Environmental Engineering-I Prof. Rajesh Bhagat Asst. Professor, CED, YCCE, Nagpur

1. Environmental Engineering-I Prof. Rajesh Bhagat Asst. Professor, CED, YCCE, Nagpur B. E. (Civil Engg.) M. Tech. (Enviro. Engg.) GCOE, Amravati VNIT, Nagpur Experience & Achievement: Selected Scientist, NEERI-CSIR, Govt. of India. GATE Qualified Three Times. Selected Junior Engineer, ZP Washim. Three Times Selected as UGC Approved Assistant Professor. Assistant Professor, PCE, Nagpur. Assistant Professor, Cummins College of Engg. For Women (MKSSS, Nagpur) Topper of Pre-PhD Course Work at UGC-HRDC, RTMNU Nagpur Mobile No.:- 8483002277 / 8483003474 Email ID :- rajeysh7bhagat@gmail.com Website:-www.rajeysh7bhagat.wordpress.com

2. UNIT-I Introduction: Importance and necessity of water supply scheme. Water Demand: Types of demand, factors affecting per capita demand, variation in demand, design period and population forecasting methods and examples. Sources of Water:Ground water – springs, infiltration galleries, Dug wells, tube wells, Surface water – stream, Lake, River, impounding reservoirs, ponds, etc. Intake Structures: Location types – river, lake, canal, reservoir, etc. 2

3. UNIT - II • Conveyance of Water:Types of pipe, joints , valves & fittings. • Hydraulic Design Aspects: Manning’s, Darcy’s Weisbach, Hazen Williams Formulae & Numerical. • Rising Main & Pumps: Types, working merits and demerits selection of pumps. 3

4. UNIT – III • Water Quality : General idea of water borne diseases, Physical, Chemical and biological characteristics of water, Standards of drinking water. • Water Treatment : Objective of treatment, unit operations and processes. • Treatment Flow sheet of conventional water treatment plant. • Aeration: Purpose, types of aerators. • Coagulation & Flocculation: Definition, Principals, types of coagulants and Reactions, coagulant doses, types of mixing and flocculation devices. 4

5. References:- Water Supply & Sanitary Engineering by G. S. Birdie & J. S. Birdie, DhanpatRai Publication, New Delhi. Water Supply Engineering (Vol. – I) by B. C. Punmia, Laxmi Publication, Delhi. Water Supply Engineering (Vol. – I) by S. K. Garg, Khanna Publishers, Delhi. Solid Waste Management by A. D. Bhide & Sunderson. Water Supply Engineering (Vol. – I) by Modi P.N., Standard Book House Rajsons Publication, New Delhi.

6. UNIT-II QUESTIONS BANK List out the various joints used in Water Supply Scheme and explain anyone. With neat sketches explain the various types of pipe Joints used in CI pipes. List out the types of pipes or conduits used in WSS and discuss their advantages. Why is pumping of water required in WSS? What factors affect the selection of pump? Describe the various types of pumps used in water supply with its advantage and disadvantage. Explain the various formulae used to determine the loss of head in pipes. Calculate the BHP of a pump, if total quantity of discharge is 900lit/sec and total head against which pump has to work is 60m, assume suitable efficiency of pump. Water is to be supplied to a town of population 2.5 lakhs. If the water work is situated at an elevation of 50m lower than the source, calculate the size of gravity mains of 25 km length. If the water demand 270 lpcd. Determine hydraulic gradient for a pipe of diameter 1.5 m carrying water at a rate of 2.4 m3/s. (Use:- f = 0.003, m = 0.011, CH = 135) Write a short note on: a) Sluice Valve, b) Checked Valve, c) Gate Valve, d) Pressure Relief Valve, e) Air Relief Valve, f) Scour Valve, g) Centrifugal Pump, h) Pipe Materials in Water Supply i) Socket Joint, j) Spigot Joint & J) Reciprocating Pump. 6

7. CONDIUT:- Any structure for transportation of water from source to WTP & subsequent distribution to city. Conveyance of Water

8. Open Channels: • Easily & cheaply constructed by cutting the grounds • Channels should be lined properly to prevent seepage • Velocity should not exceeds 0.9 m/s Aqueducts: • Closed conduit constructed with masonry or concrete • Old days rectangular aqueducts were used but now days horse shoe or circular section are used • Avg. velocity = 1.0 m/s

11. Tunnels: • Gravity conduits but sometimes water flows under pressure • Mostly constructed in horse shoe c/s but pressure tunnels have circular c/s Flumes: • Open channels supported over the ground by trestles • Used for conveying water across valleys & minor low lying areas or over drains & other obstruction coming in the way • Constructed with RCC, wood, metal, etc. • Common section are rectangular or circular

