SWM L1-L14_drhasan (Part 1).pdf

Solid and Hazardous Waste
Management
Lecture prepared by
‘Dr. Hasanliketo beliefthat solidwasteisa valuableraw
materialslocatedat a wrongplace’
Md. Mahmudul HASAN, Engr., PhD
Associate Professor and Head
Dept. of Civil Engg.
BAUST, Saidpur
(Former: Assistant Prof., Dept. of Civil Engg., UAP
Head & Assistant Prof., Dept. of Civil Engg., UITS)

Course Code: CE 4241
Corse Title: Environmental Engineering III
(Solid Waste Management)
Credit Hour: 2.0
Contact Hour: 120 min/ week (2 classes per week)
Dr. Engr. Md. Mahmudul HASAN
Course Information:
2

Reference Books
3

Reference Books
4

1. Introduction to Solid Waste Management (Chapter 1)
2. Sources, Types & Characteristics of Solid Wastes (Chapter 2)
3. Physical and Chemical Properties of Solid Wastes (Chapter 2)
4. Solid Wastes Generation (Chapter 2)
5. On-site Handling, Storage, Processing and Collection of Solid
Wastes (Chapter 3, 4)
6. Transfer Stations and Transport (Chapter 4)
7. Ultimate Disposal of Solid Wastes (Chapter 6, 7, 8, 9)
8. Resources and Energy Recovery (Chapter 5)
9. Soil Pollution
10. Industrial Solid Waste Collection and Disposal
11. Hazardous Waste Management (Chapter 10)
Course Outline:
5

Learning Outcomes (LO):
Upon completion of the course, the students will be able to:
1. Analyze different categories of solid waste with specific management
practices.
2. Design different collection systems with optimizing routes, time, cost
and resource recovery (energy and materials).
3. Conceptualize different strategies with implementation of source
reduction, on-site handling, treatment, re-use and recycling options of
solid waste.
6

Learning Outcomes (LO):
7
Attendance:
• No marks allocation
• 70% class attendance is mandatory to appear at the final examination.
Required References:
• Supplied class notes.
• Solid Waste and Hazardous Waste Management
by M. Habibur Rahman and Abdullah Al-Muyeed.
• Handbook of Solid Waste Management
by George Tchobanoglous, Frank Kreith and Marcia E. Williams.
Assessment
Method
Marks
Mark distributions on LOs and POs
Total
LO1 LO2 LO3
PO2 PO3 PO6
Test 1
20
10
Test 2 10
Assignment 10 10
Midterm exam 20 10 10 0
Final exam 50 10 10 30
Total 100 30 30 40 100

Chapter 01:
Introduction to solid waste and its
management

What is Solid Waste:
Solid waste is an inevitable by-product arising from anthropogenic and animals activities
(production and consumption) that are normally solid and that are discarded as useless or
unwanted.
It represents the loss of materials and/or energy for which the generator of the waste has
paid.
It includes solid and semi-solid materials generated from domestic, commercial and
industrial premises or processes including municipal services, water and wastewater
treatment plants, air pollution control devices, mining, and agricultural operation.
US, EPA defines solid waste as,
"any discarded, rejected, abandoned,
unwanted or surplus matter, whether or
not intended for sale or for recycling,
reprocessing, recovery or purification by
a separate operation from that which
produced the matter; or anything
declared by regulation or by an
environment protection policy to be
waste"
9

The nature and abundance of solid waste in different countries depends on:
o geographic location (region),
o climate,
o degree of industrialisation,
o available resources,
o socio-economic conditions,
o religious custom, lifestyle and behavior of consumers,
o and also on the season of the year.
Increasing population, industrialization, urbanization, economic growth and improved
standard of living has resulted increase in solid waste generation. Management of these
huge quantities of municipal solid waste has become a serious concern for
government departments, environmental protection agencies and regulatory bodies. If the
waste is not properly managed, the time is not far when our planet will be filled with waste.
Besides, waste contains materials that can be recovered; reused and recycled conserving
resources; and land required for the disposal.
According World Bank, Around the world, waste generation rates are rising. In 2012, the
worlds’ cities generated 1.3 billion tonnes of solid waste per year, amounting to a footprint of
1.2 kilograms per person per day. With rapid population growth and urbanization, municipal
waste generation is expected to rise to 2.2 billion tonnes by 2025.
1

Figure: Schematic Illustration of the
EU Legal Definition of Solid Waste
Solid
Waste
Solid
Waste
1

1

SWM may be defined as the discipline associated with the control, generation,
storage, collection, transfer and transport, processing and disposal of solid waste.
That is accord with the best principles of public health, economics, engineering,
conservation, aesthetics and that is also responsive to public attitudes.
If solid waste management is to be accomplished in an efficient manner, the
functional aspects and relationships involved must be identified and understood
clearly.
What is Solid Waste Management (SWM)?
13

Effects of poor management of solid waste
o Traditionally, health and safety have been the major concerns in the management of solid
waste with eventual effective disposal.
o However, the solid waste management system should consider both short- and long-term
effects on the environment (conservation of resources and prevention of pollution),
o and the system should be reliable and environmentally compatible.
o The following table summarizes the risk/ effects associated with improper management of
solid waste:
Breeding ground for disease
carriers
Rats, flies, mosquitoes, cockroaches, pigs, birds and other disease vectors breed in
open dumps, waste storage facilities, piles of rotten refuse, etc.
Spread of disease by animals
and other vectors, and food
Above vectors transmit diseases and pathogenic bacteria from waste to the
households; consumption of meat from animals eating infected waste.
Spread of diseases by direct
contact
Neighbourhoods, waste workers, scavengers in developing countries are in direct
contact with waste (in case of organised handling, there is a risk of accident).
People using recycled materials are also in direct contact with infected materials
(not or poorly disinfected). It has beed traced the relationship of 22 human
diseases to inadequate solid waste management like Diarrhoea, dysentery, cholera,
typhoid, salmonellosis, plague etc.
Air pollution Fine grained materials, pathogens, decomposition of waste generating greenhouse
gases and other gases, dust and smoke from burning, etc. cause pollution at
transfer stations, communal bins, dumping sites.
Soil pollution The mismanagement of solid waste also affects the productivity of soils (due to
dumping of unwanted materials)
14

o Table continued:
Contaminated water Leachate and precipitation (may contain metals, organic pollutants, hazardous
substance, etc.) from waste piles and open or inadequately protected disposal sites
contaminate surface and ground water.
Fire risk Piles of waste and gas generated by these present a fire risk.
Connection to other services Blockage of drains and sewers increase workloads to those services.
Environmental pollution Overall environmental degradation due to contamination of air, water and soil
environment via gaseous emission, particulate matter, ash, leachate, piles of
unwanted materials, etc.
Financial effects The management of solid waste absorbs a huge amount of the municipal budget,
and the cost of public cleansing, transportation, and transfer is much higher in low-
and middle-income countries compared with that of industrialised countries. The
optimisation of productivity of collection vehicles and workers involved in public
cleansing and collection services can improve the situation to achieve greater
efficiency and cutting the cost of solid waste management systems. There is also
indirect financial loss involving the costs associated with the environmental
damage.
Effects of poor management of solid waste
15

Functional elements of S. waste management
Functional elements of
waste management
system
16

Waste Generation:
On-site handling, storage and Processing:
17

Primary Collection:
Transfer Station and Secondary collection:
18

Disposal
19

Stages of S. waste management
20

What is Integrated Solid Waste Management (ISWM)?
The Integrated Solid Waste Management should be based on a logical hierarchy (an order
from most preferred to least preferred) of actions.
Its operation should be based on local resources, economics and environmental impacts
and
it should be market-oriented (the market for recycled products and recovered energy is
always sensitive to quality, quantity and price)
and
It should be flexible (the demand of recycled and recovered materials as well as the need for
different treatment methods is likely to change over time, which demands flexibility in the
design of the scheme).
The ISWM aims to manage the solid waste in an
environmentally and economically sustainable
way having twin goals:
(i) To recover maximum possible amount of
reusable materials and energy from the solid
waste stream through best available practices.
(ii) To avoid releasing the energy or matter into
the environment as a pollutant.
21

