Waste Management

1. Waste Management
Emerging Technology Course -I/II
Module 4
4/6/2024 1

2. Syllabus Content
WASTE PROCESSING TECHNIQUES & SOURCE REDUCTION,
PRODUCT RECOVERY & RECYCLING:
Purpose of processing, mechanical volume and size
reduction, component separation, drying and dewatering.
Source Reduction, Product Recovery and Recycling: basics,
purpose, implementation monitoring and evaluation of
source reduction, significance of recycling, planning of a
recycling programme, recycling programme elements,
commonly recycled materials and processes, a case study.
8 Hours
4/6/2024 2

3. What is waste processing?
• Waste Processing means the treatment of solid waste
after collection and before disposal.
• Operations that changes the characteristics of waste
include treatments.
• Processing includes but is not limited to volume
reduction, storage, separation, exchange, recovery of
energy and resources, physical, chemical, or biological
modification and the operations of a metal recycling or
salvage facility.
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4. Purpose of Processing
• The processing of wastes helps in achieving the
best possible benefit from every functional
element of the solid waste management (SWM).
• Improving efficiency of SWM system: Example-
Reusing of paper
• Recovering material for reuse:Materials that can
be recovered from solid wastes include paper,
cardboard, plastic, glass, ferrous metal, aluminium
and other residual metals.
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5. • Recovering conversion products and
energy:Combustible organic materials can be
converted to intermediate products and
ultimately to usable energy.
• This can be done either through incineration,
pyrolysis, composting or bio-digestion.
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Purpose of Processing

6. Mechanical Volume & Size
Reduction
• The main purpose is to reduce the volume
(amount) and size of waste, as compared to its
original form, and produce waste of uniform
size.
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7. Mechanical Volume & Size
Reduction
• Volume reduction or compaction:
-Volume reduction or compaction refers to dandifying
wastes in order to reduce their volume.
-Reduction in the quantity of materials
-Improved efficiency of collection and disposal of wastes
-Increased life of landfills
-Economically viable waste management system
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8. • Volume reduction or compaction:
Challenges:
-poor quality of recyclable materials sorted out
-difficulty in segregation or sorting
-Bio-degradable materials (e.g., leftover food, fruits
and vegetables) destroy the value of paper and
plastic material
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Mechanical Volume & Size
Reduction

9. • Equipment used for compaction
-Stationary equipment : Manual or automatic, light
duty and heavy duty applications.
Eg. steel containers, chambers, transport vehicles etc.
Movable equipment: wheeled and tracked equipment
used to place and compact solid wastes
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Mechanical Volume & Size
Reduction

10. • Vertical equipment: Used in waste generation points,
Mechanically/Hydraulically operated
• Rotary equipment: Paper/plastic bag compaction. Used in
apartments
• Bag: Multi bag and single bag
• Under counter: closed one to reduce odour
• Packers: used at collection stage
• Transfer trailer- closed one, Manuel or automatic
• Stationary low & high pressure : Helps to transfer waste
• Movable wheeled equipment: Helps in waste disposal
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Mechanical Volume & Size
Reduction

11. • Compactor
- Low pressure compactor (less than
7kg/cm^2): Waste collection in the large scale,
used in apartments and commercial buildings.
- High pressure compactor (More than
7kg/cm^2): Waste collection in various sizes
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Mechanical Volume & Size
Reduction

12. • Parameters related to compaction
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Mechanical Volume & Size
Reduction
where Vi = volume of waste before compaction, m3 and Vf = volume of waste
after compaction, m^3

13. • Selection of compaction equipment
- Characteristics like moisture content, size, composition, density etc
- Method of transferring and feeding wastes to the compactor, and handling.
- Potential uses of compacted waste materials
- Design characteristics such as the size of loading chamber, compaction
pressure, compaction ratio, etc
- Operational characteristics such reliability, noise
output, and air and water pollution control requirement.
-Site consideration, including space and height, access, noise and related
environmental limitations.
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Mechanical Volume & Size
Reduction

