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Changing the way of learning…, , Environment, Engineering, Civil Engineering by Sandeep Jyani, 2
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Environment, Engineering, Environment Engineering 1, , Water Supply Engineering, / Raw Water Engineering, , Waste Water Engineering, , Environment Engineering 2, , Solid Waste Management, , Air Pollution and Noise, Pollution, Civil Engineering by Sandeep Jyani, , 3
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Environment Engineering, Syllabus, 1. Public Water Supply, 2. Environment Pollution and Control, 3. Domestic Sewage, 4. Solid Waste Management, 5. Environmental Sanitation, Civil Engineering by Sandeep Jyani, , 4
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Water Supply Engineering, 1., 2., 3., 4., , Water Demand, Quality Parameters of Water, Treatment of Water, Distribution, source and Conveyance of, Water, , Civil Engineering by Sandeep Jyani, , 5
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Water Supply Engineering, Chapter 1: Water Demand, • To design a water supply scheme, we must, first estimate the population for which the, scheme should be designed., • The scheme once installed must cater for the, demand of projected population up to some, pre determined future date., , Civil Engineering by Sandeep Jyani, , 6
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Design Period:, • A water supply scheme includes huge, and costly structures such as, reservoirs, dams, pumping units,, distribution system, etc. which can, not be replaced or increased in their, capacities easily., • Various components are designed, such that future needs of the, community gets satisfied. This future, need is called Design Period., • The design period should be neither, too short nor too long, , As per Government of India, Manual (GOI), Sr. No, , Component, , Design Period, , 1, , Water treatment units, , 15 years, , 2, , Pipe Connections, , 30 Years, , 3, , Service Reservoirs (OHT or ground, Tank), , 15 Years, , 4, , Distribution System, , 30 Years, , Civil Engineering by Sandeep Jyani, , 7
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Population Forecasting, There are three main factors, responsible for growth or decline in, Population:, 1. Birth, 2. Death, 3. Migration, , Civil Engineering by Sandeep Jyani, , 8
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Population Forecasting Methods, 1. Arithmetic Progression Method, • Increase in population from, decade to decade is assumed to be, constant, , 𝑷𝒏 = 𝑷𝟎 + 𝒏𝒙, 𝑷𝒏 =Projected population after n decades, 𝑷𝟎 = initial population/ last census, , 𝒏 = number of decades between now and future, 𝒙 =average increase in population per decade, , Civil Engineering by Sandeep Jyani, , 9
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Population Forecasting Methods, c) Incremental Increase Method, • Combination of Arithmetic and Geometric Increase method, • Actual increase in each decade is found, • Average increment of increases is found, , Population after n decades from present is, given by, 𝒏(𝒏 + 𝟏), 𝑷𝒏 = 𝑷𝟎 + 𝒏𝒙 +, 𝒚, 𝟐, , 𝑷𝒏 =Projected population after n decades, 𝑷𝟎 = population of last known decade, 𝒏 = number of decades between now and future, 𝒙 =average increase of population of known decades, 𝒚 =average of incremental increase of known decades, Civil Engineering by Sandeep Jyani, , 14
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GOI Manual Recommends.., 1. Arithmetic Increase Method is, used for old cities, where growth, rate is constant, 2. For new and younger cities, we will, use geometric Progression method, 3. Whenever there is negative rate of, increase, incremental increase, method is used, 4. Incremental Increase Method, generally gives values in between, Arithmetic progression method, and Geometric Progression, Method, Civil Engineering by Sandeep Jyani, , 17
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Water Demand, , 1. Domestic Water Demand, , • Water required in private buildings, for drinking, cooking, gardening, etc., • GOI manual lays down a limit on, water consumption between 135, LPCD to 225 (Litre Per Capita per Day), • Under ordinary conditions, Minimum, domestic water requirement for a, town with full flushing system should, be taken as 200 LPCD, • For low income groups, demand can, be reduced to 135 litres per capita, per day, , Civil Engineering by Sandeep Jyani, , 18
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Water Demand, 2. Commercial/ Institutional Water, Demand, • On an average, per capita demand of, 20 LPCD is usually considered to be, enough to meet commercial and, institutional demands. For highly, commercialized cities, this value is, taken as 50 LPCD., • In Cinemas and theatres, demand is, minimum (approx. 15 LPCD) and in, hospitals, demand is maximum(340 to, 380 LPCD), Civil Engineering by Sandeep Jyani, , 19
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Water Demand, 3. Industrial Water Demand, • The industrial water demand, represents the water demand of, industries which are existing or, likely to be started in future., • For paper industries, for 1 tonne of, paper production, 200-400 Litres of, water is used., • For petroleum refinery and sugar, mills, per tonne production requires, one to two litres of water., Civil Engineering by Sandeep Jyani, , 20
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Water Demand, 4. Demand for Public Use, • This includes water requirement for, Parks, washing of roads, public, drinking, etc., • A nominal amount not exceeding 5%, of the total consumption of city is, provided as demand for public use, , Civil Engineering by Sandeep Jyani, , 21
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Water Demand, 5. Fire Demand, Following requirements must be met for Fire, Demand:, • Three jet stream are simultaneously, thrown from each hydrant, one on the, burning property and one on each, adjacent property, • Discharge in each stream should not be, less than 1100 L/min., • The minimum head available should be 12, to 15 metre and should be maintained for, 4 to 5 hours, , Civil Engineering by Sandeep Jyani, , 22
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Water Demand, 6. Losses and Thefts, • Water lost in leakage due to bad plumbing,, theft, unauthorized water connections and, other losses., • This amount is taken as 15% of total, demand, , Civil Engineering by Sandeep Jyani, , 25
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Design Capacity of Various Component of Water Supply Scheme, , Water, Treatment, Plants, , Pumping, Units, , Distribute, Service Reservoir, , DAM/Reservoir, , The pipe mains, that take water, Source of Supply, from source to, may be designed, service reservoir, for maximum daily and other, treatment units, consumption, are designed for, (1.8q), maximum daily, draft, , Pumps may be, designed for, maximum, daily draft +, some, additional, reserve, , Civil Engineering by Sandeep Jyani, , Distribution, system, should be, designed for, Total Draft, , 29
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Que 5. The total water requirement of a city, is generally assessed on the basis of, a) Maximum hourly demand, b) Maximum daily demand + fire demand, c) Average daily demand + fire demand, d) Greater of (a) and (b), , Civil Engineering by Sandeep Jyani, , 30
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Que 5. The total water requirement of a city, is generally assessed on the basis of, a) Maximum hourly demand, b) Maximum daily demand + fire demand, (Coincident draft), c) Average daily demand + fire demand, d) Greater of (a) and (b), , Civil Engineering by Sandeep Jyani, , 31
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Que 6. Water supply includes, a) Collection, transportation and, treatment of water, b) Distribution of water to, consumers, c) Provisions of Hydrants for fire, fighting, d) All of the above, , Civil Engineering by Sandeep Jyani, , 32
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Que 6. Water supply includes, a) Collection, transportation and, treatment of water, b) Distribution of water to, consumers, c) Provisions of Hydrants for fire, fighting, d) All of the above, , Civil Engineering by Sandeep Jyani, , 33
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Que 8. The distribution system in, water supplies is designed on the, basis of, a) Average daily demand, b) Peak hourly demand, c) Coincident of draft, d) Greater of (b) and (c), , Civil Engineering by Sandeep Jyani, , 36
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Que 8. The distribution system in, water supplies is designed on the, basis of, a) Average daily demand, b) Peak hourly demand, c) Coincident of draft, d) Greater of (b) and (c), , Civil Engineering by Sandeep Jyani, , 37
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Que 9. On peak hourly demand,, what is the maximum daily, consumption of the city which, have average daily consumption, of 100 000 m3?, a) 140 000, b) 170 000, c) 200 000, d) 270 000, , Civil Engineering by Sandeep Jyani, , 38
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Que 9. On peak hourly demand,, what is the maximum daily, consumption of the city which, have average daily consumption, of 100 000 m3?, a) 140 000, b) 170 000, c) 200 000, d) 270 000, , Civil Engineering by Sandeep Jyani, , 39
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Que 10. Which of the following, represents the value of hourly, variation factor?, a) 1.2, b) 1.5, c) 1.7, d) 2.5, , Civil Engineering by Sandeep Jyani, , 40
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Que 10. Which of the following, represents the value of hourly, variation factor?, a) 1.2, b) 1.5, c) 1.7, d) 2.5, , Civil Engineering by Sandeep Jyani, , 41
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Quality Parameters of Water, The Properties that ascertain, qualities of raw water are termed as, Quality Parameters., Water Impurities are Classified as:, 1. Physical, 2. Chemical, 3. Biological, , Civil Engineering by Sandeep Jyani, , 42
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Quality Parameters of Water, 1. Physical Water Quality Parameters, i., , Suspended Solids, For Suspended solids, as per Environmental Protection, Agency, the maximum permissible limit is 30mg/L for, drinking water, , Civil Engineering by Sandeep Jyani, , 43
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Quality Parameters of Water, 1. Physical Water Quality Parameters, ii. Turbidity, Measure of extent to which light is either, absorbed or scattered by suspended matter, in water. It is objectionable because:, A. Aesthetically displeasing, B. It provides absorption sites for chemical, and biological agents thereby reducing, the efficiency of further treatment, C. They may also be biologically active, which may result in causing various, diseases, D. In Natural water bodies(rivers, ponds..), turbidity interferes with light penetration, Civil Engineering reactions, by Sandeep Jyani, and hence with photosynthesis, , 44
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Quality Parameters of Water, 1. Physical Water Quality Parameters, ii. Turbidity, Measure of turbidity is done by:, A. Turbidity rod, B. Jackson’s turbidimeter, C. Bayli’s Turbidity meter, D. Nephelometer, , Civil Engineering by Sandeep Jyani, , 45
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Quality Parameters of Water, , 1. Physical Water Quality Parameters, ii. Turbidity, , 1, , Measure of turbidity is done by:, A. Turbidity rod, • Graduations are encrypted in rod in, ppm(1mg/L =ppm), • As depth of insertion increases, reading, decreases, • Turbidity which 1 mg of Silica produces in 1, litre of distilled water is taken as 1 unit, , 100, , Civil Engineering by Sandeep Jyani, , Platinum, needle, , 46
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Quality Parameters of Water, 1. Physical Water Quality, Parameters, , 1, , ii. Turbidity, B. Jackson’s Turbidity meter, • Level of water is increased till image, of flame disappears, • This method is used only when, turbidity is greater than 25ppm, • This method is not used for drinking, water, , Graduated Glass Tube, , 100, Glass Plate, , Flame, , Civil Engineering by Sandeep Jyani, , 47
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Quality Parameters of Water, 1. Physical Water Quality Parameters, ii. Turbidity, C. Bayli’s Turbidity meter and Nephelometer, • Turbidity less than 1ppm can also be, measured, • So most widely used for domestic supplies, UNIT in Nephelometer is NTU (Nephelometer, Turbidity Unit), Similarly JTU for Jackson’s Turbidity Meter, Acceptable limit for turbidity is 1 mg/L or 1 NTU, Permissible limit for turbidity is 5 mg/L or 5 NTU, Cause for rejection is 10 mg/L or 10 NTU, Civil Engineering by Sandeep Jyani, , 48
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1. Physical Water Quality Parameters, iv. Taste and Odour, • Caused by Chemicals and dissolved gases like, H2S, methane, etc industrial liquids, ammonia,, etc., • Taste and odour are objectionable because of, carcinogenic nature, • Taste and odour are measured by instrument, known as Osmoscope, • Intensity of taste and odour is measure in, Threshold Odour Number (TON), 𝑨+𝑩, 𝑨, , • 𝑻𝑶𝑵 =, • GOI recommends TON between 1 and 3, , Civil Engineering by Sandeep Jyani, , 50
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1. Physical Water Quality Parameters, v. Temperature, • Temperature affects chemical and biological, reactions, • For water supply, it should be between 10 to, 25°C and greater than 25°C is objectionable, , Civil Engineering by Sandeep Jyani, , 51
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2. Chemical Parameters, i. Dissolved solids, ii. pH, iii. Alkalinity, iv. Hardness, v. Chloride content, vi. Nitrogen Content, vii. Phosphorous, viii. Fluorides, ix. Metals, , Civil Engineering by Sandeep Jyani, , 52
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2. Chemical Parameters, i., , Dissolved solids, GOI manual recommends Acceptance Limit as, 500mg/L, Cause for rejection as 2000 mg/L, , ii. pH, , +, , • 𝒑𝑯 = −𝒍𝒐𝒈 𝑯 , where [H+] is in, moles/Litre, • AL = 6.5 – 8.5, • pH can be measure by colored, indicators like methyl orange and, phenolphthalein, , Civil Engineering by Sandeep Jyani, , Working range of methyl, orange is 3.1 to 4.4, , Working range of, phenolphthalein is 8.6 to 10.3, , 53
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2. Chemical Parameters, iv. Hardness, • Acceptable limit of hardness = 200 mg/L, • Cause for rejection = 600 mg/L, • For domestic supply it should be between 75 – 150mg/L, , v. Chloride Content, • Acceptable limit = 200 mg/L, • Cause for rejection = 1000 mg/L, , Civil Engineering by Sandeep Jyani, , 56
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2. Chemical Parameters, vi. Nitrogen Content, • Presence of Nitrogen represent presence of organic matter., • Nitrogen occurs in following forms:, 1. Free Ammonia (NH3) : indicates recent Pollution, • AL = 0.15 mg/L, • CFR= 0.30 mg/L, 2. Organic Ammonia (Albuminoid) : quantity of oxygen before, decomposition of organic matter has started, • AL = 0.30 mg/L, • CFR= 0.45 mg/L, 3. Nitrite (NO2-): indicates partly decomposed condition, • AL=0 (toxic in nature, so not acceptable), 4. Nitrate (NO3-): indicates fully oxidized organic matter, it can also indicate, old pollution, • AL = 45 mg/L, • CFR= 45 mg/L, • Blue baby disease is caused due to Nitrate, Civil Engineering by Sandeep Jyani, , 57
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2. Chemical Parameters, vii. Fluorides, • Upto 1 mg/L, it helps to prevent dental cavities, • During formation of permanent teeth, it combines chemically with, enamel, resulting in harder and stronger teeth, • Excess of it (greater than 1.5 mg/L) results in decoloration of, teeth/mottling of teeth., • Fluorides greater than 5mg/L causes deformation of Bones (Bone, Flourosis), • AL = 1 mg/L, • CFR= 1.5 mg/L, , Civil Engineering by Sandeep Jyani, , 58
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2. Chemical Parameters, viii. Metals, 1, , Metal, Acceptance Limit Cause for Rejection, Iron and Mangnese, Iron, 0.1 mg/L, 1 mg/L, Manganese, 0.05 mg/L, 0.05 mg/L, , 2, 3, 4, 5, , Copper, Sulphate, Zinc, Arsenic, , 0.05 mg/L, 100 mg/L, 5 mg/L, 0.01mg/L, , 1.5 mg/L, 400 mg/L, 15mg/L, 0.05 mg/L, , 6, , Cyanide, , 0.05 mg/L, , 0.05 mg/L, , 7, , Mercury, , 0.001 mg/L, , 0.001 mg/L, , Civil Engineering by Sandeep Jyani, , Comments, , Large quantities affects lungs and, respiratory organs, , Zinc is called nutrient of life, Causes acute toxicity to humans, cyanide renders the body, incapable of carrying oxygen, Mercury is toxic to all forms of, life. It should not be greater than, 0.001 mg/L, , 59
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3. Biological Parameters, • Most important organisms are pathogens, because they are capable of transmitting, diseases, exp (bacteria, virus, protozoa,, helminth, etc.), • Coliforms: harmless aerobic lactose fermenters, organisms, • E-coli (Escherichia-coli), , Civil Engineering by Sandeep Jyani, , 60
