For Dibrugarh University 2nd SEM NEP 2023


3.1 Wildlife; Poaching, man-‐wildlife conflicts, Conservation and mitigation.

3.2 Waste Management; Solid waste, urban waste, industrial waste and pollution;

3.3 Water management; Reuse and Rain water harvesting, Air pollution reduction and climate change mitigation


Waste Management Meaning

Waste management involves the activities required to manage waste from its inception to its final disposal. This includes the collection, transport, treatment and disposal of waste, together with monitoring and regulation of the waste management process. Waste management is intended to reduce adverse effects of waste on human health, the environment and aesthetics.

Waste can be solid, liquid, or gaseous and each type has different methods of disposal and management. Waste management deals with all types of waste, including industrial, biological and household wastes.

Waste management practices cannot be uniformly practiced in different areas. Developed and developing nations, urban and rural areas, residential and industrial sectors have to take different approaches.

  • Preventing or reducing waste generation: Extensive use of new or unnecessary products is a major cause of unchecked waste formation.
  • Recycling: Recycling serves to transform waste into products of their own genre through industrial processing. Paper, glass, aluminium, and plastic are commonly recycled.
  • Incineration: Incineration features combustion of wastes to transform them into base components, with the generated heat being trapped for deriving energy.
  • Composting: It involves decomposition of organic wastes by microbes by allowing the waste to stay accumulated in a pit for a long period of time. The nutrient rich compost can be used as plant manure.
  • Sanitary Landfill: This involves the dumping of wastes into a landfill. The base is prepared of a protective lining, which serves as a barrier between wastes and ground water, and prevents the separation of toxic chemicals into the water zone. Landfills should be created in places with low groundwater level that are far removed from sources of flooding.

Solid Waste Management

Industrialization across the world has brought a lot of good as well as bad things as well. One of the negative effects of industrialization is the creation of solid waste and consequent environmental degradation.

According to Britannica, “Solid-waste management is the collecting, treating and disposing of solid material that is discarded because it has served its purpose or is no longer useful. Improper disposal of municipal solid waste can create unsanitary conditions, and these conditions in turn can lead to pollution of the environment and to the outbreaks of vector-borne disease”

Human and animal activities generate different kinds of wastes. These wastes are generally in solid form, and may cause pollution of land, water and air unless treated and disposed off. The process of collection, transportation, treatment and disposal can be grouped under solid waste management. The increase in the quantity of solid waste is due to overpopulation, affluence and technological advancement.

Bad effects of solid wastes:

a) Open dumps are malodorous places in which disease carrying vermins such as rats and files proliferate.

b) Methane gas is released into the surrounding air due to decomposition of solid wastes by the micro-organisms.

c) Hazardous materials dissolved in this liquid contaminate underground water and solid strata.

d) The leachate consisting of a variety of chemical constituents’ seeps and pollute the ground water.

e) Absence of landfill lingers aggravate the problem furthermore.

Types of Solid Waste

Solid wastes (waste which are neither liquid nor gaseous) can be classified into:

a) Urban or municipal wastes

b) Industrial wastes

Sources of Urban Waste

– Domestic wastes: It includes a variety of materials thrown out from homes.

– Food waste, Cloth, Waste paper, Glass bottles, Polythene bags, Waste metals, plastic containers, scrap, paints etc.

– Commercial wastes: It includes wastes coming out from shops, markets, hotels, offices, institutions, etc.

– Waste paper, packaging material, cans, bottle, polythene bags, etc.

– Construction wastes: It includes wastes of construction materials. • Wood, Concrete, Debris, etc.

– Horticulture waste and waste from slaughter houses include vegetable parts, residues and remains of slaughtered animals, respectively.

– Biomedical wastes: It includes mostly waste organic materials

– Anatomical wastes, Infectious wastes, glass bottles, plastic, metal syringe, etc.

– Mining waste: A large amount of solid waste is released from the mining activities. The increase in solid waste is due to overpopulation, affluence and technological advancement.

Sources of Industrial Waste

The main source of industrial wastes are chemical industries, metal and mineral processing industries.

– Nuclear plants: Generate radioactive wastes

– Thermal power plants: Produce solid waste in the form of fly ash 3

– Chemical Industries: Produce large quantities of hazardous and toxic materials.

– Other industries: Other industries produce packing materials, rubbish, organic wastes, acid, alkali, scrap metals, rubber, plastic, paper, glass, wood, oils, paints, dyes, etc.

