UNDERSTANDING WASTES- ITS TYPES AND SOURCES

Wastes includes all those items that people no longer have any use for ,which they either intend to get rid or have already discarded.

Wastes are all those items that are required by law to be discarded. 'waste' is a much debated term, since what is waste to someone may be valuable to another. Nature fies not create waste, it is a fallout of our modern lifestyles. What needs no debate is ,waste has to be classified and understood to be able to manage. Waste management is vital to keep the environment unpolluted and  clean. 

CLASSIFICATION OF WASTE

Waste can be classified in different ways and this varies from country to country.

Classification based on Physical state

Waste can be solid ,liquid or gaseous. Liquid wastes  that are discharged into water bodies are called effluents, whereas wastes that are released into the atmosphere are referred to as emissions . The sources of such wastes could be municipal, domestic, agricultural or industrial.

Gaseous emissions from industries leads to air pollution which finally a major cause of global warming  , climate changes and acid rains. The bhopal gas tragedy ,one of the worst industrial disaster s in the world,was caused by the emission of methyl isocyanate, a poisonous gas from a pesticide factory.

  

Industries are often located near the water bodies. This is because it is easy to dump the liquid wastes into the water bodies. Even solid wastes that can dissolve in water are released into streams, rivers and oceans. Coolant from nuclear reactors is a prime example of liquid waste from industry that is released into waer bodies such as oceans and seas .

Classification based on treatability

 A simple classification to understand and manage waste,  at individual or household level is based on its degradation.

Wastes that can be decomposed by microbial action are called biodegradable wastes. They include food residues, kitchen wastes,sewage,leaf litter,paper, cardboard,rags , human and animal excreta. A large part of these wastes can be composted at the source itself, i.e,even households can have a compost pit or a vermicompost unit in their garden or rooftop to convert kitchen and garden wastes into compost.

All other wastes that cannot be degraded by the natural process are called non-biodegradable wastes. These cannot be decomposed. They can be reused or recycled but when they are discarded ,they remain in the soil for years without much  change . Plastics, metals , metal cans, asbestos, mercury , concrete, etc. They are responsible for large scale pollution of land and water ecosystems. Often they choke drains and result in accumulation of sewage and floods during the rainy season. Plastics cannot be decomposed by burning, it is unsafe as it releases carcinogenic compounds in air on burning.

Classification based on source

Wastes can be identified based on the sources from which they are generated.

This kind of classification is suitable for effective waste management.

MUNICIPAL WASTE

It consists of wastes coming from houses, street litter, sanitation residues and wastes from commercial establishments ( such as offices,hotels, restaurants and shopping complexes, but not from construction or demolition sites). This waste is also referred to as garbage or rubbish. It needs to be collected and disposed of by the local administrative bodies such as corporation or panchayat. This wastes has both biodegradable and non-biodegradable items. 

DOMESTIC WASTE

This is a part of municipal waste and refers specifically to materials generated in our households, kitchens (such as peels and food residues), paper , cardboard,rags,diapers, napkins, plastics, glass and metal items .Garden wastes also comes under this category.

COMMERCIAL WASTE

 Establishments such as offices,hotels, restaurants,bus stands, railway stations,airports, multiplexes and roadside cafes also contribute to municipal waste . This type of wastes generated at these places are similar to those as domestic wastes.

INDUSTRIAL WASTE

 Wastes produced from factories, mills and mines constitute industrial waste.

The quantity of this type of wastes has been increased rapidly since the onset of industrial revolution. 

Chemicals such as mercury,arsenic,chromium,  chlorinated organic compounds,lead, cement, asbestos,dust, broken and sharp metal pieces,broken glass are some of the examples of solid wastes that the industries produce. Various kind of slurry  are also produced as waste. Mining and metal work operations, cement factories,oil refineries ,nuclear power plants, chemical industries, pharmaceutical units, fertilizers and pesticides, rubber goods factories, paper factories, wood industries, tanneries, construction and demolition units, food and beverage industries, produce solid, liquid and gaseous wastes. The activities of commercial units such as packaging companies, supermarkets,retailers and wholesale dealers of cloth, jewelry,spices etc also produce such wastes. 

AGRICULTURAL WASTE

Agricultural waste is organic waates from plants and animal sources. Cow and other animal dung, remains of fodders, harvest,husks, pesticides and other scrap, veterinary medicines,etc are examples of wastes that agricultural activities could generate. Of alll these pesticides and fertilizers are responsible for serious degradation of land and water bodies.

Although all these above mentioned categories of wastes are the main sources 0f wastes, but two more types of wastes namely e-waste and hospital waste,  now a days are posing serious  threat to environment hence making them worth while to mention here because :

* They are increasing rapidly

*They are difficult to dispose off

*Many of them are toxic or hazardous

E-WASTE

 Electronic waste or e-waste is the term used to describe wastes that are generated from electronic appliances such as computers, laptops,TV's, DVD players, mobile phones, MP3 players,etc , which have been thrown away by the users. This kind of waste is a part of WEEE( waste from electronic and electrical equipments). Users of electronic equipment from household to commercial  and industrial activities generate this kind of wastes.

In addition to the above mentioned items, they also consists of electrical items like refrigerators, washing machines, toasters, hairdryers, automatic dispensers, used audio and video cassettes, old telephones etc. 

  

DUMPED ELECTRONIC ITEMS

Handling e-waste is a tough task in India because of 

* The vast culture and economic differences across the country

* The low level of awareness of this kind of waste among manufacturers and users

*The hazardous nature of the waste and lack of knowledge of toxins in e-waste

*The absence of organised procedure or laws  for this kind of wastes .

HOSPITAL WASTE

Hospital waste  or biomedical waste is generated during the diagnosis, treatment or other health related activities for human beings or animals. These  wastes are generated by hospitals , pathology laboratories, and certain scientific Institutions which carry out research (such as producing or testing vaccines, drugs,etc) .

Among all these the most serious concern is about the hazardous wastes from hospitals which includes

*Sharp needles ,blades, cut ampoules

*Solied and infectious cotton swabs,guazes,bandages,dressings, cultures

*Disposable needles, gloves, intravenous sets,catheters,syringes,and aprons

*Anatomical wastes such as tissues,operated parts, tumours,amputated parts,body fluids etc

* Others such as discarded medicines, chemical wastes,plastics and equipments.

Hospitals are expected to treat these wastes and make them non hazardous before disposal.

HAZARDOUS WASTE

Wastes that can easily catches fire or explode,corrode materials,or that are toxic are Hazardous.

A waste is hazardous if it can be harmful to human health and the environment when handled improperly.

Toxic wastes are harmful or fatal when taken in through food ,inhaled, or absorbed through skin. 

Hazardous wastes can be solid wastes ,effluents or emissions.

Hospitals and nuclear plants produce wastes that are highly hazardous as they are infectious or radioactive.

Toxic wastes are produced by the pharmaceutical industry,the fertilizers industry, and the tanning industry. The two chemical wastes that are also highly toxic are mercury and lead .

Household wastes that can be categorised as hazardous are old batteries,shoe polish, paint tins,old medicines,and medicine bottles.

Non toxic wastes are generally  biodegradable and easily disposable wastes which do not cause injury or death. Garbage generated in the household, rags, plant remains etc are examples of non toxic wastes. 

In the next chapter we shall look into the different methods of efficient waste management.