Processes used after collection of solid waste.

1. SOLID WASTE
MANAGEMENT
1. What are the different processes and technologies for
solid waste management in your locality?
2. What are the different biological and chemical
technology used for Solid Waste Management?
3. Briefly describe different thermal conversion
technologies and energy recovery.
SAPTARSHI GUHA

2. Solid Waste
Management process in
Vidya Nagar Colony

3. ● Waste management are the activities and actions required to manage waste
from its inception to its final disposal. This includes the collection, transport,
treatment and disposal of waste, together with monitoring and regulation of
the waste management process.
● The different processes usually adopted in Solid Waste Management are the
following:
● Open burning
● Dumping into the sea
● Sanitary Landfills
● Incineration
● Composting
● Ploughing in fields
● Hog feeding
● Grinding and discharging into sewers
● Salvaging
● Fermentation and biological digestion

4. Sanitary Landfilling of Solid Wastes
● Simple, cheap, and effective
● A deep trench (3 to 5 m) is excavated
● Refuse is laid in layers
● Layers are compacted with some mechanical equipment and covered
with earth, leveled, and compacted
● With time, the fill would settle
● Microorganisms act on the organic matter and degrade them
● Decomposition is similar to that in composting
● Facultative bacteria hydrolyze complex organic matter into simpler
water soluble organics
● These diffuse through the soil where fungi and other bacteria convert
them to carbon dioxide and water under aerobic conditions

5. ● Aerobic methanogenic bacteria utilize the methane generated and the
rest diffuses into the atmosphere
● Too much refuse shall not be buried – fire hazard
● Moisture content – not less than 60% for good biodegradation
● Refuse depth more than 3m – danger of combustion due to
compression of bottom layers – hence should be avoided
● Refuse depth is generally limited to 2m
● Temperature in the initial stages of decomposition – as high as 70
degree C – then drops
● Reclaimed areas may be used for other uses

6. 1. Bottom of the trench is
lined with impervious
material to prevent the
leachate from
contaminating
groundwater
2. A well designed and laid
out leachate collection
mechanism is to be
provided
3. Leachate so collected is
treated and then disposed
off

7. Biological and Chemical
processes for Solid
Waste Management

8. ● By definition, biological treatment is the recycling of humus,
nutrients and/or energy from biological waste by means of aerobic
(composting) or anaerobic (digesting) processing.
Biological Process
Biological Processes:
1. Composting
2. Anaerobic Digestion of Waste

9. Composting
Composting is an aerobic method
(meaning that it requires the presence of
air) of decomposing organic solid
wastes.It can therefore be used to recycle
organic material. The process involves
decomposition of organic material into a
humus-like material, known as compost,
which is a good fertilizer for plants.
Composting requires the following three
components: human management,
aerobic conditions, development of
internal biological heat.

10. Anaerobic Digestion Of Waste
● Anaerobic digestion is a collection of processes by which microorganisms break
down biodegradable material in the absence of oxygen.The process is used for
industrial or domestic purposes to manage waste or to produce fuels. Much of the
fermentation used industrially to produce food and drink products, as well as home
fermentation, uses anaerobic digestion.
● Anaerobic digestion is used as part of the process to treat biodegradable waste and
sewage sludge. As part of an integrated waste management system, anaerobic
digestion reduces the emission of landfill gas into the atmosphere. Anaerobic
digesters can also be fed with purpose-grown energy crops, such as maize.

11. Chemical Process
Chemical methods include ion exchange, precipitation, oxidation and reduction,
and neutralization. Among thermal methods is high-temperature incineration,
which not only can detoxify certain organic wastes but also can destroy them.
Special types of thermal equipment are used for burning waste in either solid,
liquid, or sludge form.
Chemical Processes:
● Oxidation and Reduction
● Ion Exchange

12. Oxidation and Reduction
● Reduction/oxidation (Redox) reactions chemically convert hazardous
contaminants to less toxic compounds that are less mobile and/or inert.
Redox reactions involve the transfer of electrons from one compound to
another.
● One compound is oxidized (loses electrons) and one is reduced (gains
electrons). Oxidizing agents most commonly used for treatment of hazardous
contaminants are ozone, hydrogen peroxide, hypochlorite, chlorine, and
chlorine dioxide.
● The reducing agents most commonly used for treatment of hazardous waste
are ferrous sulfate, sodium bisulfite, and sodium hydrosulfite. Experimental
systems have been used to oxidize trichloroethylene (TCE) and
perchloroethylene (PCE).

13. Ion Exchange Method
● Ion exchange is a water treatment method where one or more
undesirable ionic contaminants are removed from water by exchange
with another non-objectionable, or less objectionable ionic
substance.
● Both the contaminant and the exchanged substance must be
dissolved and have the same type of electrical charge (positive or
negative).
● A typical example of ion exchange is a process called “water
softening” aiming to reduce calcium and magnesium content.
Nevertheless, ion exchange is also efficient in removing toxic metals
from water.

14. Thermal Conversion
Technology

15. Thermal Conversion Technologies
● Thermal conversion is mostly used for dry (less water content)
refuse containing a high percentage of non biodegradable waste.
Infrequently, the thermal conversion possibility is valuable for
refuse-derived fuel (RDF), an advanced calorific combustible
material.
● To produce RDF, recyclable and noncombustible materials are
removed from the MSW, followed by comminution and/or
granulation of the remaining waste. Incineration is the measured
ignition of waste at high temperature and is the most extensively
used method of the thermal conversion option.

16. ● Further thermal conversion approaches (gasification and pyrolysis)
are still in the investigation stage and they are not practicable for
commercial use in large measure, possibly due to the nonexistence
of appropriate MSW characterization information, poor feedstock
value, and inappropriate strategies for facilities.

17. THANK YOU