eChapters

Q. 1 The development of a tube well should be started from :-
(A) Middle of screen      (B) Top of screen
(C) Bottom of screen     (D) Bottom of casing pipe

Urbanization, industrialization, and economic growth in India have all led to an increase in the generation of municipal solid waste (MSW) by a number of urban local bodies (ULBs). In cities with high population densities, SWM is a significant difficulty. Being a diverse country with a wide range of religious communities, customs, and traditions like India makes it more challenging to accomplish sustainable development in a country that is rapidly industrialising and improving its standard of living. Although there have been substantial changes in the social, economic, and environmental spheres, India’s SWM systems have mostly remained the same. Currently, 90% of residual waste is thrown in the informal sector rather than properly disposed of. To make SWM more sustainable, new management practises and disposal sites are needed. The inefficiency of the current waste management systems has a detrimental effect on the economy, the environment, and public health. The Ministry of Environment and Forests of India introduced regulations for garbage treatment, although there is irregular and insufficient compliance.

5.1 Waste Treatment and Disposal

Source reduction and feeding the hungry are significant considerations for decreasing avoidable food waste. However, non-edible wastes like livestock manure, agricultural wastes, and unusable food wastes are also classified as organic wastes. The environment and general public’s health may be seriously endangered by improper treatment of these wastes. Wastes can contaminate surface and ground waterways by runoff or leaching if they contain pathogens, chemicals, antibiotics, and nutrients. The breakdown of organic waste also results in the production of methane. As is well known, methane is a powerful greenhouse gas that captures more heat into the atmosphere than carbon dioxide. It is possible to remove organic waste and turn it into biogas, a sustainable energy source that can be utilised to reduce greenhouse gas emissions and the likelihood of stream pollution. Further emission reductions are made possible by replacing fossil fuels with biogas, sometimes leading to carbon-negative systems.

4.1 Biomass Energy Resource

Among the various methods for producing electricity, biomass is one of the most common. This method uses animal waste, wood pellets, etc. to produce electricity. The use of biomass energy has proven beneficial over time and has the potential to be both reliable and consistent as an alternative energy source.

Organic matter is simply referred to as biomass. Or, to put it another way, biomass is anything living or ever living, including animal waste, crop waste, garden trash, etc. As a result, biomass renewable energy is the energy produced during the use of biomass. Biomass derives and stores its energy from the sun, which is absorbed by plants through a process known as photosynthesis. Plants contain chemical energy that is passed to animals and then eaten by people. Various plant and animal products, including sugarcane, corn crops, wood chips, and even dung, can be utilised. These substances, also referred to as feedstocks, are converted into a biomass fuel.

Wastewater is defined as water that has been altered by certain substances, resulting in changes in its physical, chemical, or biological properties. These changes render it unfit for certain uses, such as the purpose of drinking. Since almost all of man’s daily activities are dependent on water, therefore ‘waste’ is discharged into the surroundings as a result of these actions. There are a number of substances that can be harmful to the environment and make people sick, including chemicals, detergents, household cleaners, dirt, microorganisms (germs), and body wastes. The water supply generates a great deal of wastewater, so it is essential that it is treated in order to reduce the amount of waste that it generates. Essentially, wastewater treatment ensures that a healthy environment is created and public health is protected by removing the majority of pollutants found in wastewater through the treatment process. Consequently, wastewater management plays an important role in protecting the planet, and public and economic health, as well as social, economic, and political stability.

The basic methods for wastewater sewerage (collection, treatment, and disposal) are as follows:

• Off-site sewerage
• Separate sewerage system
• Combined sewerage system
• On-site sewerage

Many nations have implemented separate sewage systems that transmit sewage and storm water through separate pipelines in order to separate the two. Storm water often does not contribute to a wastewater treatment facility (WWTP). Domestic sewage contains 99.9% or more water. The remaining portion is made up of bacteria

Industrial waste can be solid, liquid, or gaseous in type and is generated by industrial activities throughout a manufacturing process. Depending on its nature, it can be hazardous or non-hazardous. It is important to note that hazardous wastes can be ignitable, toxic, reactive, corrosive, or radioactive and can pose a threat to the environment. Industrial waste includes, among other things, paints, concrete, paper goods, sandpaper, metals and chemical solvents. Most industries face a significant problem associated with the disposal of waste. Due to the significant expenses involved, it is not feasible to collect and treat all of the waste due to the sizeable volume of waste produced by numerous businesses. As a result, especially in developing nations, the majority of industrial wastes are illegally deposited on wastelands like deserted fields

The word mulch was coined by Wagganor in 1960. It is derived from the German word ‘molsch’ means “easy to decay,” and mulches have widely been used for vegetable production since ancient times (Lightfoot 1994). Therefore the term mulching refers to the practice of covering the soil surface with different organic and inorganic materials, known as mulch materials to reduce moisture loss, balance wide variations in diurnal soil temperatures especially in the root zone, control weeds, insect-pests and diseases and finally enhance crop yield (Nalayini 2007; Kader et al. 2019).

