FINAL PROJECT.pptx CIVIL ENGINEERING ENVIRONMENT SEWAGE TREATMENT PLANT

Design of sewage treatment plant

1. DESIGN SEWAGE TREATMENT PLANT SHAKTI PRATAP SINGH RATHORE SHIV KUMAR VISHAL YADAV ANISHA MEENA NIKHIL SHARMA GUIDED BY- GEHNA AJMERA Govt.Engineering College Ajmer

2. CONTENT Introduction Population Forecasting Sewage Generation Design of Preliminary Treatment Design of Inlet Chamber Design of Screening Design of Grit Chamber Design of Skimming Tank Design of Primary Sedimentation Tank Design of Secondary Sedimentation Tank Design of High-Rate Trickling Filter Design of Sludge Drying Beds Efficiency of Sewage Treatment Plant Results

3. Location of Sewage Treatment Plant in Campus Location of sewage treatment plant in campus

4. INTRODUCTION OBJECTIVE: Ensure the safe disposal of wastewater to prevent pollution of water bodies. Protect public health by removing harmful contaminates from sewage. Extract valuable resources like energy and nutrients from wastewater. Promote sustainable practices by recycling treated water for non-potable uses. Meet regularity standards for wastewater discharge. SCOPE: Discuss the global significance of sewage treatment in improving water quality and public health. Primary, secondary, tertiary treatment processes. Introduction to innovative treatment technologies like membrane bioreactors, UV disinfection, and advanced oxidation process. Exploring emerging trends such as decentralized treatment system, smart monitoring, and resource recovery from wastewater.

5. How Does a Sewage Treatment Plant Work? Sewage treatment plants typically use a multi-stage process to remove contaminants from wastewater. The stages can vary depending on the size and characteristic of sewage, but they generally include: The sewage treatment process is a multi-step approach to ensure the wastewater is thoroughly cleaned. Each stage removes different types of contaminants, resulting in cleaner water with each step.

6. Flow Chart

7. POPULATION FORECASTING Growth average increment (2017 to 2024) = = 0.015 So for next 30 years (2025 to 2055) future population will be calculated with considering growth increment rate 0.015. Future Population(2025 to 2055)= 2300×0.015×30= 1035 persons Total day scholer s population= 2300+1035= 3335 persons Design no. of persons= 92+61+550= 703 So, Design sewage treatment plant for next 30 years population = 3335+703= 4038 persons   Year Population Increment 2017 2100 - 2018 2150 0.023 2019 2200 0.023 2020 1900 -0.130 2021 2000 0.052 2022 2100 0.050 2023 2200 0.047 2024 2300 0.045 TOTAL 0.11

8. Generation of Sewage Sewage generation for quarters and hostels persons in campus Ultimate design period = 30 years Forecasted population in 2055 = 703 As per IS 1172 (1993), requirement of water supply for quarters and hostels is taken as 135 LPCD respectively. Average sewage generation (quarters + hostels) = 80% of supplied water = = 0.0759 MLD= 0.0009 m 3 /s(approx.) Sewage Generation for Day Scholers A s per IS 1172 (1993), water supply requirement for flushing and other domestic purposes is taken as 45 LPCD. Average sewage generation (day scholars) = = 0.120 MLD = 0.0014 m 3 /s (approx.) Total Sewage Generation Total = 0.0759+0.120 = 0.1959 MLD ~ 0.20 MLD(approx.) Average sewage generation = 0.20 MLD= 0.0023 m 3 /s For maximum sewage flow considering peak factor as 3 Maximum sewage flow = 0.20 3 = 0.6 MLD = 0.0069 m 3 / s    

9. For designing sewer lines A s per IS 1742 For Cricular and R.C.C pipe Diameter of sewer pipe – 150 mm Gradient of sewer pipe -1in 100 Cross-section area of sewer is calculated considering the sewer as running half full = = 0.0088 m 2 Wetted perimeter (P) of sewer P = π D = 3.14×0.150 = 0.471 m Flow Velocity Sewer Pipe Line using manning formula V = R 2/3 S 1/2 V = velocity of flow in the sewer, m/sec R = Hydraulic mean radius of flow, R= A/P = 0.0088/0.471 = 0.019m(approx.) V= (1/0.013) x (0.019) 0.666 x (1/200) 0.5 = 0.388 m/s Discharge through sewer pipe line was calculated by the formula: Q = A x V = 0.0088 x 0.388= 0.00341 m 3 /s  