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Que. 11 The total solids in water, are due to presence of, a) Colloidal and settleable solids, b) Suspended and floating solids, c) Suspended and dissolved, solids, d) Colloidal and bacterial load, , Civil Engineering by Sandeep Jyani, , 61
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Que. 11 The total solids in water, are due to presence of, a) Colloidal and settleable solids, b) Suspended and floating solids, c) Suspended and dissolved, solids, d) Colloidal and bacterial load, , Civil Engineering by Sandeep Jyani, , 62
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Que. 12 Permanent hardness of, water can be removed by, a) Adding alum, b) Adding lime, c) Adding chlorine, d) Zeolite process, , Civil Engineering by Sandeep Jyani, , 63
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Que. 12 Permanent hardness of, water can be removed by, a) Adding alum, b) Adding lime, c) Adding chlorine, d) Zeolite process, , Civil Engineering by Sandeep Jyani, , 64
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Que. 13 The maximum, permissible limit for fluoride in, drinking water is, a) 0.1 mg/L, b) 1.5 mg/L, c) 5 mg/L, d) 10 mg/L, , Civil Engineering by Sandeep Jyani, , 65
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Que. 13 The maximum, permissible limit for fluoride in, drinking water is, a) 0.1 mg/L, b) 1.5 mg/L, c) 5 mg/L, d) 10 mg/L, , Civil Engineering by Sandeep Jyani, , 66
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Que. 14 Nitrates more than 45, gm/L in water leads to disease, called, a) Gastroenteritis, b) Mottled teeth, c) Polio, d) None of these, , Civil Engineering by Sandeep Jyani, , 67
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Que. 14 Nitrates more than 45, gm/L in water leads to disease, called, a) Gastroenteritis, b) Mottled teeth, c) Polio, d) None of these (blue baby METHEMOGLOBINEMIA), , Civil Engineering by Sandeep Jyani, , 68
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Que. 15 Hardness in water is, caused mainly due to, a) Chlorides and Sulphates, b) Calcium and magnesium, c) Nitrites and nitrates, d) Sodium and potassium, , Civil Engineering by Sandeep Jyani, , 69
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Que. 15 Hardness in water is, caused mainly due to, a) Chlorides and Sulphates, b) Calcium and magnesium, c) Nitrites and nitrates, d) Sodium and potassium, , Civil Engineering by Sandeep Jyani, , 70
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Que. 16 The product of H+ ions, and OH- ions in a strong alkali at, 25°C is, a) 0, b) 1, c) 10-1, d) 10-14, , Civil Engineering by Sandeep Jyani, , 71
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Que. 16 The product of H+ ions, and OH- ions in a strong alkali at, 25°C is, a) 0, b) 1, c) 10-1, d) 10-14, , Civil Engineering by Sandeep Jyani, , 72
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Que 17. Disinfection of water is, done to remove, a) Turbidity, b) Odour, c) Colour, d) Bacteria, , Civil Engineering by Sandeep Jyani, , 73
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Que 17. Disinfection of water is, done to remove, a) Turbidity, b) Odour, c) Colour, d) Bacteria, , Civil Engineering by Sandeep Jyani, , 74
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Que 18. Which of the following, method is used to forecast, population of old and very large, city?, a) Arithmetic increase method, b) Geometric progression, method, c) Graphical Method, d) Logistic curve method, , Civil Engineering by Sandeep Jyani, , 75
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Que 18. Which of the following, method is used to forecast, population of old and very large, city?, a) Arithmetic increase method, b) Geometric progression, method, c) Graphical Method, d) Logistic curve method, , Civil Engineering by Sandeep Jyani, , 76
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Que 19 The population of a town, as per census records were as, follows. Find population in the, year 2011 using arithmetic mean, method., a) 250000, b) 255000, c) 240000, d) 245000, , Population, , Year, , 2 00 000, , 1981, , 2 10 000, , 1991, , 2 30 000, , 2001, , Civil Engineering by Sandeep Jyani, , 77
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Que 19 The population of a town, as per census records were as, follows. Find population in the, year 2011 using arithmetic mean, method., a) 250000, b) 255000, c) 240000, d) 245000, , Population, , Year, , 2 00 000, , 1981, , 2 10 000, , 1991, , 2 30 000, , 2001, , Civil Engineering by Sandeep Jyani, , 78
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Que 19 The population of a town, as per census records were as, follows. Find population in the, year 2011 using arithmetic mean, method., a) 250000, b) 255000, c) 240000, d) 245000, , Population, , Year, , 2 00 000, , 1981, , 2 10 000, , 1991, , 2 30 000, , 2001, , Civil Engineering by Sandeep Jyani, , 79
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Que 20 The population of a town, as per census records were as, follows. Find population in the, year 2011 using Geometric mean, method., a) 244872, b) 245870, c) 246820, d) None of these, Population, , Year, , 2 00 000, , 1981, , 2 10 000, , 1991, , 2 30 000, , 2001, , Civil Engineering by Sandeep Jyani, , 80
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Que 20 The population of a town, as per census records were as, follows. Find population in the, year 2011 using Geometric mean, method., a) 244872, b) 245870, c) 246820, d) None of these, Population, , Year, , 2 00 000, , 1981, , 2 10 000, , 1991, , 2 30 000, , 2001, , Civil Engineering by Sandeep Jyani, , 81
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Methods of Treatment, 1., 2., 3., 4., 5., 6., 7., 8., , Screening, Aeration, Sedimentation, Coagulation, Flocculation, Filtration, Disinfection, Other Methods, Civil Engineering by Sandeep Jyani, , 82
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Methods of Treatment, 1. Screening, • Screening is done to remove the heavier suspended impurities from, the water like plants, stones, animals, etc., • Screening is generally adopted with the help of two types of screens:, 1., 2., 1., , Coarse screens, Fine Screens, , Coarse screens, , water, , • It is in the form of bars of dia 25mm and spacing of 20-100mm and spacing., These screens are generally placed 3.6 vertical to 1 horizontal, , 2., , Fine Screens, • These are generally in the form of wire mesh of size 10mm, • Fine screen is generally avoided as it gets clogged frequently and, requires cleaning at short intervals, thus increases operational cost., • As per GOI manual, it is recommended to use coarse screen instead, of fine screens and remove the finer particles in other treatment, stages, , Civil Engineering by Sandeep Jyani, , 3.6, 1, , 10, 10, , 83
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Methods of Treatment, 2. Aeration, Methods of Aeration, A. Spray Nozzle Method, • Most efficient method, • Pressurized water is used to increase, surface area of water, , Civil Engineering by Sandeep Jyani, , 85
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Methods of Treatment, 2. Aeration, Methods of Aeration, B. Cascade Aerator, • Efficiency is about 40%, , Civil Engineering by Sandeep Jyani, , 86
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Methods of Treatment, 2. Aeration, Methods of Aeration, C. Spray Tower Method, • Best method to remove iron,, manganese and CO2, , Civil Engineering by Sandeep Jyani, , 87
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Methods of Treatment, 2. Aeration, Methods of Aeration, D. Diffused air Method, • It has highest operational cost, , Civil Engineering by Sandeep Jyani, , 88
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Methods of Treatment, 3. Sedimentation, • Sedimentation Tank is of two types, 1., 2., , Quiescent Type, Continuous Type, , 1. Quiescent Type, • Quiescent Type has a detention time of, 24 hours and cleaning interval of 8 to, 12hours., • Tank is designed for maximum daily, flow (1.8q), , Civil Engineering by Sandeep Jyani, , 90
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Methods of Treatment, 3. Sedimentation, 2. Continuous Type, • There are two types of continuous flow, tanks:, 1. Horizontal flow tanks - rectangular, 2. Vertical flow tank – circular, , 1. Horizontal flow tanks:, Assumptions:, a. A particle is removed when it reaches, the bottom of settling tank, b. The concentration of suspended, particles of each size is same at all, vertical cross section, , Civil Engineering by Sandeep Jyani, , 91
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• Particles having settling velocity less than the overflow rate will not get, completely removed., • Particles having settling velocity greater than the overflow rate, will get, completely removed, , Civil Engineering by Sandeep Jyani, , 93
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Methods of Treatment, 3. Sedimentation, Data for design of Sedimentation Tank:, a) For plane sedimentation, overflow rate, V0=15000-30000 L/m2/day, b) For plane sedimentation Detention time = 3 to 4, hours, c) For Sedimentation with coagulation, overflow, rate V0=30000-40000 L/m2/day, d) For Sedimentation with coagulation, detention, time 2 -2.5 hours, e) Width of tank =10-12m, Depth of tank is taken, 3m, f) Sedimentation tank is designed for maximum, daily flow (1.8q), Civil Engineering by Sandeep Jyani, , 94
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Methods of Treatment, 4. Coagulation:, • The efficiency of sedimentation is very less when water contains very, fine suspended solids. Hence to improve efficiency, coagulation is done, along with sedimentation., • Coagulation is process in which certain chemicals known as are added, in the water so as to neutralize the changes over the particles so that, the particles can come together to increase efficiency. A certain, minimum amount of Energy is required for this process, known as, Threshold Energy which is provided in the coagulation process by, inducing rapid mixing in the water, , Entire process of Coagulation is carried out in three, steps:, A. Coagulation-Fast mixing, B. Flocculation-slow mixing, C. Sedimentation, Civil Engineering by Sandeep Jyani, , 96
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Methods of Treatment, 4. Coagulation:, D. Sodium Aluminate Na2Al2O4, , • It reacts with calcium and Magnesium present, in water to form sticky precipitate of Calcium, Magnesium Aluminate, • This process removes both temporary and, permanent hardness, • This process does not require presence of, alkalinity in water, , Civil Engineering by Sandeep Jyani, , 101
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Methods of Treatment, 4. Coagulation:, COAGULATION METHODS : Horizontal Flow Basin, TOP VIEW, , In Mixing basins, mixing is induced by creating the turbulence in water and, turbulence is created by rapid change in direction of flow of water, , Civil Engineering by Sandeep Jyani, , 102
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Methods of Treatment, 4. Coagulation:, COAGULATION METHODS : Vertical Flow Basin, FRONT VIEW, , Civil Engineering by Sandeep Jyani, , 103
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Methods of Treatment, 4. Coagulation:, Mechanical Mixers: Horizontal Mixing type, TOP VIEW, , Civil Engineering by Sandeep Jyani, , 104
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Methods of Treatment, 4. Coagulation:, Mechanical Mixers: Vertical Mixing type, FRONT, VIEW, , In Mechanical Mixers, mixing is induced in water by vigorous agitation with the, help of external power, Civil Engineering by Sandeep Jyani, , 105
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Methods of Treatment, 5. Flocculation:, , • In Flocculation, neutralized, suspended particles, are provided with sufficient contact time so as to, combine and grow in size and get finally removed, in the sedimentation process., • In order to promote the contact between, neutralized particle so as to from bigger sized flocs,, slow mixing is done, • Flocculation depends on:, 1. Turbidity : More turbidity, more will be, flocculation, 2. Type and dose of Coagulant: iron coagulant, will form heavy flocs in less time, 3. Temporal mean velocity gradient (G), Civil Engineering by Sandeep Jyani, , 106
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Methods of Treatment, 6. Filtration:, • Filtration is most often used as limiting step, to remove the flocs and finer unsedimented, particles through beds of granular materials, • Filtration also removes suspended organic, matter, microorganisms and dissolved, minerals from the water, • Two types of Filters are used, 1. Gravity Filters, 2. Pressure Filter, , Civil Engineering by Sandeep Jyani, , 107
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6. Filtration:, 1. Gravity Filters, These are the types of filter in, which head is required by water to, pass through filter medium. This, head is provided by height of water, itself over the filter medium., These are of two types:, A. Slow sand Filters, B. Rapid Sand Filters, , 2. Pressure Filters, These are the types of filter, in which head required by, water to pass through filter, medium is provided, artificially by the application, of pressure over the water, , Civil Engineering by Sandeep Jyani, , 108
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•, , •, •, •, •, •, , Effective size of sand particles is taken, to be 0.2 to 0.3mm, Head maintained at the top of sand, layer is equal to depth of sand layer, 𝒅, , 2.5-3.5m, , •, , Coefficient of Uniformity (𝐂𝐮 = 𝟔𝟎) for, 𝒅𝟏𝟎, filter medium should be 5, Design life of filters = 10 to 15 years, Frequency of cleaning is 1-3 months, During cleaning, top layer (1.5 to 3cm), of sand is removed, Rate of filtration is 2400-2800, L/m2/day, , 60 -90 cm 90-110 cm, , 1. Gravity Filters, A. Slow sand Filters, , 90-110 cm, , 6. Filtration:, , Civil Engineering by Sandeep Jyani, , SAND, , GRAVEL, SUPPORT, Plan area = 100 – 2000 m2, 109
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•, •, •, , After cleaning of filter, it is washed, with clean water and again loaded, with effluent from plane, sedimentation but this filtered water, is not used for 24-36 hours, The efficiency of this filter is 98-99%, Slow Sand Filters should be used for, small town/villages having population, < 5000, These are not used for water having, turbidity > 50 NTU, , 2.5-3.5m, , •, , 60 -90 cm 90-110 cm, , 1. Gravity Filters, A. Slow sand Filters, , 90-110 cm, , 6. Filtration:, , SAND, , GRAVEL, SUPPORT, Plan area = 100 – 2000 m2, , Civil Engineering by Sandeep Jyani, , 110
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Theory of Filtration, 1. Mechanical Straining, , • Impurities greater than the size of filter are strained over the filter, , 2. Sedimentation, , • Turbulence is removed from water during filtration hence, suspended particles tend to settle over sand partilces, , 3. Biological changes, , 𝑷𝒉𝒐𝒕𝒐𝒔𝒚𝒏𝒕𝒉𝒆𝒊𝒔, , • 𝐎𝐫𝐠𝐚𝐧𝐢𝐜 𝐦𝐚𝐭𝒕𝒆𝒓 → 𝑨𝒍𝒈𝒂𝒆, 𝑶𝒙𝒚𝒈𝒆𝒏 →, 𝑶𝒙𝒊𝒅𝒂𝒕𝒊𝒐𝒏 𝒐𝒇 𝒐𝒓𝒈𝒂𝒏𝒊𝒄 𝒎𝒂𝒕𝒕𝒆𝒓, • This dirty layer of bacteria, algae, organic matter is called as Schmutzdecke, layer, • More the thickness of schmutzdecke layer, more will be the biological efficiency, of filter, , 4. Electrolytic Changes, , • Impurities and filter media particles carry opposite charge and hence, neutralization of charge occurs in water, Civil Engineering by Sandeep Jyani, , 111
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Slow Sand Filters, • Number of filter required for treatment, depends on the area of filter, Area (m2), , Number of Filters, , <20, , 2 (including 1 standby), , 20-249, , 3 (1 standby), , 250-649, , 4 (1 standby), , 650-1200, , 5 (1 standby), , >1200, , 6 (1 standby), , Civil Engineering by Sandeep Jyani, , 112
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1. Gravity Filters, B. Rapid sand Filters, • Rapid sand filters removes suspended and, colloidal matter. It also removes, microorganisms., • In case of rapid sand filter, size of sand, particles /(filter media) is large, hence, impurities penetrate the deep inside the sand, layer., • So surface washing alone is not sufficient, so, we go for back washing, • The entire process of back washing takes 15, minutes, • Amount of water for back washing is 2-5 % of, the total water filtered. Backwashing period is, 24-48 hours, Civil Engineering by Sandeep Jyani, , 113
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1. Gravity Filters, B. Rapid sand Filters, • Area of tank 10 to 100 m2 per unit (tank), • Effective size (d10) of sand is 0.45 to 0.75mm, • Minimum free board is 0.5 m, • Base material is gravel an its depth is 45cm, •, , Coefficient of Uniformity (𝐂𝐮 =, , 𝒅𝟔𝟎, ), 𝒅𝟏𝟎, , Civil Engineering by Sandeep Jyani, , = 1.3 to 1.7, , 114