14. • Size reduction
- Known as shredding
- Large sized waste into smaller pieces
- It helps in landfilling, recovery, making the fuel
from the waste, and reduction of moisture.
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Mechanical Volume & Size
Reduction

15. • Equipment for size reduction
-Hammer mill
-Hydropulper
-Small grinders
-Chippers
-Large grinders
-Jaw crushers
-Rasp mills
-Shredders
-Cutters
Clippers
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Mechanical Volume & Size
Reduction

16. • Equipment for size reduction
Hammer mill
-Used most often in large commercial operations for reducing the size of wastes.
-Hammer mill is an impact device consisting of a number of hammers, fastened
flexibly to an inner disk, and rotates at a very high speed
-Solid wastes, as they enter the mill are hit by sufficient force, which crush or tear
them with a velocity so that they do not adhere to the hammers.
-Wastes are further reduced in size by being struck between
breaker plates and/or cutting bars fixed around the periphery of the inner chamber.
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Mechanical Volume & Size
Reduction

17. • Equipment for size reduction
Hammer mill
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Mechanical Volume & Size
Reduction

18. Equipment for size reduction
• Hydropulper
- Solid wastes and recycled water are added to the
hydropulper.
- The high speed cutting blades, mounted on a rotor in the
bottom of the unit, convert pulpable and friable materials
into slurry with a solid content varying from 2.5 to 3.5%.
- Metal, tins, cans and other non-pulpable or non-friable
materials are rejected from the side of the hydropulper
tank.
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Mechanical Volume & Size
Reduction

19. 4/6/2024 19
Mechanical Volume & Size
Reduction
Hydropulper

20. Waste shredders
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Mechanical Volume & Size
Reduction

21. Chippers
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Mechanical Volume & Size
Reduction
• 2,700 metric tonne of garbage collected from south Delhi every day.
• These machines are portable and suitable for being towed behind a truck
or a van
Source : Time of India

22. Jaw crushers
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Mechanical Volume & Size
Reduction
• The jaw crusher reduces the size of large
rocks by dropping them into a “V”-shaped
mouth at the top of the crusher chamber.
• This is created between one fixed rigid jaw
and a pivoting swing jaw set at acute angles
to each other.
• Compression is created by forcing the rock
against the stationary plate in the crushing
chamber

23. Rasp mills
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Mechanical Volume & Size
Reduction

24. • Addition of chemicals or changes in
temperature
• Incineration is the most common method
used to reduce the volume of waste
chemically
• Pyrolysis, Hydrolysis and Chemical conversions
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Chemical Volume Reduction

25. Components separation
• Recovery of valuable materials for recycling
• Removing certain components
(1) Air separation
(2) Magnetic separation
(3) Other separation techniques
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26. (1)Air separation
-Air separation is primarily used to separate lighter
materials from heavier.
-The lighter material may include plastics, paper and
paper products and other organic materials.
-Types: Conventional chute type, Zigzag air classifier,
Open inlet vibrator type
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Components separation

27. Conventional chute type
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Components separation
In this type, when the processed solid wastes
are dropped into the vertical
chute, the lighter material is carried by the
airflow to the top while the
heavier materials fall to the bottom of the
chute.

28. Zigzag air classifier
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Components separation
• Consists of a continuous vertical column with internal
zigzag deflectors through which air is drawn at a high
rate.
• Shredded wastes are introduced at the top of the
column at a controlled rate, and air is introduced at the
bottom of the column.
• As the wastes drop into the air stream, the lighter
fraction is fluidised and moves upward and out of
column, while the heavy fraction falls to the bottom.
• Best separation can be achieved through proper design
of the separation chamber, airflow rate and influent feed
rate.