Rational steps in Integrated Solid Waste Management
22

4Rs in Integrated Solid Waste Management
Reduction of S. Waste:
o The highest priority option in ISWM hierarchy.
o means to avoid or reduce the solid waste generation at the source.
o It involves reducing the amount and/or toxicity of the waste generated.
o Waste reduction may occur through the designing, manufacturing, and packaging of products with minimum toxic content,
minimum volume of material, or a longer useful life. Waste reduction may also occur at the household, commercial, or
industrial facility through selective buying patterns and the reuse of products and materials.
Reusing of S. Waste:
o Municipal solid waste generation could be reduced through reusing the items that are no longer required by someone.
o Most of our daily use products are reusable. For example, plastic bags obtained from the market are often used to pack
the household waste and transport it from the house to the waste bin. Newspapers are rolled up to make fireplace logs,
and coffee cans are used to hold bolts and screws. All of these are examples of reuse.
o Reusing is thus about extending the life or giving a second life to something that we previously considered as "garbage".
In this way, the garbage we are sending to the landfill sites will be reduced and the operational life span of the landfill site
will extend.
Recycling of S. Waste:
o The third option in the ISWM hierarchy is recycling, which involves (1) the separation and collection of waste materials; (2)
the preparation of these materials for reuse, reprocessing, and remanufacture; and (3) the reuse, reprocessing, and
remanufacture of these materials.
o Recycling is an important factor in helping to reduce the demand of resources and the amount of waste requiring disposal
by landfilling.
Resource Recovery from S. Waste:
o The fourth option in the ISWM hierarchy, resource recovery (waste transformation), involves the physical, chemical, or
biological alteration of waste.
o The transformation of waste materials usually results in the reduced use of landfill capacity.
o The reduction in waste volume through combustion is a well-known example.
What is meant by '4R' in SWM or ISWM?
23

Sustainability of Solid Waste Management (SSWM)
In the realm of waste management, sustainability can be defined as a means of
using a mix of solid waste management approaches such that it does not have any
significant diverse and delayed environmental impacts to threaten long-term
ecological sustainability.
It stresses the environmentally sound management of today’s waste to minimise
depletion and permanent damage of earth’s natural resources so as not to sacrifice
the capability of the next generation to achieve their future demands of waste
management.
To develop sustainable waste management systems, considerable attention has to
be paid, in addition to the activities outlined for Integrated Solid Waste Management:
o Integration of national and international actions/policies
o Development of legislation, and enforcement
o Control of transboundary waste movements
o Improving management capabilities
o Financing waste management (Pay-as-you-throw programmes)
o Involvement of responsible stakeholders
24

LCA of Solid Waste Management
Life cycle assessment (LCA)– also referred to as life cycle analysis or life cycle
Management
It is an appropriate environmental management tool to measure both environmental
and economic sustainability individually or together. In many situations, this tool is
applied to predict and compare the environmental impact only, and then economic life
cycle analysis is made separately.
In solid waste management, the life cycle impact assessment (LCIA) covers all steps
of the flow cycle:
o generation,
o reuse,
o separation,
o recycling,
o collection,
o treatment
o final disposal.
Life cycle assessment consists of four stages:
o goal (the scope) definition
o life cycle inventory (LCI) analysis
o life cycle impact assessment
o life cycle interpretation. 25

LCA of Solid Waste Management
Four stages of Life cycle assessment:
1. goal (the scope) definition
2. life cycle inventory (LCI) analysis
3. life cycle impact assessment
4. life cycle interpretation.
26

FCA of Solid Waste Management
Full-Cost Accounting (FCA)
It generally focuses on the three major types of measurable costs in solid waste
management –
o up-front,
o operating
o back-end costs
and these three categories together cover the ‘life cycle’ of municipal solid waste
activities from ‘cradle’ (up-front costs) to ‘grave’ (back-end costs).
FCA can also accommodate other costs such as remediation costs at inactive
sites, contingent costs, environmental and social costs, but require special
consideration as some of these costs are not easily quantifiable.
27

Solid Waste Management: Bangladesh policies
Apart from Environment Conservation Rules 1997, to improve the waste disposal
system the Government has recently formulated some policies and plans:
1. National Environmental Management Action Plan (NEMAP) (1995–2005)
2. Urban Management Policy Statement 1998
3. National Policy for Water Supply and Sanitation 1998
4. National Clean Development Mechanism (CDM) Strategy 2004
28

Definitions
Front-end waste reduction:
Reduce or eliminate the hazards of pollutants before discharging from source of
generation.
Back-end waste reduction:
Reduce or eliminate the hazards of pollutants before discharging from a
treatment/disposal option.
29

Chapter 02:
Source, Types, Generation and Properties
of Solid Waste

Biodegradable materials:
o are materials that are degraded easily by microorganisms (either aerobic or
anaerobic), into their basic elements. Most organic solid wastes are biodegradable.
Putrescible materials:
o generally comprise food waste (materials originating from the preparation and
consumption of foods), papers, paperboard, garden waste and similar materials
which decompose rapidly, particularly in warm weather, and often develop
objectionable odours.
o This category accounts for more than 55 per cent of total municipal solid waste
(MSW) in industrialised countries and as high as 90 per cent of total MSW in
developing countries.
o The quantities of putrescible materials are high in developing countries compared to
the quantities in industrialised countries.
o Another prominent difference is that the putrescible fractions of solid waste contain a
higher percentage of paper in industrialised countries than that in developing
countries.
o The mismanagement of this putrescible fraction of solid waste, particularly in
developing countries, poses a serious health hazard as it attracts disease carriers
which may endanger the human population.
Types of waste material
31

Non-putrescible materials
o decompose very slowly. Plastic, polythene bags, bottles, cans, containers and old
machines are classed under this category.
Refuse describes
o all putrescible or non-putrescible waste material that is discarded or rejected
including, but not limited to, garbage, rubbish, incinerator residue, street cleaning,
dead animals.
Leachate
o comprises liquids seeping from solid waste as it degrades and decomposes. It
generally contains decomposed waste, water and microorganisms. In landfills, it
percolates through soils, causing surface and groundwater pollution.
Types of waste material
32

1. Household
2. Commercial
3. Institutional
4. Civic Amenity
5. Treatment Plants
6. Construction
7. Sanitation
8. Mining
9. Industrial
10.Agricultural
11.Healthcare
12.Hazardous
Categories of solid waste
Municipal
Solid Waste
(MSW)
33

Composition of solid waste
Depends on:
o Socio-economic conditions
o Cultural and religious habits of the people
o Availability of resources
o Geographic location
o Season of the year
o Climatic condition
Important to know to select:
o types of storage
o types of collection
o frequency of collection
o potential for resource recovery
o choice of method of disposal.
34

Generation or Quantity of solid waste
Generation of solid wastes is a diffused process and takes place in every nook and corner of the
society.
The prominent sectors include residential , commercial , industrial and agricultural areas.
Generally the quantities generated are calculated on the basis of generation per capita per day
basis.
Solid waste generation i.e. quantity depends on:
o Status of development of a country
o Socio-economic conditions
o Culture and religious habits of people
o Availability of resources
o Geographic location
o Season of year
o Attitude of waste generators and/or manufacturers
o Availability and enforcement of laws to regulate waste, and promote
o Recycling and resource recovery
o Level of technological advancement.
Important to know:
o Knowledge of generation rates or quantity of solid waste is very important as it report
regrading the total amount of waste to be managed.
o And also for designing effective management methods for solid waste i.e. to identify
appropriate types of collection, waste collection routes and vehicles, material recycling
and recovery facilities, and waste treatment and/or disposal facilities. 35

