methods of solid waste disposal

2. METHODS OF DISPOSAL
OF
HAZARDOUS WASTE

3. HAZARDOUS WASTE
• The waste with properties that make it potentially
dangerous or harmful to human health or the
environment.
• The universe of hazardous wastes is large and
diverse.
• Hazardouswastescanbeliquids,solids,or contained gases.
Examples: Plastics, Pesticides, Medicines, Paints,
Oil, gasoline, etc, Metals Leather Textiles

6. There are mainly three methods of disposal
a. Secure landfill
b. On-site disposal
c. Other methods

7. A secure landfill for hazardous waste is designed to-
a. Confine the waste to a particular location
b. Control the leachate that drains away
c. Collect and treat the leachate
d. Control leaks.
This type of landfill issimilar tothemodern sanitary landfill.

8. The figure shows a secure landfill for hazardous chemical waste

9. On-Site Disposal:
This is the most common disposal method.
 Drains, sewers, windows, pits and so on are all used to
get rid of unwanted substances.
Both hazardous and non-hazardous wastes find their way into
the environment by this route.

10. Composting:
 The decomposition of organic matter by biological
organisms. On a household scale composting can
significantly reduce the amount of garbage.
Composting can also be done on a municipal scale.
 For example, Netherlands produced 125,000 tons of
quality compost from discarded municipal organic waste!

11. Composting municipal waste

12. Land Application:
 Desirable treatment for some biodegradable industrial
wastes (micro biodegradation),usefulness is determined
by bio persistence of the waste

13. Surface Impoundment:
Treatment, storage, or disposal of liquid hazardous wastes in
ponds.

14.  Surface impoundment involves developing a
containmentpondofsometypethatmaybelined with
plasticand/orclaytoholdanaccumulation of liquid
wasteorsludge.
 Surface impoundment ponds utilized for a specific
purpose may be labeled as lagoons, settling pond,
or tailings pond.
 After final deposition of waste, some surface
impoundments may be covered with soil.

16. Deep-well Disposal- In rock (not soil), isolated from
freshwater aquifers; waste is injected into a permeable
rock layer hundreds to thousands of meters below the
surface.
Deep-well injection of oil-field brine has been important
to control water pollution in oil fields for many years.
Deep-well injection system- disposal in sandstone or
fractured limestone capped by impermeable rock and
isolated from fresh water. Monitoring wells are a safety
precaution

17.  Deep-Well Injection for the disposal of liquid solid waste
involves injecting the wastes deep in the ground into permeable
rock formations or underground caverns. The installation of
deep wells for the injection of wastes closely follow the
practices used for the drilling and completion of oil and gas
wells.
 To isolate and protect potential water supply aquifer, the surface
casing must be set well below such aquifers, and cemented to
the surface of the well. The drilling fluid should not be allowed
to penetrate the formation that is To be used for waste disposal.
To prevent clogging of the formation, the drilling fluid is
replaced with a compatible solution.
Deep-Well Injection

18. Deep well injections has been used principally for
liquid wastes that are difficult to treat and dispose
of by more conventional methods and for
hazardous wastes. The waste may be liquid, gases,
or solids. The gases and solids are either dissolved
in the liquid or are carried along with the liquid.

20. U.S. Federal regulations recognize 5 types of disposal wells,
each with their own particular guidelines:
1. CLASS I WELLS - used for disposal of hazardous and
non-hazardous industrial or municipal wastes.
2. CLASS II WELLS - used for injection of oil field brines
and other hydrocarbon wastes.
3. CLASS III WELLS - used for solution mining processes.
4. CLASS IV WELLS - those which historically disposed of
radioactive wastes (this is no longer done).
5. CLASS V WELLS - used for any activity not mentioned
above, such as geothermal steam mining operations.

22. Deep-well Injection -- Multiple factors must be considered when
selecting a disposal well site:
 Aquifer response to injection rates, pressures, type of waste
 The location of confining structures above and below
 Site bounded vertically and laterally by confining strata
 The location of faults, fracture zones, patterns of seismicity

23.  The location of any old conduits between aquifer layers
 Physical and chemical character of the waste
 Pretreatment of the waste may be required in order to
avoid system clogging, corrosion of well casings or other
problems
Aquifers with low pressure head, high transmissivity, and
high permeability are preferred

24.  Incineration-”Thermal treatment”, is the high temperature
reduction of wastes via combustion. Incineration can attain a 75-
95% reduction in waste mass, and can destroy hazardous pollutants
with efficiencies as high as 99.99%. A wide variety of thermal
treatments exist.
 Plasma Furnace- Used to treat hazardous wastes. Operate at
incredibly high temperatures (8,000-10,000 degrees Celsius) using
gaseous Argon, and everything is atomized. Gaseous Argon is
injected into the incinerator and then spun by a radio frequency coil
until it reaches operating temperatures. A spray of hazardous waste
is then injected via a nebulizer tube, and the combustion reaction is
allowed to occur.

27.  Drawbacks are that they can only handle small amounts of
waste at any one time, and they are time consuming (in terms
of operation and maintenance) and expensive. Plasma furnaces
are extremely effective however if they are used correctly
 Incineration of Hazardous Waste -- considered to be a waste
treatment rather than a waste disposal method.
 High-temperature incinerator system to burn toxic waste.

28. CONCLUSION:
 Although India has the most comprehensive Municipal
Solid Waste (Management and Handling) Rules, 2000,
it is just a directive on paper without any enforcement
and implementation.
 Most of the municipalities cite lack of resources to
manage solid waste while the communities feel that
they have not been involved.
 They also do not like the idea of volunteering without
any financial back-up.