Solid Waste Management, Environmental Engineering, Incineration, Composting, Classification of solid waste, Waste generation, Waste Collection, Waste Storage, Hauled Container System, Stationary container system, Waste Disposal, Land filling

1. A.VENKATESH
Assistant Professor
Department of Civil Engineering
JNTU Ananthapuramu

2. SOLID WASTE:
Solid wastes are the organic and inorganic waste
materials such as product packaging, grass clippings,
furniture, clothing, bottles, kitchen refuse, paper,
appliances, paint cans, batteries, etc., produced in a
society, which do not generally carry any value to the
first user(s).

3. CLASSIFICATION
 Source-based classification
 Type-based classification

5. Source-based classification
 Residential: This refers to wastes from dwellings,
apartments, etc., and consists of leftover food,
vegetable peels, plastic, clothes, ashes, etc.
 Commercial: generated from stores, restaurants,
markets, hotels, motels, auto-repair shops, medical
facilities, etc.
 Institutional
 Municipal
 Industrial
 Agricultural

7. Type-based classification
Garbage:
This refers to animal and vegetable wastes
resulting from the handling, sale, storage, preparation,
cooking and serving of food. Garbage comprising
these wastes contains putrescible (rotting) organic
matter, which produces an obnoxious odour and
attracts rats and other vermin (which carry disease,
e.g. rodents). It, therefore, requires special attention in
storage, handling and disposal.

8. Ashes and residues:
These are substances remaining from the burning of
wood, coal, charcoal, coke and other combustible materials
for cooking and heating in houses, institutions and small
industrial establishments. When produced in large
quantities, as in power-generation plants and factories,
these are classified as industrial wastes. Ashes consist of
fine powdery residue, cinders (a small piece of partly burnt
coal or wood that has stopped giving off flames but still has
combustible matter in it) and clinker often mixed with
small pieces of metal and glass. Since ashes and residues
are almost entirely inorganic, they are valuable in landfills.

9. Combustible and Non-combustible
wastes:
These consist of wastes generated from
households, institutions, commercial activities, etc.,
excluding food wastes and other highly putrescible
material. Typically, while combustible material consists
of paper, cardboard, textile, rubber, garden trimmings,
etc., non-combustible material consists of such items
as glass, crockery, tin and aluminium cans, ferrous and
non-ferrous material and dirt.

10. Bulky wastes:
These include large household appliances such as
refrigerators, washing machines, furniture, crates (a
slatted wooden case used for transporting goods),
vehicle parts, tyres, wood, trees and branches. Since
these household wastes cannot be accommodated in
normal storage containers, they require a special
collection mechanism.

11. Street wastes:
These refer to wastes that are collected from
streets, walkways, alleys, parks and vacant plots, and
include paper, cardboard, plastics, dirt, leaves and
other vegetable matter. Littering in public places is
indeed a widespread and acute problem in many
countries including India, and a solid waste
management system must address this menace
appropriately.

12. Biodegradable and Non-biodegradable
wastes:
Biodegradable wastes mainly refer to substances
consisting of organic matter such as leftover food,
vegetable and fruit peels, paper, textile, wood, etc.,
generated from various household and industrial
activities. Because of the action of micro-organisms,
these wastes are degraded from complex to simpler
compounds. Non-biodegradable wastes consist of
inorganic and recyclable materials such as plastic, glass,
cans, metals

14. SWM system
1. Waste generation
2. Waste storage
3. Waste collection
4. Transfer and transport
5. Processing
6. Recovery and recycling
7. Waste disposal

17. Waste generation
Waste generation encompasses those activities in
which waste, be it solid or semi-solid material, no
longer has sufficient economic value for its possessor
to retain it.

19. Waste storage:
Storage is a key functional element because
collection of wastes never takes place at the source or
at the time of their generation
Waste collection:
This includes gathering of wastes and hauling
them to the location, where the collection vehicle is
emptied, which may be a transfer station (i.e.,
intermediate station where wastes from smaller
vehicles are transferred to larger ones and also
segregated), a processing plant or a disposal site.

20. Transfer and transport:
This functional element involves: the transfer of
wastes from smaller collection vehicles, where necessary to
overcome the problem of narrow access lanes, to larger
ones at transfer stations; the subsequent transport of the
wastes, usually over long distances, to disposal sites.
Processing:
Processing is required to alter the physical and
chemical characteristics of wastes for energy and resource
recovery and recycling. The important processing
techniques include compaction, thermal volume
reduction, manual separation of waste components,
incineration and composting

21. Recovery and recycling:
Recovery involves the separation of valuable
resources from the mixed solid wastes, delivered at
transfer stations or processing plants.
Waste disposal:
Disposal is the ultimate fate of all solid wastes

22. WASTE CHARACTERISTICS:
1. Physical characteristics
2. Chemical characteristics
Physical characteristics :
1. Density
2. Moisture content
Chemical characteristics:
1. Lipids
2. Carbohydrates
3. Proteins
4. Natural fibres
5. Synthetic organic material (Plastics)
6. Non-combustibles
7. Heating value

23. Density:
Density of waste, i.e., its mass per unit volume
(kg/m3) . Any normal compaction equipment can
achieve reduction in volume of wastes by 75%,
which increases an initial density of 100 kg/m3 to
400 kg/m3.

