed into the ground, creating an electric field that drives contaminants towards collection points for treatment or removal.

Targeted problems

Effective for:

• Heavy metals
• Chlorinated solvents
• Organic contaminants
• Radionuclides

Performance gains

• Non-invasive with minimal disruption to the site
• Effective in low-permeability soils
• Adaptable for use in various subsurface conditions
• Potential to enhance biodegradation when combined with other methods
• Controlled and precise application of electric fields

Enhanced Phytoremediation (EPR)

Combination of rhizodegradation with electrokinetic treatments and other interventions. There are multiple synergies: including:

1. Within the root zone recalcitrant organics can be rendered biolabile,
2. immobilisation of metalloids in biomass or iron oxides from sacrificial iron electrodes,
3. improved growth conditions and supply of contaminants,
4. vertical integration to provide ongoing treatment by redox processes and bio stimulation at depth

Targeted problems

Diffuse source terms and pathway management for:

• PAHs and other organics
• Chlorinated aliphatics
• Metalloids, e.g. arsenic

Performance gains

• Long term, low input solution,
• Resilience to contaminant toxicity
• Large area solution
• Use of renewable energy
• Applicable to a wide range of soil textures including silts and clays
• Applicable in the vadose and saturated zones

Ex situ bioremediation

Ex situ bioremediation involves removing contaminated soil and treating it above ground using biological processes to degrade contaminants. This method typically includes techniques such as land farming, composting, and biopiles.

Targeted problems

Suitable for managing:

• Petroleum hydrocarbons
• Pesticides and herbicides
• Organic contaminants

Performance gains

• Effective for large volumes of contaminated soil
• Contaminants are degraded naturally by microorganisms
• Cost-effective and sustainable
• Can be accelerated by controlling environmental conditions

Ex situ thermal treatments

Ex situ thermal treatments involve excavating contaminated soil and heating it to volatilize and remove organic contaminants. Methods include incineration, thermal desorption, and pyrolysis.

Targeted problems

Effective for removing:

• Volatile organic compounds (VOCs)
• Chlorinated solvents
• Petroleum hydrocarbons

Performance gains

• Can treat high contaminant concentrations
• Permanent destruction of many organic contaminants
• Rapid treatment compared to biological methods
• Effective for a wide range of soil types

Excavation

Excavation involves physically removing contaminated soil or material from a site for off-site treatment or disposal. This method is commonly used for smaller areas of contamination or when rapid remediation is required.

Targeted problems

Suitable for removing:

• Heavy metals
• Petroleum hydrocarbons
• Organic contaminants

Performance gains

• Immediate removal of contamination
• Highly effective for localized contamination
• Allows for complete site restoration
• Can be combined with off-site treatment technologies

Impermeable barriers

Impermeable barriers are physical structures installed in the subsurface to prevent the flow of contaminated groundwater or to contain contaminants within a specific area. These barriers are often made of materials such as bentonite clay or synthetic liners.

Targeted problems

Used for controlling:

• Chlorinated solvents
• Petroleum hydrocarbons
• Heavy metals
• Radionuclides

Performance gains

• Effective for preventing contaminant migration
• Long-term containment solution
• Minimal maintenance once installed
• Suitable for groundwater management

In situ bioremediation

In situ bioremediation enhances the natural biological processes that break down contaminants by optimizing conditions for microbial growth, such as adjusting nutrient levels and oxygen availability.

Targeted problems

Source and pathway management for:

• Petroleum hydrocarbons
• Chlorinated solvents
• Heavy metals
• Nutrients
• Pesticides

Performance gains

• Environmentally friendly due to natural degradation
• Cost-effective for large-scale sites
• Low maintenance once established
• Adaptable to diverse contaminants and conditions

In situ chemical oxidation / reduction (ISCO/R)

In situ chemical oxidation/reduction (ISCO/R) involves injecting chemical oxidants or reductants into the subsurface to chemically degrade contaminants into less harmful compounds.

