ENVIRONMENTAL ENGINEERING-I Prof. Rajesh Bhagat Asst. Professor Civil Engineering Department Yeshwantrao Chavan College Of Engineering Nagpur B. E. (Civil Engg.) M. Tech. (Enviro. Engg.) GCOE, Amravati VNIT, Nagpur Mobile No.:- 8483003474 / 8483002277 Email ID:- rajeysh7bhagat@gmail.com Website: www.rajeysh7bhagat.wordpress.com
12/21/15
UNIT-I 1) Introduction: Importance and necessity of water supply scheme. 2) Water Demand: Types of demand, factors affecting per capita demand, variation in demand, design period and population forecasting methods and examples. 3) Sources of Water: Ground water springs, infiltration galleries, Dug wells, tube wells, Surface water stream, Lake, River, impounding reservoirs, ponds, etc. 4) Intake Structures: Location types river, lake, canal, reservoir, etc. 3
UNIT - II 1) Conveyance of Water: Types of pipe, joints, valves & fittings. 2) Hydraulic Design Aspects: Manning s, Darcy s Weisbach, Hazen Williams Formulae & Numerical. 3) Rising Main & Pumps: Types, working merits and demerits selection of pumps. 4
UNIT III 1) Water Quality : General idea of water borne diseases, Physical, Chemical and biological characteristics of water, Standards of drinking water. 2) Water Treatment : Objective of treatment, unit operations and processes. 3) Treatment Flow sheet of conventional water treatment plant. 4) Aeration: Purpose, types of aerators. 5) Coagulation & Flocculation: Definition, Principals, types of coagulants and Reactions, coagulant doses, types of mixing and flocculation devices. 5
UNIT-IV 1) Sedimentation: Principles types of setting basins, inlet and outlet arrangements. 2) Clariflocculators: Principles and operation. 3) Filtration: Mechanism of filtration, types of filters RSF, SSF, pressure filters, elements of filters, UDS, design aspects of filter and operational problems in filtration. 6
UNIT-V 1) Disinfection : Purpose, Mechanism, criteria for good disinfectant, various disinfectants & their characteristics, disinfection by chlorination using different forms of chlorine. 2) Distribution Systems: Requirements for a good distribution system, methods of distribution systems and layouts of DS, appurtenance in water distribution system. 3) Leakage and leak detector. 4) Storage Reservoirs for treated water: Types, capacity of reservoir, mass curve. 7
UNIT-VI 1) Municipal Solid Waste Management: Generation sources, composition, Quality, Methods of Collection, transportation, treatment and disposal, 3Rs. 2) Examples on simple hydraulic design of pipes, estimation of population and water quality, plain sedimentation tanks, cascade only simple sizing of units no detailed design. 8
PRACTICALS: - (Min. 10 Experiment) 1) Determination of ph. 2) Determination of Conductivity 3) Determination of Chlorides. 4) Determination of Solids 5) Determination of Turbidity 6) Determination of Alkalinity Acidity. 7) Determination of Dissolved Oxygen. 8) Determination of Hardness 9) Determination of Available Chlorine 10)Determination of Residual Chlorine 11)Jar Test. 12)Bacteriological Plate count and MPN tests. 13)Only Demonstration of COD and BOD. 9
References:- 1) Water Supply & Sanitary Engineering by G. S. Birdie. 2) Water Supply Engineering by B. C. Punmia. 3) Water Supply Engineering by S. K. Garg. 4) Solid Waste Management by A. D. Bhide. 5) Environmental Engg. By Modi. 10
UNIT-I QUESTION BANK 1) Explain the importance and necessity of public water supply scheme and what are the various purposes for which water is required. 2) What are the sources of water and list of impurities to be removed from surface source of water for drinking purpose. 3) What are the components of water supply scheme. 4) What do you understand by water demand? How it is determined for a major city? Explain various types of water demands. 5) What are the factors affecting per capita demand of water and explain. 6) Explain the fluctuation in water demand. What is the effect of these variations on design of treatment units. 