29. Open inlet vibrator type
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Components separation
Important action/process:
Vibration: It helps to stratify the
material fed to the separator into
heavy and light components.
Inertial force:air pulled in through the
feed inlet imparts an initial acceleration
to the lighter particle, while the wastes
travel down the separator as they are
being agitated

30. Open inlet vibrator type
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Components separation
Air pressure:This action refers to the
injection of fluidising air in two or
more high velocity and low mass flow
curtains across the bed
An advantage of this classifier is that an air
lock feed mechanism is not required and
wastes are fed by gravity directly into the
separator inlet.

31. Factors to be considered for the selection of air separation
equipment
-Characteristics of material: Physical and chemical
-Methods of waste transfer
-Operational characteristics: reliability
-Site consideration: space, noise, & environmental limitations
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Components separation

32. (2) Magnetic separation
• Ferrous materials are usually recovered
• Magnetic recovery systems have also been used
at landfill disposal sites.
• Main objectives: reduction of wear and tear on
processing and separation equipment, degree of
product purity achieved and the required
recovery efficiency.
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Components separation

33. (2) Magnetic separation
Suspended magnet
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Components separation
A permanent magnet is used
to attract the ferrous metal
from the waste stream
When the attracted
metal reaches the
area, where there is
no magnetism, it falls
away freely.
This ferrous metal is
then collected in a
container.

34. (2) Magnetic separation
Magnetic Pulley
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Components separation
This consists of a drum type
device containing
permanent magnets or
electromagnets over which a
conveyor or a similar
transfer mechanism carries the
waste stream.
The conveyor belt conforms
to the rounded shape of the
magnetic drum and the magnetic
force pulls
the ferrous material away from the
falling stream of solid waste.

35. Selection of magnetic separation devices
-Characteristics of material
-Locations
-Site consideration
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Components separation

36. (3) Other separation techniques
Screening
Hand sorting
Inertial separation
Floatation
Optical sorting
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Components separation

37. Screening
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Components separation

38. (3) Other separation techniques
Screening
• Screening is the most common form of
separating solid wastes, depending on their size
by the use of one or more screening surfaces.
• Screening has a number of applications in solid
waste resource and energy recovery systems.
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Components separation

39. Screening
• Screens can be used before or after shredding
and after air separation of wastes in various
applications.
• The most commonly used screens are rotary
drum screens and various forms of vibrating
screens.
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Components separation

40. Screening
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Components separation

41. Selection of screening equipment
-Material specifications
-Location
-size
-Characteristics screen design
-Operational characteristics: energy requirements,
maintenance requirements, simplicity of operation,
reliability, noise output.
-Site considerations
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Components separation

42. Screening efficiency
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Components separation

43. Screening effectiveness
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Components separation

44. Hand sorting
• Manual removal of large sized materials
• prevent damage or stoppage of equipment
such as shredders or screens.
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Components separation

45. Inertial separation
• Gravity separation principles to separate
shredded solid wastes into light
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Components separation
Ballistic Inertial Separator

46. Inertial separation
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Components separation
Inclined Conveyor Separator

47. Flotation
• Light organic and other materials that float are
skimmed from the surface.
• Chemical adhesives (flocculants) are also used to
improve the capture of light organic and fine
inorganic materials.
• These materials are taken to landfill sites or to
incinerators for energy recovery.
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Components separation

48. Flotation
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Components separation

49. Hand sorting
• Manual removal of large sized materials
• prevent damage or stoppage of equipment
such as shredders or screens.
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Components separation

50. Optical sorting
• Optical sorting is used mostly to separate glass from
the waste stream.
• This can be accomplished by identification of the
transparent properties of glass to sort it from opaque
materials (stones, ceramics, bottle caps, corks).
• Drawback : An optical sorting machinery is, however,
complex and expensive.
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Components separation

51. Electronic Sorter
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Components separation

52. Drying & Dewatering
• Drying and dewatering operations are used primarily
for incineration systems, with or without energy
recovery systems.
• These are also used for drying of sludges in wastewater
treatment plants, prior to their incineration or
transport to land disposal.
• The purpose of drying and dewatering operation is to
remove moisture from wastes and thereby make it a
better fuel.
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53. 4/6/2024 53
Drying & Dewatering

