Waste management or waste disposal includes the processes and actions required to

manage waste from its inception to its final disposal.[1] This includes
the collection, transport, treatment, and disposal of waste, together with monitoring
and regulation of the waste management process and waste-related laws,
technologies, and economic mechanisms.

Waste can either be solid, liquid, or gases and each type has di erent methods of
disposal and management. Waste management deals with all types of waste,
including industrial, chemical, municipal, organic, biomedical, and radioactive
wastes. In some cases, waste can pose a threat to human health. [2] Health issues are
associated with the entire process of waste management. Health issues can also arise
indirectly or directly: directly through the handling of solid waste, and indirectly
through the consumption of water, soil, and food.[2] Waste is produced by human
activity, for example, the extraction and processing of raw materials. [3] Waste
management is intended to reduce the adverse e ects of waste on human health,
the environment, planetary resources, and aesthetics.

The aim of waste management is to reduce the dangerous e ects of such waste on the
environment and human health. A big part of waste management deals with municipal
solid waste, which is created by industrial, commercial, and household activity. [4]

Waste management practices are not the same across countries

(developed and developing nations); regions (urban and rural areas),
and residential and industrial sectors can all take di erent approaches.[5]

Proper management of waste is important for building sustainable and liveable cities,
but it remains a challenge for many developing countries and cities. A report found
that e ective waste management is relatively expensive, usually comprising 20%–50%
of municipal budgets. Operating this essential municipal service requires integrated
systems that are e icient, sustainable, and socially supported. [6] A large portion of
waste management practices deal with municipal solid waste (MSW) which is the bulk
of the waste that is created by household, industrial, and commercial
activity.[7] According to the Intergovernmental Panel on Climate Change (IPCC),
municipal solid waste is expected to reach approximately 3.4 Gt by 2050; however,
policies and lawmaking can reduce the amount of waste produced in di erent areas
and cities of the world.[8] Measures of waste management include measures for
integrated techno-economic mechanisms [9] of a circular economy, e ective disposal
facilities, export and import control[10][11] and optimal sustainable design of products
that are produced.
In the first systematic review of the scientific evidence around global waste, its
management, and its impact on human health and life, authors concluded that about
a fourth of all the municipal solid terrestrial waste is not collected and an additional
fourth is mismanaged after collection, often being burned in open and uncontrolled
fires – or close to one billion tons per year when combined. They also found that broad
priority areas each lack a "high-quality research base", partly due to the absence of
"substantial research funding", which motivated scientists often
require.[12][13] Electronic waste (ewaste) includes discarded computer monitors,
motherboards, mobile phones and chargers, compact discs (CDs), headphones,
television sets, air conditioners and refrigerators. According to the Global E-waste
Monitor 2017, India generates ~ 2 million tonnes (Mte) of e-waste annually and ranks
fifth among the e-waste producing countries, after the United States, the People's
Republic of China, Japan and Germany.[14]

E ective 'Waste Management' involves the practice of '7R' - 'R'efuse, 'R'educe',

'R'euse, 'R'epair, 'R'epurpose, 'R'ecycle and 'R'ecover. Amongst these '7R's, the first
two ('Refuse' and 'Reduce') relate to the non-creation of waste - by refusing to buy non-
essential products and by reducing consumption. The next two ('Reuse' and 'Repair')
refer to increasing the usage of the existing product, with or without the substitution of
certain parts of the product. 'Repurpose' and 'Recycle' involve maximum usage of the
materials used in the product, and 'Recover' is the least preferred and least e icient
waste management practice involving the recovery of embedded energy in the waste
material. For example, burning the waste to produce heat (and electricity from heat).
Certain non-biodegradable products are also dumped away as 'Disposal', and this is
not a "waste-'management'" practice.[15]

Principles of waste management

[edit]
 Diagram of the waste hierarchy

Waste hierarchy

[edit]

The waste hierarchy refers to the "3 Rs" Reduce, Reuse and Recycle, which classifies
waste management strategies according to their desirability in terms of waste
minimisation. The waste hierarchy is the bedrock of most waste minimization
strategies. The aim of the waste hierarchy is to extract the maximum practical benefits
from products and to generate the minimum amount of end waste; see: resource
recovery.[16][17] The waste hierarchy is represented as a pyramid because the basic
premise is that policies should promote measures to prevent the generation of waste.
The next step or preferred action is to seek alternative uses for the waste that has
been generated, i.e., by re-use. The next is recycling which includes composting.
Following this step is material recovery and waste-to-energy. The final action is
disposal, in landfills or through incineration without energy recovery. This last step is
the final resort for waste that has not been prevented, diverted, or
recovered.[18][page needed] The waste hierarchy represents the progression of a product or
material through the sequential stages of the pyramid of waste management. The
hierarchy represents the latter parts of the life-cycle for each product. [19]

Life-cycle of a product

[edit]
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The life-cycle of a product, often referred to as the product lifecycle, encompasses

several key stages that begin with the design phase and proceed through
manufacture, distribution, and primary use. After these initial stages, the product
moves through the waste hierarchy's stages of reduce, reuse, and recycle. Each phase
in this lifecycle presents unique opportunities for policy intervention, allowing
stakeholders to rethink the necessity of the product, redesign it to minimize its waste
potential, and extend its useful life.