Increasing population, declining natural resources, changing climate and political stability are the major threat to our food, nutritional as well as environmental security. It is expected that India’s population will boom to 1.5 billion by 2030 and to feed them we need approximately 341mt food grain including 315 mt cereals and 26mt pulses) (Kumar et al., 2016).

Due to continuous pressure on our food security even after independence, the cultivation has been expanded to marginal and sub marginal lands that are prone to different types of erosion. Though the rainfed farming is based on the erratic and uneven rainfall, it contributes nearly 50% food grain, 90% oilseeds and pulses and 65% cotton production.

Rainfed agriculture occupies about 1.22 billion hectare (Bha) area worldwide, which is about 82% of total area (1.5 Bha) under agriculture (Yadav et al., 2006) and contributes nearly 58% to the global food basket. It is practiced under a wide variety of agro-climatic, edaphic and socio-economic conditions and globally, rainfed agriculture accounts for more than 95% of farmed land in sub-Saharan Africa, 90% in Latin America, 75% in the Near East and North Africa; 65% in East Asia and 60% in South Asia (Singh et al., 2018). 

Drought is a recurrent feature of climate or climatic anomaly or weather related natural disaster. It occurs when the precipitation remains deficient over an extended period of time, usually for a season or more and affects water shortage in water bodies, streams, soil moisture, ground water etc. resulting into low crop production and economic performance of large regions or entire country. Drought occurs in virtually all regions varying its severity, low and high from regions to regions.

Land, water and weather are natural resources that are critical for survival. Modern agriculture requires precise information on various agro-climatic parameters like soil, crop, climate and water resources for formulating efficient agricultural planning. Out of these, water is considered most scarce input in agriculture because its availability is reducing drastically for agriculture as well as drinking purposes. Besides, declining water tables and deteriorating quality of water resources caused pollution and sewage and effluents have further multiplied the problems.

Out of 329 m ha geographical area in the country, 187.8 m ha or 53% is affected by various forms of degradation process which include 148.9 m ha affected by water erosion, 13.5 m ha by wind erosion, 13.8 m ha by chemical deterioration and 11.6 m ha by physical deterioration. The annual loss of topsoil is nearly 16.0 t/ha/year resulted in to 8.4 m t/year total nutrient loss. 

Bread, cloth and house (Roti, Kapra and Makan) are the basic need of human life and linked directly with agriculture because agriculture provides livelihood for nearly two-thirds of the population in India and it currently accounts for 14.2% of the GDP and also employs 55% of country’s total workforce. The sharp fluctuations in agricultural growth are mainly attributed to the vagaries of monsoon. Rainfed agriculture is spread over 55% of net cultivated area, contributing over 40% to the national agricultural production.

Soil is generally defined as the upper layer of earth in which plants grow. It is regarded as a source of nourishment to all animals, moving or static. From agriculture or crop production point of view, soil is loose earth surface that supports vegetation, its quality, type and density. It is generally treated as a dynamic living entity and its physic-biochemical properties are responsible for its nutritional index. Precision production technology with suitable management is the key factors for its longer sustainability.

India comes in a tropical region and so it has a tropical monsoonal climate. The climate of India is governed by mountain ranges as well as direction of rain winds like south-west and north-east monsoon and alternate season is the main feature of Indian climate. Climate in South India is generally hotter and extremely humid than that of North India.

Water is essential for life and most of the civilization flourished on bank of rivers like Indus valley, Mesopotamia, May, INCA and also destroyed in lack of water. Scarcities and famines were the common phenomena of the world civilization. Systematic dry cultivation started around 1850 and improved techniques were started in use in USA. 

Rainfed agriculture constitutes 80% of global agriculture and plays a critical role in achieving global food security. However, growing world population, water scarcity, and climate change threaten rainfed farming through increased vulnerability to 1 droughts and other extreme weather events. Out of the total population of 7.3 billion, about 1 billion are food insecure and 60% of these live in South Asia and Sub Saharan Africa.