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2. Pressure Filters, • Pressure filter is like a rapid sand filter with a, difference that complete unit is inside a closed, chamber where flow of water is under pressure and, not due to gravity, • In pressure filter, water entering is neither, flocculated, nor sedimented, • It is used for small scale works such as houses,, swimming pool, small scale industries, etc., , Civil Engineering by Sandeep Jyani, , 115
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Filter Troubles, 1. Mud Ball Formation, , • Dust/Mud from the atmosphere gets deposited on the sand surface and during inadequate, washing, the mud sinks down in the filter bed. Thereby forming mud balls, • These mud balls go on increasing in size and during back washing, they interrupt and make, the filter choke, , 2. Cracking of Filter, , • Fine sand in the top layer shrinks forming shrinkage cracks, thus flocs, mud and other, impurities penetrate deep down in the filter, thereby reducing efficiency, , 3. Air Binding, , • More and more impurities are trapped on the surface. A stage comes when the frictional, resistance by filter media exceeds the head of water over the sand., • The bottom sand then acts like a vacuum where no water can pass, thus making air bubbles, inside the sand thereby seriously affecting the operation., • To prevent air binding, filter should be frequently cleaned or depth of water over the sand, should be increased, , Civil Engineering by Sandeep Jyani, , 116
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7. Disinfection:, • Disinfection may be defined as the process of destruction of, harmful microorganisms either by physical process or, chemical process., • Physical- Boiling, UV treatment, etc., • Chemical- Chlorination, treatment by Bromine, Iodine,, Ozone, potassium permanganate, etc., , Civil Engineering by Sandeep Jyani, , 117
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7. Disinfection:, CHLORINATION, Chlorine immediately reacts with ammonia present in water to form, chloramines. Chloramines are combined form of Chlorine and are less, effective than freely available chlorine. But chloramines are stable and, remain in water for a long duration. In the usual chlorine treatment, in, which pH is kept between 5 to 7, dichloramine is predominately present., The dose of Chlorine should be sufficient so as to leave 0.2 mg/L of chlorine, after 10 minutes of contact period. This dose is called Chlorine demand of, water., 𝑵𝑯𝟑 + 𝑯𝑶𝑪𝒍 → 𝑵𝑯𝟐𝑪𝒍 + 𝑯𝟐𝑶, , 𝑵𝑯𝟐𝑪𝒍 + 𝑯𝑶𝑪𝒍 → 𝑵𝑯𝑪𝒍𝟐 + 𝑯𝟐𝑶, 𝑵𝑯𝑪𝒍𝟐 + 𝑯𝑶𝑪𝒍 → 𝑵𝑪𝒍𝟑 + 𝑯𝟐𝑶, , Civil Engineering by Sandeep Jyani, , 119
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7. Disinfection:, CHLORINATION, Types of Chlorination, A. Plane Chlorination, B. Pre Chlorination, C. Super Chlorination, , Civil Engineering by Sandeep Jyani, , 121
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7. Disinfection:, BREAK POINT CHLORINATION, , Residual, chlorine, (mg/L), , I., Destruction, of chlorine, by Reducing, compounds, , III., II., Formation of Destruction of, chlororganic chlororganic &, compounds & chloramines, chloramines, , IV, Formation of, Perchlorine and, chlorine compounds, are not destroyed, , C, , Free, Residual, Chlorine, , D (Breakpoint), , A, , B chlorine added(mg/L), Civil Engineering by Sandeep Jyani, , 124
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Source of Water, 1. Infiltration Gallery, , • Horizontal tunnels constructed at shallow depth, along the banks of a river through water bearing, strata, • These are also called as Horizontal Wells, , 2. Infiltration Well, , • These are shallow wells constructed in series along, the banks of a river in order to collect water, • These are constructed in brick masonry, , 3. Springs, , • The natural outflow of ground water at Earth Surface, is called Spring, • They are purest form of ground water, • Sometimes they may contain sulphur which increases, temperature of water hence they are called hot, springs, Civil Engineering by Sandeep Jyani, , 125
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Water Distribution, Conveyance and its Source, Methods of Distribution, Water is distributed in following, ways:, 1. Gravitational System, 2. Pumping system, 3. Combined System, , System of Supply, 1. Continuous supply, 2. Intermittent supply
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Water Distribution, Conveyance and its Source, Layout of Distribution System:, • The distribution pipe system consists of Mains, Sub, mains, Laterals, Branches and Service connections, • Distribution pipes are laid along the roads or below, footpaths depending upon local conditions, there can, be several types of system:
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Water Distribution, Conveyance and its Source, Layout of Distribution System:, 1. Dead End System (Tree System), , Used for Old towns where houses are in unplanned, way, It is easy to design and is cheap and simple, Disadvantage, i., Water can reach at a particular point only through, one route, hence if some fault occurs at one, point, water supply may get disturbed in that area, as flow is unidirectional, ii. There are many dead ends which prevent free, circulation of water, iii. Stagnant water has to be removed periodically, and this results in wastage of treated water, , Branches, , Laterals, , Sub mains, , Mains, , Dead, end
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Layout of Distribution System:, 2. Grid Iron System, , Sub mains, , Mains
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Layout of Distribution System:, 2. Grid Iron System, • It is also known as Reticular System, , • One main pipe runs through centre and branches, and laterals run in grid pattern which are inter, connected, Advantages:, Dead ends are eliminated, At the time of fire, water can be diverted to, affected areas by closing the valves of other areas, Disadvantages:, • Design is a bit difficult, size of pipes are larger and, more number of valves are required, • It is most suited for a planned city only
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Layout of Distribution System:, 3. Ring System, • This is also known as Circular system, • It consists of a main pipe all around the area, Sub mains, Laterals, , Mains
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Layout of Distribution System:, 4. Radial System, , I, , II, , III, , V, , VI, , Overhead Tank, , IV
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Layout of Distribution System:, 4. Radial System, • A very large area is divided into, several zones and at the centre of, each zone, a distribution reservoir is, kept, Advantage:, , • This method gives higher service, head and efficient water distribution
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CONVEYANCE, Conduits for Water Supply, 1. Gravity Conduits, 2. Pressure Conduits, Gravity Conduits :, Water flows under the action of Gravity flow., Gravity flow can occur in pipes, canals, aqueducts,, flumes, etc, , Pressure Conduits:, Water flows under pressure above atmospheric, pressure. These pipes can freely go up and down over, the surface and sometimes above mountains also, Civil Engineering by Sandeep Jyani, , 134
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CONVEYANCE, , Non Metallic Pipes, , Various types of Pipes under pressure :, Metallic Pipes, 1. Cast Iron pipes, • Most widely used as Mains because, they are economical, unreactive, 2. Steel Pipes, • They are used when inside pressure, is high and larger size is required, 3. Wrought iron pipe, • They are called Galvanized iron pipes, • They are easily workable and lighter, than cast iron pipes, hence they are, used as distribution inside a building, , 1. RCC pipes- mostly used as Mains, 2. Pre Stress Concrete Pipes: They can, withstand high pressure, they are, corrosion resistant, 3. Asbestos Pipe: Silica and Cement are, cemented together to a stiff material, called asbestos-Highly corrosion, resistant, 4. Plastic Pipes:, • UPVC pipe (Unplasticides Polyvinyl, Chloride), • Polyethylene pipes, • GRP (Glass reinforced pipes), , Civil Engineering by Sandeep Jyani, , 135
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JOINTS IN PIPELINES, Socket pipe, , 1. SPIGOT JOINT, • It is also called Bell and Spigot, Joint, • This is used to connect cast iron, pipes and steel pipes, , Spigot pipe, , Collar, , 2. COLLAR JOINT, • It is used for joining RCC pipes, and asbestos pipes, , Civil Engineering by Sandeep Jyani, , 136
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JOINTS IN PIPELINES, 3. EXPANSION JOINT, • Expansion joints are provided in, metal pipe at suitable interval to, take into account the change in, pipe length due to temperature, variation, • Contraction joints are not, provided for water supply lines, , Civil Engineering by Sandeep Jyani, , 137
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PIPE APPERTENANCES, Air, Valve, , Check Valve, Sluice, Valve, Drain Valve, , Check, Valve, Air, Valve, , Civil Engineering by Sandeep Jyani, , 138
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PIPE APPERTENANCES, 1. Sluice valve:, • They are also known as Gate valves or shut off valves, • These are provided to regulate the flow of water through the, pipe and are essential to divide the mains into several, sections., • These are placed usually at summit of the pressure pipes, where the pressure is low, , 2. Air Valves/ Air relief valves, • Water always carries some air with it while flowing, • This air tends to accumulate at summit of pipe, due to, accumulation of air, blockage of water takes place, so air, valve is provided at summit to release pressure, Civil Engineering by Sandeep Jyani, , 139
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PIPE APPERTENANCES, 3. Check valve / Reflux Valve / Non returning valve:, • These are automatic devices that permits the flow in one, direction only, , 4. Drain valve/ scouring valve / blow off valve, • Its function is to remove sand, silt, etc. deposited in the, pipelines, , 5. Butterfly Valve, • They regulate and stop the flow in large sized pipes, , 6. Ball Valves / Ball Float valves:, • They are used to maintain a constant level in an elevated, tank or a reservoir, , Civil Engineering by Sandeep Jyani, , 140
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PIPE APPERTENANCES, 7. Pressure Relief Valve / Safety Valve, • When the pressure of water suddenly increases and, exceeds the permissible pressure, it results in water, hammer, • The valve opens automatically to release the excess, pressure instantaneously., • Thus the pipeline is protected from bursting, , Civil Engineering by Sandeep Jyani, , 141
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Environment Engineering II, 1., 2., 3., 4., 5., 6., 7., , Waste Water Characteristics, Biochemical Reactions in waste water, Disposal of Sewage Effluents, Design of Sewerage system, Treatment of Waste water, Solid waste management, Air and noise pollution, , Civil Engineering by Sandeep Jyani, , 142
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Waste Water Characteristics, • Waste water is usually classified as, → Industrial waste water and, → Municipal waste water, • Industrial waste water with characteristics, compatible with municipal water is often, discharged into municipal sewer., • Many Industrial waste waters require pretreatment, to remove non compatible substances prior to, discharge into the municipal sewers, Civil Engineering by Sandeep Jyani, , 143
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Properties of Waste Water, Waste water = water + liquid waste originated from locality, , 1. Domestic sewage: It is a mixture of water and, liquid waste originating due to domestic, activities like washing, cooking, bathing, etc., 2. Industrial sewage: Waste water originated due to, industrial activities, 3. Storm Water Drainage: It is sewage that is, originated due to rains., Note: Combination of kitchen and Bathroom, waste is termed as sullage, Civil Engineering by Sandeep Jyani, , 144
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SEWERAGE SYSTEM, • It is a system of collection, treatment and, disposal of the treated sewage, • Sewerage system is of 3 types:, 1. Separate sewerage system, 2. Combined sewerage system, 3. Partially separate sewerage system, , Civil Engineering by Sandeep Jyani, , 145
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Physical Waste Water Parameters, • All physical water quality parameters like total solids,, suspended solids, Turbidity, colour, Temperature, etc., are applicable here also., • Sewage Consists of Both Organic & Inorganic particles, • Average temperature of sewage in India is 20°C., • As per GOI manual, 80% of water supplied goes into, the sewage., , Civil Engineering by Sandeep Jyani, , 146
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Chemical Parameters of Waste Water, Solids present in waste water can be of four forms:, 1. Suspended solids, 2. Dissolved solids, 3. Colloidal solids, 4. Settleable solids, , Civil Engineering by Sandeep Jyani, , 147
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Chemical Parameters of Waste Water, 1. Suspended solids are those which remain floating, in water. (>100nm), 2. Dissolved solids are these which dissolve in waste, water. (< 1 nm), 3. Colloidal solids are those which have particle size, in between dissolved and suspended. (1-100nm), 4. Settleable solids are that portion of solid matter, which settles out if the waste water is allowed to, remain undisturbed for 2 hours., Civil Engineering by Sandeep Jyani, , 148
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Chemical Parameters of Waste Water, The amount of various kinds of solids present in waste, water can be determined as below:, • Total amount of solids can be determined by, evaporating a known volume of waste water and, weighing the residue left. The mass of residue left, divided by the known volume of water is expressed, in mg/L, • The suspended solids are also called as Filterable, Solids that are retained on a filter of 1µm pore size., • The quantity of settleable solids with the help of, Imhoff Cone., • Waste water is allowed to stand in the cone for 2 hours, and the quantity of solids settled down in the bottom is, directly read out., Civil Engineering by Sandeep Jyani, , 149
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Chemical Parameters of Waste Water, 2. pH Value, • The alkalinity of fresh waste water is alkaline but as time passes, it becomes acidic because of the bacterial action in anaerobic, processes, , 3. Chloride content: The normal chloride content of waste, water of domestic nature is taken as 120 mg/L., 4. Dissolved oxygen (DO), • Respiration of aerobic microorganisms, • The dissolved oxygen in fresh waste water depends upon, temperature. It the temp of sewage is more, DO content will be, less., • For survival of fish, 4ppm (4mg/L) DO is required, • DO content of waste water is found out by Winkler’s method, Civil Engineering by Sandeep Jyani, , 150
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Chemical Parameters of Waste Water, 5. Chemical Oxygen Demand (COD), • COD is used to measure the content of Biodegradable as well as, Non biodegradable organic matter, , • COD – BOD = non biodegradable organic matter, , 6. Theoretical Oxygen Demand (ThOD), • Amount of oxygen required to oxidize the quantity of all organic, matter, , Civil Engineering by Sandeep Jyani, , 151
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7. Biochemical Oxygen Demand (BOD), • BOD is used as a measure of the quantity of oxygen, required for oxidation of Biodegradable organic matter, present in water sample by aerobic bio chemical reactions., • BOD of water during 5 days at 20°c is taken as standard, BOD and is approx., equal to 67% of ultimate BOD, • The BOD is determined by diluting a known volume of a, sample of waste water with a known volume of Aerated, water and then calculating DO of the diluted sample., • The diluted sample is then incubated at 20°c for 5 days the, DO at the end of 5 days is again calculated., • The difference between initial DO and final DO will indicate, the oxygen consumed, , Civil Engineering by Sandeep Jyani, , 152
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7. Biochemical Oxygen Demand (BOD), • The first Demand occurs due to, oxidation of organic matter and is, called Carbonaceous demand or First, stage demand., • The later demand occurs due to, biological oxidation of Ammonia and, is called Nitrogenous demand or II, stage demand, • Nitrogenous demand starts only after, 8 days because the reproduction rate, of Nitrification bacteria is very slow., , BOD (mg/L), , Civil Engineering by Sandeep Jyani, , Nitrogenous, demand or II, stage demand, , Carbonaceous, demand or First, stage demand, Time (days), , 154