Expression for Unit Generation Rate or solid waste quantity:
Solid waste quantities should be expressed in terms of weight.
Weight is the only accurate basis for records because tonnages can be measured directly,
regardless of the degree of compaction.
The use of weight records is also important in the transport of solid wastes because the quantity
that can be hauled is restricted by highway weight limits rather than by volume.
The general expression is:
o Residential areas waste: kg per capita per day
o Industrial waste: kg/repeatable unit of production, e.g., kg per automobile.
o Agricultural waste: kg/ton of raw product
36

Methods Used to Determine Generation Rate:
Most solid waste generation rates, reported in the literature are actually collection rates and
not generation rates. This is because many factors affect collecting all generated waste
data.
Commonly used methods are:
(i) Load count analysis (In this method, the number of individual loads is counted)
(ii) Material balances analysis (In this method, a detailed material balance analysis
for each generation source, such as an individual home or a commercial and
industrial activity is made).
(iii) Sampling from representative generation units (In this method representative
houses, shops etc are selected and sampling made for a definite period, which
may be one week, one month or one year).
37

Solution:
Assume 6 persons in a household.
Therefore total persons=1660*6= 9600
Total Solid waste generation in a week
= (10*20*170) + (10*70*1.5) + (20*0.3*50)
= 35350 kg
Unit rate of generation = 35350/9600
= 3.682 kg/cap/wk
= 0.53 kg per capita
per day
Load count analysis
38

Material balance analysis:
o As compared to load count analysis, this method gives relatively accurate value of generation rates.
o However, high expenses and large amount of work is involved as compared to load count analysis.
o This method should be used only in special circumstances. Under majority of situations, load count
analysis will serve the purpose.
o In this method, a detailed material balance analysis for each generation source, such as an individual
home or a commercial and industrial activity is made.
o Following steps can be followed for material balance analysis. These steps are also pictorially presented
in Fig:
i. Draw a system boundary around the unit to be studied.
ii. Identify all activities that cross or occur within the boundary and affect generation rate.
iii. Give generation rate in each activity.
iv. Determine the quantities of waste generated, collected and stored by using a material balance.
Fig: Material balance analysis sketch
39

Material balance analysis: Problem
Figure 2.5: Materials balance
flow diagram sketch
40

Sampling from representative generation units:
A number of houses were selected in different areas of Dhaka showing the poor middle
and rich population of the city. Calculate the waste generation rate.
1 Gulshan High 21 4 10 69.3
2 Lalmatia Middle 40 5 10 56
3 Mirpur Middle 50 5 12 126
4 Moham
madpur
Middle 45 5 8 97
5 Jatrabari Poor 46 6 10 79
6 Jurain Poor 65 6 10 71.5
41

Sampling from representative generation units:
1 Gulshan High 21 4 10 69.3 0.33
2 Lalmatia Middle 40 5 10 56 0.14
3 Mirpur Middle 50 5 12 126 0.21
4 Moham
madpur
Middle 45 5 8 97 0.27
5 Jatrabari Poor 46 6 10 79 0.17
6 Jurain Poor 65 6 10 71.5 0.11
Solution:
The generation thus obtained was 0.21 kg/capita/day
=69.3/21/10
=0.21 kg/capita/day
Average
=(0.33+0.14+0.21+0.27+0.17+0.11)/6
42

Properties of solid waste
Properties of S. Waste:
o Physical
i. Specific Weight (Density)
ii. Moisture Content
iii. Particle Size and Distribution
iv. Permeability of Compacted Waste
o Mechanical
i. Field capacity
ii. Strength Parameters
o Chemical
I. Proximate Analysis
II. Fusing Point of ash
III. Ultimate Analysis (major components)
IV. Energy Contents
o Biological
43

Physical Properties of solid waste
i. Specific Weight or Density:
It is the mass occupied by a unit volume of material i.e. it is defined as the weight of a material per unit
volume (e.g. kg/m3, lb/ft3)
Example - Food wastes has density in a range of 130-480, paper and plastics in range 40 – 130 kg m3
Usually it refers to uncompacted waste.
It varies with geographic location, season of the year, and length of time in storage. The densities of
waste in countries with low per capita income are high compared to that in industrialised countries
mostly because they contain a higher proportion of organic material, soil, ashes, and relatively small
particles.
A high-density waste capture system can reduce the volume in a solid-waste management system,
which substantially reduces the costs of:
o collection
o transportation
o final disposal
Therefore, density plays an important role:
in choosing the size and nature of collection vehicles. (For example, compacting equipment is not required
on collection vehicles handling waste from low-income communities where the density of the waste is often high. This type
of compacting equipment is essential to reduce the volume of waste in industrialised communities where relatively low-
density waste is found).
in determining the capacity of treatment and disposal facilities (the area required for a certain tonnage of
waste).
44

Typical Specific Weight Values
Components
Density (kg/m3)
Range Typical
Food wastes 130-480 290
Paper 40-130 89
Plastics 40-130 64
Yard Wastes 65-225 100
Glass 160-480 194
Tin cans 50-160 89
Aluminum 65-240 160
Condition
Density
(kg/m3)
Loose MSW, no processing or
compaction
90-150
In compaction truck 355-530
Baled MSW 710-825
MSW in a compacted landfill
(without cover)
440-740
Physical properties of solid waste
45

The moisture in a sample is expressed as percentage of the wet weight of the MSW material
For Example: Food waste consists of 50-80% of moisture content while paper and plastics
consist of only 4-10 % of moisture content.
The wet-weight method is most commonly used in the field of solid waste management.
Wet- weight Moisture content is expressed as :
Where, M= wet-weight moisture content, %
w= initial mass of sample as delivered, kg (or lb)
d= mass of sample after drying at 77°C (85 °C, 105 °C) kg (or lb)
100
x
w
d
w
M 




 −
=
ii. Moisture Content (MC%)
Size distribution is important in designing collection vehicles and mechanical recovery
systems to recover materials, and in designing biological treatment methods.
Size distribution can be measured using manually-manipulated screens and reported as
size distribution curves (which represent cumulative percentages of matter passing through
increasing screen sizes).
iii. Size Distribution
46

Typical Moisture Contents of Wastes
47

Problem 01
Estimate the overall moisture content of a solid waste sample of as collected MSW
with the typical composition given as following table:
48

Problem 01
Solution:
Step 1:
Assume delivered sample weight
of 100 lb.
Step 2:
Calculate the column 3 i.e dry
weight for each component by
using the multiplication of % by
weight and MC (%).
2.7= [9-(9*70/100)]
Step 2: Now the moisture content
of the solid waste sample using
Eq.
100
x
w
d
w
M 




 −
=
49

The permeability (hydraulic conductivity) of compacted solid waste is an important
physical property because it governs the movement of liquids & gases in a landfill.
Permeability depends on:
o Pore size distribution
o Surface area
o Porosity
iv. Permeability of Compacted Waste
50

o The field capacity of a waste sample is the fraction (or %) of water retained by a
waste sample (generally collected from a landfill site) based on the dry weight of the
sample.
o The field capacity plays an important role in designing leachate management
systems.
o The field capacity of a waste sample collected from a disposal site depends largely
on the degree of compaction, the stage of stabilisation, and the state of
decomposition (of organic waste).
o The field capacity of refuse samples range between 60 -141 % depending on the
applied stress.
Mechanical properties of solid waste
Mechanical Properties are important to design land fills and leachate management)
i. Field capacity
o The strengths of waste materials (particular once in place in landfill sites) are very
important parameters for assessing whether building structures would be stable on a
waste and stabilised soil environment if there is a possibility of such structures being
built.
o It is very difficult to establish relationships among different related parameters (e.g.
stress–strain, etc.) because of the diverse nature of waste constituents and their
degree of decomposition.
ii. Strength Parameters
51