Over the period of time, the dairy sector has added distinct significance to growing Indian economy. India contributes nearly 19.54% to the global annual milk production with an impressive upliftment of 3.6% in yearly production rate as per the latest available data from FAO International.

So far we studied direct stress (Tensile or compressive) and tangential stress (shear stress) acting on plane individually. But in many engineering problems these both stresses are acts on a plane at a same time. In such cases resultant stress on that plane will be neither pure normal nor purely shear but there will be combined effect of normal and shear stress.

When any beam is loaded, stresses are induced and so to calculate those stresses, shear force and bending moment acting at load or support location must be required to calculate.

Thermal stress arises whenever there is some increase or decrease in temperature of a body which causes either expansion or contraction in the dimension of body. If body is free to expand or contract, with the rise or fall of temperature, there exist no stress in the body. But if deformation of the body is partially or completely resisted then stresses are set up in the body which is known as Thermal Stress. However amount of stress induced in partially prevented deformation will be small than in case deformation is totally prevented.

Whenever a thin hanging wire is loaded, it elongates and the load moves downwards. Increase in length of wire is governed by the magnitude of the load and nature of wire material. Experimentally it is found that the cohesive force between the molecules of hanging wire offers resistance against the deformation.

Mechanical power is usually transmitted from one shaft to another by using belts, ropes, chains, gears and clutches.

1. Belts and ropes are utilized if distance between the shafts is large. Belts and ropes are flexible and bend easily. But slip occurs between the belt and the pulley.

Machine: It is a device capable to doing work on application of some effort. Work done by machine is to raise load or to lower load or to do some other types of work like rotation of shaft.

Hydraulic pumps are the devices utilized to transfer pressure energy to liquids at the expense of electrical energy. The electrical energy is transferred to a motor which converts it into mechanical work and a pump is coupled to the shaft. The pump converts the mechanical energy to hydraulic or potential energy. 

Hydraulic turbines is a device which transforms the hydraulic energy or potential energy existing with the working medium to mechanical energy. The working medium is normally water which run the hydraulic turbine. The hydraulic energy is available with water by virtue of its height or altitude. The water which flow through the mountains is stored by constructing a dam or reservoir.

The internal combustion (I.C) engines are functioning on open cycle wherin the air is taken from the atmosphere and the exhaust gases are sent back in the atmosphere. The sequence of operation in a 4-stroke petrol and diesel engine involves Suction compression expansion and exhaust. The precise investigation of I.C engines are very complex due to open cycle system, the working fluid enter and leaves at different condition, quality of fuel and its combustion which make the task more difficult.

Heat engines - A device which change heat received by fuel combustion into mechanical work is called a heat engine. It may be classified into two broad categories viz. are Internal and external combustion engines.[8]

The application of (VCRS) Vapour compressor refrigeration system is in the air conditioners (window, split, central or precision), car air conditioners, domestic refrigerator etc. The different parts of a domestic refrigerator are: in the hermetical sealed compressor, air cooled condenser, capillary tube, thermo expansion device, filter, rotameter, solenoid valve, temperature control sensor.

A refrigerant is heat transfer medium through which phase change occurs from liquid to vapour i.e. evaporation at low temperature and pressure in the evaporator and then the phase change occurs from gas to liquid i.e. condensation at high pressure and high temperature in the condenser. The cycle of phase change of refrigerant, continues in the refrigeration system.

Refrigeration mean cooling i.e. lower the temperature by artificial means. It is a process of attaining lower temperature of the space or product below the surrounding temperature. It further involves maintaining the lower temperature achieved.

“Steam generator or boiler is, usually, a closed vessel made of steel. Its function is to transfer the heat produced by the combustion of fuel (solid, liquid or gaseous) to water, and ultimately to generate steam” [4] . The American Society of Mechanical Engineers (ASME) [5] gives the following definition of the steam generating unit:

Steam is utilized in steam power plants, steam engines, atomic power plant, and food industry for pasteurization, sterilization, textile industry, paper industry and in railway to generate power. Steam is also utilized in process type industries like sugar industries, textile industries, chemical industries for sizing and bleaching. Steam is also employed to store energy and transported through pipes.

Thermodynamics is defined as the “branch of science which deals with the interaction between the heat and work”[1]. Thermodynamics is also sometimes stated as the science of energy. Thermodynamic deals with the principles of energy and energy conversion in engineering. It also considers the thermodynamic properties of substances. Thermodynamics deals with the conversion of heat into work and vice-versa.