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Biochemical reactions in Waste Water, • The aerobic and anaerobic are the two basic forms of Biological, stabilization reaction whose occurrence is dependent upon the, availability or non-availability of oxygen., • Aerobic Reactions taken place in the presence of free oxygen and, produce Stable inorganic end products with relatively low energy, content., • Anaerobic reactions occur in the absence of free oxygen., • Anaerobic reactions are slow and do not remove the organic content, completely., Civil Engineering by Sandeep Jyani, , 157
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Various Types of Bacteria, • Bacteria are primary decomposers of organic, material, • Bacteria require energy and material for growth, and reproduction, • Energy for bacteria is derived from biological, oxidation or reduction of organic or inorganic, compounds, • Material is derived from organic or inorganic, compounds. Bacteria are classified according to, the energy source, Civil Engineering by Sandeep Jyani, , 158
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Various Types of Bacteria, 1. AUTOTROPS: They derive both energy and material, from inorganic substances., 2. HETEROTROPHS: They derive both energy &, material from organic substances, 3. PHOTOTROPS: They utilize sunlight as energy, source and inorganic substances as material source, 4. FACULTATIVE HETROTROPS: They are capable of, functioning both in the presence and in the, absence of oxygen to oxidize organic matter., 5. AEROBIC HETROTROPS: They utilize organics in the, presence of oxygen., 6. ANAEROBIC HETROTROPS: They utilize organics in, the absence of oxygen., Civil Engineering by Sandeep Jyani, , 159
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Que 22. The depression of water table in a well due to pumping, will be maximum, a), b), c), d), , At a distance r from the well, Close to the well, At a distance R/2 from the well, None of the above, , Civil Engineering by Sandeep Jyani, , 160
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Que 22. The depression of water table in a well due to pumping, will be maximum, a), b), c), d), , At a distance r from the well, Close to the well, At a distance R/2 from the well, None of the above, , Civil Engineering by Sandeep Jyani, , 161
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Que 23. The devices that are installed for drawing water from, the sources are called as, a), b), c), d), , Aquifers, Aquiclude, Filters, Intakes, , Civil Engineering by Sandeep Jyani, , 162
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Que 23. The devices that are installed for drawing water from the, sources are called as, a), b), c), d), , Aquifers, Aquiclude, Filters, Intakes, , Civil Engineering by Sandeep Jyani, , 163
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Que 24. Maximum discharge of a tube well is about, , a), b), c), d), , 5 litres/sec, 50 litres/sec, 500 litres/sec, 1000 litres/sec, , Civil Engineering by Sandeep Jyani, , 164
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Que 24. Maximum discharge of a tube well is about, , a), b), c), d), , 5 litres/sec, 50 litres/sec, 500 litres/sec, 1000 litres/sec, , Civil Engineering by Sandeep Jyani, , 165
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Que 25. As compared to shallow wells, deep wells have, , a), b), c), d), , More depth, Less depth, More discharge, Less discharge, , Civil Engineering by Sandeep Jyani, , 166
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Que 25. As compared to shallow wells, deep wells have, , a), b), c), d), , More depth, Less depth, More discharge, Less discharge, , Civil Engineering by Sandeep Jyani, , 167
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Que 26. Ground water is usually free from, , a), b), c), d), , Suspended Impurities, Dissolved impurities, Both suspended and dissolved impurities, NOTA, , Civil Engineering by Sandeep Jyani, , 168
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Que 26. Ground water is usually free from, , a), b), c), d), , Suspended Impurities, Dissolved impurities, Both suspended and dissolved impurities, NOTA, , Civil Engineering by Sandeep Jyani, , 169
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Que 27. Polluted water is the one which, , a) Contains pathogenic bacteria, b) Consists of undesirable substances, rendering it unfit for drinking and domestic, use, c) Is safe and suitable for drinking and, domestic use, d) Is contaminated, , Civil Engineering by Sandeep Jyani, , 170
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Que 27. Polluted water is the one which, , a) Contains pathogenic bacteria, b) Consists of undesirable substances, rendering it unfit for drinking and domestic, use, c) Is safe and suitable for drinking and, domestic use, d) Is contaminated, , Civil Engineering by Sandeep Jyani, , 171
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Que 28. Which of the following is not a water, borne disease?, a), b), c), d), , Dysentery, Cholera, Typhoid, Malaria, , Civil Engineering by Sandeep Jyani, , 172
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Que 28. Which of the following is not a water, borne disease?, a), b), c), d), , Dysentery, Cholera, Typhoid, Malaria, , Civil Engineering by Sandeep Jyani, , 173
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Que 29. The most common cause of acidity in, water is, a), b), c), d), , Carbon dioxide, Oxygen, Hydrogen, Nitrogen, , Civil Engineering by Sandeep Jyani, , 174
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Que 29. The most common cause of acidity in, water is, a), b), c), d), , Carbon dioxide, Oxygen, Hydrogen, Nitrogen, , Civil Engineering by Sandeep Jyani, , 175
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Que 30. The phenolic compounds in public, water supply should not be more than, a), b), c), d), , 0.1 ppm, 0.01 ppm, 0.001 ppm, 0.0001 ppm, , Civil Engineering by Sandeep Jyani, , 176
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Que 30. The phenolic compounds in public, water supply should not be more than, a), b), c), d), , 0.1 ppm, 0.01 ppm, 0.001 ppm, 0.0001 ppm, , Civil Engineering by Sandeep Jyani, , 177
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Que 31. The maximum permissible limit for, fluoride content in drinking water is, a) 0.1 ppm, b) 1.5 ppm, c) 5 ppm, d) 10 ppm, , Civil Engineering by Sandeep Jyani, , 178
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Que 31. The maximum permissible limit for, fluoride content in drinking water is, a) 0.1 ppm, b) 1.5 ppm, c) 5 ppm, d) 10 ppm, , Civil Engineering by Sandeep Jyani, , 179
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DESIGN AND CONSTRUCTION OF SEWERS, The major roles of a sewer system :, • Improvement in the environment by removing the, sewage as it originates, • Preventing inundation of low lying areas that may be, otherwise caused by not providing sewers, • Prevention of sewage stagnations, • Avoiding cross connections with freshwater sources, by seepage, , Civil Engineering by Sandeep Jyani, , 180
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LAYING OF SEWERS, Priorities of works shall be followed during execution in sequence as:, (1) Sewage treatment plants, (2) Trunk mains, (3) Sewage pumping stations (if required), (4) Main sewers, (5) Sub main sewers, (6) Sewers (Laterals), , Civil Engineering by Sandeep Jyani, , 181
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SEWER CONSTRUCTION, 1. Removing pavement, 2. Removal of the material from the ground, and its, separation, its classification where necessary, and its, final disposal, 3. Sheeting and bracing the sides of the trench, 4. Removal of water (if any) from the trench, 5. Protection of other structures, both underground and, on the surface, whose foundations may be affected, 6. Backfilling, and, 7. Replacement of the pavement., Civil Engineering by Sandeep Jyani, , 182
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ESTIMATION OF DESIGN FLOWS, a) DESIGN PERIOD: The length of time up to which the, capacity of a sewer will be adequate is referred to as the, design period., , Central Public Health and Environmental Engineering Organization (CPHEEO), , 183
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ESTIMATION OF DESIGN FLOWS, b) POPULATION FORECAST:, • Arithmetic increase method, • Geometrical increase method, • Incremental increase method, , Civil Engineering by Sandeep Jyani, , 184
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Design Data, • Sewer should be designed to carry peak discharge i.e., maximum hourly discharge and should be checked to, ensure that at minimum discharge i.e. minimum hourly, discharge velocity generated should be greater than self, cleansing velocity, • Self Cleansing Velocity is the minimum velocity at which no, solid gets deposited at the bottom of the sewer, • To avoid erosion of pipe material, maximum velocity should, be limited as follows:, • For concrete sewer, 2.5 - 3 m/sec, • For Cast iron, 3.5 - 4.5 m/sec, , Civil Engineering by Sandeep Jyani, , 187
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SEWER APPURTENANCES, 1. Manhole, A manhole is an opening through which a man may, enter a sewer for inspection, cleaning and other, maintenance and is fitted with a removable cover to, withstand traffic loads in sewers, , Civil Engineering by Sandeep Jyani, , 189
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SEWER APPURTENANCES, 1. Manhole, • Manhole should be built at every change of alignment,, gradient or diameter, at the head of all sewers and, branches and at every junction of sewers, • The spacing of manholes above 90 to 150 m is allowed on, straight sewer lines of dia 0.9 – 1.5 m, • Spacing of manholes above 150 to 200m is allowed on, straight sewer lines of dia 1.5 – 2m, • The depth less than 1m is considered as normal manhole, and depth greater than 1.5m is considered as deep, manhole, , Civil Engineering by Sandeep Jyani, , 190
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SEWER APPURTENANCES, 1. Types of Manhole, • Straight Manhole: Built on a straight run of sewer with no, change in size of Sewer or no junctions in the sewer, • Junction Manhole: Built at every junction of two or more, sewers, • Drop Manholes: Built to connect the high level branch, sewer to the low level main sewer, , Civil Engineering by Sandeep Jyani, , 191
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SEWER APPURTENANCES, 2. Grease and Oil Traps, • Constructed on Sewer lines for excluding grease and oil, from the sewage, , 3. Catch Basin, • Rectangular chamber which allows the storm water to, enter the sewer and eliminating silt and stones, , Civil Engineering by Sandeep Jyani, , 192
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Corrosion of Concrete Sewers, • Hydrogen Sulphide is produced in Sewer lines and, it gets oxidized to Sulphuric acid which reacts with, the constituents of Cement which forms CaSO4 to, occupy greater volume than the compounds they, replace, , Civil Engineering by Sandeep Jyani, , 193
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Que 33. The minimum diameter of an opening, on a manhole is, a), b), c), d), , 25 cm, 50 cm, 75 cm, 105 cm, , Civil Engineering by Sandeep Jyani, , 196
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Que 33. The minimum diameter of an opening, on a manhole is, a), b), c), d), , 25 cm, 50 cm, 75 cm, 105 cm, , Civil Engineering by Sandeep Jyani, , 197
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Que 34. Sewage treatment units are usually, designed for, a), b), c), d), , 5-10 years, 15-20 years, 30-40 years, 50 years, , Civil Engineering by Sandeep Jyani, , 198
Page 199 :
Que 34. Sewage treatment units are usually, designed for, a), b), c), d), , 5-10 years, 15-20 years, 30-40 years, 50 years, , Civil Engineering by Sandeep Jyani, , 199
Page 200 :
Que 35. The pH value of fresh sewage is, , a), b), c), d), , Less than 7, More than 7, Equal to 7, 0, , Civil Engineering by Sandeep Jyani, , 200
Page 201 :
Que 35. The pH value of fresh sewage is, , a), b), c), d), , Less than 7, More than 7, Equal to 7, 0, , Civil Engineering by Sandeep Jyani, , 201
Page 202 :
Que 36. A sewer which receives the discharge of, a number of house sewers is called, a), b), c), d), , House Sewer, Lateral Sewer, Intercepting sewer, Sub mains sewer, , Civil Engineering by Sandeep Jyani, , 202
Page 203 :
Que 36. A sewer which receives the discharge of, a number of house sewers is called, a), b), c), d), , House Sewer, Lateral Sewer, Intercepting sewer, Sub mains sewer, , Civil Engineering by Sandeep Jyani, , 203
Page 204 :
Que 37. A manhole is generally provided at, each, a), b), c), d), , Bend, Junction, Change of gradient, All of the above, , Civil Engineering by Sandeep Jyani, , 204
Page 205 :
Que 37. A manhole is generally provided at, each, a), b), c), d), , Bend, Junction, Change of gradient, All of the above, , Civil Engineering by Sandeep Jyani, , 205
Page 206 :
Que 38. Pick up the incorrect statement from, the following:, a) Manholes are provided in Sewer pipes at, suitable intervals, b) Catch Basins are generally provided in, Sewers for carrying drainage discharge, c) Inlets are generally provided in all Sewers, d) NOTA, , Civil Engineering by Sandeep Jyani, , 206
Page 207 :
Que 38. Pick up the incorrect statement from, the following:, a) Manholes are provided in Sewer pipes at, suitable intervals, b) Catch Basins are generally provided in, Sewers for carrying drainage discharge, c) Inlets are generally provided in all Sewers, d) NOTA, , Civil Engineering by Sandeep Jyani, , 207
Page 208 :
Que 39. Before entering a manhole, a candle is, lowered into the manhole, a), b), c), d), , To illuminate it, To detect toxic gases, To give signal to adjacent manhole, To find out the presence of Oxygen, , Civil Engineering by Sandeep Jyani, , 208
Page 209 :
Que 39. Before entering a manhole, a candle is, lowered into the manhole, a), b), c), d), , To illuminate it, To detect toxic gases, To give signal to adjacent manhole, To find out the presence of Oxygen, , Civil Engineering by Sandeep Jyani, , 209
Page 210 :
Que 40. The trap which is provided to, disconnect the house drain from the street, sewer is called, a), b), c), d), , Master trap, Intercepting trap, Interception manhole, All of the above, , Civil Engineering by Sandeep Jyani, , 210
Page 211 :
Que 40. The trap which is provided to, disconnect the house drain from the street, sewer is called, a), b), c), d), , Master trap, Intercepting trap, Interception manhole, All of the above, , Civil Engineering by Sandeep Jyani, , 211
Page 212 :
Que 41. The inspection pit is a manhole, provided in a base drainage system, a), b), c), d), , At every change of direction, At every change of gradient, At every 30m interval, All of the above, , Civil Engineering by Sandeep Jyani, , 212
Page 213 :
Que 41. The inspection pit is a manhole, provided in a base drainage system, a), b), c), d), , At every change of direction, At every change of gradient, At every 30m interval, All of the above, , Civil Engineering by Sandeep Jyani, , 213
Page 214 :
Que 42. The diameter of a domestic sewer pipe, laid at gradient 1 in 100 is recommended, a), b), c), d), , 100mm, 150mm, 175mm, 200mm, , Civil Engineering by Sandeep Jyani, , 214
Page 215 :
Que 42. The diameter of a domestic sewer pipe, laid at gradient 1 in 100 is recommended, a), b), c), d), , 100mm, 150mm, 175mm, 200mm, , Civil Engineering by Sandeep Jyani, , 215
Page 216 :
Que 43. Which type of drainage system will, collect the rain water, a), b), c), d), , Primary, Secondary, Tertiary, Primary and Tertiary, , Civil Engineering by Sandeep Jyani, , 216
Page 217 :
Que 43. Which type of drainage system will, collect the rain water, a), b), c), d), , Primary, Secondary, Tertiary, Primary and Tertiary, , Civil Engineering by Sandeep Jyani, , 217
Page 218 :
Que 44. The correct relation between, theoretical oxygen demand (TOD), Biochemical, Oxygen demand (BOD) and Chemical Oxygen, demand (COD) is given by, a) TOD>BOD>COD, b) TOD>COD>BOD, c) BOD>COD>TOD, d) COD>BOD>TOD, , Civil Engineering by Sandeep Jyani, , 218
Page 219 :
Que 44. The correct relation between, theoretical oxygen demand (TOD), Biochemical, Oxygen demand (BOD) and Chemical Oxygen, demand (COD) is given by, a) TOD>BOD>COD, b) TOD>COD>BOD, c) BOD>COD>TOD, d) COD>BOD>TOD, , Civil Engineering by Sandeep Jyani, , 219
Page 220 :
Que 45. Standard EDTA solution is used to, determine, a) Hardness in water, b) Turbidity in water, c) Dissolved oxygen in water, d) Residual chlorine in water, , Civil Engineering by Sandeep Jyani, , 220
Page 221 :
Que 45. Standard EDTA solution is used to, determine, a) Hardness in water, b) Turbidity in water, c) Dissolved oxygen in water, d) Residual chlorine in water, , Civil Engineering by Sandeep Jyani, , 221
Page 222 :
Que 46. If coliform bacteria is present in a, sample of water, then the coliform test to be, conducted is, i. Presumptive coliform test, ii. Confirmed coliform test, iii. Completed coliform test, a), b), c), d), , Only (i), Both (i) and (ii), Both (i) and (iii), All of the above, Civil Engineering by Sandeep Jyani, , 222
Page 223 :