7) What are the different methods of population forecasting and explain. 8) What is Intake Structure? Explain the factors deciding the location of intake structures. Also explain the requirements of a good intake structure. 9) For the given data, forecast the population data after one, two and three decades beyond the last known decade by Arithmetic or Geometric or Incremental increase method, Census 1960 1970 1980 1990 2000 Population 25000 28000 34000 42000 47000 10) Write a short note on a) Infiltration Gallery b) Design Period c) Impounding Reservoir d) Surface water e) Springs f) Per capita Demand g) Wet Intake h) Canal Intake i)river Intake j) Wells 11
Objective of Water Supply Scheme:- To provide reliable good quality and required quantity of water for consumption and other use to public. 12
Importance & Necessity of Water Supply Scheme:- Water may be responsible for many diseases therefore it should be free from impurities. With advancement of civilization, the utility of water enormously increased & now without well organized public water supply scheme, it is impossible to run the present life. Collective effort. Water required for various purpose: Drinking & cooking Bathing & washing Lawns, gardens, crops, street washing, fire fighting, various industrial purposes, heating, air conditioners, etc 13
Water Supply System: 1) Sources of water: 2) Collection works or Intake Structure: 3) Transmission works: 4) Purification works: 5) Distribution Works: 14
Water Demand: Quantity of water required by per person per day in liters. 270 LPCD & 335 LPCD Total quantity of water required for town depends on rate of demand, population & design period. Types of demand: Domestic or residential demand 135 Commercial & Industrial demand 40 Demand for public use 25 Compensate losses demand 55 Fire demand 15 Total water Demand = 270 lpcd without full flushing system (LIG) Total water Demand = 335 lpcd with full flushing system (HIG) 15
Domestic Water Demand for Indian Cities:- It includes quantity of water required in the houses for drinking, cooking, bathing, washing, etc. It mainly depends on the habits, social status, climatic condition, & custom of people. 1. Drinking 5 lpcd 2. Cooking 5 lpcd 3. Bathing 55 lpcd 4. Washing 40 lpcd 5. Flushing of latrines 30 lpcd Total Domestic water demand = 135 lpcd as per IS 1172 1993 (R 2012) 16
Domestic Water Demand for Indian Cities:- Population upto 20000 :- I. Stand post = 40 lpcd II. House service connection = 70 100 lpcd Population > 20000 & Population < 100000 = 100 150 lpcd Population > 100000 = 150-200 lpcd. 17
Water Demand for Indian Cities IS 1172 (1993 R 2007):- For communities with population up to 20 000 and without flushing system I. water supply through standpost 40 lphd (Min) II. Water supply through house service connection 70 to 100 lphd. for communities with population 20 000 to 100,000 together with full flushing system 100 to 150 lphd for communities with population above 1,00000 together with full flushing system 150 to 200 lphd NOTE The value of water supply given as 150 to 200 litres per head per day may be reduced to 135 litres per head per day for houses for Lower Income Groups (LIG) and Economically Weaker Section of Society (EWS), depending upon prevailing conditions. 18
Water Requirements for Buildings Other than Residences IS 1172 (1993 R 2007):- Type of Building Factories where bath rooms are required to be provided Consumption Per Day, litres 45 per head Factories where no bath rooms are required to be provided 30 per head Hospital (including laundry) : a) Number of beds not exceeding 100 340 per head b) Number of beds exceeding 100 450 per head Nurses homes and medical quarters Hostels Hotel Offices Restaurants Cinemas, concert halls and theatres 135 per head 135 per head 180 per head 45 per head 70 per seat 15 per seat Schools: a) Day schools 45 per head b) Boarding schools 135 per head NOTE For fire demand in buildings refer IS 9668 : 1981.