24. Moisture content:
Moisture content is defined as the ratio
of the weight of water (wet weight - dry
weight) to the total weight of the wet waste.
Moisture increases the weight of solid
wastes, and thereby, the cost of collection
and transport.

25. Lipids:
These are bio-degradable compounds includes
fats, oils and grease, and the principal sources of lipids
are garbage, cooking oils and fats. Lipids have high
heating values, about 38,000 kJ/kg. They are
biodegradable, the rate of biodegradation is relatively
slow because lipids have a low solubility in water.

26. Carbohydrates:
These are found primarily in food and yard
wastes, which encompass sugar and polymer of sugars
(e.g., starch, cellulose, etc.) with general formula
(CH2O)x. Carbohydrates are readily biodegraded to
products such as carbon dioxide, water and methane.
Decomposing carbohydrates attract flies and rats, and
therefore, should not be left exposed for long duration.

27. Proteins:
These are compounds containing carbon,
hydrogen, oxygen and nitrogen, and consist of an
organic acid with a substituted amine group (NH2).
They are mainly found in food and garden wastes. The
partial decomposition of these compounds can result
in the production of amines that have unpleasant
odours.

28. Containers/storage bins
Stationary containers: These are used for contents to
be transferred to collection vehicles at the site of
storage

29. Small-scale Collection Vehicles

30. Non-compactor trucks Trucks with capacities of 10
– 12 m3 are effective if the
distance between the
disposal site and the
collection area is less than 15
km

31. Compactor truck
Capacities of 12 – 15 m3 due to limitations
imposed by narrow roads.
the weight of solid wastes collected per trip is 2 to 2.5 times
larger since the wastes are hydraulically compacted

34. Disposal
Uncontrolled dumping or non-engineered disposal
Sanitary landfill
Composting
Incineration
Pyrolysis

35. UNCONTROLLED DUMPING OR NON-
ENGINEERED DISPOSAL:
This is the most common method being
practiced in many parts of the world, and India
is no exception. In this method, wastes are
dumped at a designated site without any
environmental control. They tend to remain
there for a long period of time, pose health risks
and cause environmental degradation.

36. SANITARY LANDFILL:
Sanitary landfill is a fully engineered disposal
option in that the selected location or wasteland is
carefully. Operators of sanitary landfills can
minimize the effects of leachate (i.e., polluted
water which flows from a landfill) and gas
production through proper site selection,
preparation and management. This particular
option of waste disposal is suitable when the land
is available at an affordable price, and adequate
workforce and technical resources are available to
operate and manage the site

37. COMPOSTING:
This is a biological process of decomposition in
which organisms, under controlled conditions of
ventilation, temperature and moisture, convert the
organic portion of solid waste into humus-like material.
If this process is carried out effectively, what we get as the
final product is a stable, odor-free soil conditioner.

38. Incineration:
This refers to the controlled
burning of wastes, at a high temperature
(roughly 1200 – 1500C), which sterilises and
stabilises the waste in addition to reducing its
volume.

39. Pyrolysis:
This is the thermal degradation of
carbonaceous material to gaseous, liquid and solid
fraction in the absence of oxygen. This occurs at a
temperature between 200 and 900C.

42. Organic matter + O2 + aerobic bacteria ----CO2 + NH3 + H2O + other end products + energy
COMPOSTING
Composting is the biochemical degradation of the organic
fraction of solid waste material having a humus-like final product
that could be used primarily for soil conditioning.
Compost is the end product of the composting process. The
by-products of this process are carbon dioxide and water. Compost is
peaty humus, dark in colour and has earthy odour, and resembles
rich topsoil.

44. Methods of Composting
Indore and
Bangalore methods of Composting.

45. Incineration:

46. Volume reduction:
Depending on its composition, incineration reduces the volume of
solid wastes to be disposed of by an average of 90%. The weight of the solid
wastes to be dealt with is reduced by 70 – 75%.
Stabilisation of waste:
Incinerator output (i.e., ash) is considerably more inert than incinerator
input

47. Recovery of energy from waste :
Energy recovered from burning the wastes is used to generate steam
for use in on-site electricity generation