Que 46. If coliform bacteria is present in a, sample of water, then the coliform test to be, conducted is, i. Presumptive coliform test, ii. Confirmed coliform test, iii. Completed coliform test, a), b), c), d), , Only (i), Both (i) and (ii), Both (i) and (iii), All of the above, Civil Engineering by Sandeep Jyani, , 223
Page 224 :
Que 47. Alkalinity in water is expressed as, milligrams per lire in terms of equivalent, a) Calcium carbonate, b) Magnesium carbonate, c) Sodium carbonate, d) Calcium hydroxide, , Civil Engineering by Sandeep Jyani, , 224
Page 225 :
Que 47. Alkalinity in water is expressed as, milligrams per lire in terms of equivalent, a) Calcium carbonate, b) Magnesium carbonate, c) Sodium carbonate, d) Calcium hydroxide, , Civil Engineering by Sandeep Jyani, , 225
Page 226 :
Que 48. Which of the following values of pH, represents a stronger acid?, a) 2, b) 5, c) 7, d) 10, , Civil Engineering by Sandeep Jyani, , 226
Page 227 :
Que 48. Which of the following values of pH, represents a stronger acid?, a) 2, b) 5, c) 7, d) 10, , Civil Engineering by Sandeep Jyani, , 227
Page 228 :
Que 49. Turbidity is measured on, , a) Standard silica scale, b) Standard cobalt scale, c) Standard platinum scale, d) Platinum cobalt scale, , Civil Engineering by Sandeep Jyani, , 228
Page 229 :
Que 49. Turbidity is measured on, , a) Standard silica scale, b) Standard cobalt scale, c) Standard platinum scale, d) Platinum cobalt scale, , Civil Engineering by Sandeep Jyani, , 229
Page 230 :
Que 50. On standard – silica scale, the turbidity, in drinking water should be limited to, a) 10 ppm, b) 20 ppm, c) 30 ppm, d) 50 ppm, , Civil Engineering by Sandeep Jyani, , 230
Page 231 :
Que 50. On standard – silica scale, the turbidity, in drinking water should be limited to, a) 10 ppm, b) 20 ppm, c) 30 ppm, d) 50 ppm, , Civil Engineering by Sandeep Jyani, , 231
Page 232 :
Que 51. Residual chlorine in water is, determined by, a) Starch iodide method, b) Orthotolidene method, c) Both (a) and (b), d) None of these, , Civil Engineering by Sandeep Jyani, , 232
Page 233 :
Que 51. Residual chlorine in water is, determined by, a) Starch iodide method, b) Orthotolidene method, c) Both (a) and (b), d) None of these, , Civil Engineering by Sandeep Jyani, , 233
Page 234 :
Que 52. Orthotolidene test is used for, determination of, a) Dissolved oxygen, b) Residual chlorine, c) Biochemical oxygen demand, d) Dose of coagulant, , Civil Engineering by Sandeep Jyani, , 234
Page 235 :
Que 52. Orthotolidene test is used for, determination of, a) Dissolved oxygen, b) Residual chlorine, c) Biochemical oxygen demand, d) Dose of coagulant, , Civil Engineering by Sandeep Jyani, , 235
Page 236 :
Que 53. If the total hardness of water is greater, than its total alkalinity, the carbonate hardness, will be equal to, a) Total alkalinity, b) Total hardness, c) Total hardness – total alkalinity, d) Non carbonate hardness, , Civil Engineering by Sandeep Jyani, , 236
Page 237 :
Que 53. If the total hardness of water is greater, than its total alkalinity, the carbonate hardness, will be equal to, a) Total alkalinity, b) Total hardness, c) Total hardness – total alkalinity, d) Non carbonate hardness, Carbonate hardness = minimum of (total hardness, alkalinity), , Civil Engineering by Sandeep Jyani, , 237
Page 238 :
Que 54. The amount of residual chlorine left in, public water supply for safety against, pathogenic bacteria is about, a) 0.01 to 0.05 ppm, b) 0.05 to 0.5 ppm, c) 0.5 to 1.0 ppm, d) 1.0 to 5.0 ppm, , Civil Engineering by Sandeep Jyani, , 238
Page 239 :
Que 54. The amount of residual chlorine left in, public water supply for safety against, pathogenic bacteria is about, a) 0.01 to 0.05 ppm, b) 0.05 to 0.5 ppm, c) 0.5 to 1.0 ppm, d) 1.0 to 5.0 ppm, , Civil Engineering by Sandeep Jyani, , 239
Page 240 :
Que 55. The dissolved oxygen level in natural, unpolluted water at normal temperature is, found to be of the order of, a) 1 mg / litre, b) 10 mg / litre, c) 100 mg / litre, d) 1000 mg / litre, , Civil Engineering by Sandeep Jyani, , 240
Page 241 :
Que 55. The dissolved oxygen level in natural, unpolluted water at normal temperature is, found to be of the order of, a) 1 mg / litre, b) 10 mg / litre, c) 100 mg / litre, d) 1000 mg / litre, , Civil Engineering by Sandeep Jyani, , 241
Page 242 :
Que 56. The velocity of flow of water in a, sedimentation tank is about, a) 5 to 10 cm/sec., b) 15 to 30 cm/sec., c) 15 to 30 cm / minute, d) 15 to 30 cm / hour, , Civil Engineering by Sandeep Jyani, , 242
Page 243 :
Que 56. The velocity of flow of water in a, sedimentation tank is about, a) 5 to 10 cm/sec., b) 15 to 30 cm/sec., c) 15 to 30 cm / minute, d) 15 to 30 cm / hour, , Civil Engineering by Sandeep Jyani, , 243
Page 244 :
Que 57. The length of rectangular, sedimentation tank should not be more than, a) B, b) 2 B, c) 4B, d) 8 B, , Civil Engineering by Sandeep Jyani, , 244
Page 245 :
Que 57. The length of rectangular, sedimentation tank should not be more than, a) B, b) 2 B, c) 4B, d) 8 B, , Civil Engineering by Sandeep Jyani, , 245
Page 246 :
Que 58. The overflow rate for plain, sedimentation tanks is about, a) 500 to 750 liters / hour/m2, b) 1000 to 1250 liters / hour/m2, c) 1250 to 1500 liters / hour/m2, d) 1500 to 2000 liters / hour/m2, , Civil Engineering by Sandeep Jyani, , 246
Page 247 :
Que 58. The overflow rate for plain, sedimentation tanks is about, a) 500 to 750 liters / hour/m2, b) 1000 to 1250 liters / hour/m2 (when, coagulants are used), c) 1250 to 1500 liters / hour/m2, d) 1500 to 2000 liters / hour/m2, , Civil Engineering by Sandeep Jyani, , 247
Page 248 :
Que 59. Percentage of bacterial load that can be, removed from water by the process of plain, sedimentation is about, a) 10 to 25, b) 50, c) 75, d) 100, , Civil Engineering by Sandeep Jyani, , 248
Page 249 :
Que 59. Percentage of bacterial load that can be, removed from water by the process of plain, sedimentation is about, a) 10 to 25, b) 50, c) 75, d) 100, , Civil Engineering by Sandeep Jyani, , 249
Page 250 :
Que 60. For a given discharge, the efficiency of, sedimentation tank can be increased by, a) Increasing the depth of tank, b) Decreasing the depth of tank, c) Increasing the surface area of tank, d) Decreasing the surface area of tank, , Civil Engineering by Sandeep Jyani, , 250
Page 251 :
Que 60. For a given discharge, the efficiency of, sedimentation tank can be increased by, a) Increasing the depth of tank, b) Decreasing the depth of tank, c) Increasing the surface area of tank, d) Decreasing the surface area of tank, For small particles, Low overflow rate is required, hence surface area is increased, , 𝑺𝒖𝒓𝒇𝒂𝒄𝒆 𝒐𝒗𝒆𝒓𝒇𝒍𝒐𝒘 𝒓𝒂𝒕𝒆 𝑽𝟎 =, , Civil Engineering by Sandeep Jyani, , 𝑸, 𝑩𝑳, , 251
Page 252 :
Que 61. The detention period and overflow rate, respectively for plain sedimentation as, compared to sedimentation with coagulation, are generally, a) Less and more, b) Less and less, c) More and less, d) More and more, , Civil Engineering by Sandeep Jyani, , 252
Page 253 :
Que 61. The detention period and overflow rate, respectively for plain sedimentation as, compared to sedimentation with coagulation, are generally, a) Less and more, b) Less and less, c) More and less, d) More and more, , Civil Engineering by Sandeep Jyani, , 253
Page 254 :
Que 62. The amount of coagulant needed for, coagulation of water increases with, A. increase in turbidity of water, B. Decrease in turbidity of water, C. Increase in temperature of water, D. Decrease in temperature of water, The correct answer is, a) A and B, b) A and D, c) B and C, d) B and D, Civil Engineering by Sandeep Jyani, , 254
Page 255 :
Que 62. The amount of coagulant needed for, coagulation of water increases with, A. increase in turbidity of water, B. Decrease in turbidity of water, C. Increase in temperature of water, D. Decrease in temperature of water, The correct answer is, a) A and B, b) A and D, c) B and C, d) B and D, Civil Engineering by Sandeep Jyani, , 255
Page 256 :
Que 63. Alum as a coagulant is found to be, most effective when pH range of water is, a) 2 to 4, b) 4 to 6, c) 6 to 8, d) 8 to 10, , Civil Engineering by Sandeep Jyani, , 256
Page 257 :
Que 63. Alum as a coagulant is found to be, most effective when pH range of water is, a) 2 to 4, b) 4 to 6, c) 6 to 8, d) 8 to 10, , Civil Engineering by Sandeep Jyani, , 257
Page 258 :
Que 64. The detention period in coagulation, tanks is usually kept as, a) 1 to 2 minutes, b) 30 to 45 minutes, c) 2 to 6 hours, d) 2 to 6 days, , Civil Engineering by Sandeep Jyani, , 258
Page 259 :
Que 64. The detention period in coagulation, tanks is usually kept as, a) 1 to 2 minutes, b) 30 to 45 minutes, c) 2 to 6 hours, d) 2 to 6 days, , Civil Engineering by Sandeep Jyani, , 259
Page 260 :
Que 65. The alum, when added as a coagulant, in water, a) Does not require alkalinity in water for, flocculation, b) Does not affect pH value of water, c) Increases pH value of water, d) Decreases pH value of water, , Civil Engineering by Sandeep Jyani, , 260
Page 261 :
Que 65. The alum, when added as a coagulant, in water, a) Does not require alkalinity in water for, flocculation, b) Does not affect pH value of water, c) Increases pH value of water, d) Decreases pH value of water, , Civil Engineering by Sandeep Jyani, , 261
Page 262 :
Que 66. The chemical most commonly used to, increases speed of sedimentation of sewage is, a) Sulphuric acid, b) Copper sulphate, c) Lime, d) Sodium permanganate, , Civil Engineering by Sandeep Jyani, , 262
Page 263 :
Que 66. The chemical most commonly used to, increases speed of sedimentation of sewage is, a) Sulphuric acid, b) Copper sulphate, c) Lime, d) Sodium permanganate, , Civil Engineering by Sandeep Jyani, , 263
Page 264 :
Que 67. In water treatment, rapid gravity filters, are adopted to remove, a) Dissolved organic substances, b) Dissolved solids and dissolved gases, c) Floating solids and dissolved inorganic solids, d) Bacteria and colloidal solids, , Civil Engineering by Sandeep Jyani, , 264
Page 265 :
Que 67. In water treatment, rapid gravity filters, are adopted to remove, a) Dissolved organic substances, b) Dissolved solids and dissolved gases, c) Floating solids and dissolved inorganic solids, d) Bacteria and colloidal solids, , Civil Engineering by Sandeep Jyani, , 265
Page 266 :
Que 68. The rate of filtration in slow sand filters, in million liters per day per hectare is about, a) 50 to 60, b) 100 to 150, c) 500 to 600, d) 1400 to 1500, , Civil Engineering by Sandeep Jyani, , 266
Page 267 :
Que 68. The rate of filtration in slow sand filters, in million liters per day per hectare is about, a) 50 to 60, b) 100 to 150, c) 500 to 600, d) 1400 to 1500, , Civil Engineering by Sandeep Jyani, , 267
Page 268 :
Que 69. The effective size of sand particle used, in slow sand filters is, a) 0.25 to 0.35 mm, b) 0.35 to 0.60 mm, c) 0.60 to 1.00 mm, d) 1.00 to 1.80 mm, , Civil Engineering by Sandeep Jyani, , 268
Page 269 :
Que 69. The effective size of sand particle used, in slow sand filters is, a) 0.25 to 0.35 mm, b) 0.35 to 0.60 mm, c) 0.60 to 1.00 mm, d) 1.00 to 1.80 mm, , Civil Engineering by Sandeep Jyani, , 269
Page 270 :
Que 70. As compared to rapid sand filters, slow, sand filters give, A. Slower filtration rate, B. Higher filtration rate, C. Lesser efficiency in removal of bacteria, D. Higher efficiency in removal bacteria, The correct answer is, a) A and B, b) B and C, c) A and D, d) B and D, Civil Engineering by Sandeep Jyani, , 270
Page 271 :
Que 70. As compared to rapid sand filters, slow, sand filters give, A. Slower filtration rate, B. Higher filtration rate, C. Lesser efficiency in removal of bacteria, D. Higher efficiency in removal bacteria, The correct answer is, a) A and B, b) B and C, c) A and D, d) B and D, Civil Engineering by Sandeep Jyani, , 271
Page 272 :
Que 71. Assertion A: Slow sand filters are more, efficient in removal of bacteria than rapid sand, filters., Reason R: The sand used in slow sand filters is finer, than that in rapid sand filters., Select your answer based on the coding system, given below:, a) Both A and R are true and R is the correct, explanation of A., b) both A and R are true but R is not the correct, explanation of A., c) A is true but R is false, d) A is false but R is true, Civil Engineering by Sandeep Jyani, , 272
Page 273 :
Que 71. Assertion A: Slow sand filters are more, efficient in removal of bacteria than rapid sand, filters., Reason R: The sand used in slow sand filters is finer, than that in rapid sand filters., Select your answer based on the coding system, given below:, a) Both A and R are true and R is the correct, explanation of A., b) both A and R are true but R is not the correct, explanation of A., c) A is true but R is false, d) A is false but R is true, Civil Engineering by Sandeep Jyani, , 273
Page 274 :
Que 72. Air binding phenomena in rapid sand, filter occur due to, a) Excessive negative head, b) Mud ball formation, c) Higher turbidity in the effluent, d) Low temperature, , Civil Engineering by Sandeep Jyani, , 274
Page 275 :
Que 72. Air binding phenomena in rapid sand, filter occur due to, a) Excessive negative head, b) Mud ball formation, c) Higher turbidity in the effluent, d) Low temperature, , Civil Engineering by Sandeep Jyani, , 275
Page 276 :
Que 73. The percentage of filtered water, which, is used for backwashing in rapid sand filters, is, about, a) 0.2 to 0.4, b) 0.4 to 1.0, c) 2 to 4, d) 5 to 7, , Civil Engineering by Sandeep Jyani, , 276
Page 277 :
Que 73. The percentage of filtered water, which, is used for backwashing in rapid sand filters, is, about, a) 0.2 to 0.4, b) 0.4 to 1.0, c) 2 to 4, d) 5 to 7, , Civil Engineering by Sandeep Jyani, , 277
Page 278 :
Que 74. Period of cleaning of slow sand filters is, about, a) 24 – 45 hours, b) 10 – 12 days, c) 2 – 3 months, d) 1 – 2 days, , Civil Engineering by Sandeep Jyani, , 278
Page 279 :
Que 74. Period of cleaning of slow sand filters is, about, a) 24 – 45 hours, b) 10 – 12 days, c) 2 – 3 months, d) 1 – 2 days, , Civil Engineering by Sandeep Jyani, , 279
Page 280 :
Que 75. Select the correct statement., a) 5 day BOD is the ultimate BOD., b) 5 day BOD is greater than 4 day BOD, keeping other conditions same., c) 5 day BOD is less than 4 day BOD keeping, other conditions same., d) BOD does not depend on time., , Civil Engineering by Sandeep Jyani, , 280
Page 281 :
Que 75. Select the correct statement., a) 5 day BOD is the ultimate BOD., b) 5 day BOD is greater than 4 day BOD, keeping other conditions same., c) 5 day BOD is less than 4 day BOD keeping, other conditions same., d) BOD does not depend on time., , Civil Engineering by Sandeep Jyani, , 281
Page 282 :
Que 76. If Biochemical oxygen demand(BOD) of a town is 20000, kg/day and BOD per capita per day is 0.05 kg, then population, equivalent of town is, a) 1000, b) 4000, c) 100000, d) 400000, , Civil Engineering by Sandeep Jyani, , 282
Page 283 :
Que 76. If Biochemical oxygen demand(BOD) of a town is 20000, kg/day and BOD per capita per day is 0.05 kg, then population, equivalent of town is, a) 1000, b) 4000, c) 100000, d) 400000, , Civil Engineering by Sandeep Jyani, , 283
Page 284 :
Que 77. The rate of BOD exerted at any time is, a) Directly proportional ot BOD satisfied, b) Directly proportional to BOD remaining, c) Inversely proportional to BOD satisfied, d) Inversely proportional to BOD remaining, , Civil Engineering by Sandeep Jyani, , 284
Page 285 :
Que 77. The rate of BOD exerted at any time is, a) Directly proportional ot BOD satisfied, b) Directly proportional to BOD remaining, c) Inversely proportional to BOD satisfied, d) Inversely proportional to BOD remaining, , Civil Engineering by Sandeep Jyani, , 285
Page 286 :
Que 78. The ratio of 5 day BOD to ultimate BOD is about, a) 1/3, b) 2/3, c) ¾, d) 1.0, , Civil Engineering by Sandeep Jyani, , 286
Page 287 :
Que 78. The ratio of 5 day BOD to ultimate BOD is about, a) 1/3, b) 2/3, c) ¾, d) 1.0, , Civil Engineering by Sandeep Jyani, , 287
Page 288 :
Que 79. In a BOD test, 1.0 ml of raw, sewage was diluted to 100 ml and the, dissolved oxygen concentration of diluted, sample at the beginning was 6 ppm and it, was 4 ppm at the end of 5 day incubation, at 200C., The BOD of raw sewage will be, a) 100 ppm, b) 200 ppm, c) 300 ppm, d) 400 ppm, , Civil Engineering by Sandeep Jyani, , 288
Page 289 :
Que 79. In a BOD test, 1.0 ml of raw sewage was, diluted to 100 ml and the dissolved oxygen, concentration of diluted sample at the beginning, was 6 ppm and it was 4 ppm at the end of 5 day, incubation at 200C., The BOD of raw sewage will be, a) 100 ppm, b) 200 ppm, c) 300 ppm, d) 400 ppm, , Civil Engineering by Sandeep Jyani, , 289
Page 290 :
Que 80. The minimum dissolved oxygen which should always be, present in water in order to save the aquatic life is, a) 1 ppm, b) 4 ppm, c) 10 ppm, d) 40 ppm, , Civil Engineering by Sandeep Jyani, , 290
Page 291 :
Que 80. The minimum dissolved oxygen which should always be, present in water in order to save the aquatic life is, a) 1 ppm, b) 4 ppm, c) 10 ppm, d) 40 ppm, , Civil Engineering by Sandeep Jyani, , 291
Page 292 :
