Chemistry of Garbage: Chemical Characteristics of Municipal Waste

Suchandra Mukherjee

18 Aug, 2023

According to popular definitions, municipal waste management pertains to domestic and municipal waste managed and collected by or on behalf of municipalities. Waste, such as household waste (including bulky items), from businesses, office buildings, institutions, small enterprises, yard and garden waste, street sweepings, contents of litter containers, and market cleansing waste, are categorised as municipal waste. The scope of municipal solid waste covers both commercial and domestic waste generated in notified municipal areas, in either solid or semi-solid form, excluding hazardous industrial waste but including treated bio-medical waste. Waste is characterised as unwanted and non-usable materials that have no value. Municipal waste comprises the everyday items discarded by the public. It can be categorised into three types as per the Chemical Characteristics of Municipal Waste: biodegradable, recyclable, and hazardous domestic waste.

Chemical Characteristics of Municipal Waste

To effectively utilise solid wastes as fuel or for other purposes, it is crucial to understand the different chemical characteristics of municipal waste. Some of these essential traits include:

• Lipids
• Carbohydrates
• Proteins
• Natural fibres
• Synthetic organic materials (Plastics)
• Non-combustibles
• Heating value
• Ultimate analysis
• Proximate analysis

Factors for Determining the Chemical Characteristics of Municipal Waste

The factors determining the Chemical Characteristics of Municipal Waste:

• Lipids: The chemicals in this category consist of fats, oils, and grease. Solid waste with a high lipid content can benefit energy recovery processes since lipids have a substantial calorific value. During waste breakdown, lipids contribute to the liquid component as they transition from solid to liquid at slightly elevated temperatures compared to ambient conditions. While lipids are biodegradable, their decomposition rate is relatively slow due to their limited solubility in waste.

• Carbohydrates: Carbohydrates primarily originate from food and yard waste. They encompass sugars and sugar polymers like starch and cellulose. Carbohydrates are readily biodegradable, producing substances such as methane, carbon dioxide, and water.

• Proteins: Proteins, composed of carbon, hydrogen, oxygen, and nitrogen, are organic acids with substituted amine groups (NH2). They constitute 5-10% of the dry solids in solid waste and are primarily found in food and garden waste. Proteins form amino acids, but an incomplete breakdown can generate amines, emitting foul odours.

• Natural Materials: This class includes naturally occurring substances like cellulose and lignin, both resistant to biodegradation. They are commonly found in food, yard waste, and paper products. Products made of paper, cotton, and wood contain 40%, 95%, and 100% cellulose. Solid waste with a high concentration of wood or paper products is suitable for incineration due to its high flammability.

• Plastics: Plastics are highly undesirable and concerning in solid waste management due to their extreme resistance to biodegradation. Recycling plastics has become more critical to reduce the amount of plastic waste in disposal facilities. However, it is essential to note that burning polyvinyl chloride (PVC) releases dioxin and acid gas, which can cause acid rain and accelerate corrosion in the combustion system.

Collection of municipal solid wastes

The littering of municipal solid waste is strictly prohibited in cities, towns, and urban areas designated by the State Governments. To enforce this prohibition and ensure compliance, the municipal authority shall undertake the following measures:

1. Implementing house-to-house collection of municipal solid waste using various methods, such as community bin collection (central bin), house-to-house collection, and scheduled collection with pre-informed timings, indicated by musical bells on waste collection vehicles.
2. Developing a waste collection system for slums, squatter areas, and other localities, including hotels, restaurants, office complexes, and commercial areas.
3. Managing biodegradable waste from slaughterhouses, meat and fish markets, and fruits and vegetable markets by finding appropriate uses.
4. Ensuring that bio-medical and industrial wastes are not mixed with municipal solid waste and are treated and disposed of separately as per specific regulations for such waste types.
5. Hand-driven carts or small vehicles are used to transfer collected waste from residential and other areas to community bins.
6. Separately collecting and disposing of construction or demolition wastes or debris by proper guidelines. Similarly, managing wastes generated at dairies as per State laws.
7. Prohibiting the burning of waste, including garbage and dry leaves.
8. Enforcing measures to prevent stray animals from roaming around waste storage facilities or any other areas in the city or town.

Storage as per the Chemical Characteristics of Municipal Waste

Municipal authorities must establish and maintain storage facilities to ensure the surroundings remain hygienic and sanitary. The following criteria should be considered during the establishment and maintenance of storage facilities:

1. The quantity of waste generated in a specific area and the population densities should be considered when establishing storage facilities. These facilities should be strategically placed for easy access by users.
2. The design of storage facilities set up by municipal authorities or other agencies should prevent waste exposure to the open atmosphere. They should also be aesthetically pleasing and user-friendly.
3. Storage facilities, also known as ‘bins,’ should have an easy-to-operate design for efficiently handling, transferring, and transporting waste. To differentiate between waste according to the chemical characteristics of municipal waste, bins for biodegradable waste^[1] may be painted green, those for recyclable waste painted white, and those for other waste painted black.
4. Manual handling of waste should be strictly prohibited. If unavoidable constraints require manual handling, it should be performed with proper precautions and due consideration for the safety of workers.

