This brief document describes how to convert waste into energy, particularly electricity. It is a new way of waste management. It is eco-friendly and helps fight climate change which has become a global crisis.

1. Energy generation
Energy generation
through waste
through waste
Sarah Arshad
LCWU

2. Introduction
Enhanced innovation
and technology leads
to better economic
condition and more
industrialization, i.e.
more waste is
generated
Energy demand is
rising, more burning of
fossil fuels
Why not solve both
problems
simultanously?

3. Waste sources
Food waste /
Agricultural waste
Urban or Municipal
wastes
Industrial wastes
Commercial wastes
Technologies
Current technologies
Current
technologies
Future technologies
Thermal conversion methods
(incineration, pyrolysis)
Biochemical conversion (Anaerobic
digestion, ethanol fermentation)

4. Waste devastation in the furnace
70% total waste mass, 90% volume
Creates pollution
Heat generation: 80 %
Cogeneration (Heat and steam)
Pure electricity: 20%
at 750-1100 C
: 20 - 30 %
Thermal conversion
Incineration working

5. Thermal conversion
Pyrolysis
Decomposition in the absence of
Types: Conventional, fast, flash
Products: Liquid, gases, char, water
Pollution
Benefit: Cost effective,
oxygen at 300-1300 C
environmentally friendly, high caloric value
Working

6. Biochemical conversion
Anaerobic
digestion
Decomposition of O.M by
bacteria in the absence of
oxygen
Benefit: Renewable, nutrient
recovery, waste reduction
Working:
The AD first step is broken down of MSW by bacteria, and the
complex organic species are changed into simple soluble units (i.e.,
amino acids, monosaccharides and fatty acids).
In the second phase translation of disintegrated material to
organic acids (Acidogenesis) change into simpler products, such as
volatile fatty acids (VFA), H2 and CO2.
Methanogens are the third phase of AD that converts organic
acid to CH4 gas. The CH4 gas can substitute energy resulting
from fossil fuels. Other nutrient-rich digestants are formed as a
by-product used for fertilizer.

8. Ethanol
fermentation
It is a biochemical reaction that
Feedstock: Food waste
encompasses hydrolysis of sucrose and
fermentation of sugars.
Working

9. Biological hydrogen production is the hydrogen production by biological pathways, such
as direct biophotolysis, indirect biophotolysis, photofermentation, the water–gas
transfer reaction of photosynthetic heterotrophic bacteria to synthesize hydrogen,
dark fermentation, and microbial fuel cells.
Common process: The most common process to produce Biological hydrogen is by Dark
Fermentation. During the process, the organic waste is decomposed by anaerobic
bacterias in the absence of light to produce carbohydrate rich complex compounds.
These organic polymers are hydrolyzed into sugar molecule, which undergoes a series of
chemical reactions to produce biohydrogen
Biological hydrogen conversion

10. Working

11. MICROBIAL FUEL CELL
Microbial Fuel Cells (MFCs) are bio-electrochemical devices
whose constituent electro-active bacteria harvest electrons and protons by oxidising
organic matter. Electrons travel through the anode to the cathode electrode via an
external load, and cations diffuse through a cation exchange membrane that
separates the anode with the cathode. Atmospheric oxygen in the cathode reacts
with the incoming electrons and protons to produce water. To date, the highest
volumetric power density of miniaturised MFCs reported, is 667 mW/cm3. However
this is still 1000-fold lower than that of lithium-ion batteries (7.2 107 e2.16108
W/m3, with a theoretical density of 3000 kg/m3

12. MICROBIAL FUEL CELL
Benefits: Small scale MFCs benefit from lower activation losses, and higher
substrate utilisation (mass transfer), due to a decreased diffusion resistance,
which lowers the overall internal resistance. Furthermore, shorter molecular paths
allow better diffusion of protons in the biofilm, which greatly enhances pH
buffering.

13. MICROBIAL ELECTROLYSIS CELL
Microbial electrolysis cell (MEC) is a hypothetically smart green technology to
challenge the global warming and energy demand, which works electrochemically
energetic bacteria to change MSW into H2 and chemicals, such as CH4, and
acetate, hydrogen peroxide, ethanol, and formic acid.

14. MICROBIAL ELECTROLYSIS CELL
Benefits: The MEC stage holds excessive potentials for future waste
biorefineries. MECs translate biodegradable waste into value-added energy
carriers and bioproducts, making the system probably energy-positive and carbon-
neutral. The yield and rate of MEC are promoted when integrated with the
fermentation process. Exploitation of new materials, reactor configurations, and
prices are often reduced, and system efficiency is improved. Experiments show
higher understanding of the syntrophic and competition among completely different
microorganism groups. Therefore, ways for promoting syntrophic interactions or
minimizing energy and merchandize losses are often developed for system
proportion and application

15. Conclusion
Our traditional ways of handling and managing waste are not enough to solve this global
sized massive problem. Therefore, it is the need of the hour to switch to more advanced,
efficient and sustainable practices to keep this planet pollution free.