*2.1.1 Land farming*

Land farming is considered as an ex situ remediation process in which the contaminated soil is excavated and then applied into lined beds afterwards; the contaminated soil is tilled mechanically to aerate the waste. The contaminated soil is placed in several layers 0.4 m thick. A synthetic, concrete, or clay membrane is then used to cover the contaminated soil layer. Oxygen is added, and mixing occurs via ploughing, harrowing, or milling. Nutrients and moisture can be added to support the remediation method [18].

**Figure 1.** *Distribution of innovative remediation activity (source [17]).*

#### *2.1.2 Vermiremediation*

Vermiremediation is considered a less expensive and more acceptable remediation process for contaminated soil in the world. Generally, earthworms (especially *E. fetida*) have good resistance against contaminants including heavy metals and organic pollutants within the soil. This approach is carried out using the earthworms to bioaccumulate the contaminants within their bodies; moreover, these earthworms are able to biotransform or biodegrade the contaminants into harmless products with the presence of enzymes. Sinha et al. [19] reported that the earthworms have high resistivity to a number of chemical pollutants present in the soil. They concluded that 5 kg of earthworms (totalling to 10,000) are able to degrade 1000 kg of waste, converting the waste into vermicompost within only 30 days. One of the main features of this economic and environmental importance is that polluted land is not only cleansed but also improved in terms of its physical, chemical, and biological quality.

#### *2.1.3 Bio-piles*

Bio-pile is considered as an ex situ remediation process in which the contaminated soils are excavated and combined with soil amendments and then placed on a treatment area. In order to enhance the remediation process, nutrients and oxygen are pumped into the contaminated soil using air injection system, which is buried under the contaminated soil during the remediation process to provide the required oxygen. This oxygen is supplied through the contaminated soil either by positive pressure or by vacuum to support the biodegradation process [10]. Many factors such as moisture, heat, nutrients, oxygen, and pH require to be controlled to enhance biodegradation process; the height of the soil piles should be up to 20 feet. This method has been conducted successfully to treat and rehabilitate soils contaminated with non-chlorinated VOCs and fuel-contaminated soil [19]; however, chlorinated VOCs, SVOC, or pesticides might be treated as well, but the effectiveness of the process varies [14].

**153**

*The Assessment Strategy for Selecting and Evaluating Geoenvironmental Remediation*

Bioventing is considered as an in-situ bioremediation process in which the contaminated soils inject by air pump to enhance and improve the existing soil microbial, where the movement of air is designed to maximise biodegradation while minimising volatilisation [10–19]. Bioventing process is for treating permeable soils because a huge volume of air is required to reduce and degrade VOC. Low air flow rate is required during the process to supply only enough oxygen to maintain the activity of the microorganisms in residual contamination in the soil. The current method provides oxygen using air injection system, which is inserted into the vadose zone. This technology has been implemented successfully to treat and rehabilitate soils contaminated with various levels of TPH or any chemical contaminants

Windrows are considered as an ex situ remediation process in which the contaminated soils are excavated and combined with compositing materials such as bark, compost, or wood chips and then placed in windrows to increase and improve aeration process and enhance the structure of soil. Windrows are one of the waste management systems that use microbial activity to biodigest organic waste compounds and transform them into safe products. In order to transfer oxygen into contaminated soils, regular turning is conducted, thus enhancing aerobic degradation. Windrows system and waste composting are considered very similar in their methods [10–19]. Many aspects such as moisture, heat, nutrients, oxygen, and pH

Phytoremediation is the term used to describe a process based on biological technology which uses natural plant processes in improving degradation as well as eliminating contaminants in polluted groundwater or soil. In recent years, the emphasis in handling polluted ground has been slowly swung away from the conventional remove, dispose, and cap methods to a more on-site integrated technique. Attempts to develop these integrated approaches have caused a swing in awareness from reviewing the problems to addressing society's needs by devising potential solutions. It is possible to develop potentially sustainable methods such as phytorestoration and remediation which emphasise on restoring the usability as well as the land's social and economical significance. The utilisation of plants in reducing the volume, mobility, or toxicity of contaminants in soil, underground water, or any other polluted media is known as phytoremediation, which is a general term used since 1991 [20]. Several mechanisms are available to make use of plants in the process of phytoremediation for organic compounds, such as phyto-degradation, phytovolatilisation, and rhizodegradation. Many benefits can be offered by employing the phytoremediation method in either minimising risks or saving costs as compared with traditional excavation and landfilling methods, where contaminated

materials or other usual methods of implementation are carried out on-site.

Thermal desorption aims to increase the volatility of contaminants to a gas phase or allow the contaminants to be melted by heating the contaminated soil. The preparation of this method is by means of rotary kiln plants, fluid bed, or sintering strand,

need to be maintained in order to improve the biodegradation process.

*DOI: http://dx.doi.org/10.5772/intechopen.88166*

that can be aerobically biodegraded [19].

