• Solid waste is the unwanted or useless solid materials generated from human activities in residential, industrial or commercial areas. It may be categorised in three ways. According to its:
  • origin (domestic, industrial, commercial, construction or institutional) 
  • contents (organic material, glass, metal, plastic paper etc)
  • hazard potential (toxic, non-toxin, flammable, radioactive, infectious etc).
• Solid Waste Management reduces or eliminates the adverse impact on the environment & human health. A number of processes are involved in effectively managing waste for a municipality. These include monitoring, collection, transport, processing, recycling and disposal. The quantum of waste generated varies mainly due to different lifestyles, which is directly proportional to socio economic status of the urban population.

Types of Solid Waste

It can be classified into different types depending on their source: 

• Municipal Solid Waste (MSW): It consists of household waste, construction and demolition debris (CnD), sanitation residue, and waste from streets, generated mainly from residential and commercial complexes. As per the MoEF it includes commercial and residential waste generated in municipal or notified areas in either solid or semi-solid form excluding industrial hazardous wastes but including treated bio-medical wastes;
• Industrial Solid Waste (ISW): In a majority of cases it is termed as hazardous waste as they may contain toxic substances, are corrosive, highly inflammable, or react when exposed to certain things e.g. gases.
• Biomedical waste or hospital waste: It is usually infectious waste that may include waste like sharps, soiled waste, disposables, anatomical waste, cultures, discarded medicines, chemical wastes, etc., usually in the form of disposable syringes, swabs, bandages, body fluids, human excreta, etc. These can be a serious threat to human health if not managed in a scientific and discriminate manner.

Solid waste management 

• Centralised method: This method involves collection of municipal waste from all over the local area and by means of landfilling, dump outside the city/nagar panchayat limits. This process looks at door-to-door collection of solid waste by waste pickers who hand over to the collection team who then discard the collected waste in the landfill. The waste pickers are employees of the Municipal Corporation or Nagar Panchayat. The collection team is generally contracted out by a tendering process.
• De-centralized method: This is a model seen in a few places like Suryapet in Andhra Pradesh and Bangalore in Karnataka. The waste is collected ward-wise and is segregated at source into bio-degradable and non-biodegradable. The biodegradable waste is composted at a nearby facility by different methods of aerobic and anerobic composting. The non-biodegradable waste is further categorised into paper, plastic, metal and other waste and then further collected by recyclers for up-cycling or downcycling of products

Treatment methods for solid waste 

• Thermal treatment: Incineration is the combustion of waste in the presence of oxygen, so that the waste is converted into carbon dioxide, water vapour and ash. Also labeled Waste to Energy (WtE) method, it is a means of recovering energy from the waste. It’s advantages include waste volume reduction, cutback on transportation costs and reduction of greenhouse gas emissions. However, when garbage is burned, pollutants, such as mercury, lead, dioxins may be released into the atmosphere, and cause health issues.
• Pyrolysis and gasification: In this method, thermal processing is in complete absence of oxygen or with less amount of air. 
• Biological treatment methods: This involves using micro-organisms to decompose the biodegradable components of waste. The 2 types of processes: Aerobic: This needs the presence of oxygen and includes windrow composting, aerated static pile composting & in-vessel composting, vermi-culture etc. Anaerobic digestion: Takes place in the absence of oxygen. 
• Landfills and open dumping: Sanitary landfills: It is the controlled disposal of waste on land in such a way that contact between waste and the environment is significantly reduced and the waste is concentrated in a well defined area. Dumps are open areas where waste is dumped exposing it to natural elements, stray animals and birds. With the absence of any kind of monitoring and no leachate collection system, this leads to the contamination of both land and water resources.

Integrated Solid Waste Management (ISWM):

Recycling 

• Recycling is when waste is converted into something useful. It reduces the amount of waste that needs to be treated, the cost of its handling, its disposal to landfills and environmental impacts. It also reduces the amount of energy required to produce new products and thus helps conserve natural resources. Upcycling and downcycling are two common words used when it comes to recycling.
  • Upcycling implies upgrading of a commodity by different processes of recycling. An example of upcycling is to make roads out of cheap plastic.
  • Downcycling implies downgrading a commodity by different processes of recycling. An example of downcycling is breaking down of high quality plastics at high temperature into different lower quality plastics. 
• There are a large set of informal waste collectors in India. They are called local waste dealers or ‘Kabadiwallahs’. They collect and sort dry waste into aluminium, plastic, paper, glass, etc. In some cases, these local waste dealers have tie ups with waste pickers who supply to them the waste from nearby areas. In addition to the waste pickers, the dealers also collect dry waste from individuals, apartments and institutions.

Responsibility & stakeholders 

• Solid Waste Management is a state subject and it is the responsibility of the state government to ensure that appropriate solid waste management practices are introduced in all the cities and towns in the state. However, SWM is a municipal function and it is the urban local bodies (ULB) that are directly responsible for it. The ULBs are required to plan, design, operate, and maintain the SWM in their respective cities/towns. 
• The role of the Government is broadly to formulate policy guidelines and provide technical assistance to the states/cities whenever needed. It also assists the state governments and local bodies in human resource development and acts as an intermediary in mobilizing external assistance for implementation of solid waste management projects.
• There are several NGOs, waste trade unions and experts who have become crucial stakeholders.

Rules and regulations associated with SWM

• Under the 74th Constitutional Amendment, Disposal and management of Municipal Solid Waste is one of the 18 functional domains of the Municipal Corporations and Nagar Panchayats. The various rules and regulations for solid waste management are:
  • The Bio-Medical Waste (Management And Handling) Rules, 1998
  • Municipal Solid Waste (Management And Handling) Rules 2000
  • The Plastic Waste (Management And Handling) Rules, 2011
  • E-Waste (Management And Handling) Rules, 2011

How each one of us can reduce waste?

Waste is everybody’s responsibility. A waste reduction strategy can be incorporated by each of us whether at home or at work by following the 4 Rs principle. 

• Reduce: At home you can begin by purchasing things with lesser packaging, more durable & refillable items, carry your own shopping bag, avoid disposable items and reduce the use of plastics. At office one can cut down on paperwork, use electronic mail for communication.
• Reuse:You can donate your old clothes, books, phones and lots more. You can reuse old bottles, jars as storage bins and buy rechargeable items rather than disposable ones.
• Recycle: Segregate your waste for better disposal and purchase recycled/ green products. A ton of paper from recycled material conserves about 7,000 gallons of water, 17-31 trees, 60 lb of air pollutants and 4,000 KWh of electricity. You can recycle or compost your organic waste directly at source- leaving very little waste to reach the landfill.
• Recovery or reclaim: Various mechanical, biological and caloric systems and technologies can convert, reprocess or break up waste into new materials or energy. This means turning waste into fuel for manufacturing processes or equipment designed to produce energy