Que 81. Dissolved oxygen in streams is, a) Maximum at noon, b) Minimum at noon, c) Maximum at midnight, d) Same throughout the day, , Civil Engineering by Sandeep Jyani, , 292
Page 293 :
Que 81. Dissolved oxygen in streams is, a) Maximum at noon, b) Minimum at noon, c) Maximum at midnight, d) Same throughout the day, , Civil Engineering by Sandeep Jyani, , 293
Page 294 :
Que 82. Facultative bacteria are able to work in, a) Presence of oxygen only, b) Absence of oxygen only, c) Presence as well as in absence of oxygen, d) Presence of water, , Civil Engineering by Sandeep Jyani, , 294
Page 295 :
Que 82. Facultative bacteria are able to work in, a) Presence of oxygen only, b) Absence of oxygen only, c) Presence as well as in absence of oxygen, d) Presence of water, , Civil Engineering by Sandeep Jyani, , 295
Page 296 :
Que 83. The means of access for inspection and, cleaning of sewer line is known as, a) Inlet, b) Manhole, c) Drop manhole, d) Catch basin, , Civil Engineering by Sandeep Jyani, , 296
Page 297 :
Que 83. The means of access for inspection and, cleaning of sewer line is known as, a) Inlet, b) Manhole, c) Drop manhole, d) Catch basin, , Civil Engineering by Sandeep Jyani, , 297
Page 298 :
Que 84. Sewerage system is designed for, a) maximum flow only, b) Minimum flow only, c) Average flow only, d) Maximum and minimum flow, , Civil Engineering by Sandeep Jyani, , 298
Page 299 :
Que 84. Sewerage system is designed for, a) maximum flow only, b) Minimum flow only, c) Average flow only, d) Maximum and minimum flow, , Civil Engineering by Sandeep Jyani, , 299
Page 300 :
Que 85. Sewage treatment units are designed for, a) Maximum flow only, b) Minimum flow only, c) Average flow only, d) Maximum and minimum flow, , Civil Engineering by Sandeep Jyani, , 300
Page 301 :
Que 85. Sewage treatment units are designed for, a) Maximum flow only, b) Minimum flow only, c) Average flow only, d) Maximum and minimum flow, , Civil Engineering by Sandeep Jyani, , 301
Page 302 :
Que 86. Laying of sewers is usually done with the help of, a) Theodolite, b) Compass, c) Sight rails and boning rod, d) A plane table, , Civil Engineering by Sandeep Jyani, , 302
Page 303 :
Que 86. Laying of sewers is usually done with the help of, a) Theodolite, b) Compass, c) Sight rails and boning rod, d) A plane table, , Civil Engineering by Sandeep Jyani, , 303
Page 304 :
Que 87. Corrosion in Concrete Sewers is caused by, a) Septic conditions, b) Dissolved oxygen, c) Chlorine, d) nitrogen, , Civil Engineering by Sandeep Jyani, , 304
Page 305 :
Que 87. Corrosion in Concrete Sewers is caused by, a) Septic conditions, b) Dissolved oxygen, c) Chlorine, d) nitrogen, Hydrogen Sulphide is produced in Sewer lines and, it gets oxidized to Sulphuric acid which reacts, with the constituents of Cement which forms, CaSO4 to occupy greater volume than the, compounds they replace, Civil Engineering by Sandeep Jyani, , 305
Page 306 :
Que 88. If the sewage contains Grease and, fatty acids, these are removed in, a) Grit chambers, b) Detritus tanks, c) Skimming tanks, d) Sedimentation tanks, , Civil Engineering by Sandeep Jyani, , 306
Page 307 :
Que 88. If the sewage contains Grease and, fatty acids, these are removed in, a) Grit chambers, b) Detritus tanks, c) Skimming tanks, d) Sedimentation tanks, , Civil Engineering by Sandeep Jyani, , 307
Page 310 :
Que 90. Aerobic bacterias, a) Flourish in the presence of free oxygen, b) consume organic matter as their food, c) oxidise organic matter in sewage, d) All the above., , Civil Engineering by Sandeep Jyani, , 310
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Que 90. Aerobic bacterias, a) Flourish in the presence of free oxygen, b) consume organic matter as their food, c) oxidise organic matter in sewage, d) All the above., , Civil Engineering by Sandeep Jyani, , 311
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Que 91. If 2% solution of a sewage sample is incubated for 5 days at, 20°C and depletion of oxygen was found to be 5 ppm, B.O.D. of the, sewage is, a) 200 ppm, b) 225 ppm, c) 250 ppm, d) None of these, , Civil Engineering by Sandeep Jyani, , 312
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Que 91. If 2% solution of a sewage sample is incubated for 5 days at, 20°C and depletion of oxygen was found to be 5 ppm, B.O.D. of the, sewage is, a) 200 ppm, b) 225 ppm, c) 250 ppm (5 * 100/2), d) None of these, , Civil Engineering by Sandeep Jyani, , 313
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Que 92. If D is the diameter of upper circular, portion, the overall depth of a standard egg, shaped section, is, a) D, b) 1.25 D, c) 1.5 D, d) 1.75 D, , Civil Engineering by Sandeep Jyani, , 314
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Que 92. If D is the diameter of upper circular, portion, the overall depth of a standard egg, shaped section, is, a) D, b) 1.25 D, c) 1.5 D, d) 1.75 D, , Civil Engineering by Sandeep Jyani, , 315
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Que 93. Self-cleansing velocity is, a) velocity at dry weather flow, b) velocity of water at flushing, c) velocity at which no accumulation remains in the drains, d) velocity of water in a pressure filter., , Civil Engineering by Sandeep Jyani, , 316
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Que 93. Self-cleansing velocity is, a) velocity at dry weather flow, b) velocity of water at flushing, c) velocity at which no accumulation remains in the drains, d) velocity of water in a pressure filter., , Civil Engineering by Sandeep Jyani, , 317
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Que 94. A rainfall may be classified as acidic if its, pH value is less or equal to, a) 6, b) 7, c) 5, d) 6.5, , Civil Engineering by Sandeep Jyani, , 318
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Que 94. A rainfall may be classified as acidic if its, pH value is less or equal to, a) 6, b) 7, c) 5, d) 6.5, , Civil Engineering by Sandeep Jyani, , 319
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Que 95. Rate of flow of sewage is generally assumed, a) more than the rate of water supply, b) equal to the rate of water supply, c) less than the rate of water supply, d) at 150 litres per capita, , Civil Engineering by Sandeep Jyani, , 320
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Que 95. Rate of flow of sewage is generally assumed, a) more than the rate of water supply, b) equal to the rate of water supply, c) less than the rate of water supply, d) at 150 litres per capita, , Civil Engineering by Sandeep Jyani, , 321
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Que 96. The gradient of sewers depends upon, a) velocity of flow, b) diameter of the sewer, c) Discharge, d) all the above., , Civil Engineering by Sandeep Jyani, , 322
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Que 96. The gradient of sewers depends upon, a) velocity of flow, b) diameter of the sewer, c) Discharge, d) all the above., , Civil Engineering by Sandeep Jyani, , 323
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DISPOSAL OF SEWAGE EFFLUENTS, After treatment, the sewage effluents, generally is disposed off by two methods., 1. Dilution, (disposal in water)., 2. Effluent irrigation or Broad irrigation or, sewage farming, (disposal on land), , Civil Engineering by Sandeep Jyani, , 324
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DISPOSAL OF SEWAGE EFFLUENTS, 1. Dilution:, • Disposal by dilution is the process in which the, treated sewage or the effluent from the sewage, treatment plant is discharged into a river stream,, or a large body of water, such as a lake or sea., • The discharged sewage, in due course of time, is, purified by what is known as self purification, process of natural waters, , Civil Engineering by Sandeep Jyani, , 325
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DISPOSAL OF SEWAGE EFFLUENTS, 1. Dilution:, Standards of Dilution, for discharging of, waste water into rivers, , Dilution factor, Above 500, , Between 300 to 500, , Between 150 to 300, , Less than 150, , Civil Engineering by Sandeep Jyani, , Standards of Purification required, No treatment such as sewage can be, directly discharged into the volume of, dilution water., Primary treatment such as plain, sedimentation should be given to, sewage, and the effluents should not, contain suspended solids more than, 150 ppm., Treatment such as sedimentation,, screening and essentially chemical, precipitation are required. The seage, efficient, should, not, contain, suspended solids more than 60 ppm., Complete through treatment should, be given to sewage. The sewage, effluent, should, not, contain, suspended solids more than 30 ppm., And its 𝐁𝐎𝐃𝟓 at 183° should not, exceed 20 ppm., 326
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Dilution in Rivers and self-purification of, Natural streams, • When sewage is discharged into a natural body of, water, the receiving water gets polluted due to, waste products, present in sewage effluents, • But the conditions do not remain so forever,, because the natural forces of purification, such as, dilution, sedimentation, oxidation reduction in, sunlight, etc; go on acting upon the pollution, elements, and bring back the water into its original, condition, • This automatic purification of polluted water, in, due course, is called the self purification, phenomenon., Civil Engineering by Sandeep Jyani, , 328
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Natural forces of purification which affect selfpurification process, 1. Physical forces., a) Dilution and dispersion: When sewage of concentration 𝑪𝑺 flows at, the rate 𝑸𝑺 into a river stream with concentration 𝑪𝑹 flowing at the, rate 𝑸𝑹 , the concentration C of the resulting mixture is given by, 𝑪𝒔 𝑸𝒔 + 𝑪𝑹 𝑸𝑹, 𝑪=, 𝑸𝑺 + 𝑸 𝑹, , b) Sedimentation, c) Sun-Light: the sun light has a bleaching and stablishing effect of, bacteria. It acts through the biochemical reactions., , Civil Engineering by Sandeep Jyani, , 329
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Natural forces of purification which affect selfpurification process, 2. Chemical forces aided by biological forces:., a) Oxidation:, • The oxidation of the organic matter present in, sewage effluents, will start as soon as the sewage, outfalls into the river water containing dissolved, oxygen., • The deficiency of oxygen so created will be filled, up by the atmospheric oxygen., • This is the most important action responsible of, effecting self purification of rivers, , Civil Engineering by Sandeep Jyani, , 330
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Natural forces of purification depends on, 1., 2., 3., 4., , Temperature, Turbulence, Hydrography, Available dissolved oxygen and the amount and, type of organic matter present, 5. Rate of re-aeration, etc., , Civil Engineering by Sandeep Jyani, , 331
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Natural forces of purification depends on, • At higher temperature, the capacity to maintain, the D.O. concentration is low; while the rate of, biological and chemical activities are high, causing, thereby rapid depletion of D.O., • The larger amount of D.O. present in water, the, better and earlier the self-purification will occur., • Algae which absorbs 𝑪𝑶𝟐 and gives oxygen, is thus,, very helpful in the self-purification process, , Civil Engineering by Sandeep Jyani, , 332
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Zones of pollution in a River-system, A polluted stream undergoing, self-purification can be divided, into the following four zones, 1. Zone of degradation:, • D.O. is reduced to about 40% of, the saturation value., Reoxygenation (i.e. re-areation), occurs but is slower than deoxygenation., , Civil Engineering by Sandeep Jyani, , 333
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Zones of pollution in a River-system, 2. Zone of active decomposition:, • This zone is marked by heavy, pollution. It is characterized by, water becoming greyish and, darker than in the previous zone., D.O. concentration falls down to, zero, and anaerobic conditions, may set in with the evolution of, gases like 𝑪𝑯𝟒 , 𝑪𝑶𝟐 , 𝑯𝟐 𝑺 etc., , Civil Engineering by Sandeep Jyani, , 334
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Zones of pollution in a River-system, 3. Zone of recovery:, • In this zone B.O.D. falls down and, D.O. content rises above 40% of, the saturation value. The organic, material will be mineralized to, form nitrates, sulphates,, phosphates, carbonates etc., , Civil Engineering by Sandeep Jyani, , 335
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Zones of pollution in a River-system, 4. Zone of clear Water:, • In this zone, the river attains its, original conditions with D.O., rising up to the saturation value., • When once a river water has, been polluted, it will not be safe, to drink it, unless it is properly, treated., , Civil Engineering by Sandeep Jyani, , 336
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Oxygen deficit of a polluted river stream., • Oxygen deficit (D) = Saturated D.O. –, Actual D.O., • Oxygen deficit can be found out by, knowing the rates of de-oxygenation and, re-oxygenation, • If de-oxygenation is more rapid than the, re-oxygenation, an oxygen deficit results., , Civil Engineering by Sandeep Jyani, , 337
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Disposal of waste waters in lakes and, management of lake waters, • The study of lakes is called limnology., • Aerobic depth of water in a lake is called epilimnion zone., • The lower depth of lakes which remains cooler, poorly mixed and, anaerobic called the hypolimnion zone., • In winter season entire depth of lakes behaves aerobic., , Civil Engineering by Sandeep Jyani, , 338
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2. DISPOSAL ON LAND, Disposal of sewage effluents on land for, irrigation, • In this method, the sewage effluent, (treated or diluted) is generally, disposed off by applying it on land., • The percolating water may join the, water table, • The degree of treatment of raw sewage, depend upon the type of soil of the land, Civil Engineering by Sandeep Jyani, , 339
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Quality standards for waste water effluents to, be discharged on land for irrigation, Characteristic / Constituent of, effluent waste water, 𝐁𝐎𝐃𝟓, pH value, Total Dissolved Solid (TDS), Oil and grease, Chlorine (as CL), Boron, Sulphates, , Tolerance limit as per IS:, 3307-1965, 500 mg/1, 5.5 to 9.0, 2100 mg/1, 30 mg/1, 600 mg/1, 2 mg/1, 1000 mg/1, , Civil Engineering by Sandeep Jyani, , 340
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Effluent irrigation and sewage farming, • In effluent irrigation (or broad irrigation), the chief, consideration is the successful disposal of sewage,, while in sewage farming, the chief consideration is, the successful growing of the crops., , Civil Engineering by Sandeep Jyani, , 341
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Sewage Sickness., • When sewage is applied continuously on a piece of, land, the soil pores or voids may get filled up and, clogged with sewage matter retained in them, • Free circulation of air will be prevented, and, anaerobic condition will develop within the pores., • The aerobic decomposition of organic matter will, stop, and anaerobic decomposition will start, • The organic matter will thus, of course, be, mineralized, but with the evolution of foul gases like, 𝑯𝟐 𝑺, 𝑪𝑶𝟐 and 𝑪𝑯𝟒 ., • This phenomenon of soil getting clogged is known as, sewage sickness., , Civil Engineering by Sandeep Jyani, , 342
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Preventive measures for Sewage Sickness, • Primary treatment of sewage, • Choice of land, • Under-drainage of soil, • Giving rest to the land, • Rotation of crops, • By sewage in shallow depths., , Civil Engineering by Sandeep Jyani, , 343
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TREATMENT OF SEWAGE, Classification of Treatment processes, 1. Preliminary treatment., • It consists solely in separating the floating, materials and also heavy settleable inorganic, solids. This treatment reduces the BOD of the, waste water by about 15 to 30%., • Screening is done for removing floating papers,, rags, clothes etc, • Skimming tank is used for removing oils and, greases., , Civil Engineering by Sandeep Jyani, , 344
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TREATMENT OF SEWAGE, Classification of Treatment processes, 2. Primary Treatment, • It removes large suspended organic solids, • This is accomplished by sedimentation in settling, basins, • The effluent contains a large amount of suspended, organic material and has high BOD, , 3. Secondary or biological Treatment, • It is accomplished through biological decomposition, of organic matter which can be carried out either, under aerobic or anaerobic conditions, • Bacteria decompose the fine organic matter to, produce clear effluent, Civil Engineering by Sandeep Jyani, , 345
