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.
Government has set up a Swachh Bharat Kosh (Clean India Fund) to attract funds from corporate and individuals to improve sanitation facilities, particularly in schools. Apart from this, measure like putting garbage bins at every hundred metres, public toilets at every kilometre will also help in keeping the roads cleaner.
According to the United Nations, around half of the India’s population defecate in open putting people at risk of cholera, diarrhoea, dysentery, hepatitis A and typhoid etc. According to a recent study by World Health Organization (WHO), lack of hygienic conditions and cleanliness cost around INR6,500 to each Indian every year.