Introduction on

solid waste management

Mentore Vaccari, Francesco Vitali

CeTAmb, UNIVERSITY OF BRESCIA

 What is waste?
2

Exercise:
Give your own definition of waste
 What is waste?
3

An item is viewed as waste as soon as it has become worthless to the

initial owner.

According to Directive 2006/12/EC on waste:

"waste" shall mean any substance or object … which the holder discards
or intends or is required to discard
 What is municipal solid waste?
4

All those wastes which are neither liquid (ie. wastewater discharges)
nor gaseous (i.e. atmospheric emissions)

Refers to solid wastes from houses, streets and public places, shops,
offices, and hospitals, which are very often the responsibility of
municipal or other governmental authorities. Solid waste from in-
dustrial processes are generally not considered "municipal" however
they need to be taken into account when dealing with solid waste as
they often end up in the municipal solid waste stream.
 What is municipal solid waste?
5

Classification by source

Household garbage
Also referred to as residential refuse or domestic waste, this
category comprises wastes that are the consequence of
household activities.

food preparation, sweeping,

cleaning, gardening wastes, old
clothing, oldExamples?
furnishings, packaging
and reading matter, faecal material
(where bucket latrines are used). Residential waste:
0.3 -0.6 kg/cap/day
 What is municipal solid waste?
6

Classification by source

Commercial waste
from stores, markets, offices, restaurants and hotels. The wastes typically consist
of packaging and container materials, used office supplies, and food wastes.

Commercial waste:
0.1 -0.2 kg/cap/day
 What is municipal solid waste?
7

Classification by source

Institutional waste
from schools, government offices,
hospitals, police and religious
buildings are included in this category.

This category generally involves

a large portion of paper rather
than food. Institutional waste:
0.05 -0.2 kg/cap/day
 What is municipal solid waste?
8

Classification by source

Street sweeping

this category always includes dirt and

litter. However it may also contain
appreciable amounts of household
refuse, drain cleanings, human faecal
matter and animal manure.

Street sweeping:
0.05 -0.2 kg/cap/day
 Other categories of waste
9

Classification by source

Health care waste Construction and

demolition debris

Sanitation residues Industrial waste

 Health care waste
10

All the waste generated by health-care establishments, research

facilities and laboratories. In addition, it includes the waste
originating from “minor” or “scattered” sources.
(WHO, 1999)

Hazardous health-care waste:

75 - 90% of general waste (similar to domestic waste)
10 - 25% is hazardous (infectious, chemical, sharps, etc.)
 Construction and demolition debris
11

Construction and demolition (C&D) debris

consists of the materials generated during
the construction, renovation, and
demolition of buildings, roads, and bridges.
C&D debris often contains bulky, heavy
materials that include:
• concrete,
• wood,
• asphalt,
• gypsum,
• metals,
• bricks,
• glass,
• plastics,
• salvaged building components (doors,
windows, etc.)
• trees, earth, rock, etc. from clearing sites.
 Sanitation residues
12

Where sewerage is not the major means of managing

human excreta and sludge, there are sanitation residues
from latrines.

Because night soil is commonly

collected at night, there is little
supervision of the workers. Being
unaccountable, these workers have a
strong tendency to dump the night
soil in the closest possible
inconspicuous location relative to
their collection service area.
 Industrial waste
13

Industrial wastes come from processing and non-processing

industries, as well as utilities: packaging materials, food wastes,
spoiled metal, plastic and textiles, fuel burning residuals, and spent
processing chemicals are among the wastes within this category.

The composition is site-

specific, and depends on
the natural resources and
markets which provide
the base for a given city's
industrial activity.
 Nature of waste
14

It encompasses the ways in which one can describe,

quantify and characterise waste. Inlcudes:

Generation rates Density

Composition Moisture content

 Nature of waste
15

What does the nature of waste affect?

POTENTIAL FOR
RECOVERY
STORAGE

COLLECTION
EQUIPMENT AND
WORKFORCE
METHOD AND SANITARY AND
FREQUENCY OF ENVIRONMENTAL
COLLECTION IMPACT
 Nature of waste
16

Generation rates

They describe how quickly a certain quantity of waste is generated. It is

usually defined as the average amount of waste generated by one person
in one day.
Ghana
 Nature of waste
17

Density

It is the mass of an object made of that material divided by its volume

(kg/m3).
 Nature of waste
18

Composition

Solid waste is a heterogeneous material, composed of many different

substances. A composition analysis of waste describes the proportion of
different substances that make up the waste.
 Nature of waste
19

Waste composition in Juba’s different quarters (2010 assessment)

