Management of solid waste may be defined as the control of
generation, segregation, storage, collection, transfer and transport,
processing, and disposal of waste based on scientific principles. This
includes all technological, financial, institutional, and legal and
policy aspects involved for solving the whole spectrum of issues related
with solid wastes. The term ‘waste’ usually relates to materials
produced by human activity, and the process is generally undertaken to
reduce their effect on the health and environment. Waste that is not
properly managed can create serious health or social problems in a
community
In many countries, solid waste management has become a top
priority. Solid Waste Management (SWM) is a system for handling of all
type of garbage. The end goal is to reduce the amount of garbage
clogging the streets and polluting the environment. Climate change and
effects of greenhouse gas emissions have made SWM, one of the most
pressing environmental challenges globally as well as locally. It is
well understood that inappropriate SWM practices, such as improper
incineration and uncontrolled disposal of wastes are major contributors
to greenhouse gas emissions.
Based on the source of generation, solid waste can be classified
into residential, commercial, institutional, industrial, agricultural
etc. There are mainly two categories of wastes based on the
type-biodegradable and non-biodegradable. This classification is based
on physical, chemical and biological characteristics of wastes.
Biodegradable wastes mainly refer to substances consisting of organic
matter such as leftover food, vegetables 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.
There are various functional elements associated with the
management of solid wastes such as segregation, collection,
transportation, processing and disposal which are given below:
Waste generation: Wastes are generated at the start of any process,
and thereafter, at every stage as raw materials are converted into
goods for consumption. The source of waste generation determines
quantity, composition and waste characteristics.
Waste storage: Storage of waste after collection and before
transportation to the processing/disposal site is an important
functional component. The time of storage depends on the type of waste.
For example, the biodegradable waste cannot be stored for long in a
storage container because of its putrescible nature. There are many
options for storage like plastic containers, conventional dustbins (of
households), used oil drums, large storage bins (for institutions and
commercial areas or servicing depots), etc.
Waste collection: Collection refers to mainly two aspects;
collection from the source of generation to the next collection point
and collection from that point to the large vehicles for transportation
or to the transfer stations and finally to the processing plant/disposal
area. Collection depends on the number of containers, frequency of
collection, types of collection services and routes. Collection is done
either directly through the municipal services to franchised services or
contracts. Recently, collection of waste from the source to the next
step is carried out by Self Help Groups (SHGs) in many cities in India,
which is very common in the state of Kerala.
Transfer and transport: This functional element involves transfer
of wastes from smaller collection vehicles to larger ones at transfer
stations and the subsequent transport of the waste to disposal sites
Processing: Processing of waste is the most important functional
component of SWM system, which leads to various types of resource
recovery, recycling, energy generation, production of organic manure,
etc. There are many processing techniques, which will be discussed in
detail later.
Disposal of final rejects: Disposal of final rejects after resource
recovery is one of the important functional components of SWM system.
This is mainly achieved through construction of engineered sanitary
landfill. Engineering principles are followed to confine the wastes to
the smallest possible area, reduce them to the lowest particle volume by
compaction at the site and cover them after each day’s operation to
reduce exposure to vermin.
Climate has a major influence in SWM planning. In cold climates
like in Srinagar, Shimla etc, drifting snow and frozen ground interfere
with landfill operations, and therefore, trenches must be dug in summer
and cover material stockpiles for winter use. Tropical climates, on the
other hand, are subject to sharp seasonal variations from wet to dry
season, which cause significant changes in the moisture content of solid
waste, varying from less than 50% in dry season to greater than 65% in
wet months. Collection and disposal of wastes in the wet months are
often problematic. High temperatures and humidity cause solid wastes
decompose far more rapidly than in colder climates.
In India usually a community storage system is practiced where
individuals deposit their waste in bins located at street corners and at
specific intervals. The containers generally are constructed of metal,
concrete, or a combination of the two. Community storage may reduce the
cost of waste collection, and can minimize problems associated with lack
of onsite storage space. However, unless these community storage
arrangements are conveniently located, householders tend to throw their
wastes into the roadside gutters for clearance by street sweeping crews.
Even where storage arrangements are conveniently located, wastes tend
to be strewn around the storage area, partly due to indiscipline and
partly as a result of scavenging of the wastes by rag-pickers and stray
animals.
Commercial sector like shops, offices, hotels, etc. all use the
community waste bins in most of the places and their wastes are also
collected along with the household wastes except in a rare number of
commercial complexes where they pay a negotiated fee to the Municipal
Authorities for collecting waste from their premises.
The larger proportion of organic matter in MSW indicates the
desirability of biological processing of waste. Though composting was a
prevalent biological processing practice in India, in the past due to
non-availability of adequate space in the urban centers and poor
segregation of wastes, composting has been discontinued as a practice.
Recently efforts are being taken to popularize waste segregation and
composting.
Waste management is now gaining the importance it deserved from the
policy makers because of its significance in making the quality of life
better particularly at urban centers. The Ministry of Urban Development
(MoUD) has approved a project to Centre for Environment and Development
to set up a Centre of Excellence (CoE) on ‘Solid Waste and Waste Water
Management ’. The basic objective was to develop the capacity of the
institution to support the Urban Local Bodies (ULB) in the country on
solid waste and waste water management related activities. The CoEs will
work with selected ULBs to develop strategies and framework to
implement activities.
Now a days, three important concepts have emerged in the waste management-
1)Waste hierarchy - The waste hierarchy refers to the "4 Rs"
concept (reduce, reuse, recycle and recover), which classify waste
management strategies according to their desirability in terms of waste
minimization. It remains the keystone of most waste minimization
strategies. The main aim is to extract the maximum practical benefits
from products and to generate the minimum amount of waste.
2)Polluter pays principle - It is a principle where the polluting
party pays for the impact caused to the environment. Here, it refers to
the requirement for a waste generator to pay for appropriate disposal of
the waste.
3)Extended producer responsibility – EPR is a strategy designed to
promote the integration of all costs associated with products throughout
their life cycle (including end-of-life disposal costs) into the market
price of the product. This means that firms which manufacture, import
and/or sell products are required to be responsible for the products
after their useful life as well as during manufacture.
It is required to make the solid waste management a comprehensive
strategy, above mentioned three concepts must be integrated with any
waste management strategy. Apart from the general solid waste,
proportion of e-waste (electronic waste) is consistently increasing
likely to increase more with the increasing use of mobile phones,
computers laptops and other electronic gadgets etc. Therefore above
concepts must be integrated with electronic industry in order to reduce
the hazards of e-waste.
In 2000, the Municipal Solid Waste (Management and Handling) Rules
lay down the steps to be taken by all municipal authorities to ensure
management of solid waste according to best practices. However solid
waste management in India is yet to get the desired place but programmes
like Jawaharlal Nehru National Urban Renewal Mission (JNNURM) provide
incentive for good waste management. Greater Hyderabad Municipal
Corporation was awarded the “Best City” for 2009-10 for its efforts to
improve Solid Waste Management under the Jawaharlal Nehru National Urban
Renewal Mission. Though in 2010, only 27.8 percent of total population
was residing in urban areas but urban population is growing at much
faster rate than rural one and therefore, urban areas will witness a
spurt in growth. In this scenario, if waste management is not properly
followed, instead of witnessing urbanization, India may witness the
slumisation.
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Ankit Shukla