54. Types
(i) Convection drying: In this method, hot air is in
direct contact with the wet solid waste stream.
(ii) Conduction drying: In this method, the wet solid
waste stream is in contact with a heated surface.
(iii) Radiation drying: In this method, heat is
transmitted directly to the wet solid waste stream
by radiation from the heated body.
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Drying & Dewatering

55. Counter current Direct-Heat Rotary Drum Dryer
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Drying & Dewatering
Heating the wet material
Drying the material
Heating of material to
its discharge
temperature and
evaporation of
moisture

56. Selection of drying equipment
-Properties of material
-Moisture content
-Specification of final product
-Nature of operation
-Operational characteristics
-Site considerations
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Drying & Dewatering

57. Dewatering
-Waste water treatment
-Removal of sledges
-Purpose is to reduce the liquid volume
-Methods: Centrifugation and filtering
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Drying & Dewatering

58. Source Reduction
What is source reduction?
• Source reduction, also known as waste prevention.
• Reducing waste before it is generated is a logical way to
save costs and natural resources, and preserve the local
environment.
• waste reduction cuts the municipal and commercial
costs involved in waste collection and disposal.
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59. Purpose of source reduction
• Product reuse
• Material volume reduction
• Toxicity reduction: reduces the adverse environmental
impacts
• Increased product lifetime
• Decreased consumption : reduced consumption of
materials that are not reusable
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Source Reduction

60. Implementation of source reduction
• Education and research: Schools, business
organisation, research centres etc.
• Financial incentives & disincentives: Related to
economy
• Regulations: Local and national authorities.
Quality control regulation, tax restrictions
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Source Reduction

61. Monitoring of source reduction
-To identify the possible reduction area
-Makes the operations more efficient
-Employment generation
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Source Reduction

62. Life Cycle Analysis (LCA)
• Trade-offs between source reduction, durability,
recyclability, use of recycled material and other
environmental benefits.
Evaluation
• Following factors to be considered: Social &
economic equity, administrative feasibility, 3-R
concept,
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Source Reduction

63. Significance of Recycling
• Recycling is perhaps the most widely recognised form of source reduction.
-Economic significance
-Cost reduction: Saving cost of transportation, service and production
-Employment: new opportunities
-Energy saving : Less energy consumption
-Reduce healthcare cost : Improved health and sanitary conditionsin urban
areas
-Saving costs for other public utilities
-Environmental and health significance: Improvement in health care
-Improved environment: Reducing pollution
-Natural resource conservation: Minimize the excess of production
-Social significance: Improved the standard of society
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64. Planning of Recycling programme
• Planning for recycling involves understanding markets, assessing local
expertise, setting goals and fostering public participation.
- Build local expertise: Begin with small scale project
- Understand and develop a recycling market: Market survey, market
research, market fluctuations.
- Public education & involvement: Responsibility and liabilities
- Assesses local waste stream: Knowledge of local waste stream
- Augment existing programme: Team formation, recycling program
etc.
- Set goals & objectives: Mission and vision
- Co-ordinate the program : Public service & recycling
- Evaluate the program:
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65. Recycling Programme
• Recycling programmes are designed according
to the needs and priorities of the
communities.
• Elements of a recycling programme include
source separation, curb side (kerbside)
collection, material resource facilities and full
stream processing.
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66. Source separation
• Source separation refers to the segregation of
the recyclable and reusable materials at the
point of generation.
• Source separation may be voluntary or
mandated
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Recycling Programme

67. • Drop-off/buy-back
• A drop-off programme requires residents to
separate the recyclable materials and bring them
to a specified drop-off or collection centre.
• A recycling centre can be established at the same
location where residents deliver waste.
• Mobile recycling drop-off trailers can also be
used.
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Recycling Programme