Chemical properties of solid waste
Chemical Properties: (are important in assessing the alternative treatment or processing
and/or recovery options. )
The chemical composition of solid waste may be characterised in several ways, including:
i. Proximate Analysis
ii. Fusing Point of ash
iii. Ultimate Analysis (major components)
iv.Energy Contents
i. Proximate Analysis
Proximate analysis is used to evaluate the combustion properties of solid waste and to
determine the possibility of its use in combustion systems. It frequently involves the
determination of:
o Moisture Content – loss of moisture when heated to 105oC for 1 h.
o Volatile Combustible Matter (VCM)– loss of weight due to combustion of gases
on ignition at 950oC in the absence of oxygen i.e. in a covered crucible.
o Fixed Carbon – residue left when VCM is removed
o Ash content – weight of residue after combustion at 950oC in an open crucible.
52

Typical Proximate Analysis Values (% by weight)
53

ii. Fusing Point of ash
o Fusing point of ash is the temperature at which the ash resulting from the burning of
waste will form a solid (clinker) by fusion and agglomeration.
o Typical fusing temperatures: 1100 - 1200˚ C
o It is a mass balance analysis of chemical and thermal processes.
o It is used to ascertain the percentage of each element present in a waste sample and to
define the proper mix of waste materials to achieve suitable C/N ratios for biological
conversion processes.
o It frequently involves calculating the percentage of the five primary elements C, H, O, N,
S and the ash fraction contains both residues from the combustion of the organic matter
in the waste, and in many situations, a percentage of inorganic material.
o Further analysis of ash is important to determine the percentage of heavy metals in it
that they may pose significant environmental problems for the ultimate disposal of the
ash.
o The determination of halogens are often included in an ultimate analysis.
iii. Ultimate analysis
54

Typical data on ultimate analysis of combustible materials found in SW
55

Typical data in elemental analysis (% by weight)
Typical Chemical Composition of typical MSW
56

iv. Energy Contents
o Energy content or calorific value and often
said as heating value is essential for evaluating
its potential for use as a fuel in a combustion
system.
o Depends on the constituents of the waste
sample.
o The energy content of an organic fraction of
solid waste can be determined experimentally
by using a bomb calorimeter.
o If energy content values for different
components and/or primary elements of solid
waste are not available, the approximate energy
content of individual waste materials can be
estimated by using modified the Dulong formula:
57

Inert residue and energy content of residential MSW
58

Average composition and heating values for MSW
➢The average energy content of typical MSW is ~10,000 kJ/kg
59

Problem 02
Determine the energy value of a typical sample of municipal solid waste of 100kg
with the average composition shown in Tables:
60

Problem 02
Solution:
1. Determine the energy value for each of the constituent of municipal solid
waste using Equation:
And make the table:
=338.2*49.1+1430*(6.6-(37.6/8))+95.4*0.2
61

Problem 02
Solution (continue):
2. Determine energy values using a computation table (Solid waste *Energy)
=32.5*19342
3. Energy content = 1790385/100 = 17,904 kJ/kg (ANSWER)
62

Problem 03
Determine the energy content of 100kg of typical municipal solid waste having
following composition:
63

Problem 03
Solution:
1. Make the summation of mass and compositions of all components (last raw of table):
64

Problem 03
Solution:
2. Prepare a summary table from the provided data
Total wet mass,
100-(28.7+3.32+16.4+1.72+0.16+4.1)=45.6
2. Convert the moisture content (H2O) reported in step 1 to hydrogen and oxygen
a. Hydrogen = 2/18 × 45.6kg = 5.06 kg
b. Oxygen = 16/18 × 45.6 = 40.53 kg
3. Prepare a revised summary table computing percentage of the chemical constituents
of municipal solid wastes:
65

Problem 03
H= 3.32 + 5.06 = 8.38 kg
O= 16.4 + 40.53 = 56.93 kg
4. Estimate the energy content of the waste using following Equation and above data table
We get,
kJ/kg (ANSWER)
66

Biological properties of solid waste
Biological Characteristics
The organic fraction of MSW (excluding plastics ,rubber and leather) can be classified as:
o Water-soluble constituents -sugars, starches, amino acids and various organic acids
o Hemicellulose-a product of 5 and 6-carbon sugars
o Cellulose -a product of 6-carbon sugar glucose
o Fats, oils and waxes -esters of alcohols and long-chain fatty acids
o Lignin -present in some paper products
o Lignocellulose-combination of lignin and cellulose
o Proteins -amino acid chains
67

Biological properties of solid waste
Biodegradability of Sold waste
Volatile solids (VS), determined by ignition at 550˚C, is often used as a measure of the
biodegradability of the organic fraction of MSW. However, not all organic materials are easily
degradable.
Some of the organic constituents of MSW are highly volatile but low in biodegradability (e.g.
Newsprint) due to lignin content.
The most important biological characteristic of the organic fraction of MSW is that almost all
the organic components can be converted biologically to gases and relatively inert organic
and inorganic solids.
The production of odors and the generation of flies are also related to the putrescible nature
of the organic materials.
Biodegradable fraction produces-
o odours
o Hydrogen sulfide, H2S (rotten eggs)
o Methyl mercaptans
o Aminobutyric acid
o Methane is odourless.
o Attracts flies, vermin, rodents (vectors)
68

Calculation of biodegradable fraction of MSW
69

Transformation Processes in MSW Management
70

Forecasting Future waste
Forecasting Future waste quantities and the Factors to be considered :
o waste generation rate
o waste characteristics
o rate of population growth
o degree of commercial and industrial development
o per capita consumption
o future policy directives and their effect on waste management practices
71

Chapter 03:
Source reduction,
On-site Handling, Processing and
Storage of S. Waste

On-site Handling, Processing and Storage of S. Waste
The second important element in the solid waste management is the onsite
handling, storage and processing.
Onsite handling means the activities associated with the handling of solid waste
until it is placed in the containers used for its storage before collection. It also
includes the moving of loaded containers to the collection point and to return the
empty containers after collection to the storage locations.
73

On site storage of S. Waste
On site storage means the temporary storage of waste while awaiting collection.
Solid waste may be generated at source on a continuous basis throughout the day and night. It is generally
collected by external actors on specified time and therefore, on-site storage is essential to contain waste
materials prior to their collection.
The efficiency and effectiveness of a particular collection system largely depends on the method of storage
of solid wastes at the point of collection. In an organized solid waste management system, particularly in
many industrialised countries, storage containers have been developed to be compatible with waste
collection vehicles. This reduces collection times, increases efficiency, and maximises the productivity of
collection crews and the collection system.
A golden rule of solid waste management is "containerization" that states "once picked up solid waste
should never be thrown again on the ground; always put it in the container and from small container into
bigger container or a collection vehicle". In one word it can be expressed as "containerization".
On-site storage of solid waste is influenced by a number of factors which need to be considered including:
i. type of storage containers used
ii. container locations,
iii. public health and aesthetics.
iv. availability of resources for waste management
v. available methods for waste collection and further transportation
Storage at source or near source of generation may be broadly classified as:
i. individual storage on premises
ii. communal storage.
74