Targeted problems

Source and pathway management for:

• Petroleum hydrocarbons
• Chlorinated solvents
• Pesticides
• Heavy metals

Performance gains

• Rapid reduction of contaminant concentrations
• Adaptable to various contaminants
• Minimal disturbance to the environment
• Cost-effective for complex contamination issues

In situ flushing to change contaminant mobility

In situ flushing involves the injection of water or other suitable fluids to mobilize and remove contaminants from soil or groundwater. This method aims to enhance the mobility of contaminants, making it easier to extract and treat them.

Targeted problems

Source and pathway management for:

• Petroleum hydrocarbons
• Chlorinated solvents
• Heavy metals
• Pesticides
• Nutrients

Performance gains

• Effective for removing contaminants trapped in soil
• Improves extraction efficiency
• Minimal disturbance to site infrastructure
• Reduces long-term monitoring needs

In situ stabilisation

In situ stabilization involves mixing stabilizing agents with contaminated soil to reduce the mobility and bioavailability of contaminants. This method doesn't remove contaminants but minimizes their environmental impact by immobilizing them.

Targeted problems

Useful for controlling:

• Heavy metals
• Radionuclides
• Organic contaminants

Performance gains

• Cost-effective compared to excavation
• Minimal site disruption
• Reduces leaching and contaminant migration
• Long-term containment with minimal maintenance
• Versatile in various soil types and conditions

In situ thermal

In situ thermal remediation involves heating the subsurface to enhance the volatilization, degradation, or extraction of contaminants. Heat is applied through steam injection, electrical resistance heating, or other methods to increase contaminant mobility.

Targeted problems

Effective for treating:

• Chlorinated solvents
• Petroleum hydrocarbons
• Volatile organic compounds (VOCs)

Performance gains

• Rapid treatment compared to other methods
• Can target difficult contaminants in low-permeability soils
• Effective in removing high-concentration contaminant zones
• Can be combined with other methods for enhanced effectiveness
• Reduces contaminant mass in a short timeframe

Monitored Bioaugmentation (MBR)

Aerobic TCE/DCE degradation without the need for added substrates, improved dispersion of introduced pollutant degrading bacteria

Targeted problems

Pathway management for:

• Chloroethenes

Performance gains

• Broadens range of readily treatable aquifers
• No substrate needed, so avoids impact on aquifer quality and secondary emissions (CH4 H2S, VC)
• Genomics based validation of bioaugmentation
• Faster & cheaper (aerobic and reduced complexity)

Monitored Natural Attenuation (MNA)

Monitored Natural Attenuation (MNA) refers to the reliance on natural attenuation processes to achieve site-specific remediation objectives within a timeframe that is reasonable compared to other methods. These processes include biodegradation, dispersion, dilution, sorption, volatilisation, and chemical or biological stabilisation, transformation, or destruction of contaminants.

Targeted problems

Source and pathway management for:

• Petroleum hydrocarbons
• Chlorinated solvents
• Heavy metals
• Nutrients (e.g., nitrates, phosphates)
• Pesticides and herbicides
• Radionuclides

Performance gains

• Petroleum hydrocarbons
• Chlorinated solvents
• Heavy metals
• Cost-effective due to minimal active intervention
• Low disturbance to site ecosystems
• Adaptable to a wide range of contaminants and site conditions
• Long-term sustainability with minimal maintenance
• Reduced risk of exposure to contaminants during treatment

Mycoremediation

Mycoremediation employs fungi (particularly white-rot fungi) to degrade, transform, or sequester environmental contaminants. Fungi produce powerful extracellular enzymes that break down complex organic molecules.