Processing of MSW as per the Chemical Characteristics

Municipal authorities must implement appropriate technologies, or a combination thereof, to effectively utilise waste and reduce the burden on landfills. The following criteria should be considered:

1. Biodegradable wastes should undergo processes like composting, vermicomposting, anaerobic digestion, or any other suitable biological processing to stabilise the waste.
2. Mixed waste that contains recoverable resources should be directed towards recycling.
3. In specific cases, incineration with or without energy recovery can be utilised for waste processing.

If the municipal authority or the facility operator intends to use other advanced technologies, they should approach the Central Pollution Control Board to obtain the prescribed standards before applying for authorisation.

Disposal of municipal solid wastes

The practice of landfilling will be limited to non-biodegradable and inert waste and other waste that cannot be recycled or processed biologically. Landfilling will also be permitted for residues from waste processing facilities, and pre-processing rejects based on the chemical characteristics of municipal waste. However, landfilling mixed waste should be avoided unless it is deemed unsuitable for waste processing. In unavoidable situations or until alternate facilities are installed, landfilling will follow appropriate regulations.

Role of SPCB

Due to the pollution and health hazards associated with the disposal of municipal solid wastes, the Pollution Control Boards are responsible for encouraging civic authorities to manage these wastes properly. While the primary responsibility for solid waste management lies with local municipal authorities, the Pollution Control Boards should collaborate closely by conducting essential surveys and offering technological support. The Central Pollution Control Board and State Pollution Control Boards at the national and state levels are tasked with disseminating information and raising awareness among relevant authorities and the public.

Measures by the CPCB and SPCB

The Central Pollution Control Board (CPCB) and State Pollution Control Boards (SPCBs) have been making efforts, within their authorised powers under relevant Acts and Rules, to encourage local authorities to implement appropriate measures for the treatment and disposal of domestic sewage and municipal solid waste. To establish a systematic approach for effective municipal waste (sewage and solid waste) management, the CPCB issued directives to all SPCBs under section 18 of the Water (Prevention and Control of Pollution) Act, 1974.

Rulesfor Waste Management in India

The following rules and regulations are in effect in the country:

1. Municipal Solid Waste Rules 2000 – This addresses the management and handling of municipal solid waste as per the chemical characteristics of municipal waste, making municipal authorities responsible for tasks such as collection, storage, segregation, transportation, processing or disposal of municipal solid waste.
2. Biomedical Waste (Management and Handling) Regulations 1998 – These regulations govern the management and handling of biomedical waste and apply to individuals or entities involved in generating, collecting, storing, transporting, disposing, processing, or handling biomedical waste.
3. E-waste Regulations 2010 – This regulation oversees electrical and electronic waste management and handling.

Procedure for Municipal Solid Waste Management Authorization

Anyone involved in waste management activities, including solid waste management, must obtain authorisation from the pollution control board. They need to seek prior approval from the SPCB/PCC by applying in Form I of the SWM Rules. The SPCB will review the authorisation proposal and conduct relevant inquiries upon receiving the Form I application from the local body or any authorised agency. Within 60 days, the Board can issue the authorisation in Form II to the local body, facility operator, or any other authorised agency designated by the local body. This authorisation will include compliance criteria and environmental standards outlined in Schedule I and II, along with any additional conditions, as necessary. The State Pollution Control Board or pollution control committee will oversee and ensure adherence to the environmental standards and requirements outlined in Schedule I and II of the Rules for waste processing and disposal sites.

Documents required for Municipal Solid Waste Management Authorization

1. Authorised Signatory Aadhar
2. and PAN Card
3. GST Certificate
4. Proof of Ownership of Site (Rent/Lease Agreement)
5. Factory License/Trade License
6. Layout Plan
7. Process Flow Chart
8. Details of the Machinery Installed

Conclusion

Understanding the chemical characteristics of municipal waste is crucial for effective waste management and environmental protection. From lipids and carbohydrates to proteins and natural materials, each component of municipal waste demands specific treatment and disposal strategies. Non-combustibles, heating value, ultimate analysis, and proximate analysis further contribute to assessing waste disposal options. By recognising and addressing the diverse chemical traits of municipal waste, we can strive towards more sustainable waste management practices, minimising environmental impact and promoting a cleaner, healthier future for our communities. It is recommended to take expert advice to learn about the kinds of documents and compliances required as per the Chemical Characteristics of Municipal Waste.

Read our Article : Understanding Solid Waste Management: A Comprehensive Guide

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