WASTE MANAGEMENT
Waste management is all those activities and action required to
manage waste from its inception to its final disposal.[1] This includes
amongst other things, collection, transport, treatment and disposal of
waste together with monitoring and regulation. It also encompasses the
legal and regulatory framework the relates to waste management
encompassing guidance on recycling etc.
The term usually relates to all kinds of waste, whether generated during
the extraction of raw materials, the processing of raw materials into
intermediate and final products, the consumption of final products, or
other human activities,[1] including municipal (residential, institutional,
commercial), agricultural, and special (health care, household
hazardous wastes, sewage sludge).[2] Waste management is intended to
reduce adverse effects of waste on health, the environment or aesthetics.
Waste management practices are not uniform among countries
(developed and developing nations); regions (urban and rural area), and
sectors (residential and industrial).
Contents
1 Central principles of waste management
o 1.1 Waste hierarchy
o 1.2 Life-cycle of a Product
o 1.3 Resource efficiency
o 1.4 Polluter pays principle
2 Waste handling and transport
o 2.1 Waste handling practices
3 Disposal solutions
o 3.1 Landfill
o 3.2 Incineration
4 Recycling
5 Re-use
o 5.1 Biological reprocessing
o 5.2 Energy recovery
o
o
o
5.3 Pyrolysis
5.4 Resource recovery
5.5 Sustainability
6 Benefits
7 Challenges in developing countries
Central principles of waste management
There are a number of concepts about waste management which vary in
their usage between countries or regions. Some of the most general,
widely used concepts include:
Waste hierarchy
The waste hierarchy refers to the "3 Rs" reduce, reuse and recycle. The
waste hierarchy is represented as a pyramid because the basic premise is
for policy to take action first and prevent the generation of waste. The
next step or preferred action is to reduce the generation of waste i.e. by
re-use. The next is recycling which would include composting.
Following this step is material recovery and waste-to-energy. Energy
can be recovered from processes i.e. landfill and combustion, at this
level of the hierarchy. The final action is disposal, in landfills or
through incineration without energy recovery.
Life-cycle of a Product
The life-cycle begins with design, then proceeds through manufacture,
distribution, use and then follows through the waste hierarchy's stages
of reuse, recovery, recycling and disposal. Each of the above stages of
the life-cycle offers opportunities for policy intervention, to rethink the
need for the product, to redesign to minimize waste potential, to extend
its use.[4] The key behind the life-cycle of a product is to optimize the
use of the world's limited resources by avoiding the unnecessary
generation of waste.
Resource efficiency
Resource efficiency reflects the understanding that current, global,
economic growth and development can not be sustained with the
current production and consumption patterns. Resource efficiency is the
reduction of the environmental impact from the production and
consumption of these goods, from final raw material extraction to last
use and disposal.
Polluter pays principle
The Polluter pays principle is a principle where the polluting party pays
for the impact caused to 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 material
Waste handling and transport
Waste collection methods vary widely among different 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 practices
Curbside collection is the most common method of disposal in most
European countries, Canada, New Zealand and many other parts of the
developed world in which waste is collected at regular intervals by
specialised trucks.Waste collected is then transported to an appropriate
disposal facility.
Disposal solutions
Landfill
Disposal of waste in a landfill involves burying the waste and this remains a
common practice in most countries. Landfills were often established in
abandoned or unused quarries, mining voids or borrow pits. A properly
designed and well-managed landfill can be a hygienic and relatively
inexpensive method of disposing of waste materials. Older, poorly designed
or poorly managed landfills and open dumps can create a number of adverse
environmental impacts such as wind-blown litter, attraction of vermin, and
generation of liquid leachate. Another common product of landfills is gas
(mostly composed of methane and carbon dioxide), which is produced from
anaerobic breakdown of organic waste. This gas can create odor problems,
kill surface vegetation and is a greenhouse gas.
Design characteristics of a modern landfill include methods to contain
leachate such as clay or plastic lining material. Deposited waste is normally
compacted to increase its density and stability and covered to prevent
attracting vermin (such as mice or rats). Many landfills also have landfill gas
extraction systems installed to extract the landfill gas. Gas is pumped out of
the landfill using perforated pipes and flared off or burnt in a gas engine to
generate electricity.
Incineration
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 disposal of residue of both solid waste management and
solid residue from waste water management. This process reduces the
volumes of solid waste to 20 to 30 percent of the original volume.
Incineration and other high temperature waste treatment systems are
sometimes described as "thermal treatment". Incinerators convert waste
materials into heat, gas, steam, and ash.
Spittelau incineration plant in Vienna
Recycling
Recycling is a resource recovery practice that refers to the collection and
reuse of waste materials such as empty beverage containers. The materials
from which the items are made can be reprocessed into new products.
Material for recycling may be collected separately from general waste using
dedicated bins and collection vehicles, a procedure called kerbside
collection.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, polyethylene and PET bottles, glass
bottles and jars, paperboard cartons, newspapers, magazines and light paper,
and corrugated fiberboard boxes.
Re-use
Biological reprocessing
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 efficiencies. The intention of biological processing in waste
management is to control and accelerate the natural process of
decomposition of organic matter
An Active compost heap
Energy recovery
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.[16] 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 offsetting the need for energy from fossil sources
as well as reduce methane generation from landfills.[16] Globally, waste-toenergy accounts for 16% of waste management.
Anaerobic digestion component of Lbeck mechanical biological
treatment plant in Germany, 2007
Pyrolysis
Pyrolysis is a process of thermo-chemically decomposition of organic
materials by heat in the absence of oxygen which produces various
hydrocarbon gases.The rate of pyrolysis increases with temperature. In
industrial applications, temperatures are above 430 C (8 Fast pyrolysis
produces liquid fuel for feedstocks like wood. Fast pyrolysis produces liquid
fuel for feedstocks like wood. Slow pyrolysis produces gases and solid
charcoal.
Resource recovery
Resource recovery is the systematic diversion of waste, which was intended
for disposal, for a specific next use.[21] It is the processing of recyclables to
extract or recover materials and resourcesResource recovery is not only
environmentally important, but it is also cost effective.[23] It decreases the
amount of waste for disposal, saves space in landfills, and conserves natural
resources.
As an example of how resource recycling can be beneficial, many of the items
thrown away contain precious metals which can be recycled to create a
profit, such as the components in circuit boards.
Sustainability
The management of waste is a key component in a business' ability to
maintaining ISO14001(International Organization for Standardization
for environmental certification) accreditation. Companies are
encouraged to improve their environmental efficiencies each year by
eliminating waste through resource recovery practices, which are
sustainability-related activities.
Benefits
Waste is not something that should be discarded or disposed of with no
regard for future use. It can be a valuable resource if addressed
correctly, through policy and practice.
1. Economic - Improving economic efficiency through the means
of resource use, treatment and disposal.
2. Social - By reducing adverse impacts on health by proper waste
management practices
3. Environmental - Reducing or eliminating adverse impacts on the
environmental through reducing, reusing and recycling
Challenges in developing countries
Waste management in cities with developing economies and economies
in transition experience exhausted waste collection services,
inadequately managed and uncontrolled dumpsites and the problems are
worsening.[4] Problems with governance also complicate the situation.
Waste management, in these countries and cities, is an ongoing
challenge and many struggle due to weak institutions, chronic underresourcing and rapid urbanization.[4] All of these challenges along with
the lack of understanding of different factors that contribute to the
hierarchy of waste management, affect the treatment of waste