Factors Affecting the Rate of Demand:- 1) Size of city. 2) Climatic condition. 3) Living standard of people. 4) Habits and activities. 5) Industrial & Commercial activities. 6) Quality of water supply. 7) Pressure in the distribution system. 8) System of sanitation. 9) Cost of water & policy of metering 10) System of supply. 20
Total Draft:- 1) Maximum hourly demand or sum of maximum daily demand & fire demand, which ever is more is taken as Total Draft. 2) Max. daily demand = 1.8 x Annual avg. daily demand. 3) Max. hourly demand = 2.7 x Annual avg. hourly demand. 4) Max. hourly demand = 1.5 x Avg. hourly demand of max. daily demand. 5) Fire demand = 15 lpcd 6) Max. seasonal demand = 1.3 x annual avg. daily demand. 7) Max. monthly demand = 1.4 x annual avg. daily demand. 8) Max. daily demand when added to the fire demand is known as coincident draft. 22
Fire Demand:- Water required for fire fighting is usually known as fire demand. Fire demand = 15 lpcd. Kuichling s formula :- best for Indian cities Q = 3182 P Where, P is population in thousand 23
Design Period:- 1) A reasonable future period for which provision is made. 2) The number of years for which the design of the water works or structure have been done is known as Design Period. 3) Generally, water supply projects are designed for design period of 20 to 40 years. 4) Time lay between the design & completion should not be more than 2 years. Components Design Periods in Years Dams 50 Pumps 15 Water Treatment Units 15 Water Conveying Mains 30 Clear Water Reservoir 15 Distribution System 30 24
Factors should be kept in view while fixing the Design Period:- 1) Availability of fund. (More & Less) 2) Life of components & material used. ( More & More) 3) Rate of interest on the loan taken to compete project. (More & Less) 4) Anticipated expansion rate of the town. (More & Less) It should not be too large to become a burden on the present users or to short to be uneconomical. Components Source of supply Pipe main Water Treatment Units Pumps Distribution System Reservoir Design Demands Max. daily demand Max. daily demand Max. daily demand or twice avg. daily demand Twice avg. daily demand Total Draft Hourly fluctuation, fire demand, emergency etc. 25
Points to be considered while designing Water Supply Scheme:- 1) Financial Aspect or availability of fund. 2) Population. 3) Quality of raw water& treated water. 4) Rate of consumption. 5) Source of water supply. 6) Topography of area. 7) Trends of town developments 8) Sanitary system. 26
Population Forecasting Determination of the population at the end of design period. Various Methods:- 1. Arithmetical Increase method 2. Geometrical Increase Method 3. Incremental Increase Method 4. Decreasing Rate of Growth Method 5. Graphical Extension Method 6. Graphical Comparison Method 7. Zoning or Master Plan Method 8. Ratio or Correlation Method 9. Growth Composition Analysis Method 10. Logistic Curve Method Population depends upon living conditions, environment, industrial potential, state of development, location w.r.t. road & rail links, climatic condition, etc. 27
Arithmetic Increase Method 1) Rate of change of population with time is constant. 2) Applicable to old and large cities 3) Also applicable to cities with no industrial growth and reached a saturation or max. development 4) Yields lower results for rapidly growing cities Pn = (Po + n.x) Where, Po = latest known population Pn = Prospective population after n decades x = avg. increase in population per decade 28
Geometrical Increase Method 1) % increase in population from decade to decade is constant. 2) Avg. % of growth of last few decades is determined and from this forecasting is done. Pn = Po (1 + ( r / 100)) n Where, Po = latest known population Pn = Prospective population after n decades r = geometric mean % increase in population 29
Incremental Increase Method 1) Best method for any city whether old or new. 2) Combination of first two methods. 3) First the avg. of increase in population is calculated according to arithmetical increase method 4) Then the avg. of the net increment increase is added to this. Pn = Po + n. x + ( ( (n (n + 1) ) / 2 ) y ) Where, Po = latest known population Pn = Prospective population after n decades y = avg. of incremental increase in population 30
Simple Graphical Method 1) Graphical extension method. 2) Graph plotted for a city between time & population. 3) Then graph is smoothly extended to the desired time. 4) Very approximate result & Unsafe to use alone 31
Comparative Graphical Method 1) Graphical comparison method. 2) City under consideration may be developed same as the selected similar cities developed in the past. 3) Based on logical background. 4) Precise & reliable methods. 32
Logistic Curve Method 1. Decreasing rate of growth method. 2. Birth, death, migration etc. don t produce extraordinary changes. 3. Population-time curve under such condition would be an ideal one known as a logistic curve (S-shape) as shown. 4. Quite rational method for the cities whose rate of increase goes on reduce, as they reach saturation.. 33
Ratio Method 1) Ratio and correlation method. 2) Population growth of smaller city is related to the growth of a bigger city. 3) Future population of the city is determined by taking same rate of growth. 4) past growth rate of city under consideration are also compared. 5) According future rate of growth for that city is worked out. 6) Not accurate method. 34