Typical storage containers for waste used in industrialised countries: (Table 3.3, Pg. 89; Figures)
Portable galvanised iron bins – Traditional galvanised iron bins (25 gallon to 32 gallon capacity is common
in UK) – other sizes available.
Portable plastic bins – In many industrialised countries, traditional galvanised iron bins have been
superseded by standard plastic versions. These are used for both manual and mechanised collection.
Plastic/paper bags (sacks) – Bin liner method of collection is popular in many localities. Plastic bags are
more common. Although paper bags have been used in some communities they have proved to be
expensive.
Portable roll-out containers – used for mechanised collection, and becoming a very popular method of
sorting and collecting waste.
Demountable – Demountable containers are becoming popular with many municipalities throughout the
world. The bin structure itself is moveable. When the bin is full it is replaced with an empty bin and the bin
structure and a special vehicle takes its contents to the disposal site and the bin is emptied. The empty bin
is then used as the replacement for a full bin elsewhere.
75

Typical designs used in developing countries: (Table 3.4, Pg. 92; Figures)
Enclosures (Fixed Containers) – Enclosures are probably the most common communal storage method.
They are essentially masonry walls or wooden screens which contain the waste. They are typically situated
on roadsides or adjacent to open spaces.
Depots – Depots are typically single storey buildings about the size of a large garage. They are large so
should only be used in areas with very high population densities in order that the distance that must be
travelled to dispose of waste is not too great.
Fixed storage bins – Fixed storage bins are typically small bins (<2m3) built from masonry or concrete
blocks. They do not have an entrance but the walls are low enough for the deposition of waste over the top
(typically 1.2-1.5m). A service hatch is provided in one wall for the collection of waste that is raked out by
collectors.
76

Design of Storage Containers: The major factors that play an important role in designing storage
containers to store materials at or near the source of generation are outlined below:
Nature of waste: This influences the choice of container material and whether extra treatment is required
for maintenance. For example, the use of steel to store corrosive waste requires thicker walls and/or
additional coating.
Size: The container should be large enough to accommodate the generated waste. Otherwise the people
creating the waste would require additional containers, and wastes could be dropped outside the container
(in a communal collection system).
Capacity margin: There should a capacity margin but consideration should be given to maximising the
density of the waste.
Compatibility: The container should be compatible with the collection equipment.
Standardisation: This can help to maximise labour and transport productivity, particularly in primary
collection. It is also important for mechanised collection systems in the case of secondary collection. A
proper assessment is needed on the applicability and affordability of a mechanized system, particularly in
the poorer parts of the developing world.
Efficiency: The size and shape of collection containers should be such that the collection efficiency is
maximised. For example, in the case of mechanized collection systems, storage containers should be
compatible with the type of collection vehicle. Where material recovery from storage containers by external
actors is intended, the size of the container should give easy access for the recovery of selected materials.
The shape of the container should allow it to be emptied easily and not require digging out of waste
materials, as this could demand additional manpower to maintain the system. Size and shape should ensure
that the container does not quickly become blocked.
77

Design of Storage Containers:
Convenience: The container should make it easy for the waste generators to deposit material, and for
external actors to collect the waste. For example, communal containers should be easily accessible and
easy to use. For example, the container height should be based on the maximum weight a child can lift,
particularly in developing countries. For mechanised curb side collection systems, large containers must
have wheels to facilitate bringing them to collection points. Any doors or lids that require special effort to
open them are not convenient for the user.
Public health and aesthetic: Size and shape of the container should minimise the exposure and contact of
different actors involved in solid waste management with the waste. Closed storage containers, particularly
to store biodegradable materials, should be used at or near the source of generation to improve public health
and aesthetics. However, if they contain biodegradable materials, particularly in warm humid climate, lids or
doors should require less effort to use, or they may be left open and become a breeding ground for rats,
flies, and other disease vectors. Design of containers should be such that the accumulated waste is
protected from rain.
Social: The possibility of theft, damage, fire-raising, scavenging, etc. should be considered.
Cost: The container should be cost-effective (cheap to build and easy to maintain). The cost assessment
should include life-cycle assessment including operation, maintenance, and manpower requirements for
transferring waste to the collection vehicle.
Ownership: Ownership is very important, particularly in developing countries. For example, ownership by
collection agencies always guarantees compatibility and indicates to the waste generator that a service is
being provided .
78

Size of storage containers
The size of a storage container can be calculated using the following simple
equation
Size of storage container = (N × G× F) / D + capacity margin
Where,
N = number of population served (nos, cap);
G = average rate of waste generation (kg/cap/day);
F = weekly frequency of collection (= 7 days/ numbers of collection trip)
D = density (kg/m3)
Color coding for onsite solid waste
segregation
79

What is Source reduction and on site processing of S. waste?
Source reduction is a way of on site processing of solid waste that means reducing
the amount and/or toxicity of waste before it enters the municipal waste
management system or is discharged into the environment.
On-site processing includes separation of components and treatment of solid
wastes at or near the source of generation that involves grinding, sorting,
compaction; shredding, composting and incineration etc.
Sometimes both the terms use together as “source reduction and onsite processing
of solid waste”
The key concepts around on-site processing and source reduction are:
i. reduce the volume i.e. minimization of waste
ii. alter the physical form
iii. resource recovery i.e waste utilization to generate less waste that
eliminating the need of disposal
iv. hazard reduction i.e. finding the ways to reduce toxicity of the waste.
v. separation of different fractions of waste
On-site processing and source reduction of S. waste
80

On-site processing and source reduction of S. waste
Advantages of on-site processing and source reduction are:
1) generation of clean recyclable materials
2) It reduces the quantity of general waste and minimises the toxicity of the general
waste stream (if hazardous materials are diverted).
3) removal of hazardous materials from general waste streams in order to minimise
health risks to the general population, particularly the waste handlers
4) improved working condition within recycling plants
5) improved efficiency of energy recovery processes
6) It diverts the different fractions of material present in the waste stream to locations for
appropriate treatment in the solid waste management system thus helping to operate
the waste treatment system cost-effectively
7) Appropriate sorting of components of solid waste at source ensures the quality of the
end product from (biological) treatment units and significantly influences the market
any end product.
8) minimisation of overall waste management costs.
9) Within an industrial setting, on-site processing reduces waste treatment costs,
minimises the regulatory burden and maximises production economics.
10) It reduces the consumption of energy through reuse of goods by consumers and use
of minimum quantities of materials in industry. This leads to the production of fewer
products, which ultimately saves the energy required to collect raw materials, to
produce the products, and to transport them to the consumers.
11) Emissions at treatment and disposal sites are reduced.
81

Source reduction of S. waste
82

Source reduction of S. waste
Implementation of Source Reduction and On-site Processing
Source reduction and on-site processing can be effectively implemented by
i. raising public awareness (through education programmes, legislation, etc.)
ii. to change the behaviour of consumers and industries
iii. to place the responsibility for certain products on manufacturers (product-
stewardship) throughout the product’s entire life cycle including its disposal.
o These approaches encourage selective buying patterns, and the reuse of materials and
products. They help manufacturers and industries to practice waste minimisation and
hazard reduction through efficient design, green manufacturing strategies, increased
product life, and packaging with minimum toxic content and efficient use of packaging
materials.
o In many countries, different types of labelling are used to categorise products that meet
certain environmental criteria (for example, ‘Blue Angle’ in Germany; ‘White Swan’ in
Sweden, Norway, and Denmark, ‘Eco Mark’ in Japan, and ‘Environmental Choice’ in
Canada). German experience has shown that such labelling helps to shift the markets
towards environmentally superior products.
The success of source reduction and on-site processing depends primarily on:
i. competence of waste generators ii. motivation of waste generators
iii. economic incentives convenience iv. environmental education
v. legislation. 83

On-site processing of S. waste
84

Problem 01:
Estimate the energy of the remaining solid wastes if 80 per cent of the cardboard, 90 per cent
of wood and 70 per cent of the paper is recovered by the homeowner havng the following
percentage distribution data:
85