10. DESIGN OF PRELIMINARY TREATMENT Design of Inlet Chamber unit Inlet chamber is the first structure to receive the raw sewage collected through underground sewers. It is a rectangular shaped tank constructed at the entrance of the sewage treatment plant. Design flow discharge = 0.0069 cumec Detention time = 60 sec Volume of inlet chamber required = V req = flow x detention time = 0.0069 x 60 = 0.414 m 3 As suming depth = 0.8 m Area = V req / D A= 0.52 m 2 A ssuming length: width = 3:1 Lx B = 3B x B = 3B 2 = 0.52B = 0.42 m ≈ 0.5 mL = 1.26m ≈ 1.5 m Check Volume designed V des = 0.5 x 1.5 x 0.8 = 0.6 m 3 whereas as above, V req = 0.414 m So V des > V req , hence OK. Receiving chamber is designed for the size of 0.5m x 1.5m x 0.8m (SWD) + 0.3m (FB) So, after providing free board, overall depth of the tank will be 1.1 m.

11. Design of Screening unit Assuming the velocity at average flow is 0.2 m/s for hand cleaned bar screens. Vertical projected area of screen openings- = 0.0069 / 0.2 = 0.0345 m 2 Clear spacing between bars = 20 mm = 0.02m, Shape of bars = M.S. Flats Size of the bars = 10 mm x 50 mm (width x depth), thickness of bars = 10 mm These bars are welded together with plate from downstream side to avoid deformation. Assuming the channel has width W and depth D, Efficiency coefficient of bars = = 20/(20+10)= 2/3   Screening removes objects such as rags, paper, plastics, and metals to prevent damage and clogging of downstream equipment, piping, and appurtenances .

12. Vertical projected gross area of screen = 0.0345×3/2= 0.0517 m 2 If 20 bars are provided, the number of openings will be 21. The gross width of screen and thus of the screen channel is obtained as = + 21 }= 0.62m So, Depth of screen channel D = 0.0517/0.62 = 0.083m ~ 0.1m Assuming top of the screen to be 0.25 m above the highest flow level, and a free board of 0.3 m, we obtain Total depth of screen channel D = d + (0.25 + 0.3)= 0.1 + 0.25 + 0.3 = 0.65 m Velocity of flow in screen channel V = 0.111 m/s Head loss through the screen H L = 0.0729(V 2 -v 2 ) = 0.0729(0.2 2 -0.111 2 ) = 2.01mm This will be the head loss when screen is clean. However, if the screen is half clogged, V = 2 x 0.2 = 0.4 m/s H L = 0.0729(V 2 -v 2 ) = 0.0729 {(0.4) 2 – (0.111) 2 } = 10.76 mm  

13. Design of Grit Chamber unit Grit chamber is a type of sedimentation basin placed in front of the screens to remove the inorganic particles having specific gravity of 2.65 Peak flow of sewage = 0.0069 cumec and assuming average detention period = 180 s Volume of grit chamber = Peak flow x Detention period, V = 0.0069 x 180 = 1.24 m 3 In order to drain the channel periodically for routine cleaning and maintenance only one chamber is used. Therefore Volume of chamber = V = 1.24 m 3 Assuming depth as 1.2 m and width to depth ratio 1.5:1, width will be 1.8 m. Length of channel L = L = ~ 0.6m Increasing the length by about 20% to account for inlet and outlet Providing length = 0.6 x 1.20 = 0.72 m ≈ 0.8 m Therefore, grit chamber is designed for 0.8 m x 1.8 m x 1.2 m + 0.5 m (FB)   Grit chamber unit purpose is to slow down the flow of sewage in order to remove grit materials, which include sand, ash and clinkers, eggshells, bone clips, and many other inorganic elements.

