Recycling Of Waste Materials

Q1. Give scientific reasons 1. Cow dung and crop residue should not be used as fuel. Ans. Cow dung and crop residue should not be used as fuel because 1. Agriculture wastes like crop residue and cow dung can be used as manures for crop. 2. Further, using these waste products, valuable biogas can be prepared. 3. These materials are not efficient fuels. 4. The burning of these material cause air pollution. 2. The present era is called the ‘Plastic age’ Ans. The present era is called the ‘Plastic age’ because 1. During the last few decades, a variety of plastics with different properties have been invented. 2. Thus the use of plastics in everyday life is increasing very fast. 3. Plastic items are replacing metal and wooden items. 3. It is beneficial to use compost fertilizers than chemical fertilizers for agriculture. Ans. 1. Compost manures are not acidic and therefore can be used for any type of soil. 2. They not only add nutrients but also improve its texture. 3. Composting reduces health hazard as pathogens are destroyed during composting. 4. It controls pollution due to wastes. Hence, it is beneficial to use compost fertilizers than chemical fertilizers for agriculture. Q2. Define 1. Recycling:- Recycling means use of the material over and over again. 2. Wastes:- The rejected materials are called wasters. 3. Biodegradation:- The process in which complex organic molecules are converted into simpler inorganic compounds due to some living beings, is called as biodegradation. 4. Non – degradable wastes:- The waste products, which cannot be degraded through biological activities, are called non – degradable waste. Metals, glass, plastics are non – degradable wastes. Q3. Answer the following:1. What are wastes? How are they classified according to their origin? Ans. The rejected materials are called wastes. Wastes are classified according to their origin as follows. 1. Human wastes:- Human urine and fasces.

2. Animal wastes:- Diary wastes include cow dung and urine. Slaughter house waste is a mixture of blood, urine, organ, etc. Sheep, goat poultry and fishery also contribute to wastes. 3. Urban wastes:- House hold garbage and kitchen wastes including paper, plastic items and metals articles. Besides, sewage is the main bulk of urban waste, which is poured in the large bodies of water. 4. Crop residue:- The crop residues include crop stubble, straw, wasted fodder, stick and weeds. 5. Industrial wastes:- Waste products of the industries are called as industrial effluents. Pulp mills, tanneries, textile mills, refineries and chemical fertilizers plants release complex organic compounds. 2. Explain the procedure of composting:Ans. Composting:- It is the process of decomposition of plants and animals remain, through microbial activity. Procedure:1. Pits of various dimensions are dug. 2. All sort of agricultural wastes, trash, dried leaves are spread in the pit as the layer of 6 to 8 cm. 3. This layer is t hen covered with the layer of dung of 3 to 4 cm thickness. 4. Water is sprinkled over these layers. 5. In this fashion, many alternate layer of plant and animal remains and dung are arranged in the pit. The pit then covered with soil. After some weeks, valuable manure is formed in the pit. 3. Explain recycling of waste materials help in ecological balance. Ans. 1. Due to various human activities, all sorts of wastes are generally thrown away in the random manner. 2. The wastes are composed of different organic substances, a large number of organisms are attracted towards such wastes. 3. Bacterial from soil and air start the process of decomposition odour. AS a result, insects are attracted towards the decomposing matter. 4. Insects like flies, cockroaches are responsible for the spread of contagious disease like cholera, typhoid, and dysentery. 5. These wastes products go on occupying more and more space. In this manner the ecological balance around us is disturbed. Hence, recycling of waste materials help us in the ecological balance. 4. Explain the working of gobar – gas plant. Ans. 1. The process of fermentation of biomass takes place in a brick lined well called as digester. 2. The dung in the form of slurry is filled in the digester. 3. The digester is covered with a dome begins to rise and floats.

5. Through an opening on the top of the drum the gas carried to the kitchen by pipes. 6. Continuous gas production is possible by daily feeding the digester through a funnel. 7. The spent slurry over flows from the top and is collected in a pit. It is periodically transferred to the manure pit. 5. Explain “Recycling is a must” Ans. 1. All the resources of basic raw materials like ores, materials, fuels etc. are limited on the earth. 2. These resources cannot be replenished. 3. However, there has been a steady increase in the consumption and demand for all the basic raw materials. 4. Moreover, if all the non degradable waste products are haphazardly (randomly) dumped some where, they go on occupying more and more space. Hence, recycling of waste products is a must. 6. What are the advantages of bio – gas? Ans. The advantages of bio – gas are as follows 1. It burns with a bluish flame and does not produce smoke. 2. It burns without emitting foul odour. 3. It is an efficient fuel. 4. The slurry formed in the production of biogas is used as fertilizer. 7. Name the constituent of bio – gas and give their approximate percentages. Ans. The constituents of bio – gas and their approximate percentages are_ 1. Methane __________ 60% 2. Carbon dioxide _______ 30% 3. Hydrogen __________ 10% Q4. Distinguish between Biodegradable wastes and Non – degradable wastes. Biodegradable wastes 1. Waste materials, which can be decomposed through biological activity of micro – organisms, are called biodegradable waste. 2. This type of waste is degraded in nature. 3. This type of waste does not remain accumulated in nature.

Non – degradable wastes 1. The waste products, which cannot be degraded through the biological activities, are called non – degradable wastes. 2. This type of waste is not degraded in nature. 3. This type of waste remains accumulated in nature.

Q5. Classify the following waste in to biodegradable and non degradable wastes. (Paper, Plastic bags, Food wastes, Dairy wastes, Slaughter house wastes, Worn out utensils, Broken glass vessels, Rusted iron wires, Used slippers, Cabbage leaves, Paper bags, Cattle waste, Animal excreta, Dead Plants, Insecticide, Industrial effluent, Nuclear waste, Metal, Dung, Glass) Biodegradable wastes 1. Paper 2. Food wastes 3. Dairy wastes 4. Slaughter house wastes 5. Cabbage leaves 6. Paper bags 7. Cattle waste 8. Animal excreta 9. Dead plants 10. Dung

Non degradable wastes 1. Plastic bags 2. Worn out utensils 3. Broken glass vessels 4. Rusted iron wires 5. Used slippers 6. Insecticide 7. Industrial effluent 8. Nuclear waste 9. Metal 10. Glass