Solid Waste Management

Solid Waste Management

• Solid waste management is a planned process of collection, storage, transportation, processing of disposable of solid wastes in safe and economic manner.

• On the basis of nature of solid wastes, it can be categorized into three types.

1. Urban or municipal wastes.

2. Industrial wastes

3. Hazardous wastes.

 

1. Objective of Solid Waste Management

1. The primary objective of solid waste management is reducing and eliminating adverse impacts of waste materials on human health and environment.

2. To control, collect, process, dispose of solid wastes in an economical way consistent with the public health protection.

3. To support economic development and superior quality of life.

4. Implementation of technologically simple farm composting plants (essentially in the agricultural holdings situated near the production areas in the partners’ territories), with small and adequate scales. Possibility of giving an added value to the agricultural activity through the availability of an additional source of income for managing the treatment and selling resultant compost.

5. Identification of Waste and its Minimization at the Source

6. Collection, Segregation and Storage at the Site of Collection

7. Safe transportation of Solid Waste

8. Proper treatment of Solid Waste

9. Energy recovery and effective disposal of solid waste.

 

2. Sources of Municipal / Urban Wastes

• The municipal solid waste consists of following wastes.

1. Domestic wastes 2. Commercial wastes

3. Construction wastes 4. Biomedical wastes

1. Domestic wastes

• Domestic waste includes various wastes from houses.

Examples

• Food waste, cloth, waste paper, glass, polythene, metals dust etc.

2. Commercial wastes

• Commercial wastes include waste coming out from shops, market, offices, institutions and hotels.

Examples

• Packaging material, waste papers, cans, bottles, rubber, plastic etc.

3. Construction wastes

• The construction wastes include the wastes of construction materials.

Examples

• Wood, concrete, debris, lime, cement, tin, Plaster of Paris (PoP) etc.

4. Biomedical wastes

• Biomedical waste includes the organic materials.

Examples

• Anatomical wastes, infectious wastes.

Types and characteristics of municipal wastes

• The municipal wastes can be categorized into two categories.

1. Bio-degradable wastes

2.  Non-bio-degradable wastes

1. Bio-degradable wastes

• The urban solid waste materials, which can be degraded by micro-organisms are called bio-degradable wastes.

Examples

• Food, vegetables, tea leaves, egg shells, fruits etc.

2. Non-bio-degradable

• The part of urban solid waste materials, which can not be degraded by micro-organisms are called non-bio-degradable wastes.

Examples

• Polythene bags, Plaster of Paris (PoP), scrap materials, etc.

 

3. Sources of Industrial Wastes

• The main sources of industrial wastes are chemical industries, processing industries etc.

• The constituents of industrial waste are :

1. Nuclear power plants  2. Thermal power plants

3. Chemical industries  4. Other industries

1. Nuclear power plants

• It generates radio-active wastes

2. Thermal power plants

• Thermal power plant produces flyash, hot water, unburnt fuel.

3. Chemical Industries

• It produces large quantities of toxic-chemicals, oxides, acids.

4. Other industries

• It includes packing material, wood, scrap material, oil, paint, dyes, lime, cement, rubber, organic wastes, acids, alkalis.

 

4. Hazardous Wastes

• The hazardous wastes are those wastes which cause substantial danger to all living things including human, plant or animal life.

Sources of hazardous wastes

• Chemical manufacturing industries

• Petroleum refineries

• Paper mills

• Smelters

• Radio-active substances

Types arid characteristics of hazardous wastes

1. Toxic wastes

• They are poisonous even in very small amounts.

a) Acute toxicity - These wastes have immediate effect on humans or animals and causes death.

b) Chronic toxicity - It causes long term effect and slowly results in irrepairable harm.

2. Reactive wastes

• These wastes react with air. water, heat and generate toxic gases.

Examples : Gun powder, nitroglycerine.

3. Corrosive wastes

• These wastes destroy materials and living tissues by chemical reaction.

Examples : Acids, bases.

4. Infectious wastes

• It spreads infections to exposed persons.

Examples : Used bandages, human tissue from surgery, hypodermic needles.

 

5. Process in Solid Waste Management

• An integrated approach to the waste management is to be adopted. The waste management hierarchy includes following components.

1. Reduce  2. Reuse  3. Recycle  4. Recover  5. Dispose

 

• All above activities are arranged in a hierarchical manner. The first priority is waste avoidance, means not producing the waste. If the waste is produced then quantity should be minimized.

• The second priority is reuse i.e. maximizing recovery by reuse and recycling of suitable waste materials.

• The three components i.e. reduce, reuse and recycle together is called waste prevention.

• Once the possibilities of waste prevention are exhausted, the next priority is reduce to the volume of residual wastes being passed on for final disposal i.e. extracting resources in the form of products or energy in the process. Fig. 4.6.4 shows waste management hierarchy.

Methods of disposal of solid waste

• Disposing of municipal solid wastes can be done by any of the following methods :

1. Land fill - Spreading waste on land after few years it becomes compact which is then covered by soil.

2. Incineration - Waste is reduced by burning and then disposed.

3. Composting - Organic waste is fertilized or decomposed making it useful for growing plants and trees.

 

6. Green Chemistry

• Green chemistry is a philosophy of chemical research and engineering that encourages the design of products and process that minimizes the use and generation of hazardous substances. It is also called as sustainable chemistry.

• Twelve principles of Green chemistry

1. Prevention

2. Atom economy

3. Less hazardous chemical syntheses

4. Designing safer chemicals

5. Safer solvents and auxiliaries

6. Design of energy efficiency

7. Use of renewable feed stock

8. Reduce derivates

9. Catalysis

10. Design for degradation

11. Real time analysis for pollution prevention

12. Inherently safer chemistry for accident prevention.

 

7. E-Waste

• Electronic waste describes and includes old, end-of-life electronic appliances such as computers, lap tops, TVs, DVD players, mobile phones, mp3 players , tape drives networking products, servers, etc., which have been disposed of by their original users (corporates, business establishments, government agencies and households) in most cases.

• It comprises of relatively expensive and essentially durable products used for data processing, telecommunications or entertainment by the said users.

• E-waste is growing exponentially simply because the markets in which these products are produced are also growing rapidly as many parts of the world cross over to the other side of the Digital Divide'.

• The changing lifestyle of people and urbanization has lead to increasing rates of consumption of electronic products. This has made electronic waste management an issue of environment and health concern.

• E-wastes are considered dangerous, as certain components of some electronic products contain materials that are hazardous, depending on their condition and density.

• The hazardous content of these materials pose a threat to human health and environment.

• E-waste contains different hazardous constituents such as - lead, cadmium, mercury and plastic.

• Discarded computers, televisions, VCRs, stereos, copiers, fax machines, electric lamps, cell phones, audio equipment and batteries if improperly disposed can leach lead and other substances into soil and groundwater.

• Many of these products can be reused, refurbished, or recycled in an environmentally sound manner so that they are less harmful to the ecosystem.

a. Disposal of E-waste

• The toxic substance of E-waste affects environment and human severly. Hence proper disposal and recycling is must for E-wastes. Different methods of E-waste disposal are -

1. Landfill  

2. Incineration

3. Reuse     

4. Recycle

1. Landfill

• Landfill method is suitable for quantitatively small e-waste i.e. domestic and small users. E-waste is piled up and covered with other domestic waste and soil.

2. Incineration

• E-waste is burnt in controlled environment. The toxic gases or smoke is released into atmosphere.

3. Reuse

• The spares and components are removed from the device and with some modification, they are used for other applications.

4. Recycle

• The important ingredients of E-waste is collected and sent to manufacturing companies producing similar components.