14. Design of Skimming Tank unit Surface Area of the Tank, A = 6.22 x 10 -3 x q / V r m 2 Providing depth of skimming tank as 1.5m with detention time 3 minutes and length to breadth ratio as 1: 1, q = 0.0069 x 24 x 60 x 60 = 596.16 m 3 /day Vr = 0.25 m/min = 0.25 x 60 x 24 = 360 m/day A = 6.22 x 10 -3 x 596.16 / 360 ≈ 0.01 m 2 Therefore, L = B = 0.1m ≈ 300 mm Skimming tank is designed for the size 0.3 m x 0.3 m x 1.5 m + 0.3m (FB) The skimmer removes the floatable solids and liquids like oil and grease so that the wastewater can be further processed

15. DESIGN OF PRIMARY SEDIMENTATION TANK UNIT Average quantity of sewage = 0.20 MLD Maximum quantity of sewage = 0.6 MLD Assuming surface loading rate = 40 m 3 /m 2 /day Therefore, surface area of tank= 5 m 2 Check for peak flow condition: The surface overloading rate (SOR) at peak flow = 0.6 ×10 3 / 5 = 120 m 3 /m 2 /day Now, surface area = 0.6 x 10 3 / 40 = 15 m 2 Assume width = 3.0 m, therefore theoretical length = 15/3 = 5 m Hence, provide a tank of total length = 5 + 1(inlet + outlet) = 6 m{inlet and outlet of 0.5 m} Flow rate x detention time = depth x surface area = volume of tank   FIG- PRIMARY SEDIMENTATION TANK UNIT

16. = = surface settling rate Providing detention time of 2 hours, liquid depth required = 40 x 2/24 = 3.34 m = 3.4 m flow through velocity = = 0.0001 m/sec < 1 cm/sec, hence OK. At peak flow, flow through velocity = = 0.03cm/sec < 1 cm/sec, hence OK.(Horizontal velocity is checked for non-scouring velocity i.e. less than 0.06 m/sec.) Providing total depth = 3.4 + 0.3 (free board) + 0.25 (space for sludge) = 3.95 m, say 4m Hence, primary sedimentation tank is designed for dimensions 6 m (length) x 6 m (width) x 4 m (depth) + 0.5m (FB).  

17. DESIGN OF SECONDARY SEDIMENTATION TANK Quantity of sewage flowing into the filter = 0.20 MLD BOD left in sewage entering per day in filter unit (Kg) =Total BOD x 0.7 x quantity of sewage =330x0.7x0.20 = 46.2 Kg Total BOD left in the effluent per day = total quantity of sewage x desired BOD concentration = 0.20 x 20 = 4 Kg BOD removed by the filter = BOD left in sewage entering per day – BOD left in effluent per day = 46.2 – 4 = 42.2 Kg Filter area (A) is calculated by the formula; A = = = 5 m 2 Where A = filter area in m 2 V = Volume of sewage (in m 3 /day) surface loading = 40 m 3 /m 2 /day Efficiency of the filter (ƞ) = = Recirculation factor F Where R = 1.5 {as per IS: 8413 (part 1)} Hence, F = 1.89   The secondary sedimentation tank removes bio-flocculated solids. They produce effluent sufficiently classify to meet discharge standards and must concentrate the biological solids to minimize the quantity of sludge to handle.

18. Volume of the filter V Where , Y = total BOD in Kg F = Recirculation factor So, V = 767.31m 3 Surface area of the trickling filter (assuming depth = 4m) Diameter (d) of circular trickling filter is calculated by formula d = = 15.62m   Trickling Filter

19. Results S.NO. DESIGN PARAMETERS Value 1 Design period 30 years 2 Estimated population by the year 4038 persons 3 Water supply per capita 135lpcd, 45lpcd 4 Total volume of sewage (estimated) 0.02MLD 5 Average discharge 0.0023cumec 6 Maximum discharge 0.0069cumec 7 Dimension of inlet chamber L=1.5m, W=0.5m, D=0.8m, F=0.3m 8 Dimension of coarse screen W=0.62, D=0.1m, F=0.3m 9 Dimension of grit chamber L=0.8m, W=1.8m, D=1.2m, F=0.5m 10 Dimension of skimming tank L=0.3m, W=0.3m, D=1.5m,F=0.3m 11 Dimension of primary sedimentation tank L=6m, W=6m,D=4m,F=0.5m 12 Dimension of trickling filter Diameter=15.62m, D=4m 13 Dimension of sludge drying bed L=12.5m, W=4m, D=0.3m 14 Efficiency of STP 93.9%

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