During the design phase, considerations can be made to ensure that products are
created with fewer resources, are more durable, and are easier to repair or recycle.
This stage is critical for embedding sustainability into the product from the outset.
Designers can select materials that have lower environmental impacts and create
products that require less energy and resources to produce.

Manufacturing o ers another crucial point for reducing waste and conserving
resources. Innovations in production processes can lead to more e icient use of
materials and energy, while also minimizing the generation of by-products and
emissions. Adopting cleaner production techniques and improving manufacturing
e iciency can significantly reduce the environmental footprint of a product.

Distribution involves the logistics of getting the product from the manufacturer to the
consumer. Optimizing this stage can involve reducing packaging, choosing more
sustainable transportation methods, and improving supply chain e iciencies to lower
the overall environmental impact. E icient logistics planning can also help in reducing
fuel consumption and greenhouse gas emissions associated with the transport of
goods.

The primary use phase of a product's lifecycle is where consumers interact with the
product. Policies and practices that encourage responsible use, regular maintenance,
and the proper functioning of products can extend their lifespan, thus reducing the
need for frequent replacements and decreasing overall waste.

Once the product reaches the end of its primary use, it enters the waste hierarchy's
stages. The first stage, reduction, involves e orts to decrease the volume and toxicity
of waste generated. This can be achieved by encouraging consumers to buy less, use
products more e iciently, and choose items with minimal packaging.

The reuse stage encourages finding alternative uses for products, whether through
donation, resale, or repurposing. Reuse extends the life of products and delays their
entry into the waste stream.

Recycling, the final preferred stage, involves processing materials to create new
products, thus closing the loop in the material lifecycle. E ective recycling programs
can significantly reduce the need for virgin materials and the environmental impacts
associated with extracting and processing those materials.

Product life-cycle analysis (LCA) is a comprehensive method for evaluating the

environmental impacts associated with all stages of a product's life. By systematically
assessing these impacts, LCA helps identify opportunities to improve environmental
performance and resource e iciency. Through optimizing product designs,
manufacturing processes, and end-of-life management, LCA aims to maximize the use
of the world's limited resources and minimize the unnecessary generation of waste.

In summary, the product lifecycle framework underscores the importance of a holistic

approach to product design, use, and disposal. By considering each stage of the
lifecycle and implementing policies and practices that promote sustainability, it is
possible to significantly reduce the environmental impact of products and contribute
to a more sustainable future.

Resource e iciency

[edit]

Main article: resource e iciency

Resource e iciency reflects the understanding that global economic growth and
development can not be sustained at current production and consumption patterns.
Globally, humanity extracts more resources to produce goods than the planet can
replenish. Resource e iciency is the reduction of the environmental impact from the
production and consumption of these goods, from final raw material extraction to the
last use and disposal.

Polluter-pays principle

[edit]

The polluter-pays principle mandates that the polluting parties pay for the impact on
the environment. With respect to waste management, this generally refers to the
requirement for a waste generator to pay for appropriate disposal of the unrecoverable
materials.[20]

History

[edit]

Main article: History of waste management

Throughout most of history, the amount of waste generated by humans was

insignificant due to low levels of population density and exploitation of natural
resources. Common waste produced during pre-modern times was mainly ashes and
human biodegradable waste, and these were released back into the ground locally,
with minimum environmental impact. Tools made out of wood or metal were generally
reused or passed down through the generations.

However, some civilizations have been more profligate in their waste output than
others. In particular, the Maya of Central America had a fixed monthly ritual, in which
the people of the village would gather together and burn their rubbish in large
dumps.[21][irrelevant citation]

Modern era

[edit]

Edwin Chadwick's 1842 report The Sanitary Condition of the

Labouring Population was influential in securing the passage of the first legislation
aimed at waste clearance and disposal.