Also Read: Environmental Science Chapterwise Notes for 2nd SEM NEP 2023

– Unit 1: Environmental Science Notes

– Unit 2: Environmental Degradation Notes


Measures to Control Solid Waste

i) Sanitary Landfill: This is the most popular solid waste disposal method used today. Disposing of waste in a landfill involves burying the waste, in abandoned or unused places. In this method garbage is spread out in thin layers, compacted and covered with clay, sand or plastic liner. The liners protect the ground water from being contaminated. When the landfill is full, it is covered with layers of sand, clay, top soil and gravel to prevent seepage of water.

ii) Incineration: It is the hygienic way of disposing solid waste. It is a thermal process (controlled combustion) in which the waste material is converted to heat, gas, steam and ash, which can be used for electrical generation and domestic heating. It is suitable for hazardous, organic and medical wastes. Combustible substance should be separated and removed before incineration process. Wet municipal waste should be preheated before incineration process. It reduces the volume of waste up to 20 or 30% of the original volume.

iii) Composting: It is a popular method by which bulk organic matter is converted into fertilizer by biological action. Microorganisms like fungi, bacteria convert degradable organic waste into broken, odourless mass called humus, which is a good fertilizer. Separated compostable waste is dumped in underground trenches in layers of 1.5m and finally covered with soil of 20 cm and left for decomposition. Sometimes, actinomycetes are introduced for active decomposition. Biological action will start within two to three days. Good quality environmental friendly manure is formed from the compost and can be used for agricultural purpose.

iv) Vermi Composting: It has become very popular in the last few years. In vermi composting, earthworms are added to the compost. These help to break the waste and the added excreta of the worms makes the compost rich in nutrients. It is very useful biofertilizer and soil conditioner.

Water Conservation

Water is essential to human existence and ecosystems and a vital element for human development. Thus, water availability is a global issue. Although, water is the most widely occurring substance on Earth, it is a well-known fact that only about 2.5% is fresh water and the rest is salt water. Of the 2.5% of freshwater, its biggest portion is locked up in glaciers and permanent snow cover. Thus, in reality, only about 1 % of the world’s freshwater is readily available and accessible for direct human use.

Water availability is becoming an increasingly crucial issue for Asia. In recent years, evidence indicates that water is becoming increasingly affected by erratic weather patterns, as has already happened to countries such as Indonesia and China, which have experienced droughts and inevitable food shortages.

Reasons for Shortage of Water:

a) Climatic changes

b) Misuse of water by industries and farmers,

c) High Population growth

d) Loss of water during distribution

Aim of Water preservation

Studies show that by 2025 more than half the people around the world will not have enough water. Preservation of water is very essential for the existence of mankind. Water conservation includes all the policies, strategies and activities made to sustainably manage the use of fresh water and to meet its future human demand. That’s why preservation of water is the demand of present world. The goals of water conservation efforts include:

– Ensuring availability of water for future generations.

– Energy conservation.

– Habitat conservation by minimising human water use which helps to preserve fresh water habitats for local wildlife and water quality.

How to conserve water for future?

a) Implementation of drip irrigation to save water.

b) Promotion of recycling and use of water by industries.

c) Construction of dams and water reservoirs to capture rainfall and use such reserve water during draughts.

d) Educate people about the importance of water and motivate them to save water.

e) Regular monitoring of ground water.

f) Research and development in field of water preservation.

Rain water harvesting

Rain water harvesting is one of the most effective methods of water management and water conservation. Rainwater harvesting is the system of collection, accumulation and deposition of rain water with the help of artificially designed system rather than allowing it to run off. It can be collected from rivers or roofs and in many places, the water collected is redirected to a deep pit reservoir with percolation. The harvested water can be used as drinking water, irrigation activities, industrial use, and ground water recharge.

Need and Importance of Rain water harvesting

Rainwater is one of the simplest and oldest methods of self-supply of water for house-holds.

a) It provides an independent water supply in case of shortage of water.

b) It provides water when there is a drought.

c) It helps in the availability of potable water as it is substantially free of salinity.

d) It helps in meeting growing demand of water due to high growth of population.

e) It helps in creating awareness about the importance of water conservation.

f) It is a cheap and reliable source of clean water.

Methods of Rain Water harvesting

Rain water harvesting can be undertaken through a variety of ways

a) Capturing runoff from rooftops – Roof water harvest

b) Capturing runoff from local catchments – Land harvest

c) Capturing seasonal floodwaters from local streams

d) Conserving water through watershed management

e) For Urban & Industrial Environment –

– Roof & Land based RWH

– Public, Private, Office & Industrial buildings

– Pavements, Lawns, Gardens & other open spaces

Advantages of Rain water harvesting

a) Provides self-sufficiency to water supply

b) Reduces the cost for pumping of groundwater

c) Provides high quality water, soft and low in minerals

d) Improves the quality of ground water through dilution when recharged to groundwater

e) Reduces soil erosion in urban areas

f) Rooftop rain water harvesting is less expensive

g) Rainwater harvesting systems are simple which can be adopted by individuals

Watershed Management

Watershed Management seeks to manage water supply, the quality of water, drainage, water rights and the overall planning and utilisation of watersheds. It is the study of the relevant characteristics of a watershed aimed at sustainable distribution of its resources and creating and implementing plans and programmes that affect the plant animal and human communities within the watershed boundary. It is an integrated and interdisciplinary approach. It must consider the social, economic and institutional factors operating within and outside the watershed.

Importance of Watershed Management

a) It relates to soil and water conservation in the watershed which includes proper land use, protection of land against all forms of degradation, flood protection, water conservation and harvesting, proper management of surface and ground water. The requirement of watershed management has increased in this time of water shortage.

b) It helps to recharge groundwater. Afforestation of degraded areas is an important aspect of watershed management.

c) Watershed management can preserve water for the existence of a human race and environmental protection.

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