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FUNCTIONS AND TYPES OF TRAPS BEING USED, IN SANITARY PLUMBING SYSTEM, • Traps: These may be defined as fittings, placed at, the ends of the soil pipes or the sullage pipes, (waste pipes) to prevent the passage of foul gases, from the pipes to the outside. This is possible, because traps do enclose or maintain water seal, between the pipe and the outside, • Soil pipes: These are the pipes which carry the night, soil, and, • Sullage pipes are the pipes which carry the sullage, from bathrooms and kitchens, Civil Engineering by Sandeep Jyani, , 346
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TYPES OF TRAPS, • Depending upon their shapes., i. P –traps, ii) Q–traps, • Depending upon their use., , iii) S–traps., , 1. Floor traps or Nahani trap: A floor trap or Nahani trap is, provided at the head of each house drain., 2. Gully trap: A gully trap is provided at the junction of an, unfoul roof or room drain and a foul bath or a kitchen, drain., 3. Intercepting trap: An intercepting trap is provided at the, junction of a house sewer and a municipal sewer., Civil Engineering by Sandeep Jyani, , 347
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AIR POLLUTION, Air pollution can be defined as the, presence of air contaminants in the, outdoor atmosphere in sufficient, quantities of such characteristics and of, such duration that it becomes injurious to, health, plants or to properties and also, interfere with the comfortable enjoyment, of life and property., , Civil Engineering by Sandeep Jyani, , 349
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Sources and Classification of Air Pollution, • Natural Contaminants, • Natural fog, bacteria and products of volcanic eruption, , • Aerosols, • Also called as Particulates, • It comprises of dust, smoke, mist, fog and fumes, , • Gases and Vapours, , Civil Engineering by Sandeep Jyani, , 350
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Sources and Classification of Air Pollution, • Aerosols, • It refers to dispersion of solid or liquid particles of microscopic size in gaseous media, such as dust, smoke or mist, Dust: It is produced by crushing, grinding, etc. of organic and inorganic materials, • Size: 1 to 1000 𝝁 (micron), • Sizes less than 5 𝝁 do not settle in the ground surface and remain in suspension, Smoke: It is finely divided particles produced by incomplete combustion. It consists of, mainly carbon or its compounds, • Particle size: 0.5 – 1 𝝁, Mist: Mist refers to dispersion of water droplets in the atmosphere in low, concentration, • Particle size: < 10 𝝁, Civil Engineering by Sandeep Jyani, , 351
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Sources and Classification of Air Pollution, • Aerosols, Fog: If mist concentration is very high, such that it obscure visibility, the mist is, called Fog, Fumes: These are fine solid particles generated by condensation from the, gaseous state. Fumes flocculate and then settles on the ground, , Civil Engineering by Sandeep Jyani, , 352
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Sources and Classification of Air Pollution, 2.Gases, • Sulphur Dioxide, •, •, •, •, •, , Produced by burning sulfur containing fossil fuels (coal, oil), Coal-burning power plants major source, One of the major components of acid rain, Reacts in atmosphere to produce acids, When inhaled, can be very corrosive to lung tissue, , • Hydrogen Sulphide, • Foul smelling gas, • Formed due to anaerobic biological decomposition, volcanoes and natural water springs, • Major industries that produce H2S are paper and pulp, , Civil Engineering by Sandeep Jyani, , 353
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Sources and Classification of Air Pollution, 2.Gases, , • Hydrogen Fluoride, , • Major source is manufacture of phosphate fertilizers, Aluminium industries, brick plants, etc, • It causes more damage to plants as compared to animals, , • Nitrogen Oxides, •, •, •, •, , They are the second most abundant air pollutants after sulphur dioxide, Automobile engine is the main source, Industries where nitric acid is produced, There are seven types of oxides of Nitrogen, a), b), c), d), e), f), g), , N2O, NO (Nitric oxide = pollutant), NO2 (Nitrogen dioxide=pollutant), N2O3, N2O4, NO, N2O5, Civil Engineering by Sandeep Jyani, , 354
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Sources and Classification of Air Pollution, 2.Gases, • Carbon Monoxide, •, •, •, •, , Produced by burning of organic material (coal, gas, wood, trash, etc.), Automobiles biggest source (80%), Toxic because binds to hemoglobin, reduces oxygen in blood, Not a persistent pollutant, combines with oxygen to form CO2, , Civil Engineering by Sandeep Jyani, , 355
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Primary and Secondary Air Pollution, • Primary air pollutants - Materials that when released pose health, risks in their unmodified forms or those emitted directly from, identifiable sources., • Secondary air pollutants - Primary pollutants interact with one, another, sunlight, or natural gases to produce new, harmful, compound, , Civil Engineering by Sandeep Jyani, , 356
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Primary and Secondary Air Pollution, • Primary air pollutants, • Five major materials released directly into the atmosphere in unmodified, forms., -Carbon monoxide, -Sulphur dioxide, -Nitrogen oxides, -Hydrocarbons, -Particulate matter, , Civil Engineering by Sandeep Jyani, , 357
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Primary and Secondary Air Pollution, 2.Secondary Air Pollutants, • Ozone, • Ozone (O3) is a highly reactive gas composed of three oxygen atoms., • It is both a natural and a man-made product that occurs in the Earth's upper atmosphere, (the stratosphere) and lower atmosphere (the troposphere)., , • PAN (peroxy acetyl nitrate), • Photochemical smog, • Aerosols and mists (H2SO4), , Civil Engineering by Sandeep Jyani, , 358
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Effects of Air Pollution, • Human Health Effects, , • Exposure to air pollution is associated with, numerous effects on human health, including, pulmonary, cardiac, vascular, and neurological, impairments., • The health effects vary greatly from person to, person. High-risk groups such as the elderly,, infants, pregnant women, and sufferers from, chronic heart and lung diseases are more, susceptible to air pollution, • Children are at greater risk because they are, generally more active outdoors and their lungs, are still developing., • Exposure to air pollution can cause both acute, (short-term) and chronic (long-term) health, effects., , Civil Engineering by Sandeep Jyani, , 359
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Effects of Air Pollution, • Human Health Effects, , • Acute effects are usually immediate and often reversible, when exposure to the pollutant ends. Some acute health, effects include eye irritation, headaches, and nausea., • Chronic effects are usually not immediate and tend not to be, reversible when exposure to the pollutant ends. - Some, chronic health effects include decreased lung capacity and, lung cancer resulting from long-term exposure to toxic air, pollutants., , • Effects on Human respiratory system, , • Both gaseous and particulate air pollutants can have, negative effects on the lung, • Solid particles can settle on the walls of the trachea, bronchi,, and bronchioles., • Damage to the lungs from air pollution can inhibit this, process and contribute to the occurrence of respiratory, diseases such as bronchitis, emphysema, and cancer, , Civil Engineering by Sandeep Jyani, , 360
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ACID RAIN, • It results when sulphur oxides and nitrogen oxides react with water, vapour and sunlight and are chemically converted to strong acidic, compounds(H2SO4 and HNO3), • If pH of rain is less than 5.6, it is called as Acid Rain, • At pH= 5.6, it is called as Clean Rain, • It affects vegetation, soils and results in complete vanishing of, greenery, • It causes damage to monuments, buildings, etc, • Remedy: To neutralize acidity of soil, it is treated with lime, Civil Engineering by Sandeep Jyani, , 361
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Global Warming and Green house effect, • Green house effect is caused due to, •, •, •, •, , CO2 (Carbon dioxide 57%), CH4 (Methane 12%), N2O (Nitrous Oxide 6%), CFCs (25%), , • Average temperature of earth is increasing due to which polar ice caps are, melting and ocean level is rising, • Climate changes, , Civil Engineering by Sandeep Jyani, , 362
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Que 98. Which out of the following has maximum global warming, potential?, a)CFC, b)Nox, c)CH4, d)CO2), , Civil Engineering by Sandeep Jyani, , 366
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Que 100. Deposit gauges are provided with copper sulphate solution, a)To prevent growth of bacteria, b)To prevent growth of algae, c)To scare birds, d)To prevent the decomposition of SPM, , Civil Engineering by Sandeep Jyani, , 368
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Que 100. Deposit gauges are provided with copper sulphate solution, a)To prevent growth of bacteria, b)To prevent growth of algae, c)To scare birds, d)To prevent the decomposition of SPM, , Civil Engineering by Sandeep Jyani, , 369
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Que 101. Green house effect of CO2 is, a)Permitting the outside solar radiation to reach the ground but, preventing terrestrial radiation from the ground into the space, b)Permitting the solar radiation of short length and reradiated, terrestrial heat of long wave length, c)Reflecting the heat rays into the space thereby keeping the, temperature of earth unaffected, d)Causing absorption of heat from troposphere and thereby decreasing, the temperature of Earth with increase in CO2 concentration, Civil Engineering by Sandeep Jyani, , 370
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Que 101. Green house effect of CO2 is, a)Permitting the outside solar radiation to reach the ground but, preventing terrestrial radiation from the ground into the space, b)Permitting the solar radiation of short length and reradiated, terrestrial heat of long wave length, c)Reflecting the heat rays into the space thereby keeping the, temperature of earth unaffected, d)Causing absorption of heat from troposphere and thereby decreasing, the temperature of Earth with increase in CO2 concentration, Civil Engineering by Sandeep Jyani, , 371
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Que. 102 The device used for easy separation of dry dust of 10-100 𝝁𝒎, size is, a)Cyclone, b)Gravity settling chamber, c)Bag filter, d)scrubber, , Civil Engineering by Sandeep Jyani, , 372
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Que. 102 The device used for easy separation of dry dust of 10-100 𝝁𝒎, size is, a)Cyclone, b)Gravity settling chamber, c)Bag filter, d)scrubber, , Civil Engineering by Sandeep Jyani, , 373
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Que. 103 The velocity of exit waste gases should be a minimum of ……., Of wind speed to prevent down drought, a)½, b)1 ½, c)2 ½, d)3 ½, , Civil Engineering by Sandeep Jyani, , 374
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Que. 103 The velocity of exit waste gases should be a minimum of ……., Of wind speed to prevent down drought, a)½, b)1 ½, c)2 ½, d)3 ½, , Civil Engineering by Sandeep Jyani, , 375
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Que 104. Which of the following are primary air pollutants?, a)Sulphur dioxide and Nitrogen oxides, b)Ozone and carbon monoxide, c)Sulphur dioxide and ozone, d)Nitrogen oxide and ozone, , Civil Engineering by Sandeep Jyani, , 376
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Que 104. Which of the following are primary air pollutants?, a)Sulphur dioxide and Nitrogen oxides, b)Ozone and carbon monoxide, c)Sulphur dioxide and ozone, d)Nitrogen oxide and ozone, , Civil Engineering by Sandeep Jyani, , 377
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Que 105. The path taken by the continuous, discharge of gaseous effluents emitted from, chimney is commonly known as…., a)Lapse rate, b)Inversion, c)Plume, d)NOTA, , Civil Engineering by Sandeep Jyani, , 378
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Que 105. The path taken by the continuous, discharge of gaseous effluents emitted from, chimney is commonly known as…., a)Lapse rate, b)Inversion, c)Plume, d)NOTA, , Civil Engineering by Sandeep Jyani, , 379
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Que 106. The rate of accumulation of sludge in septic tanks is, recommended, a)30 litres/person/year, b)25 litres/person/year, c) 30 litres/person/month, d)25 litres/person/month, , Civil Engineering by Sandeep Jyani, , 380
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Que 106. The rate of accumulation of sludge in septic tanks is, recommended, a)30 litres/person/year, b)25 litres/person/year, c) 30 litres/person/month, d)25 litres/person/month, , Civil Engineering by Sandeep Jyani, , 381
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Que. 107 Pick up the correct statement from the, following :, a)In treated sewage, 4 PPm of D.O. is essential, b)Only very fresh sewage contains some, dissolved oxygen, c)The solubility of oxygen in sewage is 95% that, is in distilled water, d)All the above., , Civil Engineering by Sandeep Jyani, , 382
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Que. 107 Pick up the correct statement from the, following :, a)In treated sewage, 4 PPm of D.O. is essential, b)Only very fresh sewage contains some dissolved, oxygen, c)The solubility of oxygen in sewage is 95% that is in, distilled water, d)All the above., , Civil Engineering by Sandeep Jyani, , 383
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Que 108. The screens are fixed, a)perpendicular to the direction of flow, b)parallel to the direction of flow, c)at an angle 30° to 60° to the direction of flow, d)none of these., , Civil Engineering by Sandeep Jyani, , 384
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Que 108. The screens are fixed, a)perpendicular to the direction of flow, b)parallel to the direction of flow, c)at an angle 30° to 60° to the direction of flow, d)none of these., , Civil Engineering by Sandeep Jyani, , 385
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Que 109. Clogging of sewers, is caused due to, a)Silting, b)greasy and oily matters, c)domestic wastes thrown in manholes, d)all the above., , Civil Engineering by Sandeep Jyani, , 386
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Que 109. Clogging of sewers, is caused due to, a)Silting, b)greasy and oily matters, c)domestic wastes thrown in manholes, d)all the above., , Civil Engineering by Sandeep Jyani, , 387
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Que 110. The coagulant widely used for sewage treatment, is, a)Alum, b)ferric chloride, c)ferric sulphate, d)chlorinated copperas., , Civil Engineering by Sandeep Jyani, , 388
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Que 110. The coagulant widely used for sewage treatment, is, a)Alum, b)ferric chloride, c)ferric sulphate, d)chlorinated copperas., , Civil Engineering by Sandeep Jyani, , 389
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Que 111. House connections to the laterals is generally made by, a)R.C.C., b)P.C.C., c)Cast iron, d)Glazed stoneware, , Civil Engineering by Sandeep Jyani, , 390
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Que 111. House connections to the laterals is generally made by, a)R.C.C., b)P.C.C., c)Cast iron, d)Glazed stoneware, , Civil Engineering by Sandeep Jyani, , 391
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Que 112. Dilution method of disposing off sewage, is not preferred to, a)when sewage is fresh, b)when diluting water has high dissolved oxygen content, c)when diluting water is used for water supply near the point of sewage, disposed, d)when the diluting water is having flow currents, , Civil Engineering by Sandeep Jyani, , 392
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Que 112. Dilution method of disposing off sewage, is not preferred to, a)when sewage is fresh, b)when diluting water has high dissolved oxygen content, c)when diluting water is used for water supply near the point of sewage, disposed, d)when the diluting water is having flow currents, , Civil Engineering by Sandeep Jyani, , 393
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Que 113. For house drainage minimum gradient is, a)1 in 60, b)1 in 80, c)1 in 10, d)1 in 400, , Civil Engineering by Sandeep Jyani, , 394
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Que 113. For house drainage minimum gradient is, a)1 in 60, b)1 in 80, c)1 in 10, d)1 in 400, , Civil Engineering by Sandeep Jyani, , 395
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Que 114. Bio-chemical oxygen demand (BOD) for the first 20 days in, generally referred to, a)initial demand, b)first stage demand, c)carbonaceous demand, d)all of these, , Civil Engineering by Sandeep Jyani, , 396