Waste fraction Hai Amarat Gudele Kator Munuki Tong Ping

Vegetable/putresci 0.0% 12.2% 5.1% 0.0% 18.5%

bile matter
Paper 10.2% 21.4% 13.5% 13.9% 13.5%

Textiles 4.8% 0.0% 0.0% 0.0% 1.1%

Plastics 21.0% 18.5% 18.4% 12.4% 14.2%

Grass/leaves/wood 25.2% 18.5% 20.3% 27.0% 19.0%

Leather/rubber 0.0% 0.0% 0.0% 0.0% 1.7%
Metals 17.7% 5.5% 8.2% 11.3% 3.3%

Glass/ceramic 11.9% 4.6% 9.0% 13.7% 11.4%

Miscellaneous 9.2% 19.2% 25.5% 21.8% 17.5%

TOTAL 100.0% 100.0% 100.0% 100.0% 100.0%

 Nature of waste
20

Moisture content

It is a measure of the amount of water in the waste. It is usually

expressed as the percentage of the weight of water in a substance
compared to its total wet weight.

It is largely
influenced by the
waste
composition.
 Generation & Composition
Nature of waste
21

Low- Middle- High-

(at collection point) Income Income Income
Countries Countries+ Countries
*
Waste generated 0.4 - 0.6 0.5 - 0.9 0.7 - 1.8
kg/cap. & day CH = 1.1
Waste density 250 - 500 170 - 330 100 - 170
kg/m3
Water content 40 - 80 40 - 60 20 - 30
%
Composition
Organic 40 - 85 20 - 65 20 - 50
CH = 22
Paper, Cardboard 1- 10 15 - 40 15 - 40
(21)
Glass & ceramics 1 - 10 1 - 10 4 - 10
(3)
Metal 1-5 1-5 3 - 13
(6)
Plastics 1-5 2-6 2 - 13
(13)
Dust & ash 1 - 40 1 - 30 1 - 20
(5)
* Countries with GDP < US$ 360 per year per capita; + Countries with GDP > US$ 360, < US$ 3’500 per year per capita
source: Cointreau (1982) and BUWAL (1994)
Nature of waste
22
 Waste production in the world
23

30

25
Solid Waste Generation

+1,5% per year

(billion tons / year)

Africa
20

15
Northern
America
10
Europe
5
Asia

2000 2005 2010 2015 2020 2025 2030 2035 2040 2045 2050

12.5 billion tons / year in 2000 Over 25 billion tons / year in 2050

Source: Visvanathan, 2008

 Effects of inadequate municipal SWM
24

Health risk for the population, due to:

• proliferation of disease carrying vectors (rats, mosquitoes,
flies, etc.)
• direct contact with waste (children + waste pickers)
• air pollution through burning
• odours
• blocking of drains and flooding
• visual pollution
Health risk for workers
Water and soil pollution
Waste & health
25
 Waste & health
26

Demographic and Health Surveys data show significant increases in the

incidence of sickness among children living in households where
garbage is dumped, or burned, in the yard. Typical examples include
twice as high diarrhoea rates and six times higher prevalence of acute
respiratory infections, compared to the areas where waste is collected
regularly.

Uncollected solid waste clogs drains and causes flooding and subsequent
spread of water-borne diseases. Blocked storm drains and pools of stagnant
water provide breeding and feeding grounds for mosquitoes, flies and
rodents. Collectively, these can cause diarrhoea, malaria, parasitic
infections.

Fonte: UN-Habitat (2009), Solid Waste Management in the World’s Cities

 Waste & health
27

Effects on community living next to MSW disposal

Hazardous waste present a mixture of potential hazards, which include chemical, physical and
biological hazards. The short-term human health effects that have been investigated in relation to
residential proximity to hazardous waste sites, include reproductive effects and developmental
effects in children. Studies have suggested that there may be an association between these outcomes
and exposures to the emissions from toxic disposal sites. Long-term effects, such as cancer, have
also been looked at, and some positive correlation has been found.
Another important human health effect is the psychological impact that proximity to these sites have
on communities. These include elevated levels of anxiety, insomnia, depression, headaches and
nausea.
Municipal solid waste disposal sites also present a mixture of physical, chemical and biological hazards.
Physical hazards manifest themselves in injuries such as strains, sprains, lacerations, amputations,
contusions, and even, death; these physical exposures are primarily seen among solid waste workers,
rather than surrounding communities. However, chemical and biological hazards are associated with the
inappropriate disposal of the waste itself and with emissions from the sites. These hazards have
been found to be associated with both acute and chronic human health effects in solid waste workers.
These health effects include dermatological; respiratory; cardiovascular; gastrointestinal and
neurologic effects.