Following the onset of the Industrial Revolution, industrialisation, and the sustained
urban growth of large population centres in England, the buildup of waste in the cities
caused a rapid deterioration in levels of sanitation and the general quality of urban
life. The streets became choked with filth due to the lack of waste clearance
regulations.[22] Calls for the establishment of municipal authority with waste removal
powers occurred as early as 1751, when Corbyn Morris in London proposed that "... as
the preservation of the health of the people is of great importance, it is proposed that
the cleaning of this city, should be put under one uniform public management, and all
the filth be...conveyed by the Thames to proper distance in the country".[23]

However, it was not until the mid-19th century, spurred by increasingly

devastating cholera outbreaks and the emergence of a public health debate that the
first legislation on the issue emerged. Highly influential in this new focus was the
report The Sanitary Condition of the Labouring Population in 1842[24] of the social
reformer, Edwin Chadwick, in which he argued for the importance of adequate waste
removal and management facilities to improve the health and wellbeing of the city's
population.

In the UK, the Nuisance Removal and Disease Prevention Act 1846 began what was to
be a steadily evolving process of the provision of regulated waste management in
London.[25] The Metropolitan Board of Works was the first citywide authority that
centralized sanitation regulation for the rapidly expanding city, and the Public Health
Act 1875 made it compulsory for every household to deposit their weekly waste in
"moveable receptacles" for disposal—the first concept for a dustbin.[26] In the Ashanti
Empire by the 19th century, there existed a Public Works Department that was
responsible for sanitation in Kumasi and its suburbs. They kept the streets clean daily
and commanded civilians to keep their compounds clean and weeded. [27]

Manlove, Alliott & Co. Ltd. 1894 destructor furnace. The

use of incinerators for waste disposal became popular in the late 19th century.

The dramatic increase in waste for disposal led to the creation of the
first incineration plants, or, as they were then called, "destructors". In 1874, the first
incinerator was built in Nottingham by Manlove, Alliott & Co. Ltd. to the design of
Alfred Fryer.[23] However, these were met with opposition on account of the large
amounts of ash they produced and which wafted over the neighbouring areas. [28]
Similar municipal systems of waste disposal sprung up at the turn of the 20th century
in other large cities of Europe and North America. In 1895, New York City became the
first U.S. city with public-sector garbage management.[26]

Early garbage removal trucks were simply open-bodied dump trucks pulled by a team
of horses. They became motorized in the early part of the 20th century and the first
closed-body trucks to eliminate odours with a dumping lever mechanism were
introduced in the 1920s in Britain.[29] These were soon equipped with 'hopper
mechanisms' where the scooper was loaded at floor level and then hoisted
mechanically to deposit the waste in the truck. The Garwood Load Packer was the first
truck in 1938, to incorporate a hydraulic compactor.

Waste handling and transport

[edit]

Main articles: Waste collection vehicle, Waste collector, and Waste sorting

Moulded plastic, wheeled waste bin in Berkshire, England

Waste collection methods vary widely among di erent countries and regions.
Domestic waste collection services are often provided by local government
authorities, or by private companies for industrial and commercial waste. Some areas,
especially those in less developed countries, do not have formal waste-collection
systems.

Waste handling and transport

[edit]

Curbside collection is the most common method of disposal in most European

countries, Canada, New Zealand, the United States, and many other parts of the
developed world in which waste is collected at regular intervals by specialised trucks.
This is often associated with curb-side waste segregation. In rural areas, waste may
need to be taken to a transfer station. Waste collected is then transported to an
appropriate disposal facility. In some areas, vacuum collection is used in which waste
is transported from the home or commercial premises by vacuum along small bore
tubes. Systems are in use in Europe and North America.

Main article: Automated vacuum collection

In some jurisdictions, unsegregated waste is collected at the curb-side or from waste

transfer stations and then sorted into recyclables and unusable waste. Such systems
are capable of sorting large volumes of solid waste, salvaging recyclables, and turning
the rest into bio-gas and soil conditioners. In San Francisco, the local government
established its Mandatory Recycling and Composting Ordinance in support of its goal
of "Zero waste by 2020", requiring everyone in the city to keep recyclables and
compostables out of the landfill. The three streams are collected with the curbside
"Fantastic 3" bin system – blue for recyclables, green for compostables, and black for
landfill-bound materials – provided to residents and businesses and serviced by San
Francisco's sole refuse hauler, Recology. The city's "Pay-As-You-Throw" system
charges customers by the volume of landfill-bound materials, which provides a
financial incentive to separate recyclables and compostables from other discards.
The city's Department of the Environment's Zero Waste Program has led the city to
achieve 80% diversion, the highest diversion rate in North America. [30] Other
businesses such as Waste Industries use a variety of colors to distinguish between
trash and recycling cans. In addition, in some areas of the world the disposal of
municipal solid waste can cause environmental strain due to o icial not having
benchmarks that help measure the environmental sustainability of certain
practices.[31]

Waste segregation

[edit]