68. • Curbside programme
-Separate collection system
-Residents to separate different materials that
are stored in their own containers and collected
separately.
-Separate container for recycling items
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Recycling Programme

69. • Storage and collection of recyclables
-Collection of source-separated materials is a
necessary component of recycling programme.
-Resident convenience: Participation from residents
-Collection crew convenience: loading and sorting
activities should be as simple as possible.
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Recycling Programme

70. • Storage and collection of recyclables continued…
-Cost effectiveness
- Maximise collection crew and vehicle productivity with
minimum cost.
-Integrity of materials
-The storage and collection system should keep
recyclables in the best shape possible. It should be
properly handled, dry and contaminant free.
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Recycling Programme

71. • Collection vehicles for recycling
-Several storage bins
-Easy loading and unloading, flexible
compartments and protection from weather
-Closed vehicle container
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Recycling Programme

72. • Processing equipment for recycling
- Use the equipment like Glass crushers,
Magnetic separators, Wood grinders, Scales
(Quality of material), balers (densify many types
of materials), and Can densifiers (Can crushers
are used to densify aluminium and steel cans)
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Recycling Programme

73. • Material recovery facilities (MRF)
-MRF (pronounced ‘murf’) is a centralised facility
that receives, separates, processes and markets
recyclable material.
-MRF depends on : Market demand, Separate
collection, Quantities of materials, Number of
different recyclables, and Quantities of materials
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Recycling Programme

74. • Full stream processing
-High technology separation technique
-Refuse derived fuel (RDF) preparation:
combustible material separation
-Municipal waste composting : concentrate the
compostable portion of municipal solid waste
-Material recovery:recover and resell certain
materials
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Recycling Programme

75. • Characteristics/Tools used to separate the
materials
-Rotating screens are used to separate materials of
different sizes
-Air classifier is used to separate the lighter material
-Heavy fraction is mechanically or manually sorted
to recover saleable materials such as cardboard
-Ferrous material is extracted using a magnet system
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Recycling Programme

76. Commonly Recycled Materials and
Process
• Paper and cardboard
• Glass
• Metals
• Plastic
• Batteries and tyres
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77. Paper and cardboard
-13% of the total domestic solid waste
-Paper recycling is one of the most profitable
activities
-It reduces the demand for wood and energy
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Commonly Recycled Materials and
Process

78. Paper and cardboard
-Recovered paper is classified as newsprint,
corrugated cardboard, mixed paper (including
magazines, junk mail and cardboard), high-grade
paper (white office paper, photocopying paper),
and pulp substitute paper (usually mill scrap).
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Commonly Recycled Materials and
Process

79. • Material inputs: Paper/cardboard scrap,
magazines, newspapers, computer paper,
wrapping paper, craft sacks, cartons, etc.
• Product outputs: Paper sheets, boxes, filter
paper, mosquito mats (to absorb chemical
repellent), merchandising packets, decorative
items, etc.
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Commonly Recycled Materials and
Process

80. 4/6/2024 80
Commonly Recycled Materials and
Process
Finishing process
Fabrication process
Various machines:
Beater
Sieving screen
Cardboard making unit
Calendaring machine

81. Hand made paper
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Commonly Recycled Materials and
Process

82. Glass
• Glass is one of the most commonly recycled
materials.
• Glass generally accounts for 2.5% by weight of
the total solid waste generated.
• Recycling of broken glass reduces the risk of
diseases caused by cuts and wounds.
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Commonly Recycled Materials and
Process

83. Glass
• Glass manufacturers purchase glass for
reprocessing into new, clear, green and brown
glass jars and bottles.
• The market for recovered glass has been strong
and stable for brown and clear containers.
• Use semi mechanical process.
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Commonly Recycled Materials and
Process

84. Semi mechanical process
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Commonly Recycled Materials and
Process

85. Types of tools used for recovery of glass
• Furnace : For melting purpose , over 1400
degree Celsius
• Semi-mechanical die: Fixing die
• Air compressor: Molten glass into die
• Printing machine : Printing trademark
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Commonly Recycled Materials and
Process

