Solid Waste Management: Techniques and Impact

Ans. The processes involved in composting are as follows -

Sorting and shredding

• The decomposable materials in the waste are isolated from metal, glass, and other inorganic items through sorting operations. 
• Shredding reduces the size of the waste, resulting in a material with uniform mass. 
• It is accomplished with rotary shredders and hammer mills.

Digesting and processing

• Pulverized waste is then ready for composting either in an enclosed mechanical facility or by the open windrow method.
• Depending on the moisture conditions of the area, it may take up to five or eight weeks for the complete digestion of the waste. 
• Due to the metabolic action of aerobic bacteria, temperatures in an active compost pile reach up to 65 ° Celsius that kills the pathogenic organisms present in the waste material.
• Digested compost must be processed before it is used as a soil container or mulch. 
• The processing process includes drying, screening, granulating, and pelletizing. 

Ans. Waste can mainly be classified as - 

• Solid wastes – These are the unwanted substances discarded by human society. These include industrial wastes, urban wastes, agricultural wastes, radioactive wastes, and biomedical wastes.
• Liquid wastes – These are the wastes generated from flushing, washing, or manufacturing processes of industries.
• Gaseous wastes – These are the wastes that are released in gaseous form from automobiles, factories, or from the burning of fossil fuels such as petroleum. They get mixed with the other gases in the atmosphere and occasionally cause smog or acid rain.

Ans. Some of the sources of solid waste are -

• Residential - Single and multifamily housings are one of the primary sources of solid waste. It includes the types of waste produced by the residential sector such as food waste, plastics, leather, glass, wood, metals, papers, and other items like tires, electronics, batteries, used oil, and more.
• Industrial - Industries largely contribute to the production of solid waste. The types of solid waste produced by the industries include packaging and housekeeping waste, food waste, construction debris, and other hazardous waste like asbestos.
• Commercial - Commercial buildings such as offices, hotels, restaurants, and stores also contribute to the generation of solid waste. The type of waste produced by the commercial sector includes food waste, rubber waste, plastics, packaging materials, glass, paper, metals, wood, etc.
• Municipal Services - Streets, water treatment plants, parks, and recreational areas contribute to the production of solid waste. The types of waste generated by municipal services include street waste, tree trimming waste, dead leaves, and other waste from the park.
• Agriculture - The types of solid agricultural waste include pesticides and spoilt food.

Ans. These are methods of solid waste management. They can be put into use as follows -

1. a) Landfills - In sanitary landfills, the garbage is spread out in thin layers and is compressed. It is then covered with plastic foam or soil. There are several layers of sand and plastics at the bottom of landfills to prevent the contamination of groundwater due to percolation or leaching. In a similar way, when completed, it is covered with layers of clay, sand, and gravel to prevent the seepage of water.
2. b) Incineration - Incineration involves the burning of solid waste at a high temperature until it is turned into ashes. Incinerators are designed in a special way to recycle heat energy known as waste-to-energy plants which are much more expensive. The volume of the waste in the collection center is largely reduced; however, gaseous pollutants are emitted into the air.

Ans. Pyrolysis is a process of chemical decomposition wherein the solid waste is subjected to heat up to 430 degrees Celsius. This is done in the presence of oxygen and at a specific pressure. The solid waste is then converted into carbon, ash, and some liquid. This method is effective in managing solid waste. However, it can lead to incomplete combustion that can in turn produce toxic residues that will again require proper treatment.

Ans. Solid waste management is important as -

• It is really important to manage and handle solid waste as per the prescribed law in order to prevent environmental pollution. 
• The waste needs to be managed for environmental hygiene. 
• It will also help in controlling diseases, thereby promoting public health.

Ans. The three main principles of waste management are as follows - 

• Reduce - Try to decrease the amount of waste you produce. Only buy things that you absolutely require. 
• Reuse - Use the items again and again. It can also be done through recycling and making the item ready for reuse.
• Recycle - Recycling refers to the process of converting waste materials into new ones so that they can be used again.

Ans. A poor solid waste management system can lead to the following impacts -

• Littered Surroundings - Due to an improper waste management system, heaps of garbage are formed that become a menace to the environment.
• Impact on Human Health - Improper waste disposal can also affect the health of the population that lives nearby the landfills or the polluted area. The health of workers involved in the waste disposal and other employees of the landfill facilities are also at greater risk due to a poor waste management system. Exposure to wastes that are not treated can lead to blood infections, skin irritations, respiratory problems, and even reproductive issues.
• Environmental Problems - Solid wastes from various types of industries are a source of toxic and hazardous metals, wastes, and chemicals. When released into the environment, these solid wastes can lead to various problems for the environment that may alter or negatively affect the productivity of the soils in that particular area.
• Groundwater and Soil Pollution - Toxic materials and chemicals can also seep into the soil which can further pollute the groundwater. During the process of collection of solid waste, the hazardous wastes usually mix with the ordinary garbage which makes the disposal process even harder and risky.