Further information: Waste separation

Recycling point at the Gdańsk University of Technology

This is the separation of wet waste and dry waste. The purpose is to recycle dry waste
easily and to use wet waste as compost. When segregating waste, the amount of
waste that gets landfilled reduces considerably, resulting in lower levels of air and
water pollution. Importantly, waste segregation should be based on the type of waste
and the most appropriate treatment and disposal. This also makes it easier to apply
di erent processes to the waste, like composting, recycling, and incineration. It is
important to practice waste management and segregation as a community. One way
to practice waste management is to ensure there is awareness. The process of waste
segregation should be explained to the community. [32]

Segregated waste is also often cheaper to dispose of because it does not require as
much manual sorting as mixed waste. There are a number of important reasons why
waste segregation is important such as legal obligations, cost savings, and protection
of human health and the environment. Institutions should make it as easy as possible
for their sta to correctly segregate their waste. This can include labelling, making
sure there are enough accessible bins, and clearly indicating why segregation is so
important.[33] Labeling is especially important when dealing with nuclear waste due to
how much harm to human health the excess products of the nuclear cycle can
cause.[34]

Hazards of waste management

[edit]

There are multiple facets of waste management that all come with hazards, both for
those around the disposal site and those who work within waste management.
Exposure to waste of any kind can be detrimental to the health of the individual,
primary conditions that worsen with exposure to waste
are asthma and tuberculosis.[35] The exposure to waste on an average individual is
highly dependent on the conditions around them, those in less developed or lower
income areas are more susceptible to the e ects of waste product, especially though
chemical waste.[36] The range of hazards due to waste is extremely large and covers
every type of waste, not only chemical. There are many di erent guidelines to follow
for disposing di erent types of waste.[37]

Diagram showing the multiple ways that incineration is

hazardous to the population
The hazards of incineration are a large risk to many variable communities, including
underdeveloped countries and countries or cities with little space for landfills or
alternatives. Burning waste is an easily accessible option for many people around the
globe, it has even been encouraged by the World Health Organization when there is no
other option.[38] Because burning waste is rarely paid attention to, its e ects go
unnoticed. The release of hazardous materials and CO2 when waste is burned is the
largest hazard with incineration.[39]

Financial models

[edit]

In most developed countries, domestic waste disposal is funded from a national or

local tax which may be related to income, or property values. Commercial and
industrial waste disposal is typically charged for as a commercial service, often as an
integrated charge which includes disposal costs. This practice may encourage
disposal contractors to opt for the cheapest disposal option such as landfill rather
than the environmentally best solution such as re-use and recycling.

Financing solid waste management projects can be overwhelming for the city
government, especially if the government see it as an important service they should
render to the citizen. Donors and grants are a funding mechanism that is dependent
on the interest of the donor organization. As much as it is a good way to develop a
city's waste management infrastructure, attracting and utilizing grants is solely reliant
on what the donor considers important. Therefore, it may be a challenge for a city
government to dictate how the funds should be distributed among the various aspect
of waste management.[40]

An example of a country that enforces a waste tax is Italy. The tax is based on two
rates: fixed and variable. The fixed rate is based on the size of the house while the
variable is determined by the number of people living in the house.[41]

The World Bank finances and advises on solid waste management projects using a
diverse suite of products and services, including traditional loans, results-based
financing, development policy financing, and technical advisory. World Bank-financed
waste management projects usually address the entire lifecycle of waste right from
the point of generation to collection and transportation, and finally treatment and
disposal.[6]

Disposal methods

[edit]
Landfill

[edit]

This section is an excerpt from Landfill.[edit]

A landfill in Łubna, Poland in 1999

A landfill[a] is a site for the disposal of waste materials. It is the oldest and most
common form of waste disposal, although the systematic burial of waste with daily,
intermediate and final covers only began in the 1940s. In the past, waste was simply
left in piles or thrown into pits (known in archeology as middens).

Landfills take up a lot of land and pose environmental risks. Some landfill sites are
used for waste management purposes, such as temporary storage, consolidation and
transfer, or for various stages of processing waste material, such as sorting,
treatment, or recycling. Unless they are stabilized, landfills may undergo severe
shaking or soil liquefaction of the ground during an earthquake. Once full, the area
over a landfill site may be reclaimed for other uses.

A landfill compaction vehicle in action.

Spittelau incineration plant in Vienna

Incineration
[edit]

Main article: Incineration

Tarastejärvi Incineration Plant in Tampere, Finland

Incineration is a disposal method in which solid organic wastes are subjected to

combustion so as to convert them into residue and gaseous products. This method is
useful for the disposal of both municipal solid waste and solid residue from
wastewater treatment. This process reduces the volume of solid waste by 80 to 95
percent.[42] Incineration and other high-temperature waste treatment systems are
sometimes described as "thermal treatment". Incinerators convert waste materials
into heat, gas, steam, and ash.