Master Plan or Zoning Method 1) Modern and most useful method. 2) Best for big cities and medium cities. 3) City should have provision of master plan. 4) City divided into several zones based on specific use. Residential Commercial Industrial 5) City develop in a definite way based on the master plan. 6) Laws & regulations enforced by municipal corporation & other local bodies 35
Growth Composition Analysis Method 1) Based on the fact that the change in population mainly occurs due to birth, death and migration. 2) Population can be forecast, If these three factors are properly analyzed. Future Pop n = Present Population + Net Natural Change + Migration Where, Net natural change is the difference between birth & death. 36
Que. 1: The population of town for the last four census years was recorded as below. Determine the population in 2011 by using Arithmetic Increase Method: Census Population Increase in Population 1971 11092 -- 1981 13751 2659 1991 15206 1455 2001 19723 4517 Sol.: Avg. increase in popn per decade (x) = 8631/3 = 2877 Pn = (Po + n.x) Pn = (19723 + 1x2877) = 22600 37
Que. 2: The population of town for the last four census years was recorded as below. Determine the population in 2011 by using Geometric Increase Method: Census Population Increase in Population % increase in population 1971 11092 -- -- 1981 13751 2659 23.97 1991 15206 1455 10.58 2001 19723 4517 29.70 Sol.: Avg. % increase in population per decade (r) = 64.25/3 = 21.42% Geometric Mean % in population in decade (r) = (23.97 * 10.58 * 29.70 ) 1/3 =19.6% Pn = Po (1 + ( r / 100)) n Pn = 19723 (1 + (19.6 / 100)) 1 Pn = 23589
Que.3 With the help of following data, calculate the population at the end of next three decades by Geometric Increase Method: Census Population Increase in Population % increase in population 1940 80000 -- -- 1950 120000 40000 50.00 1960 168000 48000 28.57 2070 228580 60580 36.06 Sol.: Avg. % increase in population per decade (r) = 114.63/3 = 38.21% Geometric Mean % in population in decade ( r ) = (50 * 28.57 * 36.06 ) 1/3 = 37.21% Pn = Po (1 + ( r / 100)) n Pn = 228580 (1 + (37.21 / 100)) 3 Pn = 590466.8 or (603471.3)
Que. 4: The population of town for the last four census years was recorded as below. Determine the population in 2011 by using Incremental Increase Method: Census Population Increase in Population Incremental increase 1971 11092 -- -- 1981 13751 2659 -- 1991 15206 1455-1204 2001 19723 4517 3062 Sol.: Avg. increase in population per decade (x) = 8631/3 = 2877 Avg. incremental increase in population per decade (y) = 1858/2 = 929 Pn = Po+n.x+(((n(n+1))/2)y) Pn = 19723+(1x2877)+(((1(1+1))/2)929) Pn = 23529 40
Que. 5: The population of the city are as below. Year Population 1911 20,000 1921 25,000 1931 35,000 1941 45,000 1951 55,000 1961 65,000 1971 75,000 1981 85,000 Determine the population in 2011 by using Arithmetic Increase, Geometric and Incremental Increase Method: 41
Que. 6: The population of the city are as below.: Year Population 1930 25,000 1940 28,000 1950 34,000 1960 42,000 1970 47,000 Find out the population after one two and three decade beyond last known decades by using Arithmetic Increase, Geometric and Incremental Increase Method? 42
Sources of Water: 1) Earth s surface is covered by 71% water. 2) Essential for life can survive only a few days without water. 3) Small fraction (.014%) is readily available for human use.
Sources of Water Surface sources of water:- River & Stream. Lakes & Ponds. Impounded Reservoir. Oceans. Sub Surface Sources of water:- Wells. Springs. Infiltration Galleries.
Surface Sources of Water: 1) In which water flows over the surface of earth. 2) Directly available for water supply. River: 1) Most important source of water. 2) Formed due to discharge of water from many springs & streams. 3) Most of cities are settled near the rivers. 4) Perennial or non-perennial. 5) Quality of water is not reliable due to large amounts of silt, sand, etc. 6) Disposal of sewage in river is further contaminate the water. 7) River water must b properly analyzed and well treated before supplying to the public.
Streams: 1) In hilly regions streams are formed by the runoff. 2) The streams are flow in valleys and are the main source of water to villages of hills. 3) The quality of water is good except first runoff. 4) Small streams are not suitable but perennial streams may be used by providing barrages across them. Lakes & Ponds: 1) A natural large size depression formed within the surface of the earth. 2) Difference between pond & lake is only that of size. 3) Quantity of water in lake depends on catchment area, annual rainfall, porosity of ground, etc. 4) Lakes at high altitudes contains almost pure water which can be used without any treatment. 5) The quality of large lake is good than that of small lakes.
Impounded Reservoir:- 1) A barrier in the form of a dam may be constructed across the river, so as to form a pool of water on the upstream side of river. 2) This pool or artificial reservoir is known as impounded reservoir. 3) The quality of water is not much different from that of natural lake. 4) Objective is to store water & stabilize flow of water to fulfill the need of water in summer season. 5) Main source of water for big cities.
