Contaminated sites are brought back to a state that poses no immediate or future risks to humans and the environment by conducting site remediation. Site Clean up or Remediation involves the removal, reduction, immobilization or neutralization of contaminants on a contaminated site to minimize the adverse effects of the contaminants on public health/safety and the effects on the environment.

Remediation/Clean-up procedure involves several stages including:

• Characterization - identification of the various contaminants on the site. This typically occur in a couple of phases depending on where you are located in the world: Two phases (Preliminary and Detailed Investigation in United Kingdom and most Europe) and three phases I, II and III in North America. The result of a previous phase determines the need to proceed or not to proceed to the next phase.
• Delineation - defining the extents (laterally and vertically) of the contaminations. The concentrations of contaminants determined from stage 1 is compared to the preset "threshold" levels to determine the areas and levels of exceedances. Where the thresholds are exceeded, there would be need for remediation/clean-up. The volumes or other quantitative measures of exceedances would have to be determined as well.
• Planning (developing a Remedial Action Plan and costing) - identifying the various options for clean up (remedial technologies), choosing a method (s) of clean up appropriate, costing the chosen approach/approaches.
• Actual remediation - Implementation of the plan using the chosen remedial technologies.

Remedial Action Plan (RAP)) is developed following the site assessment studies. The RAP identifies the remediation approaches that are appropriate for the clean-up of the different streams of wastes on a site. Site cleanup technologies reduce the contaminant levels or the levels of risks on used sites to levels pre-specified, by regional standards or site specific studies, as protective of humans and ecology.

The actual remediation involves the construction works that attempt to bring the contaminated site to a state that does not pose hazards to humans and environment. It may involve excavation works, demolition, building of new structures etc.