Solid
Waste
Solid
waste refers to non-soluble material such as agricultural refuse, industrial
waste,
mining residues, demolition waste, municipal garbage
or even sewage sludge. Most of these kindof wastes cannot be recycled or
rehabilitated for further use.
Solid
Waste Management
Solid waste management is the entire process
involved in the recycling process. Solidwaste management starts with the trucks
picking up recyclables, delivering them to the recycling.
Solid waste management (SWM) is associated with the
control of waste generation, its storage, collection, transfer and transport,
processing and disposal in a manner that is in accordance with the best
principles of public health, economics, engineering,
conservation, aesthetics, public
attitude and other environmental
considerations.
Put
differently, the SWM
processes differ depending
on factors such as economic status
(e.g., the ratio
of wealth created
by the production
of primary products to
that derived from manufactured goods, per capita income,etc.), degree of industrialisation, social development
(e.g., education, literacy, healthcare,
etc.) and quality
of life of a
location. In addition,regional, seasonal and economic differences influence the SWM
processes.
CLASSIFICATION OF SOLID WASTES
Solid wastes are the organic and inorganic waste
materials such as product packaging, grass clippings, furniture, clothing,
bottles, kitchen refuse, paper,
appliances, paint cans, batteries, etc., produced in a society, which do not generally carry any value to the
first user(s). Solid wastes, thus, encompass both a heterogeneous mass of
wastes from the urban community as well as a more homogeneous accumulation of
agricultural, industrial and mineral wastes. While wastes have little or no
value in one setting or to the one who wants to dispose them, the discharged
wastes may gain significant value in another setting. Knowledge of the sources
and types of solid wastes as well as the information on composition and the
rate at which wastes are generated/ disposed is, therefore, essential for the
design and operation of the functional elements associated with the management
of solid wastes.
1 Source-based classification
(i)
Residential: This refers to wastes from
dwellings, apartments, etc.,
and
consists of leftover food, vegetable peels, plastic, clothes, ashes, etc.
(ii)
Commercial: This refers to wastes
consisting of leftover food, glasses,
metals, ashes, etc., generated from stores,
restaurants, markets, hotels, motels, auto-repair shops, medical facilities,
etc.
(iii)
Institutional: This mainly consists of
paper, plastic, glasses, etc., generated from educational, administrative and
public buildings such as schools, colleges, offices, prisons, etc.
(iv)
Municipal: This includes dust, leafy
matter, building debris, treatment plant residual sludge, etc., generated from
various municipal activities like construction and demolition, street cleaning,
landscaping, etc.
(v)
Industrial: This mainly consists of process
wastes, ashes, demolition and construction wastes, hazardous wastes, etc., due
to industrial activities.
(vi)
Agricultural: This mainly consists of
spoiled food grains and vegetables, agricultural remains, litter, etc.,
generated from fields, orchards, vineyards, farms, etc.
(vii) Open
areas: this includes wastes from areas such as Streets, alleys, parks, vacant
lots, playgrounds, beaches, highways, recreational areas, etc.
2. Type-based
classification
Classification of wastes based on types, i.e.,
physical, chemical, and biological characteristi cs of wastes, is as follows.
(i)
Garbage: This refers to animal and
vegetable wastes resulting from the
handling, sale,
storage, preparation, cooking
and serving of food. Garbage comprising these wastes contains putrescible (rotting) organic
matter, which produces an obnoxious odour and attracts rats and other vermin.
It, therefore, requires special attention in storage, handling and disposal.
(ii) Ashes and residues: These are substances
remaining from the burning of wood, coal, charcoal, coke and other combustible
materials for cooking and heating in houses, institutions and small industrial
establishments. When produced in large quantities, as in power-generation
plants and factories, these are classified as industrial wastes. Ashes consist
of fine powdery residue, cinders and clinker often mixed with small pieces of
metal and glass. Since ashes and residues are almost entirely inorganic, they
are valuable in landfills. (iii) Combustible and non-combustible wastes: These
consist of wastes generated from households, institutions, commercial
activities, etc., excluding food wastes and other highly putrescible material.
Typically, while combustible material consists of paper, cardboard, textile,
rubber, garden trimmings, etc., non-combustible material consists of such items
as glass, crockery, tin and aluminium cans, ferrous and non-ferrous material
and dirt.
