Hi Kevin. Before briefing you on this, first of all I would like to wish you all the very best for your exams. I have worked for a few years in a company which specialized in providing
environmental remediation services and
environmental hazardous waste services so I can definitely help you on this.
Environmental remediation is the process of removing contaminants from soil, groundwater or surface water in order to protect the public and the environment.
Remediation technologies are generally classified into two methods:
Ex-situ methods – In this method, contaminated soil or fluid is removed and then treatment is done. Ex situ remediation can take place either on site or at some off site location. Some of the technologies which follow ex-situ approach are pump and treat, ion exchange, reverse osmosis, dehalogenation, vapor extraction, soil washing and off-site disposal.
In-situ methods – In this method, soil is not removed to treat the contamination. Technologies which use in-situ are soil vapor extraction, bioventing, geotechnical systems, brownfields cap, natural Attenuation (IT) etc.
Some technologies like chemical oxidation, biodegradation use both in-situ and ex-situ applications.
Both have their own pros and cons. Ex-situ treatments take shorter time and the uniformity of treatment is assured. But ex situ approach requires excavation of soils which can raise the cost of the treatment.
Comparatively, in-situ cleanups are less expensive but they take a longer time and the uniformity of treatment is not certain.
Mattew