This ppt deals with Hazardous waste management, it's law and hazardous site remediation

1. Mumbai University
B.E. SEM VII (Civil Engineering)
DLOC: Municipal Solid and Hazardous Waste Management
(SHWM)
Module 5
Hazardous Waste Management
By
Mrs. Puja Kadam
M.E. ( Civil and Environmental )
Assistant Professor
Department of Civil Engineering,
VCET, Vasai

26. Hazardous Site Remediation
The overall objective in remediating hazardous waste sites is the protection of
human health and the environment by reducing risk. There are three primary
approaches which can be used in site remediation to achieve acceptable levels
of risk:
•the hazardous waste at a site can be contained to preclude
additional migration and exposure
•the hazardous constituents can be removed from the site to make them more
amenable to subsequent ex situ treatment, whether in the form
of detoxification or destruction
•the hazardous waste can be treated in situ (in place) to destroy or otherwise
detoxify the hazardous constituents

27. Hazardous Site Remediation
• Each of these approaches has positive and negative ramifications.
Combinations of the three principal approaches may be used to address the
various problems at a site.
• There is a growing menu of technologies available to implement each of these
remedial approaches.
• Given the complexity of many of the sites, it is not uncommon to have
treatment trains with a sequential implementation of various in situ and/or ex
situ technologies to remediate a site.
• Hazardous waste site remediation usually addresses soils and groundwater .

28. Hazardous Site Remediation
• However, it can also include wastes, surface water, sediment , sludges,
bedrock, buildings, and other man-made items.
• The hazardous constituents may be organic, inorganic and, occasionally,
radioactive.
• They may be elemental ionic, dissolved, sorbed, liquid, gaseous, vaporous,
solid, or any combination of these.

29. Hazardous Site Remediation- In situ Techniques
• Containment is one of the available treatment options. There are several
reasons for using containment techniques.
• A primary reason is difficulty in excavating the waste or treating the hazardous
constituents in place.
• This may be caused by construction and other man-made objects located over
and in the site.
• Excavation could also result in uncontrollable releases at concentrations
potentially detrimental to the surrounding area.
• At many sites, the low levels of risks posed, in conjunction with the relative
costs of treatment technologies, may result in the selection of a containment
remedy.

30. Hazardous Site Remediation- In situ Techniques
• One means of site containment is the use of an impermeable cap to reduce
rainfall infiltration and to prevent exposure of the waste through erosion .
• Another means of containment is the use of cut-off walls to restrict or direct the
movement of groundwater.
• In situ solidification can also be used to limit the mobility of contaminants.
Selection among alternatives is very site specific and reflects such things as
the site hydrogeology , the chemical and physical nature of the
contamination, proposed land use , and so on. Of course, the resultant risk
must be acceptable.

31. Hazardous Site Remediation- In situ Techniques
• As with any in situ approach, there is less control and knowledge of the
performance and behavior of the technology than is possible with off-site
treatment.
• Since the use of containment techniques leaves the waste in place, it usually
results in long-term monitoring programs to determine if the remediation
remains effective.
• If a containment remedy were to fail, the site could require implementation of
another type of technology.

32. Hazardous Site Remediation- Ex Situ Techniques
• The ex situ treatment of hazardous waste provides the most control over the
process and permits the most detailed assessments of its efficacy.
• Ex situ treatment technologies offer the biggest selection of options, but
include an additional risk factor during transport.
• Examples of treatment options include incineration ; innovative thermal
destruction, such as infrared incineration; bioremediation ;
stabilization/solidification; soil washing; chemical extraction; chemical
destruction; and thermal desorption.

33. Hazardous Site Remediation
• Another approach to categorizing the technologies available for hazardous
waste site remediation is based upon their respective levels of demonstration.
• There are existing technologies, which are fully demonstrated and in routine
commercial use.
• Performance and cost information is available.
• Examples of existing technologies include slurry walls, caps, incineration,
and conventional solidification/stabilization.

34. Hazardous Site Remediation
• The next level of technology is innovative and has grown rapidly as the number of sites
requiring remediation grew.
• Innovative technologies are characterized by limited availability of cost and performance
data.
• More site-specific testing is required before an innovative technology can be considered
ready for use at a site.
• Examples of innovative technologies are vacuum extraction, bioremediation, soil
washing/flushing, chemical extraction, chemical destruction, and thermal desorption.
• Vapor extraction and in situ bioremediation are expected to be the next innovative
technologies to reach "existing" status as a result of the growing base of cost and
performance information generated by their use at many hazardous waste sites.