(iv) Bulky wastes: These include large household
appliances such as refrigerators, washing machines, furniture, crates, vehicle
parts, tyres, wood, trees and branches. Since these household wastes cannot be
accommodated in normal storage containers, they require a special collection
mechanism.
(v)
Street wastes: These refer to wastes
that are collected from streets, walkways, alleys, parks and vacant plots, and
include paper, cardboard, plastics, dirt, leaves and other vegetable matter.
Littering in public places is indeed a widespread and acute problem in many
countries including India, and a solid waste management system must address
this menace appropriately.
(vi)
Biodegradable and non-biodegradable
wastes: Biodegradable wastes mainly refer to substances consisting of organic
matter such as leftover food, vegetable and fruit peels, paper, textile, wood,
etc., generated from various household and industrial activities. Because of
the action of micro-organisms,
these wastes are degraded from complex to simpler
compounds. Non-biodegradable wastes consist of inorganic and recyclable
materials such as plastic, glass, cans, metals, etc.
(vii) Dead animals: With regard to municipal wastes,
dead animals are those that die naturally or are accidentally killed on the
road. Note that this category does not include carcasses and animal parts from
slaughter-houses, which are regarded as industrial wastes. Dead animals are
divided into two groups - large and small. Among the large animals are horses,
cows, goats, sheep, pigs, etc., and among the small ones are dogs, cats,
rabbits, rats, etc. The reason for this differentiation is that large animals
require special equipment for lifting and handling when they are removed. If
not collected promptly, dead animals pose a threat to public health since they
attract flies and other vermin as they decay. Their presence in public places
is particularly offensive from the aesthetic point of view
as
well.
(viii) Abandoned vehicles: This category includes
automobiles, trucks and trailers that are abandoned on streets and other public
places. However, abandoned vehicles have significant scrap value for their
metal, and their value to collectors is highly variable.
(ix)
Construction and demolition wastes:
These are wastes generated as a result
of construction, refurbishment, repair and
demolition of houses, commercial buildings and other structures. They consist
mainly of earth, stones, concrete, bricks, lumber, roofing and plumbing
materials, heating systems and electrical wires and parts of the general
municipal waste stream.
(x) Farm Wastes: These wastes result from diverse
agricultural activities such as planting, harvesting, production of milk,
rearing of animals for slaughter and the operation of feedlots. In many areas,
the disposal of animal waste has become a critical problem, especially from
feedlots, poultry farms and dairies.
(xi) Hazardous wastes: Hazardous wastes are those
defined as wastes of industrial, institutional or consumer origin that are
potentially dangerous either immediately or over a period of time to human
beings and the environment. This is due to their physical, chemical and
biological or radioactive characteristics like ignitability, corrosivity,
reactivity and toxicity. Note that in some cases, the active agents may be
liquid or gaseous hazardous wastes. These are, nevertheless, classified as
solid wastes as they are confined in solid containers. Typical examples of
hazardous wastes are empty containers of solvents, paints and pesticides, which
are frequently mixed with municipal wastes and become part of the urban waste
stream. Certain hazardous wastes may cause explosions in incinerators and fires
at landfill sites. Others such as pathological wastes from hospitals and
radioactive wastes also require special handling. Effective management practices should
ensure that hazardous wastes are stored, collected, transported and
disposed of separately, preferably after suitable treatment to render them
harmless.
(xii)
Sewage wastes: The solid
by-products of sewage treatment are classified as sewage wastes. They are
mostly organic and derived from the treatment of organic sludge separated from
both raw and treated sewages. The inorganic fraction of raw sewage such as grit
and eggshells is separated at the preliminary stage of treatment, as it may
entrain putrescible organic matter with pathogens and must be buried without
delay. The bulk of treated, dewatered sludge is useful as a soil conditioner
but is invariably uneconomical. Solid sludge, therefore, enters the stream of
municipal wastes, unless special arrangements are made for its disposal.
Related Topics
Privacy Policy, Terms and Conditions, DMCA Policy and Compliant
Copyright © 2018-2023 BrainKart.com; All Rights Reserved. Developed by Therithal info, Chennai.