Fonte: Englehardt et al. (2000), Solid Waste Management Health and Safety Risks: Epidemiology and
Assessment to Support Risk Reduction
 Integrated solid waste management
28

Goal of integrated municipal solid waste management

 interventions to provide a hygienic environment,

 to involve policies, facilities, services, and behaviour

so that:
 people can lead healthy and productive lives
 the natural environment is protected and enhanced

Integration across various disciplines is

necessary!
 Integrated solid waste management
29

Waste management hyerarchy

 Integrated solid waste management
30

Goals:
to protect environmental health
to promote the quality of the urban environment
to support the efficiency and productivity of the
economy
to generate employment and income

Principles:
• minimise waste generation
• maximise waste recycling and reuse
• ensure the safe and environmentally correct disposal of
waste
 Integrated solid waste management
31

Key aspects

Careful analysis of the problem

Entitlement of weakest groups of population

Waste seen as a resource

Involvement of all the stakeholders

Finanacial sustainability

Integration with other infrastructures

 MSW management
32

Based on four steps:

1. Waste storage at or near the point of generation

2. Collection of waste

3. Waste treatment/recycling

4. Disposal of waste
Solid waste flow
33
 Storage at the source
34

Two types of storage

1. separate (i.e. household) storage units
2. communal storage units

Separate (i.e. household) storage units:

- non-standardised (by the collection agency) containers:
- temporary containers, such as cardboard cartons, plastic bags,
etc.
- permanent containers, such as plastic or metal bins
- standardised (by the collection agency) containers:
- usually permanent containers
- relatively valuable items, attractive to thieves and for
alternative uses such as food and water storage
 Storage at the source
35

Communal storage units:

- stationary units:
- open depots
- three sided masonry units
- four sided masonry units with door opening and no roof

- portable units:
- large steel drums
- liftable metal containers (for use with trucks equipped
with hydraulic lifts)
- wood or metal trailers (for use with tractor)
-roll-on metal containers (for use with trailer truck bodies)
 Storage at the source
36

Generally, none of stationary units is recommendable, because of:

- scavenging activities of animals
- breeding of flies and other vectors is not limited
- manual labour is required for removal of the waste

Portable units:
- are suitable for large buildings as well as densely populated areas
- allow the transport unit to be used efficiently (transport of full
containers to the disposal site)
but
- are difficult to be sized and placed
 Collection techniques
37
Three basic types of collection techniques:

1. Human powered collection equipments

- pushcarts, wheel barrows, two-wheeled dollies with baskets
- useful in neighbourhoods with limited access
- good ways are necessary for this type of equipment to be effective

2. Animal powered collection equipment

- horse, mule or oxen-drawn carts
- applicable in cities with mainly low-moving traffic

3. Motorised collection vehicles

- tractors with trailers
- trucks which lift portable containers
- payloaders in concert with tipper trucks
 Transfer station
38
Waste collected from an area may be:
- directly hauled to a disposal site by the collection equipment
- transferred to another size or type of equipment for hauling

Transfer stations:
- not only places where waste is passed from one form of transport to
another, in order to optimize productivity of the collection equipment and
crew

but

- places where the waste can be compacted, processed, or separated and

recycled

By means of these activities, the quantity of waste requiring ultimate

disposal can be greatly reduced
 Waste recycling
39
Main recyclable materials:
Organic matter → composting
Plastic → plastic production, combustible
Paper → paper production, combustible
Metals → metals production, others
Glass → glass production

Recycling is common at the household: the primary generator recycles

materials for direct use

It can be carried on also:

- at the communal storage
- during collection

Recyclables can be sold if there is a favourable market

 Waste disposal
40

Incineration is not appropriate

- excessive costs
- complicate technology

Landfill is the alternative way

but

It has to be designed, realized and managed properly

in order to reduce its environmental impact
 MSWM improvement: necessary data
41

Referring to technical aspects, the following information have to be

acquired in order to define the most appropriate SWM system:

Existence of regulations concerning SWM and protection of soil, water

and air
Existence and characteristics of urban planning activities
Number of inhabitants and their distribution on the territory
Type/number of households and their distribution on the territory;
Population density in homogeneous areas
Number, type and dimension of no-households waste generators:
commercials, industries, schools, public and private offices, etc.
Waste quantity produced by different sources (households, industry,
commercial, street sweeping, etc…)
 MSWM improvement: necessary data
42

• Waste composition (in terms of paper, organic matter, plastic, etc.)

• Waste density
Existing plants and treatment facilities
Existing equipments and maintenance conditions
Characteristics of road system
Reports about previous or current projects dealing with solid waste
management and urban planning
Climatic, morphologic, hydrologic, geologic, hydrogeologic
characteristics of the area
Investment, operating and maintenance costs for plants,
equipments, facilities, etc..
Labour cost