12. Tunnels:

13. Flumes:

14. Pipes: • Circular conduits in which water flows under pressure or gravity • Now days pressure pipes have eliminated the use of channels, aqueduct, tunnels, etc. • Made up of various material • Cast Iron • Wrought Iron • Steel (MS) • Cement Concrete • Asbestos Cement • Timber • Plastic • Copper • Lead • Vitrified Clay

15. Carrying capacity of pipe (Coefficient of roughness) • Durability and life of pipe • Type of fluid or water to be conveyed & its corrosive effects • Internal and external corrosion problems • Type of soil • Strength of the pipe & measured by its ability to resist internal pressure and external loads • Availability of funds • O & M cost • Safety, economy, & availability of pipe • Maximum permissible diameter • Ease or Difficulty of transportation , handling and laying and jointing under different conditions • Skilled labor Factors Affecting Selection of Pipe Material:-

16. Cast Iron Pipes: • Long life about 100 years • High corrosion resistant ability • Used when pipe diameter is less than 90 cm • Length of pipe is 3 to 6m • Bell & spigot joints are for CI pipes in distribution system while flanged joints are for rising main • Economical, strong, durable & long life • Corrosion resistant • Easy to join with each other • Impact resistance • Cant be used if pressure greater than 7 kg/cm3 • Uneconomical when dia. More than 120 cm • Erosion of pipe from inside • Roughness from inside causes reduction of flow • Very heavy and difficult to transport • Brittle and fragile

17. Cast Iron Pipes:

18. Steel Pipes: • Used for mainlines & where pressure are high & dia. is more • Jointed by welding or riveting or flexible joints or other filler joints • Available in small or large diameter • Prevented from internal corrosion through coal tar / asphalt lining • High Tensile strength • Very light weight & withstand high pressure • Less thickness as compared to CI pipe • Best suited for high dynamic loading • Laying & joining easy • Life is 25 to 30 years • Cant withstand external loads • Affected by corrosion & costly to maintain • Flow carrying capacity gets reduced due to riveting • Cant used in distribution system

19. Steel Pipes:

20. Concrete Pipes: • Used when water flows under gravity • Plain concrete pipes used when dia. Upto 60 cm & Above 60 cm dia. RCC pipes are used • Normally 1:2:2 concrete mix is used in manufacturing • Bell & spigot , collar joint and flush joints are used • Corrosion resistant • Smooth from inside hence reduces frictional losses • Long life = 75 years • Carrying capacity doesn’t reduces with time • Low maintenance cost • Suitable to resist external loads • Heavy & difficult to handled • May get cracked during transportation • Repairing is difficult • Cant withstand high pressure

21. Concrete Pipes:

22. Asbestos Cement Pipes:- • Mixture of Portland cement and asbestos fibers • Manufactured from 5 to 130 cm in dia. • Withstand high pressure from 3.5 to 25 kg/cm2 • Not affected by salt, acids & other corrosive materials & remains smooth • Very light therefore easy to transport & handle • Easily cut, fitted, drilled trapped and jointed • Offer less friction therefore good carrying capacity • Costly • Fragile and brittle • Very weak in sustaining impact • Not durable • Cant be laid in exposed places

23. Asbestos Cement Pipes:-

24. Plastic Pipes:- • Now days plastic pipes are extensively used • Corrosion resistance, light weight, economical • PVC pipes most commonly used among plastic pipes in India • Internal plumbing and rural supply scheme • High smooth flow with reduced friction losses • Withstand to high moist & corrosive environment • Immune to chemicals • Do not provide any favorable condition to bacteria • Joining, bending & installation is easy • Not strong like CI pipe • Thermal expansion coefficient is high • Plastic imparts taste to water

25. Wrought Iron Pipes: • Manufactured by rolling the flat plates of the metal to the proper diameter & welding the edges • Coated or galvanized with zinc to increase the life • Should be used in building to protect from corrosion Cement lined Cast Iron Pipes: • Cast iron pipes are lined with cement to protect them against corrosion • Have very small coefficient of friction Vitrified Clay Pipes: • Extensively used for carrying sewage and drain water • Provide smooth surface and free from corrosion • Length of pipe = 60 to 120 cm

26. Vitrified Clay Pipes:

27. Copper and Lead Pipes: • Copper pipes are not liable to corrosion • Used in house connection and carrying hot water • Can withstand high internal pressure • Lead pipes are not used in India bcoz causes lead poisoning • Used in sanitary fitting & chlorination & alum dosing Wooden Pipes: • Light weight, Easy to laid • Easily repaired, Cheap, Life = 30 to 35 years • Corrosion resistance, Low coefficient of friction • Leak under varying pressure hence, not suitable for intermittent supply system • Collapse under heavy external load

