The first three chapters of this book aim to identify and classify remediation technologies from the point of view of physicochemical or biological technology and the main physical phases where contaminants occur and should be treated. The remediation principle is based on the reactor approach, which suggests that remediation technologies can be characterized by quantifiable parameters such as mass transport; input and output; physicochemical or biological transformation; and mass balance in the same way as in any engineering technology even if the processes are performed in situ or ex situ.

Planning requires the knowledge of tools, operations, modes of application, expected impacts of the chosen technological parameters and overall efficiencies. All positive and negative impacts, risks and benefits of the technology should be predicted beforehand and confirmed after completion. It is essential to verify the technologies, especially in the case of new technologies, new locations, or unknown geochemical and soil conditions. Environmental, social, and economic risks and benefits should be planned and assessed in order to keep their acceptable balance. Evaluation of the efficiencies and verification of the technology require a multi-skilled team that can select and determine the scope of application and the key parameters and prepare the monitoring plan to acquire the necessary (measured) data for a complex evaluation. The evaluation should cover the direct impacts of processes during their application and the overall impact of the activity on the local environment and its users. In addition to local aspects, the assessment should include watershed-scale and global impacts, and sustainability analysis in the widest context. Potential damage before, during and after remediation (clean-up, rehabilitation) of a small site or a large area may have extensive and long-term impacts on the health of the ecosystem, the human population around the watershed or the global atmosphere, but also on the region’s social, economic, and cultural landscape. The first three chapters give a general overview of remediation technologies and some of them will be discussed in detail. The last chapter will discuss technology verification and sustainability assessment of environmental remediation.