Incineration is carried out both on a small scale by individuals and on a large scale by
industry. It is used to dispose of solid, liquid, and gaseous waste. It is recognized as a
practical method of disposing of certain hazardous waste materials (such as
biological medical waste). Incineration is a controversial method of waste disposal,
due to issues such as the emission of gaseous pollutants including substantial
quantities of carbon dioxide.

Incineration is common in countries such as Japan where land is more scarce, as the
facilities generally do not require as much area as landfills. Waste-to-energy (WtE) or
energy-from-waste (EfW) are broad terms for facilities that burn waste in a furnace or
boiler to generate heat, steam, or electricity. Combustion in an incinerator is not
always perfect and there have been concerns about pollutants in gaseous emissions
from incinerator stacks. Particular concern has focused on some very
persistent organic compounds such as dioxins, furans, and PAHs, which may be
created and which may have serious environmental consequences and some heavy
metals such as mercury[43] and lead which can be volatilised in the combustion
process..

Recycling

[edit]

Main article: Recycling

 Steel crushed and baled for recycling

Recycling is a resource recovery practice that refers to the collection and reuse of
waste materials such as empty beverage containers. This process involves breaking
down and reusing materials that would otherwise be gotten rid of as trash. There are
numerous benefits of recycling, and with so many new technologies making even
more materials recyclable, it is possible to clean up the Earth.[44] Recycling not only
benefits the environment but also positively a ects the economy. The materials from
which the items are made can be made into new products. [45] Materials for recycling
may be collected separately from general waste using dedicated bins and collection
vehicles, a procedure called kerbside collection. In some communities, the owner of
the waste is required to separate the materials into di erent bins (e.g. for paper,
plastics, metals) prior to its collection. In other communities, all recyclable materials
are placed in a single bin for collection, and the sorting is handled later at a central
facility. The latter method is known as "single-stream recycling".[46][47]

A recycling point in Lappajärvi, Finland

The most common consumer products recycled include aluminium such as beverage
cans, copper such as wire, steel from food and aerosol cans, old steel furnishings or
equipment, rubber tyres, polyethylene and PET bottles, glass bottles and
jars, paperboard cartons, newspapers, magazines and light paper, and corrugated
fiberboard boxes.

PVC, LDPE, PP, and PS (see resin identification code) are also recyclable. These items
are usually composed of a single type of material, making them relatively easy to
recycle into new products. The recycling of complex products (such as computers and
electronic equipment) is more di icult, due to the additional dismantling and
separation required.

The type of material accepted for recycling varies by city and country. Each city and
country has di erent recycling programs in place that can handle the various types of
recyclable materials. However, certain variation in acceptance is reflected in the
resale value of the material once it is reprocessed. Some of the types of recycling
include waste paper and cardboard, plastic recycling, metal recycling, electronic
devices, wood recycling, glass recycling, cloth and textile and so many more.[48] In July
2017, the Chinese government announced an import ban of 24 categories of
recyclables and solid waste, including plastic, textiles and mixed paper, placing
tremendous impact on developed countries globally, which exported directly or
indirectly to China.[49]

Re-use

[edit]

Biological reprocessing

[edit]

Main articles: Composting, Home composting, Anaerobic digestion, and Microbial fuel
cell

An active compost heap

Recoverable materials that are organic in nature, such as plant material, food scraps,
and paper products, can be recovered through composting and digestion processes
to decompose the organic matter. The resulting organic material is then recycled
as mulch or compost for agricultural or landscaping purposes. In addition, waste gas
from the process (such as methane) can be captured and used for generating
electricity and heat (CHP/cogeneration) maximising e iciencies. There are di erent
types of composting and digestion methods and technologies. They vary in complexity
from simple home compost heaps to large-scale industrial digestion of mixed
domestic waste. The di erent methods of biological decomposition are classified as
aerobic or anaerobic methods. Some methods use the hybrids of these two methods.
The anaerobic digestion of the organic fraction of solid waste is more environmentally
e ective than landfill, or incineration.[50] The intention of biological processing in
waste management is to control and accelerate the natural process of decomposition
of organic matter. (See resource recovery).

