energy from solid waste- source,types and environmental implications

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Page 1: ENERGY FROM SOLID WASTE-        SOURCE,TYPES AND ENVIRONMENTAL IMPLICATIONS
Page 2: ENERGY FROM SOLID WASTE-        SOURCE,TYPES AND ENVIRONMENTAL IMPLICATIONS

ENERGY FROM SOLID WASTE- SOURCE,TYPES ANDENVIRONMENTAL IMPLICATIONS.

Page 3: ENERGY FROM SOLID WASTE-        SOURCE,TYPES AND ENVIRONMENTAL IMPLICATIONS

INTRODUCTIONSolid waste are non-liquid, non-soluble

materials ranging from municipal garbage to industrial waste which contain complex and hazardous substances.

Population growth, Increasing urbanization, Industrialization, and standard of living have contributed to rise in both the amount and variety of waste generated in most countries.

The technology of recovering energy from solid waste

will play a significant role in mitigating issues relating to waste and will also result in reduction of overall quantity of waste.

Page 4: ENERGY FROM SOLID WASTE-        SOURCE,TYPES AND ENVIRONMENTAL IMPLICATIONS
Page 5: ENERGY FROM SOLID WASTE-        SOURCE,TYPES AND ENVIRONMENTAL IMPLICATIONS

SOURCES AND TYPES OF SOLID WASTE

Page 6: ENERGY FROM SOLID WASTE-        SOURCE,TYPES AND ENVIRONMENTAL IMPLICATIONS
Page 7: ENERGY FROM SOLID WASTE-        SOURCE,TYPES AND ENVIRONMENTAL IMPLICATIONS
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WASTE AS A RENEWABLE SOURCE OF ENERGYThe enormous increase in the quantity of waste materials generated by human activity and their potential harmful effects on the general environment and public health, have led to an increasing awareness about an urgent need to adopt scientific methods for safe disposal of wastes. 

Page 10: ENERGY FROM SOLID WASTE-        SOURCE,TYPES AND ENVIRONMENTAL IMPLICATIONS

What are conversion technologies?

Technologies used to convert solid waste into useful products, chemicals and fuels are referred as conversion technology.

Page 11: ENERGY FROM SOLID WASTE-        SOURCE,TYPES AND ENVIRONMENTAL IMPLICATIONS

WASTE-TO-ENERGY CONVERSION PATHWAYS

Various technologies are available for realizing the potential of waste as an energy source, ranging from very simple systems for disposing of dry waste to more complex technologies capable of dealing with large amounts of industrial waste.

There are three main pathways for conversion of organic waste material to energy – thermo chemical, biochemical and physicochemical.

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Page 13: ENERGY FROM SOLID WASTE-        SOURCE,TYPES AND ENVIRONMENTAL IMPLICATIONS

Thermochemical conversion

It is characterized by higher temperatures and faster conversion rates.

Best suited for lower moisture feedstock.Thermochemical routes can convert the

entire organic (carbon) portion of suitable feedstock to energy.

Inorganic fraction (ash) of a feedstock does not contribute to the energy products but may increase nutrient loading in wastewater treatment and disposal facilities.

Page 14: ENERGY FROM SOLID WASTE-        SOURCE,TYPES AND ENVIRONMENTAL IMPLICATIONS

Thermochemical conversion

It include…

Incineration

Gasification

Pyrolysis

Page 15: ENERGY FROM SOLID WASTE-        SOURCE,TYPES AND ENVIRONMENTAL IMPLICATIONS

Waste Incineration• The incineration technology is the controlled

combustion of waste with the recovery of heat to produce steam which in turn produces power through steam turbines.

• Volume and weight reduced.

• Incineration can be done at generation site .

• Air discharges can be controlled and small disposal area required.

Page 16: ENERGY FROM SOLID WASTE-        SOURCE,TYPES AND ENVIRONMENTAL IMPLICATIONS

GasificationPartial oxidation process, pure oxygen,

oxygen enriched air, hydrogen, or steam.

Produces electricity, fuels (methane, hydrogen, ethanol, synthetic diesel), and chemical products.

Temperature > 700oC.

More flexible than incineration, more technologically complex than incineration or pyrolysis, more public acceptance.

Page 17: ENERGY FROM SOLID WASTE-        SOURCE,TYPES AND ENVIRONMENTAL IMPLICATIONS

Pyrolysis

Thermal degradation of carbonaceous materials.

Lower temperature than gasification (400 – 700oC)

Absence or limited amount of oxygen.Products are pyrolitic oils and gas, solid char.Distribution of products depends on

temperaturePyrolysis oil is used for (after appropriate post-

treatment) liquid fuels, chemicals, adhesives, and other products.

A number of processes directly combust pyrolysis gases, oils, and char.

Page 18: ENERGY FROM SOLID WASTE-        SOURCE,TYPES AND ENVIRONMENTAL IMPLICATIONS

Biochemical conversion

It include …

Anaerobic digestion (occurs in controlled reactors or digesters and also in a less controlled environment in landfills)

Anaerobic fermentation (for example, the conversion of sugars from cellulose to ethanol)

Biochemical conversion proceeds at lower temperatures and lower reaction rates than other conversion processes.

Page 19: ENERGY FROM SOLID WASTE-        SOURCE,TYPES AND ENVIRONMENTAL IMPLICATIONS

Physicochemical conversion

It include … Transesterification (biodiesel production)Physical and chemical synthesis of

products from feedstockThe combustible fraction of the waste is

converted into high-energy fuel pellets which may be used in steam generation.

Fuel pellets have several distinct advantages over coal and wood because it is cleaner, free from incombustibles, has lower ash and moisture contents, is of uniform size, cost-effective, and eco-friendly.

Page 20: ENERGY FROM SOLID WASTE-        SOURCE,TYPES AND ENVIRONMENTAL IMPLICATIONS

ENVIRONMENTAL IMPLICATIONS OF

WASTE-TO-ENERGY

ADVANTAGES

Majority of waste that goes into landfills can be reused.

Always a reliable source of fuel as people will always have waste.

The fuel is obtained cheaply.

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DISADVANTAGES

Public is not convinced that Waste to Energy facilities are clean and free of harmful chemicals.

Waste to Energy facilities are expensive to construct.

Air Pollution from combustion process.

Possibility of toxic ash as a byproduct and it may leach into groundwater and make it impure.

Page 22: ENERGY FROM SOLID WASTE-        SOURCE,TYPES AND ENVIRONMENTAL IMPLICATIONS

Waste-to-energy plants offer benefits of environmentally safe waste management and disposal, as well as the generation of clean electric power.  Waste-to-energy facilities produce clean, renewable energy through thermo chemical, biochemical and physicochemical methods.

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