29. Pipe are manufactured in small length of 2 to 6 m for the facilities in handling, transportation and placing in position. • These small pieces of pipes are then joined together after placing in position, to make one continuous length of pipe line. Types of Joints:- • Bell & Spigot Joint • Flanged Joined • Mechanical Joined • Flexible Joint • Expansion Joint • Screwed Joint • Collar Joint • A. C. Pipe Joint Pipe Joints:-

30. Socket and Spigot joint. • Commonly used for CI pipes. • One end is enlarged is called socket or bell while other is normal end (spigot). • Spigot inserted into socket & empty space is filled by molten lead • Joint is flexible but requires skilled labor • May be used for RCC pipes • For economy sometimes cement mortar are also used in place of lead • Hemp yarn fiber uses to maintain the alignment Bell and spigot joint

31. Mostly used for temporary pipe lines (CI, Concrete pipes, etc.) • Flanges at both ends • Pipes two ends are brought in perfect level to join each other. • Before flanges bolted rubber gasket are placed. • Cant be used where vibration and deflection of pipes, etc. flanged joint

32. Two plain ends are joined together by means of mechanical coupling. • Used in CI, Wrought Iron & Steel pipes. • Mechanical Victaulic joint consist of a U shaped rubber ring enclosed by a metal housing made in two parts. • These two parts are then bolted together to form a ring around the pipe. • Mechanical Dresser Coupling joint consists of an iron ring & gasket which are slipped over each abutting ends of the pipes and an iron sleeve is inserted. • The iron rings are then tighten by nuts & bolts. mechanical joint

33. Where settlement is likely to occur after the laying of the pipes specially on curves. • Pipes can be laid at angle • If one pipe is given any deflection the ball shaped portion will move inside the socket and the joint will remain waterproof in all the positions. flexible joint

34. CI, Concrete Pipes • Where pipes expand or contract due to change in temperature • Thus checks the thermal stresses in the pipes. expansion joint

35. Connecting small diameter CI, WI, & galvanized pipes. • Ends of pipes have threads on outside, while coupling or socket has threads on the inner side. • Zinc paint or hemp yarn should be placed in the threads of the pipe to make water tight joint. screwed joint

36. Mostly uses for joining big diameter concrete & asbestos cement pipes. • Two ends of pipes are brought in one level • 1:1 cement mortar is filled in the space between pipe & collar as shown. collar joint

37. Small diameter Asbestos cement pipe • Two ends of pipes are kept against each other & then two rubber ring will be slipped over the pipes. • The coupling will be pushed over the rubber rings as shown in figure. Rubber rings make the joint water proof. Simplex joint

38. Water pipes can be laid at any depth, below the hydraulic gradient line, the velocity in the pipes depends on the pressure head at the point. • The hydraulic gradient line should neither too high nor too low. It should be near to pipe line. • If the velocity is kept low, large diameter pipe will be required to carry the required quantity of water. • If the velocity is kept high, cost of pumping, pipe & its fitting will increase. • Self cleansing velocity ie no silting or normal velocity- 0.6 to 3 m/s (0.9 to 1.5 m/s) 0.9 m/s Hydraulic Design Aspects

39. This formula usually used in determining the loss of head in the gravity conduits. • This formula equally applicable to the turbulent flow in pressure pipes. • HL = (m2 x V2 x L) / (R 4 / 3) • HL = Head Loss in m. • m = Manning’s Constant or roughness coefficient = 0.011 • L = Length of pipe line in meter. • V = velocity of flow in m/s • R = Hydraulic mean depth = (Area / Perimeter) = (d/4) • d= Diameter of pipe in meter. Manning’s Formula

40. This formula is widely used now days in designing the pipe lines. • The value of CH is more for smoother pipe and less for rough pipe. • V = 0.85 x CH x R 0.63 x S 0.54 • HL = (10.68 x L x Q 1.852 ) / ( CH1.852 x D 4.87 ) • CH = Coeff. Of Hydraulic Capacity = 135 • L = Length of pipe line in meter. • V = velocity of flow in m/s • R = Hydraulic mean depth = (Area / Perimeter) = (d/4) • S = slope of energy line or pipe. Hazen Williams Formula

41. DracysWeisbach Formula • HL = (f x L x V2) / (2 x g x d) • g = Acceleration due to gravity in m/s2 = 9.81 m/s2 • F = friction factor = 0.02 to 0.075. • L = Length of pipe in m. • d = Diameter of pipe in m. • Q = Discharge through pipe in m3/s • V = Velocity through Pipe in m/s = Q /A