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Que 114. Bio-chemical oxygen demand (BOD) for the first 20 days in, generally referred to, a)initial demand, b)first stage demand, c)carbonaceous demand, d)all of these, , Civil Engineering by Sandeep Jyani, , 397
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Que 115. Flocculated particles do not change their, a)Size, b)Shape, c)Weight, d)none of these, , Civil Engineering by Sandeep Jyani, , 398
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Que 115. Flocculated particles do not change their, a)Size, b)Shape, c)Weight, d)none of these, , Civil Engineering by Sandeep Jyani, , 399
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Que 116. Disposal to sewage in large cities, is done in, a)Irrigation, b)Dilution, c)Oxidation, d)putrifaction, , Civil Engineering by Sandeep Jyani, , 400
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Que 116. Disposal to sewage in large cities, is done in, a)Irrigation, b)Dilution, c)Oxidation, d)putrifaction, , Civil Engineering by Sandeep Jyani, , 401
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Que 117. For evaporation and measurement of settlable solids, the, apparatus used, is, a)a jar, b)a breaker, c)a test tube, d)an Imhoff cone, , Civil Engineering by Sandeep Jyani, , 402
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Que 117. For evaporation and measurement of settlable solids, the, apparatus used, is, a)a jar, b)a breaker, c)a test tube, d)an Imhoff cone, , Civil Engineering by Sandeep Jyani, , 403
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Que 118. Removal of oil and grease from sewage, is known, a)Screening, b)Skimming, c)Filtration, d)none of these., , Civil Engineering by Sandeep Jyani, , 404
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Que 118. Removal of oil and grease from sewage, is known, a)Screening, b)Skimming, c)Filtration, d)none of these., , Civil Engineering by Sandeep Jyani, , 405
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Que 119. The gas which may cause explosion in sewers, is, a)Carbon dioxide, b)Methane, c)Ammonia, d)Carbon monoxide, , Civil Engineering by Sandeep Jyani, , 406
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Que 119. The gas which may cause explosion in sewers, is, a)Carbon dioxide, b)Methane, c)Ammonia, d)Carbon monoxide, , Civil Engineering by Sandeep Jyani, , 407
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Que 120. In sewers the effect of scouring is more on, a)top side, b)bottom side, c)horizontal side, d)all sides, , Civil Engineering by Sandeep Jyani, , 408
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Que 120. In sewers the effect of scouring is more on, a)top side, b)bottom side, c)horizontal side, d)all sides, , Civil Engineering by Sandeep Jyani, , 409
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Que 122. The drop man holes are generally provided in sewers for, a)industrial areas, b)large town ships, c)hilly town ships, d)cities in plains., , Civil Engineering by Sandeep Jyani, , 412
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Que 122. The drop man holes are generally provided in sewers for, a)industrial areas, b)large town ships, c)hilly town ships, d)cities in plains., , Civil Engineering by Sandeep Jyani, , 413
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Que 123. The liquid wastes from kitchens, bath rooms and wash basins,, is not called, a)liquid waste, b)Sullage, c)Sewage, d)None, , Civil Engineering by Sandeep Jyani, , 414
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Que 123. The liquid wastes from kitchens, bath rooms and wash basins,, is not called, a)liquid waste, b)Sullage, c)Sewage, d)None, , Civil Engineering by Sandeep Jyani, , 415
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Que 1., Assertion A: The consumption of water increases with increase in, the distribution pressure, Reason R: Higher distribution pressure causes more loss and, wastage of water, a) Both A and R are true and R is the correct explanation of A, b)Both A and R are true but R is not the correct explanation of A, c) A is true but R is false, , d)A is false but R is true, , Civil Engineering by Sandeep Jyani, , 416
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Que 2. The per capita consumption of a locality is, affected by, i. Climatic condition, ii.Quality of water, iii.Distribution pressure, The correct options are, a)Only i, b)Both i and ii, c)Both i and iii, d)All i, ii and iii, , Civil Engineering by Sandeep Jyani, , 417
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Que 3. Which one of the following causes a, decrease in per capita consumption?, a)Use of metering system, b)Good quality of water, c)Better standard of living of the people, d)Hotter climate, , Civil Engineering by Sandeep Jyani, , 418
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Que 4. The hourly variation factor is usually taken, as, a)1.5, b)1.8, c)2.0, d)2.7, , Civil Engineering by Sandeep Jyani, , 419
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Que 5. The type of valve which is provided on the, suction of pipe in tube well is, a)Air relief valve, b)Reflux valve, c)Pressure relief valve, d)Sluice valve, , Civil Engineering by Sandeep Jyani, , 420
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Que 6. Disinfection efficiency is, a)reduced at higher pH value of water, b)Unaffected by pH value of water, c)Increased at higher pH value of water, d)Highest at pH value equal to 7, , Civil Engineering by Sandeep Jyani, , 421
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Que 7. As compared to cast iron pipes, steel pipes, are, a)Heavier, b)Stronger, c)Costlier, d)Less susceptible to corrosion, , Civil Engineering by Sandeep Jyani, , 422
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Que 8. The method of analysis of distribution, system in which the domestic supply is neglected, and fire demand is considered is, a)Circle method, b)Equivalent pipe method, c)Hardy cross method, d)Electrical analysis method, , Civil Engineering by Sandeep Jyani, , 423
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Que 9. Which of the following methods of analysis, of water distribution system is most suitable for, long and narrow pipe system?, a)Circle method, b)Equivalent method, c)Hardy cross method, d)Electrical analysis method, , Civil Engineering by Sandeep Jyani, , 424
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Que 10. The type of valve which is provided to, control the flow of water in the distribution system, at street corners and where the pipelines intersect, is…?, a)Check valve, b)Sluice valve, c)Safety valve, d)Scour valve, , Civil Engineering by Sandeep Jyani, , 425
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Que 11. A pipe conveying sewage from plumbing, system of a single building to common sewer or, point of immediate disposal is called, a)House sewer, b)Lateral sewer, c)Main sewer, d)Submain sewer, , Civil Engineering by Sandeep Jyani, , 426
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Que 12. Which of the following sewers is preferred, for combined system of sewage?, a)Circular sewer, b)Egg shaped sewer, c)Rectangular sewer, d)None of these, , Civil Engineering by Sandeep Jyani, , 427
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Que 13. The suitable system of sanitation for area, of distributed rainfall throughout the year with less, intensity is, a)Separate system, b)Combined system, c)Partially separate system, d)Partially combined system, , Civil Engineering by Sandeep Jyani, , 428
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Que 14. The water carriage system of collection of, waste products, a)Is cheaper in initial cost than dry conservancy, system, b)Requires treatment before disposal, c)Creates hygienic problem, d)All of the above, , Civil Engineering by Sandeep Jyani, , 429
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Que 15. The time of concentration is defined as, a)The time taken by rainfall water to run from most, distant point of water shed to the inlet of sewer, b)The time required for flow of water in sewer to, the point under consideration, c)Sum of (a) and (b), d)Difference of (a) and (b), , Civil Engineering by Sandeep Jyani, , 430
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Que 16. The specific gravity of sewage is, a)Much greater than 1, b)Slightly less than 1, c)Equal to 1, d)Slightly greater than 1, , Civil Engineering by Sandeep Jyani, , 431
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Que 17. The self cleansing velocity fir all sewers in, India is usually, a)Less than 1.0 m/sec, b)1.0 m/sec to 1.2 m/sec, c)1.5 m/sec to 2 m/sec, d)3.0 m/sec to 3.5 m/sec, , Civil Engineering by Sandeep Jyani, , 432
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Que 18. The slope of sewer shall be, a)Given in the direction of natural slope of ground, b)Given in the direction opposite to natural slope, of ground, c)Zero, d)Steeper than 1 in 20, , Civil Engineering by Sandeep Jyani, , 433
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Que 19. The design discharge for the separate, sewer system shall be taken as, a)Equal to dry weather flow (DWF), b)2 x DWF, c)3 x DWF, d)6 x DWF, , Civil Engineering by Sandeep Jyani, , 434
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Que 20. The design discharge for the sewer system, shall be taken as, a)Equal to dry weather flow (DWF), b)Rainfall + DWF, c)Rainfall + 2 DWF, d)Rainfall + 6 DWF, , Civil Engineering by Sandeep Jyani, , 435
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Que 21. The minimum and maximum diameters of, sewers shall preferably be, a)15cm and 100cm, b)15cm and 300cm, c)30cm and 450 cm, d)60 cm and 300 cm, , Civil Engineering by Sandeep Jyani, , 436
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Que 22. The main disadvantage of cement concrete, sewers is, a)Less strength, b)Difficulty in construction, c)Difficulty in transportation due to heavy weight, d)Less life, , Civil Engineering by Sandeep Jyani, , 437
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Que 23. Most suitable section of sewer in separate, sewage system is, a)Rectangular section, b)Circular section, c)Standard form of egg shaped sewer, d)Modified egg shaped sewer, , Civil Engineering by Sandeep Jyani, , 438
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Que 24. An egg shaped section sewer, a)Is economical than circular section, b)Provides self cleansing velocity at low discharges, c)Is more stable than circular section, d)Is easy to construct, , Civil Engineering by Sandeep Jyani, , 439
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Que 25. The velocity of flow does not depend on, a)Grade of sewer, b)Length of sewer, c)Hydraulic mean depth of sewer, d)Roughness of sewer, , Civil Engineering by Sandeep Jyani, , 440
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Que 26. The type of sewer which is suitable for, both combined and separate system is, a)Circular sewer, b)Egg shaped sewer, c)Horse shoe type sewer, d)Semi elliptical sewer, , Civil Engineering by Sandeep Jyani, , 441
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Que 27. The characteristics of fresh and septic, sewage respectively are, a)Acidic and alkaline, b)Alkaline and acidic, c)Both acidic, d)Both alkaline, , Civil Engineering by Sandeep Jyani, , 442
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Que 28. The pathogens are killed by, a)Nitrification, b)Chlorination, c)Oxidation, d)None of the above, , Civil Engineering by Sandeep Jyani, , 443
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Que 29. Which of the following retards the self, purification of stream?, a)Higher temperature, b)Sunlight, c)Satisfying oxygen demand, d)None of the above, , Civil Engineering by Sandeep Jyani, , 444
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Que 30. Sewage treatment units are designed for, a)5-10 years, b)15-20 years, c)30-40 years, d)40-50 years, , Civil Engineering by Sandeep Jyani, , 445
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Que 31. Settling velocity increases with, a)Specific gravity of solid particles, b)Size of particles, c)Depth of tank, d)Temperature of liquid, , Civil Engineering by Sandeep Jyani, , 446
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Que 32. Standard BOD is measured at, a)20°C – 1 day, b)25°C – 3 day, c)20°C – 5 day, d)30°C – 5 day, , Civil Engineering by Sandeep Jyani, , 447
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Que 33. The correct relation between theoretical, oxygen demand (TOD), Biochemical Oxygen, demand (BOD) and Chemical Oxygen demand, (COD) is given by, a) TOD>BOD>COD, b) TOD>COD>BOD, c) BOD>COD>TOD, d) COD>BOD>TOD, , Civil Engineering by Sandeep Jyani, , 448
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Que 34. Septic tank is a, i. Settling tank, ii.Digestion tank, iii.Aeration tank, The correct answer is, a)Only i, b)(i) and (ii), c)(i) and (iii), d)Only (iii), , Civil Engineering by Sandeep Jyani, , 449
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Que 35. The maximum efficiency of BOD removal is, achieved in, a)Oxidation Pond, b)Oxidation ditch, c)Aerated lagoons, d)Trickling filters, , Civil Engineering by Sandeep Jyani, , 450
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Que 36. In facultative stabilization pond, the, sewage is treated by, a)Aerobic bacteria only, b)Algae only, c)Dual action of aerobic bacteria and anaerobic, bacteria, d)sedimentation, , Civil Engineering by Sandeep Jyani, , 451
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Que 37. Composting and lagooning are the, methods of, a)Sludge digestion, b)Sludge disposal, c)Sedimentation, d)Filtration, , Civil Engineering by Sandeep Jyani, , 452
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Que 38. Turbidity is measured on, a) Standard silica scale, b) Standard cobalt scale, c) Standard platinum scale, d) Platinum cobalt scale, , Civil Engineering by Sandeep Jyani, , 453
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Que 39. The pipe which is used to carry the, discharge from sanitary fittings like bath rooms,, kitchen, etc is called?, a)Waste pipe, b)Soil pipe, c)Vent pipe, d)Antisiphonage pipe, , Civil Engineering by Sandeep Jyani, , 454
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Que 40. Most of the bacteria in sewage are, a)Parasitic, b)Saprophytic, c)Pathogenic, d)anaerobic, , Civil Engineering by Sandeep Jyani, , 455
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Que 41. The gas from sludge digestion tank is, mainly composed of, a)Nitrogen, b)Carbon dioxide, c)Hydrogen Sulphide, d)Methane, , Civil Engineering by Sandeep Jyani, , 456
Page 457 :
Que 42. The process of lagooning is primarily a, means of, a)Reducing the excessive flow in sewers, b)Disposing of sludge, c)Increasing the capacity of storage reservoirs, d)Increasing flow of sewage through Imhoff tanks, , Civil Engineering by Sandeep Jyani, , 457
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Que 43 . The biological treatment of sewage, effluents is essentially a process of, a)Oxidation, b)Dehydration, c)Reduction, d)alkalinization, , Civil Engineering by Sandeep Jyani, , 458
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Que 44. Chlorine is used in the treatment of, sewage to, a)Help grease separation, b)Aid flocculation, c)Increase the biochemical oxygen demand, d)Cause bulking of activated sludge, , Civil Engineering by Sandeep Jyani, , 459
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Que 45. Ozone layer in the upper atmosphere is, getting destroyed owing to its reaction with, a)Carbon dioxide, b)Hydrogen peroxide, c)Oxides of nitrogen, d)CFCs, , Civil Engineering by Sandeep Jyani, , 460
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Que 46. The intensification of green house effect is, attributed to the increased level of, a)Carbon dioxide, b)Carbon monoxides, c)CFCs, d)Sulphur dioxides, , Civil Engineering by Sandeep Jyani, , 461
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Que 47. Electrostatic precipitators are used as, pollution control device for the separation of, a)SO2, b)Nox, c)Hydrocarbon, d)Particulate matter, , Civil Engineering by Sandeep Jyani, , 462
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Que 48. Select the secondary air pollutants among, the following:, a)Ozone and carbon monoxide, b)Peroxy acycl nitrate (PAN) and ozone, c)Peroxy acycl nitrate (PAN) and carbon monoxide, d)Carbon monoxide and sulphur dioxide, , Civil Engineering by Sandeep Jyani, , 463
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Que 49. The primary pollutant caused by, incomplete combustion of organic matter is, a)Ozone, b)Carbon monoxide, c)Sulphur dioxide, d)None of the above, , Civil Engineering by Sandeep Jyani, , 464
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Que 50. The spray tower can be used to control, a)Gaseous pollutants only, b)Particulate pollutants only, c)Both (a) and (b), d)NOTA, , Civil Engineering by Sandeep Jyani, , 465