Solution:
1. Determine the energy value for each of the constituent of municipal solid waste using
Equation:
And make the table:
=338.2*49.1+1430*(6.6-(37.6/8))+95.4*0.2
86

2. Determine energy values using a computation table (Solid waste *Energy)
=32.5*19342
3. Energy content = 1790385 kJ for 100 kg of solid waste.
87

4. Determine the energy content and weight of 80 per cent of the cardboard in the original
sample.
Energy content of 80% cardboard
= 0.80 * 61460 kJ [Table in step 2]
= 49168 kJ
Weight of 80% cardboard
= 0.80 * 4 kg [Table in step 2
= 3.2 kg
5. Determine the energy content and weight of 90 per cent of the wood in the original
sample.
Energy content of 90% wood
= 0.90 * 54270 kJ [Table in step 2]
= 48843 kJ
Weight of 90% wood
= 2.7 kg
88

6. Determine the energy content and weight of 70 per cent of the paper in the original
sample.
Energy content of 70% paper
= 0.70 * 527520 kJ [Table in step 2]
= 369264 kJ
Weight of 70% paper
= 24.5 kg
7. Determine the total energy and weight and energy content per kg of the original sample
after cardboard, wood and paper have been recovered:
Total Energy after recovery
= (1,790,385 – 49,168 – 48,843– 369,264) kJ
= 1,323,110 kJ
Total weight after salvage
= (100 – 3.2– 2.7 – 24.5) kg
= 69.6 kg
Energy content per kg after recovery
= 1323110 kJ/69.6 kg = 19,010 kJ/kg
89

Chapter 04:
Collection and Transfer & Transport of S.
Waste

o The term “collection of solid waste” (by external stakeholders) refers not only
the gathering or picking up of solid waste from its various sources or from
communal storage facilities, but also transportation/hauling of this waste to the
final disposal site.
o It also considers all activities related to loading of waste into collection vehicles,
and unloading of waste from collection vehicles at communal collection points,
processing places, transfer stations and final disposal sites.
o Waste collection, taken to encompass all these aspects of transfer to final
disposal site, is the largest cost element in most municipal solid waste
management systems, accounting for 60–70 per cent of costs in industrialised
countries, and 70–90 per cent of costs in developing and transition countries.
o Thus it is a very important functional element in solid waste management
systems and its efficient management can result in significant cost savings.
Collection of S. waste
91

Solid waste collection is a multiphase process having at least five distinct phases
as shown in the Fig 4.1.
92

Phase I: Transferring the solid waste to waste collection bins placed inside or
outside the home by individual house owner.
Phase II: Transfer the refuse from bins to collection truck, which is generally done
by the collection crew of the solid waste management department.
Phase III: Collection of the solid waste from several homes, commercial and
business centers, educational institutions etc.
Phase IV: Transfer of the collected waste on the planed routes in order to
maximize the collection efficiency, reducing the fuel consumption and reducing the
haul distance. The route is planned in such a way that the last collection point is at
minimum distance from the waste disposal or processing facility.
Phase V: Last phase of the collection system is the transfer of the collected waste
to the disposal or processing facility as planned before.
93

Frequency of solid waste collection:
The frequency of waste collection by external stakeholders greatly influences the
waste collection costs and depends on a no. of factors such as:
i. Quantity of waste
ii. Rate of generation
iii. Characteristics of waste
iv. Climate
v. Density & type of housing
vi. Availability of space within the premises
vii. Size & type of storage facilities (small, large, individual or communal)
viii. Attitude of generators
ix. Available resources
94

The following divisions of collection systems may help the solid waste
manager to optimize the design and operation of collection services more
efficiently, particularly if a wide range of collection vehicles is required. They are:
1. Primary collection; 2. Secondary collection
1. Primary Collection System:
The first stage of collection system which involves the transportation of collected
waste from or near the source of generation by external stakeholders to the final
disposal sites but more often it involves transportation to communal collection bins
or points, processing or transfer station.
Although this service is not common in poorer parts of the developing world, but
increasing no. of micro enterprises and (or) community based organizations
forming in wealthier communities (both in industrialized and developing countries)
perform this task.
2. Secondary collection System:
It involves the collection of waste from communal bins, storage points or transfer
station and transportation to the final disposal site.
95

Collection Types:
The basic collection scheme on the basis of availability of services is categorized
into four groups. They are:
i. Communal collection
ii. Block collecton
iii. Kerbside/ Alley collection
iv. Door- to –door (house to house) collection
96

Collection Types:
i. Communal collection
o In this case, waste generators are responsible for bringing their waste to one or a
number of specified communal collection points or bins.
o Communal collection of solid waste are common (for all categories of waste) in low-
income countries where cost saving is more important than service provision, as this
system reduces considerably the number of collection points.
o The principal disadvantage of this system is that containers/collection points are located
in a public place (lacking ownership by the public) which, in many situations, leads to
indiscriminate disposal of waste outside the container.
o Thus, the actual economy of this system mostly depends on public co-operation (for
example, in cases of poor public co-operation, waste generators may transfer their waste
to the street cleansing services or outside the bin which will increase the cost of public
cleansing services). It is therefore essential to pay more attention to improving the
design, and operation and maintenance practices to increase public acceptance, and to
optimise the productivity of collection system.
o Communal (sometimes called ‘bring’) collection in many industrialised countries are more
common for a selected fraction of waste materials (such as used furniture or household
electrical appliances and garden waste).
o The use of portable storage containers maximises the productivity of labour and vehicles
of such collection system.
97

Collection Types:
ii. Block collection
o Waste generators are responsible for bringing their waste to collection vehicles
(vehicles follow are predetermined route at prescribed intervals) at the time of
collection.
o The collection vehicles generally stop at all street intersections or selected
collection points & a bell is rung on their arrival so people can bring their waste
to the collection vehicles.
o This system has low to medium labour and vehicle productivity, but it minimizes
the spread of waste on streets.
o A regular and well organized collection services is essential so that generators
know exactly when to bring out their waste.
98

Collection Types:
iii. Kerb-side/ Alley collection
o Waste generators place the waste containers or bags (sacks) on the kerb or in
the alley on a specific day (or specific days) for collection by external actors. They
retrieve their containers from the kerb or alley after the waste has been collected.
o This is most common in
industrialized countries and in the
wealthier communities of some
developing countries.
o A regular and well organized
collection service is essential so
that generators know exactly when
to leave out their waste. In case of
irregular collection, generators may
place their storage container
permanently at the kerb.
o The sparse collection (once
weekly) may be a cost effective
option.
99

Kerbside / Alley Collection :
100

Collection Types:
iv. Door- to –door (house to house) collection
o Generators place waste containers at their back gate or intermediate vicinity of
their property on a specific day (or days) for collection.
o The collection crews enters each property, takes out the containers or bags & if
appropriate sets the containers back after emptying waste into collection
vehicles.
o This is more common in industrialized countries, but an increasing no. of micro
enterprises and/ or community based organizations are forming in wealthier
communities in many developing countries.
o This is aesthetically and environmentally more satisfactory but comparatively
more expensive (increased labour costs) as it involves entering all premises.
101

Collection Methods:
Collection methods on the basis of mode of operation may be broadly catagorised
into two systems:
(1) Hauled Container System (HCS)
(2) Stationary Container System (SCS).
102

In this system, the loaded containers are taken to the disposal site or transfer facility
for unloading, and empty containers are returned to their original location or any
other location.
Three different vehicles are used in HCS
i.e., hoist truck, tilt-frame truck
and trash-trailer.
Advantages and disadvantages of HCS
are given in table:
HCS is further of two types:
i. Conventional mode type
ii. Exchange container mode type
103

hoist truck
Tilt frame truck Trash trailer truck
Hauled Container System (HCS)
104