Sub Surface Source of Water: Wells: 1) The water which gets stored in the ground water reservoir through infiltration, etc. is known as underground water or subsurface water. 2) This water is generally pure because it undergoes natural filtration during the percolation through the soil pores. 3) Less contaminated but rich in in dissolved salts, minerals, etc. These are the artificial structure created by the excavation of trends into a ground. Depending upon depth & method of construction wells are classified. 1) Shallow well 2) Deep well 3) Tube well
Shallow Well: 1) These are constructed in the uppermost layers of earth s surface. 2) Diameter varies from 2m to 6m. 3) May be lined or unlined. 4) Quantity of water available from shallow well is generally is limited.
Deep Well: Obtain their quota of water from an aquifer below an impervious layers. Water consist of dissolved salts & become hard.
Tube Well: 1) It is deep well having diameter of 5cm to 20 cm. 2) Obtains its quota of water from number of aquifer. 3) Depth of well depends on the quality of water required. 4) Usually depth is about 30 to 50 m but it may be even go upto 300m is some dry areas.
Springs: 1) When ground water reappears at the ground surface it is called as springs. 2) It is formed near the hills. 3) Quantity of water is provided is less, hence suitable for small town. 4) Certain springs sometimes discharge hot water due to the presence of sulphur in them. 5) Springs are usually formed under three general condition of geological formation as below: A. Artesian springs B. Gravity springs C. Surface springs
Artesian Springs: The ground water comes to the surface under pressure. This formed due to presence of crack in impervious layer. These kind of source provide uniform quantity of water through out the year.
Gravity Springs: This springs develop due to overflowing of the ground water. When the ground water table rises high & such a springs is known as gravity spring. Flow from such a spring varies with rise or fall of the ground water table.
Surface Springs: This spring will be formed when subsoil water is exposed to the ground surface by the obstruction of an impervious layer. The quantity of water available is small and uncertain. Cut off wall may be constructed to develop such a springs.
Infiltration Galleries: 1) Artificially constructed structure use for collecting underground water near river, stream and lakes 2) Horizontal canal type constructed structure with hole on sides at right angle to the direction flow of underground water. 3) Consist of open jointed perforated concrete pipes embedded in a sandy subsurface. 4) These pipes are surrounded by aggregates. 5) Ground water percolated through aggregates into pipes & conveyed to a sump well.
Factors Governing The Selection of Source of Water:- 1) The quantity of available water. 2) Quality of water. 3) Distance of source of supply. 4) General topography of area. ( Not be uneven) 5) Elevation of source of supply.
Intake Structure:- Use for admitting water from surface sources & conveying it further to WTP. Masonary or concrete structure with an aim of providing clear water free from pollution. Components of Intake structure:- A. Conduit with protective works B. Screens at open ends C. Gates and valves to regulate flow
Submerged Intake:- constructed entirely under water & used to obtain water from lake. Exposed Intake:- in the form of well or tower constructed near the bank of a river. Common due to its simplicity in operation. Intake structure Reservoir Lake Canal River Wet Dry
Site Selection:- 1) Reqd. quantity of water even at worst condition. 2) Near to WTP. 3) Quality of water. 4) Well upstream of points of discharge of waste. 5) Good foundation condition. 6) Scope for future expansion. 7) Not get flooded. 8) Not be located on curves. 9) Never near the navigation channels.
Wet Intake :- 1) Concrete circular shell. 2) Water up to reservoir level. 3) Under gravity or pressure. 4) Opening into outer shell & inner shaft. 5) Gates on inner shaft. 6) Full of water even when gates are closed.
Dry Intake:- 1) Water enters directly into conduit. 2) Entry through ports controlled gates. 3) No water inside when gates closed.
River Intake:- 1) Circular masonry tower of 4 to 7m in dia. 2) Constructed along the bank of river. 3) Required quantity of water even in dry period. 4) Water enters in sump well through penstock. 5) To prevent entry of floating matter, screens fitted to penstock. 6) No. of penstocks at different level. 7) Operation of penstock valve by wheels at pump house..
Reservoir Intake:- 1) RCC masonary dam reservoir. 2) Intake pipes fixed at different level. 3) Screens at mouth of intake pipe. 4) Sluice valve at the top of intake tower. 5) Entered water in vertical portion taken out by outlet pipe.
Canal Intake:- 1) No necessity of ports at different levels. 2) Simple structure on bank of canal. 3) Side opening with coarse screen. 4) Water entry controlled by gate valve from top.
Lake Intake:- 1) Submersible intake. 2) Constructed in the bed of lake below LWL. 3) No obstruction to navigation. 4) No danger from floating bodies, etc. 5) Two or more pipes provided to get reqd. water quantity.