42. Que. 1. Water has to be supplied to a town with one lakh population at the rate of 150 liter/capita/day from a river 2000m away. The difference in elevation between the lowest water level in the sump and the reservoir is 40m. If the demand has to be supplied in 8 hours, determine the size of the main and the brake horse power of the pump required. Assume maximum demand as 1.5 time the average demand. Assume f = 0.03, velocity in the pipe = 2.4 m/s and efficiency of pump = 80%. • Sol: Avg. Water Demand = 100000 x 150 = 15 MLD • Maximum Water Demand = 1.5 x 15 = 22.5 MLD • Max. Discharge Required, Q = (22.5 x 106 ) / (103 x 8 x 60 x 60) = 0.7812 m3 /s • A = ( Q / v) :- ( ∏ / 4 ) x d2 = ( 0.7812 / 2.4 ) d = 0.644m • HL = (f x L x V2) / (2 x g x d) • HL = (0.03 x 2000 x 2.42) / (2 x 9.81 x 0.644) = 27.36 • Required lift head between sump and reservoir = 40m • Total Head Against which pump has to work = 40 + 27.36 = 67.36m • Brake Horse Power = (γw x Q x H ) / (η x 0.7457) • = (9.81 x 0.7812 x 67.36 ) / (0.8 x 0.7457) • =865.3 BHP (645.2 K Watt)

43. Que. 2. For a town with a population of 2 lakhs, a water supply scheme is to be designed. The maximum daily demand may be assumed as 200 liters/capita/day. The storage reservoir is situated 5 km away from the town. Assuming loss of head from source to town as 10m and friction factor for the pipe material as 0.048, recommend the size of supply main. 50% of daily demand has to be pumped in 8 hours for the proposed scheme. • Sol: Maximum Daily Water Demand = 200 LPCD • Maximum Water Demand = 200000 x 200 = 40 MLD • Maximum Water Demand for which supply main is to be designed = 50% of daily demand • Q = (50 / 100) x 40 x 106 Liters per 8 hours • Q = (50 / 100) x (40 x 106) / (8 x 60 x 60) • Q = 0.694 m3 /s L = 5000 m HL = 10 m f = 0.048 • HL = (f x L x v2) / (2 x g x d) • 10 = (0.048 x 5000 x v2) / (2 x 9.81 x d) • v = ( Q / (∏ /4)) x d2 v = ( 0.694 / (3.14 /4)) x d2 v = 0.884 / d2 • 10 = (0.048 x 5000 x (0.884 d2)2) / (2 x 9.81 x d) • d = 0.99 m

44. The hydraulic machines which convert the mechanical energy into hydraulic energy is called as pumps. • The device or machine which is used to lift the water from lower elevation to higher elevation. Pumps

45. Classification of Pumps • Based on Principle of operation:- • Displacement pump • Reciprocating pump • Rotary pump • Centrifugal pump • Airlift pump • Impulse pump • Based on the type of power required:- • Electrically Driven Pump • Gasoline Engine pump • Steam Engine pump • Based on the type of service:- • Low lift pump • High Lift Pump • Deep Well pump • Booster pump • Stand by pump

46. To lift the raw water from the source of supply, such as lake, reservoir, river or well, etc • At WTP, to lift the water for various operation such as back washing of filters, pumping of chemicals, dewatering of tanks, etc • To lift the treated water to overhead tanks or elevated distribution reservoir. • To deliver treated water to the consumer’s taps at reasonable pressure. • To increase the discharge or velocity by boosting up the pressure in water distribution network. • To supply water under pressure for fire hydrants. NECESSITY OF PUMPING

47. Capacity of the pump. • Number of pump units required. • Suction conditions. • Lift (total head). • Discharge condition &variations in the load. • Floor space requirement. • Flexibility of operation. • Starting and priming characteristics. • Type of drive required. • Initial cost and running costs. • Labor requirements. • Quantity and quality of water to be pumped. • Life. SELECTION OF PUMPS

48. The displacement pumps are those in which liquid is sucked by mechanically inducing vacuum in a chamber. • It actually displaced due to the thrust exerted on it by a moving member. • Lifting the liquid (water) to the desired height . • The pump consist of one or more chambers which alternatively filled and emptied with the liquid. • TWO TYPES :- • Reciprocating pump • Rotary pump DISPLACEMENT PUMPS

49. The mechanical energy is converted into hydraulic energy by sucking the liquid into cylinder in which exerts the thrust on the liquid and increases its hydraulic energy, the pump is called as reciprocating pump. • Suitable for lifting relatively clean water. • Against high and fluctuating head. • PARTS:- A cylinder, Suction pipe, Delivery pipe, Suction valve & Delivery valve • WORKING:- • Consist of a piston which move to and fro in a close fitting cylinder • Connected to the suction and delivery pipes • A non–return valve which admits water in one direction only. RECIPROCAING PUMP