Energy recovery

[edit]

Main article: Waste-to-energy

Energy recovery from waste is the conversion of non-recyclable waste materials into
usable heat, electricity, or fuel through a variety of processes, including combustion,
gasification, pyrolyzation, anaerobic digestion, and landfill gas recovery.[51] This
process is often called waste-to-energy. Energy recovery from waste is part of the non-
hazardous waste management hierarchy. Using energy recovery to convert non-
recyclable waste materials into electricity and heat, generates a renewable energy
source and can reduce carbon emissions by o setting the need for energy from fossil
sources as well as reduce methane generation from landfills.[51] Globally, waste-to-
energy accounts for 16% of waste management.[52]

The energy content of waste products can be harnessed directly by using them as a
direct combustion fuel, or indirectly by processing them into another type of fuel.
Thermal treatment ranges from using waste as a fuel source for cooking or heating and
the use of the gas fuel (see above), to fuel for boilers to generate steam and electricity
in a turbine. Pyrolysis and gasification are two related forms of thermal treatment
where waste materials are heated to high temperatures with
limited oxygen availability. The process usually occurs in a sealed vessel under
high pressure. Pyrolysis of solid waste converts the material into solid, liquid, and gas
products. The liquid and gas can be burnt to produce energy or refined into other
chemical products (chemical refinery). The solid residue (char) can be further refined
into products such as activated carbon. Gasification and advanced Plasma arc
gasification are used to convert organic materials directly into a synthetic gas (syngas)
composed of carbon monoxide and hydrogen. The gas is then burnt to produce
electricity and steam. An alternative to pyrolysis is high-temperature and pressure
supercritical water decomposition (hydrothermal monophasic oxidation).

Pyrolysis
[edit]

Main article: Pyrolysis

Pyrolysis is often used to convert many types of domestic and industrial residues into
a recovered fuel. Di erent types of waste input (such as plant waste, food waste,
tyres) placed in the pyrolysis process potentially yield an alternative to fossil
fuels.[53] Pyrolysis is a process of thermo-chemical decomposition of organic
materials by heat in the absence of stoichiometric quantities of oxygen; the
decomposition produces various hydrocarbon gases.[54] During pyrolysis, the
molecules of an object vibrate at high frequencies to the extent that molecules start
breaking down. The rate of pyrolysis increases with temperature. In industrial
applications, temperatures are above 430 °C (800 °F). [55]

Slow pyrolysis produces gases and solid charcoal. [56] Pyrolysis holds promise for
conversion of waste biomass into useful liquid fuel. Pyrolysis of waste wood and
plastics can potentially produce fuel. The solids left from pyrolysis contain metals,
glass, sand, and pyrolysis coke which does not convert to gas. Compared to the
process of incineration, certain types of pyrolysis processes release less harmful by-
products that contain alkali metals, sulphur, and chlorine. However, pyrolysis of some
waste yields gases which impact the environment such as HCl and SO 2.[57]

Resource recovery

[edit]

Main article: Resource recovery

Resource recovery is the systematic diversion of waste, which was intended for
disposal, for a specific next use.[58] It is the processing of recyclables to extract or
recover materials and resources, or convert to energy.[59] These activities are
performed at a resource recovery facility.[59] Resource recovery is not only
environmentally important, but it is also cost-e ective.[60] It decreases the amount of
waste for disposal, saves space in landfills, and conserves natural resources. [60]

Resource recovery, an alternative approach to traditional waste management, utilizes

life cycle analysis (LCA) to evaluate and optimize waste handling strategies.
Comprehensive studies focusing on mixed municipal solid waste (MSW) have
identified a preferred pathway for maximizing resource e iciency and minimizing
environmental impact, including e ective waste administration and management,
source separation of waste materials, e icient collection systems, reuse and
recycling of non-organic fractions, and processing of organic material through
anaerobic digestion.

As an example of how resource recycling can be beneficial, many items thrown away
contain metals that can be recycled to create a profit, such as the components in
circuit boards. Wood chippings in pallets and other packaging materials can be
recycled into useful products for horticulture. The recycled chips can cover paths,
walkways, or arena surfaces.

Application of rational and consistent waste management practices can yield a range
of benefits including:

1. Economic – Improving economic e iciency through the means of resource use,

treatment, and disposal and creating markets for recycles can lead to e icient
practices in the production and consumption of products and materials
resulting in valuable materials being recovered for reuse and the potential for
new jobs and new business opportunities.

2. Social – By reducing adverse impacts on health through proper waste

management practices, the resulting consequences are more appealing to civic
communities. Better social advantages can lead to new sources of employment
and potentially lift communities out of poverty, especially in some of the
developing poorer countries and cities.

3. Environmental – Reducing or eliminating adverse impacts on the environment

through reducing, reusing, recycling, and minimizing resource extraction can
result in improved air and water quality and help in the reduction of greenhouse
gas emissions.