Targeted problems

Suitable for addressing:

• Petroleum hydrocarbons (diesel, oil)
• Polycyclic aromatic hydrocarbons (PAHs)
• Pesticides and herbicides
• Polychlorinated biphenyls (PCBs)
• Heavy metals (biosorption)

Performance gains

• Degrades recalcitrant organic compounds
• Effective in diverse environmental conditions
• Can treat contaminated wood and paper products
• Rapid colonisation and treatment
• Produces extensive enzyme systems
• Complements phytoremediation approaches

Permeable reactive barriers

Permeable reactive barriers (PRBs) are installed in the subsurface to intercept and treat contaminated groundwater as it flows through. The barrier contains reactive materials that degrade or immobilize contaminants.

Targeted problems

Effective for treating:

• Chlorinated solvents
• Heavy metals
• Nutrients (e.g., nitrates)
• Organic contaminants

Performance gains

• Long-term solution with low maintenance
• Non-invasive once installed
• Cost-effective for passive groundwater treatment
• Can target specific contaminants with tailored reactive media

Phytoremediation

Phytoremediation involves using plants to remove, stabilize, or degrade contaminants from soil, water, or air. Certain plants can absorb contaminants through their roots, which are then stored or transformed into less harmful compounds.

Targeted problems

Suitable for addressing:

• Heavy metals
• Petroleum hydrocarbons
• Pesticides and herbicides
• Nutrients (e.g., nitrates, phosphates)

Performance gains

• Environmentally friendly and sustainable
• Low-cost with minimal site disturbance
• Improves soil structure and ecosystem health
• Suitable for large areas
• Potential for landscape restoration

Pump and treat

Pump and treat involves extracting contaminated groundwater through wells and treating it at the surface before discharging it back into the environment. This method is commonly used for groundwater remediation.

Targeted problems

Effective for treating:

• Chlorinated solvents
• Petroleum hydrocarbons
• Heavy metals

Performance gains

• Proven technology with extensive use in groundwater remediation
• Adaptable to various contaminants and site conditions
• Can be combined with in situ methods for enhanced results
• Continuous treatment option with real-time monitoring

Soil vapour extraction / venting and bioventing

Soil vapour extraction (SVE) involves applying a vacuum to the soil to extract volatile and semi-volatile organic compounds (VOCs and SVOCs) from the subsurface, while bioventing supplies oxygen to enhance biodegradation.

Targeted problems

Source and pathway management for:

• Petroleum hydrocarbons
• Volatile organic compounds (VOCs)
• Chlorinated solvents
• Nutrient management

Performance gains

• Effective for volatile contaminants
• Minimal disturbance to the site
• Enhances natural biodegradation
• Cost-effective for large sites

Soil washing and related ex situ treatments

Soil washing involves physically separating contaminants from soil particles by scrubbing them in a water-based solution. This method is often combined with other treatments to enhance contaminant removal.

Targeted problems

Applicable for removing:

• Heavy metals
• Organic contaminants
• Petroleum hydrocarbons

Performance gains

• Removes contaminants from soil rather than immobilizing them
• Can be applied to various soil types
• Allows recovery of treated soil for reuse
• Reduces the volume of hazardous waste

Solidification / stabilisation

Solidification/stabilization involves mixing contaminated soil with binding agents (e.g., cement, lime) to encapsulate contaminants and prevent their migration. It reduces the mobility and bioavailability of contaminants.

Targeted problems

Effective for:

• Heavy metals
• Organic contaminants
• Radionuclides

Performance gains

• Long-term containment solution
• Cost-effective for large sites
• Reduces leaching and contaminant mobility
• Minimal maintenance post-treatment

Vitrification

Vitrification involves heating contaminated soil or waste to extremely high temperatures, melting the material and transforming it into a glass-like solid. This method immobilizes contaminants by trapping them in a stable, inert matrix.

Targeted problems

Effective for immobilizing:

• Heavy metals
• Radionuclides
• Asbestos

Performance gains

• Permanent immobilization of contaminants
• Produces a stable, durable end product
• Minimal environmental impact post-treatment
• Can be applied to highly hazardous waste