*2.1.4 Bioventing*

*2.1.5 Windrow*

*2.1.6 Phytoremediation*

**2.2 Thermal desorption**

*The Assessment Strategy for Selecting and Evaluating Geoenvironmental Remediation DOI: http://dx.doi.org/10.5772/intechopen.88166*

#### *2.1.4 Bioventing*

*Geopolymers and Other Geosynthetics*

*2.1.2 Vermiremediation*

*Distribution of innovative remediation activity (source [17]).*

**Figure 1.**

*2.1.3 Bio-piles*

Vermiremediation is considered a less expensive and more acceptable remediation process for contaminated soil in the world. Generally, earthworms (especially *E. fetida*) have good resistance against contaminants including heavy metals and organic pollutants within the soil. This approach is carried out using the earthworms to bioaccumulate the contaminants within their bodies; moreover, these earthworms are able to biotransform or biodegrade the contaminants into harmless products with the presence of enzymes. Sinha et al. [19] reported that the earthworms have high resistivity to a number of chemical pollutants present in the soil. They concluded that 5 kg of earthworms (totalling to 10,000) are able to degrade 1000 kg of waste, converting the waste into vermicompost within only 30 days. One of the main features of this economic and environmental importance is that polluted land is not only cleansed but also improved in

Bio-pile is considered as an ex situ remediation process in which the contaminated soils are excavated and combined with soil amendments and then placed on a treatment area. In order to enhance the remediation process, nutrients and oxygen are pumped into the contaminated soil using air injection system, which is buried under the contaminated soil during the remediation process to provide the required oxygen. This oxygen is supplied through the contaminated soil either by positive pressure or by vacuum to support the biodegradation process [10]. Many factors such as moisture, heat, nutrients, oxygen, and pH require to be controlled to enhance biodegradation process; the height of the soil piles should be up to 20 feet. This method has been conducted successfully to treat and rehabilitate soils contaminated with non-chlorinated VOCs and fuel-contaminated soil [19]; however, chlorinated VOCs, SVOC, or pesticides might be treated as well, but the effective-

terms of its physical, chemical, and biological quality.

**152**

ness of the process varies [14].

Bioventing is considered as an in-situ bioremediation process in which the contaminated soils inject by air pump to enhance and improve the existing soil microbial, where the movement of air is designed to maximise biodegradation while minimising volatilisation [10–19]. Bioventing process is for treating permeable soils because a huge volume of air is required to reduce and degrade VOC. Low air flow rate is required during the process to supply only enough oxygen to maintain the activity of the microorganisms in residual contamination in the soil. The current method provides oxygen using air injection system, which is inserted into the vadose zone. This technology has been implemented successfully to treat and rehabilitate soils contaminated with various levels of TPH or any chemical contaminants that can be aerobically biodegraded [19].

### *2.1.5 Windrow*

Windrows are considered as an ex situ remediation process in which the contaminated soils are excavated and combined with compositing materials such as bark, compost, or wood chips and then placed in windrows to increase and improve aeration process and enhance the structure of soil. Windrows are one of the waste management systems that use microbial activity to biodigest organic waste compounds and transform them into safe products. In order to transfer oxygen into contaminated soils, regular turning is conducted, thus enhancing aerobic degradation. Windrows system and waste composting are considered very similar in their methods [10–19]. Many aspects such as moisture, heat, nutrients, oxygen, and pH need to be maintained in order to improve the biodegradation process.

### *2.1.6 Phytoremediation*

Phytoremediation is the term used to describe a process based on biological technology which uses natural plant processes in improving degradation as well as eliminating contaminants in polluted groundwater or soil. In recent years, the emphasis in handling polluted ground has been slowly swung away from the conventional remove, dispose, and cap methods to a more on-site integrated technique. Attempts to develop these integrated approaches have caused a swing in awareness from reviewing the problems to addressing society's needs by devising potential solutions. It is possible to develop potentially sustainable methods such as phytorestoration and remediation which emphasise on restoring the usability as well as the land's social and economical significance. The utilisation of plants in reducing the volume, mobility, or toxicity of contaminants in soil, underground water, or any other polluted media is known as phytoremediation, which is a general term used since 1991 [20]. Several mechanisms are available to make use of plants in the process of phytoremediation for organic compounds, such as phyto-degradation, phytovolatilisation, and rhizodegradation. Many benefits can be offered by employing the phytoremediation method in either minimising risks or saving costs as compared with traditional excavation and landfilling methods, where contaminated materials or other usual methods of implementation are carried out on-site.

#### **2.2 Thermal desorption**

Thermal desorption aims to increase the volatility of contaminants to a gas phase or allow the contaminants to be melted by heating the contaminated soil. The preparation of this method is by means of rotary kiln plants, fluid bed, or sintering strand, which is considered as fast method nevertheless; this method is classified as the most expensive remediation process. It is possible for contaminants such as VOC or SVOC to be vaporised and then rise to the unsaturated zone where they are collected using vacuum system to start another treatment procedure. For geological materials with moderate to high permeability, it is recommended to apply steam. The time it takes depends on three major factors: type and amounts of chemicals present, size and depth of the polluted area, type of soil and situations present [21].