86. Metals
• Ferrous metals like iron, steel, etc., and non-ferrous
metals like aluminium, copper, zinc, lead, silver, etc.,
are some of the metals.
• Metals account for 2% of total solid waste generated.
• Using recycled metals substantially reduces operating
costs of industries.
• Metal scrap is cheap and the energy consumption is
lower when products are manufactured from scrap.
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Commonly Recycled Materials and
Process

87. Metals
• Both ferrous and non-ferrous metals can be prepared
for sale through some combination of processing by
flattening, baling, and shredding of the material.
(i) Material inputs: Aluminium, brass, copper, zinc, tin,
iron, steel, etc.
(ii) Product outputs: Sanitary and gas fittings, funnels,
buckets and storage bins, reinforced steel bars, hand
tools, etc.
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Commonly Recycled Materials and
Process

88. Metal processing
• Ferrous metals are processed by iron
industries to produce iron bars, and channels,
angles
• Ingot (Pure metal pieces) extraction
• Use annealing process: Makes the metal sharp
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Commonly Recycled Materials and
Process

89. Plastics
• Average 8% by weight of the total amount of domestic
waste, plastic is one of the major constituents in waste
stream.
• Un-recycled plastic, when burned, contributes to
greenhouse gases.
• Local treatments: flattening, baling (raw or finished
material tightly bound with cord ), or granulating
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Commonly Recycled Materials and
Process

90. Plastics
• plastic-resin recycling technology :Recycling of
high-density polyethylene, low-density
polyethylene & polyethylene terephthalate.
• (i) Material input: Plastic scrap (thermoplastic
and thermosetting).
• (ii) Product output: Toys, boxes, slippers, shoes,
pellets, buckets, cans, etc.
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Commonly Recycled Materials and
Process

91. Plastic processing
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Commonly Recycled Materials and
Process
a compact mass
Small rounded piece

92. Batteries
• -Market value
-concern over the toxic compound including lead,
cadmium and mercury present in many batteries.
-Automobiles use lead acid battery, which contains lead
and sulphuric acid, both hazardous materials
-Household batteries come in a variety of types including
alkaline, carbon, zinc, silver, nickel, cadmium, etc
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Commonly Recycled Materials and
Process

93. Batteries
• Battery reprocessing includes breaking open
the batteries, neutralising the acid, chipping
the container for recycling and smelting the
lead to produce recyclable lead.
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Commonly Recycled Materials and
Process

94. Tyres
-The use of chipped or shredded tyres as a
source for fuel is growing.
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Commonly Recycled Materials and
Process

95. Case study: Source reduction and
recycling in Bangalore
• Source reduction, including reuse and recycling, can
help reduce waste disposal and handling costs, because
it avoids the costs of municipal composting, landfilling
and combustion (Meaning of source reduction).
• Source reduction also conserves resources and
• reduces pollution, including greenhouse gases that
contribute to global warming (Importance).
• Waste reduction, reuse and recycling, thus, play an
important role in SWM (Need).
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96. • In Bangalore, 66% of the waste generated is collected
for recovery, i.e., about 2,373 tonnes per day.
• While 722 tonnes per day is reused, the rest (i.e.,
1,450tonnes) goes for recycling.
• The agents involved in the collection and recovery of
wastes in the city include waste pickers, IWB (i.e.,
itinerant waste buyer), middlemen (or intermediaries),
the municipality and recycling units (both large and
small).
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Case study: Source reduction and
recycling in Bangalore

97. 4/6/2024 97
Case study: Source reduction and
recycling in Bangalore

98. • Of the 1450 tonnes collected for recycling,
1077.8 tonnes come from intermediaries, 60.4
come from IWB and 312 tonnes come from
waste pickers.
• This amounts to 40% of the total waste (i.e.,
3613 tonnes per day) generated.
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Case study: Source reduction and
recycling in Bangalore

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