A. Hauled container system: Conventional mode
In this system the emptied containers are brought back at the same locations, from
where they were picked up. The working is shown by the schematic in Fig. (a).
105

B. Hauled container system: Exchange container mode
In this system the collection vehicle carries one extra empty container, puts the empty
container at first pick-up location, picks the loaded container, hauls the loaded
container to the disposal site, and returns the empty container to the next pick up
location and so on. At the end of the day's work, the last container, emptied by the
vehicle is taken to the garage. The working is shown by the schematic in Fig. (b).
106

Comparison of Conventional Mode and Exchange Container Modes of
HCS
107

Analysis of Hauled Container Collection System
hauled container system with conventional Mode: For
one day's work, an empty truck comes from the garage
to the work area, picks up the loaded container from the
first location, goes to the disposal site or transfer station
or MRF, unloads the wastes and hauls back the empty
container to the original location, deposits the empty
container and moves on to the second location. It
repeats this process by performing a number of trips
until at the end of the day's work it goes back to the
garage. For the purpose of the system's analysis, the
time spent in various activities will be counted as shown
in Fig. 4.12.
108

Analysis of Hauled Container Collection System
109

(2) Stationary Container System (SCS).
In this system, containers used for the storage of waste remain at the point of
collection. the loaded containers are emptied into the body of the collection vehicle,
while the containers are put back at their places. A number of containers can thus
be emptied per trip of collection vehicle. The loaded vehicle then moves to the
disposal site or transfer station, is unloaded there and starts its next trip.
The schematic of the operation is shown in Fig. 4.9.
The collection vehicles used are usually compactor trucks.
These systems may be used for all types of wastes.
These are of two types
(i) SCS with mechanically loaded vehicles
(ii) SCS with manually loaded vehicles.
110

(2) Stationary Container System (SCS)
Following figure shows the schematic of operational sequence for stationary
container system:
111

(2) Stationary Container System (SCS)
SCS with mechanically loaded vehicles
112

Comparison of hauled containers system (HCS) and stationary containers
system (SCS)
113

Collection route
Analysis of collection system provides vehicle and labor requirements information. The next
step is to laydown/decide the collection routes.
This exercise, i.e. chalking out of the best collection routes, is necessary to use both work
force and equipment in the best possible way.
This exercise is actually a trial and error process. There are no fixed rules that can be applied
to all situations.
Following guidelines/factors should be kept in mind while laying out routes:
i. Existing policies, regulations regarding S.W.M. must be identified.
ii. Existing system conditions such as crew sizes, vehicle types must be coordinated.
iii. All the vehicles should almost travel equal distances, and carry equal amount of loads.
iv. When possible, routes should begin and end near arterial streets of the city.
v. The first container should be served from the farthest end and the last container from
nearest to the disposal site.
vi. In hilly areas the route should start from the top of the grade and proceed downward as
the vehicle becomes loaded.
vii. Wastes generated at the traffic congested locations should be collected in early hours of
the day.
114

Collection Routes: Procedure for developing layout
The procedure of layout of collection routes involves four steps:
Step 1: Preparation of location map showing the pickup locations and the peculiar data for
HCS or SCS.
Step 2: Data analysis, and preparation of information summary table.
Step 3: Preliminary layout of routes.
Step 4: Evaluation of preliminary routes and development of balanced routes by hit and trial.
Step 1 is general for both hauled container system and stationary container system,
while steps 2, 3 and 4 are different for the two systems.
115

Transfer and Transport of S. waste
Transfer and transport refers to the means, facilities and appurtenances used to
affect the transfer of waste from one location to another (usually to more distant
location).
Typically, the waste from relatively small collection vehicle is transferred to larger
vehicle and is transported to distant location for safe disposal or further
processing.
According to Texas
administration code (TAC),
transfer station is defined as “a
facility used for transferring
solid waste from collection
vehicles to long-haul vehicles.
It is not a storage facility such
as one where individual
residents can dispose their
wastes”.
Transfer station provides a link
between the community's solid
waste collection program and
waste disposal or processing
facility as shown in the Fig.5.1.
116

Transfer station: Factors for planning & design
In the planning and design of transfer stations a number of factors should be
considered, including:
i. location – governed by the proximity of the collection routes, access to the
major haulage routes, isolation from the community
ii. quantity of waste to be transferred/handled
iii. types and number of primary and secondary vehicles served
iv. types of transfer operations
v. equipment requirements
vi. waste characteristics
vii. climate
viii. sanitation provision
ix. costs.
117

Transfer station: Benefits
1) Costs--The main reason for waste transfer is to optimize the productivity of vehicles and
collection crews as they remain closer to routes, while larger vehicles make the longer trip
to processing and disposal sites and ultimately reduces overall costs. It can also be
integrated with other functional elements of integrated waste management options
(recycling , resources recovery & waste –to- energy facility) to improve overall waste mgt.
performance.
2) Minimize collection vehicle routing complexities-- Makes the planning process more
flexible and a combination of human & animal powered small motorized and more
sophisticated vehicles with hydraulic or pneumatic system can be used in different areas
depending on the accessibility to those areas and collection method.
3) Provide an opportunity to increase waste density-- In areas where compaction vehicles
are not available, transfer station may be use d to compact the waste so that greater
quantities can be carried( most economical) at once to the final disposal sites.
4) Minimize illegal waste dumping--Particularly in developing countries where the human-and
–animal powered and small motorized vehicles are used for the collection of waste are
often unsuitable for traveling long distances.
5) Minimize traffic congestion—It reduces the no. of vehicles for long distance haulage and
may reduce fuel consumption thus reduce environmental pollution.
118

Transfer station: Benefits
6) Can serve as a controlled place for sorting and processing the waste- Particularly in many
low income countries where a thriving informal economy exists in recycling of waste,
these stations can minimize health hazard and may limit the amount of waste picking that
is done in the streets, which will reduce the amount of waste that is scattered around
communal bins and waste accumulation points.
7) Reduce maintenance costs of collection vehicles—These vehicles stay on well paved
roads and are not traveling on rough roads, particularly in landfill sites.
8) Improve waste dumping efficiency at final disposal site– A reduced no. of vehicles at the
disposal sites.
119

Transfer station: Problems
1) Increased traffic volume, noise and air pollution in the surrounding areas.
2) Unless they are properly maintained there is a potential for environmental damage
(lechate, odour, disease carriers, aesthetic and similar problem) in surrounding areas.
Transfer station: Locations
Whenever possible, transfer stations should be located:
i) As near as possible to the weighted center of the individual solid waste production
areas to be served,
ii) Within easy access of major arterial highway routes as well as near secondary or
supplemental means of transportation,
iii) Where there will be a minimum of public and environmental objection to the transfer
operations, and
iv) Where construction and operation will be most economical.
120

Transfer station: Types
Based on the mode used to load the transport vehicles, transfer stations are
classified into three general types:
i.Direct discharge
ii.Storage discharge
iii.Combination of direct and storage discharge types.
121

Transfer station: Cost Comparison
122

Transfer station: Example, Japan
123

Collection vehicles
The careful selection of a vehicle to use in a given situation is crucial for a well functioning solid waste
management system. The collection vehicles selected should be appropriate to:
1) territory – hilly, plain land, density of housing
2) access road – width of road, type of surface, corner radius, maneuvering space
3) transport regulations – permitted maximum load
4) travel distance – distance to communal/transfer station or final disposal site
5) integration – possibility of integration with existing practices
6) performance – convenience (loading height, etc.), material loading/unloading efficiency,
operating dimensions and turning radius, safety mechanism
7) type of properties – detached dwellings, high-rise dwellings, commercial building, etc.
8) storage facilities – enclosure, bins, roll-out bins, bags, etc.
9) type and density of collection points – door-to-door, kerbside, communal collection, etc.
10) quantity of waste – rate of generation and frequency of collection
11) waste characteristics – constituents, abrasive, dense, low-density
12) traffic levels – vehicles should be harmonious with existing traffic
13) standardisation – minimise overall maintenance costs
14) payload capacity – the amount of waste that can be carried depends on the body weight
of vehicles (that is, vehicles with lower body weight can carry more waste)
15) size of cab – often it is overlooked although it does not cost much
16) technical know-how – availability of skilled labour for operation and maintenance
17) cost – capital, operation and maintenance cost.
124

