• Waste management is the collection, transport,
processing or disposal, managing and monitoring
of waste materials. The term usually relates to
materials produced by human activity, and the
process is generally undertaken to reduce their
effect on health, the environment or aesthetics.
Waste management is a distinct practice
from resource recovery which focuses on
delaying the rate of consumption of natural
resources. All waste materials, whether they
are solid, liquid, gaseous or radioactive fall within
the remit of waste management.
• Waste management practices can differ
for developed and developing nations,
for urban and rural areas, and
for residential and industrial producers.
Management of non-hazardous waste residential
and institutional waste in metropolitan areas is
usually the responsibility of local government
authorities, while management for non-
hazardous commercial and industrial waste is
usually the responsibility of the generator subject
to local, national or international authorities.
Types of waste
Generally, waste could be liquid or solid waste. Both of them could be
hazardous. Liquid and solid waste types can also be grouped into
organic, re-usable and recyclable waste.
Let us see some details below:
• Liquid type:
Waste can come in non-solid form. Some solid waste can also be
converted to a liquid waste form for disposal. It includes point source and
non-point source discharges such as storm water and wastewater.
Examples of liquid waste include wash water from homes, liquids used for
cleaning in industries and waste detergents.
• Solid type:
Solid waste predominantly, is any garbage, refuse or rubbish that we make
in our homes and other places. These include old car tires, old
newspapers, broken furniture and even food waste. They may include any
waste that is non-liquid.
• Hazardous type:
Hazardous or harmful waste are those that potentially threaten public health or
the environment. Such waste could be inflammable (can easily catch
fire), reactive (can easily explode),corrosive (can easily eat through metal)
or toxic (poisonous to human and animals).
• Organic type:
Organic waste comes from plants or animals sources. Commonly, they include food
waste, fruit and vegetable peels, flower trimmings and even dog poop can be
classified as organic waste. They are biodegradable (this means they are easily
broken down by other organisms over time and turned into manure). Many people
turn their organic waste into compost and use them in their gardens.
• Recyclable type:
Recycling is processing used materials (waste) into new, useful products. This is
done to reduce the use of raw materials that would have been used. Waste that
can be potentially recycled is termed "Recyclable waste". Aluminum products (like
soda, milk and tomato cans), Plastics (grocery shopping bags, plastic bottles), Glass
products (like wine and beer bottles, broken glass), Paper products (used
envelopes, newspapers and magazines, cardboard boxes) can be recycled and fall
into this category.
Sources of waste
Municipal sources of waste:
This includes trash or garbage from households, schools, offices, market places, restaurants
and other public places.
They include everyday items like food debris, used plastic bags, soda cans and plastic water
bottles, broken furniture, grass clippings, product packaging, broken home appliances and
Medical/Clinical sources of waste:
Medical/clinical waste, normally refers to waste produced from health care facilities, such as
hospitals, clinics, surgical theaters, veterinary hospitals and labs. They tend to be classified as
hazard waste rather than general waste.
• Items in this group include surgical items, pharmaceuticals, blood, body parts, wound
dressing materials, needles and syringes
Agricultural sources of waste:
Typically, this is waste generated by agricultural activities. These include horticulture, fruit
growing, seed growing, livestock breeding, market gardens and seedling nurseries.
• Waste items in this group include empty pesticide containers, old silage wrap, out of date
medicines and wormers, used tires, surplus milk, cocoa pods and corn husks.
When cars are all old and not working again, where do they end up? Many people just leave
them to rust in the fields, but there is a better way to deal with them. In many cities, these
vehicles are sent to the plant, where all the removable parts are taken out for recycling. The
rest is flattened up and shredded into peice for recycling. The last bits that cannot be used
again is sent to a landfill.
Industrial sources of waste:
Since the industrial revolution, the rise in the number of industries manufacturing
glass, leather, textile, food, electronics, plastic and metal products has significantly
contributed to waste production. Take a look at the things in your home, every item there
was probably manufactured and possibly, waste was produced as a result.
Construction/demolition sources of waste:
Construction waste is that resulting from the construction of roads and building. Sometimes
old buildings and structures are pulled down (demolished) to make space for new ones. This
is particularly common in old cities that are modernizing. This is called demolition waste.
Waste items include concrete debris, wood, earth, huge package boxes and plastics from the
building materials and the like.
Electronic sources of waste:
This is waste from electronic and electrical devices. Think of DVD and music
players, TV, Telephones, computers, vacuum cleaners and all the other electrical stuff in your
home. These are also called e-waste, e-scrap, or waste electrical and electronic equipment
Some e-waste (like TV) contains lead, mercury, cadmium, and brominated flame retardants.
These are harmful to humans and the environment. It is therefore important that the right
authorities ensure the proper disposal of such waste.
Methods of disposal
• 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 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 as
organic waste breaks down anaerobically. 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 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 managment. 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.
• 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 emission of gaseous pollutants.
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 are sorted directly from mixed waste streams and are known as kerb-side
recycling, it requires the owner of the waste to separate it into various different
bins (typically wheelie bins) prior to its collection.
• The most common consumer products recycled include aluminium such as
beverage cans, copper such as wire, steel 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
• 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 difficult, 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 different 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.
The management of waste is a key component in a business' ability
to maintaining accreditation. Companies are encouraged to
improve their environmental efficiencies each year by eliminating
waste through resource recovery practices, which are sustainability-
related activities. One way to do this is by shifting away from waste
management to resource recovery practices like recycling materials
such as glass, food scraps, paper and cardboard, plastic bottles and
• 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.
• 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 pyrolisis is high temperature and
pressure supercritical water decomposition (hydrothermal monophasic
• moving any food/liquid remains from cans, packaging, and designing
products that use less material to achieve the same purpose (for example,
light weighting of beverage cans).[
• Resource recovery:-
Resource recovery (as opposed to waste management) uses LCA (life cycle
analysis) attempts to offer alternatives to waste management. For mixed MSW
(Municipal Solid Waste) a number of broad studies have indicated that
administration, source separation and collection followed by reuse and recycling of
the non-organic fraction and energy and compost/fertilizer production of the
organic material via anaerobic digestion to be the favoured path.
• Avoidance and reduction methods:-
An important method of waste management is the prevention of waste material
being created, also known as waste reduction. Methods of avoidance include
reuse of second-hand products, repairing broken items instead of buying
new, 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, packaging, ...[ and designing products that use less material to achieve the
same purpose (for example, light weighting of beverage cans).[