4. Inter-generational Equity – Following e ective waste management practices

can provide subsequent generations a more robust economy, a fairer and
more inclusive society and a cleaner environment.[18][page needed]

Waste valorization

[edit]

This section is an excerpt from Waste valorization.[edit]

Waste valorization, beneficial reuse, beneficial use, value recovery or waste

reclamation[61] is the process of waste products or residues from an economic process
being valorized (given economic value), by reuse or recycling in order to create
economically useful materials.[62][61][63] The term comes from practices in sustainable
manufacturing and economics, industrial ecology and waste management. The term
is usually applied in industrial processes where residue from creating or processing
one good is used as a raw material or energy feedstock for another industrial
process.[61][63] Industrial wastes in particular are good candidates for valorization
because they tend to be more consistent and predictable than other waste, such
as household waste.[61][64]

Historically, most industrial processes treated waste products as something to be

disposed of, causing industrial pollution unless handled properly.[65] However,
increased regulation of residual materials and socioeconomic changes, such as the
introduction of ideas about sustainable development and circular economy in the
1990s and 2000s increased focus on industrial practices to recover these
resources as value add materials.[65][66] Academics focus on finding economic value to
reduce environmental impact of other industries as well, for example the
development of non-timber forest products to encourage conservation.

Liquid waste-management

[edit]

Liquid waste is an important category of waste management because it is so di icult

to deal with. Unlike solid wastes, liquid wastes cannot be easily picked up and
removed from an environment. Liquid wastes spread out, and easily pollute other
sources of liquid if brought into contact. This type of waste also soaks into objects like
soil and groundwater. This in turn carries over to pollute the plants, the animals in the
ecosystem, as well as the humans within the area of the pollution. [67]

Industrial wastewater

[edit]

This section is an excerpt from Industrial wastewater treatment.[edit]

Wastewater from an
industrial process can be converted at a treatment plant to solids and treated water
for reuse.
Industrial wastewater treatment describes the processes used for treating
wastewater that is produced by industries as an undesirable by-product. After
treatment, the treated industrial wastewater (or e luent) may be reused or released to
a sanitary sewer or to a surface water in the environment. Some industrial facilities
generate wastewater that can be treated in sewage treatment plants. Most industrial
processes, such as petroleum refineries, chemical and petrochemical plants have
their own specialized facilities to treat their wastewaters so that the pollutant
concentrations in the treated wastewater comply with the regulations regarding
disposal of wastewaters into sewers or into rivers, lakes or oceans.[68]: 1412 This applies
to industries that generate wastewater with high concentrations of organic matter (e.g.
oil and grease), toxic pollutants (e.g. heavy metals, volatile organic compounds) or
nutrients such as ammonia.[69]: 180 Some industries install a pre-treatment system to
remove some pollutants (e.g., toxic compounds), and then discharge the partially
treated wastewater to the municipal sewer system. [70]: 60

Most industries produce some wastewater. Recent trends have been to minimize such
production or to recycle treated wastewater within the production process. Some
industries have been successful at redesigning their manufacturing processes to
reduce or eliminate pollutants.[71] Sources of industrial wastewater include battery
manufacturing, chemical manufacturing, electric power plants, food industry, iron
and steel industry, metal working, mines and quarries, nuclear industry, oil and gas
extraction, petroleum refining and petrochemicals, pharmaceutical
manufacturing, pulp and paper industry, smelters, textile mills, industrial oil
contamination, water treatment and wood preserving. Treatment processes include
brine treatment, solids removal (e.g. chemical precipitation, filtration), oils and grease
removal, removal of biodegradable organics, removal of other organics, removal of
acids and alkalis, and removal of toxic materials.

Sewage sludge treatment

[edit]

This section is an excerpt from Sewage sludge treatment.[edit]

 Sludge treatment in anaerobic digesters at a sewage
treatment plant in Cottbus, Germany

Sewage sludge treatment describes the processes used to manage and dispose
of sewage sludge produced during sewage treatment. Sludge treatment is focused on
reducing sludge weight and volume to reduce transportation and disposal costs, and
on reducing potential health risks of disposal options. Water removal is the primary
means of weight and volume reduction, while pathogen destruction is frequently
accomplished through heating during thermophilic digestion, composting,
or incineration. The choice of a sludge treatment method depends on the volume of
sludge generated, and comparison of treatment costs required for available disposal
options. Air-drying and composting may be attractive to rural communities, while
limited land availability may make aerobic digestion and mechanical dewatering
preferable for cities, and economies of scale may encourage energy
recovery alternatives in metropolitan areas.