Collection vehicles: Types
1. Human- and animal-powered vehicles
i. handcarts and three-wheeled pedal carts.
ii. animal panniers (bags or buckets carried over the back of the animal) and
animal carts.
2. Motorised vehicles
i. compaction vehicles
ii. semi-compaction vehicles
iii. non-compaction vehicles
iv. container handling systems.
125

Collection vehicles: Types
126

Collection vehicles: Maintenance
Purchase of waste collection vehicles does not solve the waste management problem unless
they are properly maintained. The overall productivity of a vehicle depends on the total amount
of time the vehicle remains operational during its productive life. Generally vehicle maintenance
is being carried out in the following two ways:
1. Preventive maintenance
2. Breakdown maintenance
1. Preventive maintenance
o the service of vehicles that occurs when they seem to be working efficiently in order to
identify problems before they occur.
o Preventive maintenance should be carried out at regular intervals that are generally
based on the distance travelled or hours of operation of a vehicle. Minor preventive
maintenance activities should be carried out daily and weekly. The activities that need to
be carried out at each maintenance event will vary according to the vehicle, both its
general type and manufacture.
2. Breakdown maintenance
o Breakdown/crisis maintenance is the repair of the vehicle once problems have
already occurred.
o In many developing countries, this is the only sort of maintenance that occurs. It is
easy to plan and works simply as a response to problems as they occur. However, it
may lead to long down times (the length of time that the vehicle is out of operation).
127

Economic cost of collection systems in SWM
The economic costs of solid waste collection include:
1) planning and design
2) procurement, operation and maintenance of waste collection equipment
3) (vehicles, storage container, as well as cost of workshop/garage facilities
4) and auxiliary civil works)
5) skilled and unskilled labour, and drivers involved directly in collection
services
6) a percentage of administrative costs
7) resource recovery (if there is a resource recovery system not at source
but in the collection stream).
These costs vary greatly between and even within countries, and depend largely
on available local resources (fuel costs, availability of spare parts, land prices,
etc.) and local economy (salary, labour cost).
128

EIA of collection systems in SWM
The major environmental impacts associated with collection systems involve:
i. consumption of energy and generation of atmospheric emissions
ii. production storage facilities (e.g. bags, bins)
iii. maintenance of storage containers
iv. treatment (e.g. separation, home composting) of waste materials at
sources environmental benefits.
129

Analysis of Hauled Container Collection System : Problem 01
Solution:
130

131

132

Analysis of Stationary Container Collection System : Problem 02
133

134

(d)
135

136

137

Suppose the annualized cost of purchasing, fueling and maintaining a compactor
truck is given by the following expression:
Annualized cost ($/yr) = 25000 + 4000V
Where, V is the truck volume in cubic yards.
Suppose these trucks require two person crews, with labor charged at $24 per hr
each (including benefits).
Perform an economic analysis of the collection system, in which a 14.4 yd3 truck
collects solid waste from 340 households each day.
Each household generates 60 lbs of solid waste per week.
The trucks and crew work 5 days per week and curb-side pickup is provided once
a week for each house.
What is the cost per ton of solid waste collected and what is the cost per
household?
Solution:
Assuming 8-hr working days, for 5 days/week and 52 weeks/yr, the annualized
cost of labor per truck would be
Labor cost = 2 persons × $24/hr × 8 hr/d × 5 d/wk × 52 wk/yr
= $99840/yr Given,
Crew size = 2 persons / truck
Labor charge = $24 per hr each
138

Annualized truck cost ($/yr) = 25000 + 4000 × 14.4
= $82600/yr
Total annual cost of truck and crew = $82600 + $99840 = $182440/yr
Over a 5-day week, 1700 households (5 × 340 = 1700) are served by each truck.
The total amount of solid waste collected by 1 truck in 1 yr is
Annual solid waste = (1700 households × 60 lb/week × 52 wk/yr) / 2000 lb/ton
= 2652 ton/yr
Therefore,
Annual cost per ton = ($182440/yr) / (2652 ton/yr) = $68.80/ton
Annual cost per household = ($182440/yr) / 1700 households = $107.32/yr
However, the total amount billed to each customer will be considerably higher after
incorporating transfer station fees, administrative costs, overhead, profits and so on.
Given,
Annualized cost = 25000 + 4000V
Truck volume, V =14.4 yd3
Given,
Refuse collected from 340 HHs/day
Solid waste generation rate = 60
lbs/week
139

140

Problem: Costs of a Transfer Station and Its Vehicles
A transfer station handling 300 tons/day, 5 days per week, costs $5 million to build
and $150000 per year to operate. An individual tractor-trailer costs $140000 and
carries 15 tons/trip. Operation and maintenance costs (including fuel) of the truck
are $50000/yr; the driver makes $40000 per year (including benefits). The capital
costs of the building and transfer trucks are to be amortized over a 10-yr period
using a 12% discount factor.
Suppose, it takes 30 minutes to make a one-way trip from the transfer station to the
disposal site and 7 round trips per day are made.
Find the transfer station and hauling cost in dollars per ton.
141

Solution:
142

A variable trucking cost over
variable trip time, along with
the fixed cost of the transfer
station itself, results in the
following graph:
143

Problem: Costs of a Transfer Station and Its Vehicles
Determine the break-even time for a stationary-container system and a separate
transfer and transport system for transporting wastes collected from a metropolitan
area to a landfill disposal site. Assume the following cost and system data are
applicable:
1. Transportation costs:
(a) Stationary-container system using an 18 m3 compactor = $20/h
(b) Tractor-trailer transport unit with a capacity of 120 m3 = $25/h
2. Other costs:
(a) Transfer station operating cost, including amortization = $0.40/m3
(b) Extra cost for unloading facilities for Tractor-trailer transport unit = $0.05/m3
3. Other data:
(a) Density of wastes in compactor = 325 kg/m3
(b) Density of wastes in transport units = 150 kg/m3
144

145

Comparison of two systems:
(i) Before the break-even time, SCS seems to be more economic
(ii) At break-even time, two systems are indifferent.
(iii) After the break-even time, transfer transport system seems to be more economic
146

Solution:
Find unit cost Tk./m3/min
A. Hauled container system: 8 m3 @ Tk.
8/hr
1 m3 cost = 8/8 = Tk. 1/m3/hr
= Tk. 1/60 /m3/min
= Tk. 0.0167/m3/min
B. Stationary container system: 20 m3 @ Tk.
12/hr
1 m3 cost = 8/8 = Tk. 12/(20*60)/m3/min
= Tk. 0.01 /m3/min
Tractor-trailer:
120 m3 @ Tk.16/hr
1 m3 cost = 16/(120*60)
= Tk. 0.0022 /m3/min
Determine the break-even time for a hauled container system and a stationary
container system as compared to a system using transfer and transport operations,
when the following data are applicable:
1. Transportation costs:
a) HCS using a hoist truck with 8-m3 container = Tk. 8/hr.
b) SCS using 20-m3 compactor = Tk. 12/hr.
c) Tractor-trailer transpor t unit 120-m3 capacity = Tk. 16/hr.
2. Transfer station costs:
Amortization and operation Costs = Tk. 0.35/m3
147

Find unit costs for different haul times as shown in table below and plot them:
148

Haul time (min)
149

Thanks
150

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