Sludge is mostly water with some amounts of solid material removed from liquid
sewage. Primary sludge includes settleable solids removed during primary treatment
in primary clarifiers. Secondary sludge is sludge separated in secondary clarifiers that
are used in secondary treatment bioreactors or processes using inorganic oxidizing
agents. In intensive sewage treatment processes, the sludge produced needs to be
removed from the liquid line on a continuous basis because the volumes of the tanks
in the liquid line have insu icient volume to store sludge.[72] This is done in order to
keep the treatment processes compact and in balance (production of sludge
approximately equal to the removal of sludge). The sludge removed from the liquid line
goes to the sludge treatment line. Aerobic processes (such as the activated
sludge process) tend to produce more sludge compared with anaerobic processes. On
the other hand, in extensive (natural) treatment processes, such
as ponds and constructed wetlands, the produced sludge remains accumulated in the
treatment units (liquid line) and is only removed after several years of operation. [73]

Sludge treatment options depend on the amount of solids generated and other site-
specific conditions. Composting is most often applied to small-scale plants with
aerobic digestion for mid-sized operations, and anaerobic digestion for the larger-
scale operations. The sludge is sometimes passed through a so-called pre-thickener
which de-waters the sludge. Types of pre-thickeners include centrifugal sludge
thickeners,[74] rotary drum sludge thickeners and belt filter presses.[75] Dewatered
sludge may be incinerated or transported o site for disposal in a landfill or use as an
agricultural soil amendment.[76]

Energy may be recovered from sludge through methane gas production during
anaerobic digestion or through incineration of dried sludge, but energy yield is often
insu icient to evaporate sludge water content or to power blowers, pumps, or
centrifuges required for dewatering. Coarse primary solids and secondary sewage
sludge may include toxic chemicals removed from liquid sewage by sorption onto
solid particles in clarifier sludge. Reducing sludge volume may increase
the concentration of some of these toxic chemicals in the sludge. [77]

Avoidance and reduction methods

[edit]

Main article: Waste minimization

An important method of waste management is the prevention of waste material being

created, also known as waste reduction. Waste minimization is reducing the quantity
of hazardous wastes achieved through a thorough application of innovative or
alternative procedures.[78] Methods of avoidance include reuse of second-hand
products, repairing broken items instead of buying new ones, designing products to be
refillable or reusable (such as cotton instead of plastic shopping bags), encouraging
consumers to avoid using disposable products (such as disposable cutlery), removing
any food/liquid remains from cans and packaging,[79] and designing products that use
less material to achieve the same purpose (for example, lightweighting of beverage
cans).[80]

International waste trade

[edit]

This section is an excerpt from Global waste trade.[edit]

The global waste trade is the international trade of waste between countries for
further treatment, disposal, or recycling. Toxic or hazardous wastes are often
imported by developing countries from developed countries.
The World Bank Report What a Waste: A Global Review of Solid Waste Management,
describes the amount of solid waste produced in a given country. Specifically,
countries which produce more solid waste are more economically developed and
more industrialized.[81] The report explains that "Generally, the higher the economic
development and rate of urbanization, the greater the amount of solid waste
produced."[81] Therefore, countries in the Global North, which are more economically
developed and urbanized, produce more solid waste than Global South countries.[81]

Current international trade flows of waste follow a pattern of waste being produced in
the Global North and being exported to and disposed of in the Global South. Multiple
factors a ect which countries produce waste and at what magnitude, including
geographic location, degree of industrialization, and level of integration into the global
economy.

Numerous scholars and researchers have linked the sharp increase in waste trading
and the negative impacts of waste trading to the prevalence of neoliberal economic
policy.[82][83][84][85] With the major economic transition towards neoliberal economic
policy in the 1980s, the shift towards "free-market" policy has facilitated the sharp
increase in the global waste trade. Henry Giroux, Chair of Cultural Studies at
McMaster University, gives his definition of neoliberal economic policy:

"Neoliberalism ...removes economics and markets from the discourse of social

obligations and social costs. ...As a policy and political project, neoliberalism is
wedded to the privatization of public services, selling o of state functions,
deregulation of finance and labor, elimination of the welfare state and unions,
liberalization of trade in goods and capital investment, and the marketization
and commodification of society."[86]

Given this economic platform of privatization, neoliberalism is based on expanding

free-trade agreements and establishing open-borders to international trade
markets. Trade liberalization, a neoliberal economic policy in which trade is
completely deregulated, leaving no tari s, quotas, or other restrictions on
international trade, is designed to further developing countries' economies and
integrate them into the global economy. Critics claim that although free-market trade
liberalization was designed to allow any country the opportunity to reach economic
success, the consequences of these policies have been devastating for Global South
countries, essentially crippling their economies in a servitude to the Global
North.[87] Even supporters such as the International Monetary Fund, “progress of
integration has been uneven in recent decades.”[88] Specifically, developing countries
have been targeted by trade liberalization policies to import waste as a means
of economic expansion.[89] The guiding neoliberal economic policy argues that the way
to be integrated into the global economy is to participate in trade liberalization and
exchange in international trade markets.[89] Their claim is that smaller countries, with
less infrastructure, less wealth, and less manufacturing ability, should take in
hazardous wastes as a way to increase profits and stimulate their economies. [89]