1. 24 – Wastewater Conveyance Demand Analysis April, 18, 2013 Professor Doran CEE 410

2. Learning goals for today are to improve understanding of: Sewer system Design Service Areas Sewer system Design Year Dry Weather and Wet Weather Flows Design Year Population for Service Area Per-capita Dry Weather Average Flow Design Year Dry Weather Average Flow Wet Weather Flow Components Peak Wet Weather Design Flow

3. Learning goals for today are to improve understanding of: Sewer system Design Service Areas Sewer system Design Year Dry Weather and Wet Weather Flows Design Year Population for Service Area Per-capita Dry Weather Average Flow Design Year Dry Weather Average Flow Wet Weather Flow Components Peak Wet Weather Design Flow

4. Learning goals for today are to improve understanding of: Sewer system Design Service Areas Sewer system Design Year Dry Weather and Wet Weather Flows Design Year Population for Service Area Per-capita Dry Weather Average Flow Design Year Dry Weather Average Flow Wet Weather Flow Components Peak Wet Weather Design Flow

5. Learning goals for today are to improve understanding of: Sewer system Design Service Areas Sewer system Design Year Dry Weather and Wet Weather Flows Design Year Population for Service Area Per-capita Dry Weather Average Flow Design Year Dry Weather Average Flow Wet Weather Flow Components Peak Wet Weather Design Flow

6. Learning goals for today are to improve understanding of: Sewer system Design Service Areas Sewer system Design Year Dry Weather and Wet Weather Flows Design Year Population for Service Area Per-capita Dry Weather Average Flow Design Year Dry Weather Average Flow Wet Weather Flow Components Peak Wet Weather Design Flow

7. Learning goals for today are to improve understanding of: Sewer system Design Service Areas Sewer system Design Year Dry Weather and Wet Weather Flows Design Year Population for Service Area Per-capita Dry Weather Average Flow Design Year Dry Weather Average Flow Wet Weather Flow Components Peak Wet Weather Design Flow

8. Learning goals for today are to improve understanding of: Sewer system Design Service Areas Sewer system Design Year Dry Weather and Wet Weather Flows Design Year Population for Service Area Per-capita Dry Weather Average Flow Design Year Dry Weather Average Flow Wet Weather Flow Components Peak Wet Weather Design Flow

9. Learning goals for today are to improve understanding of: Sewer system Design Service Areas Sewer system Design Year Dry Weather and Wet Weather Flows Design Year Population for Service Area Per-capita Dry Weather Average Flow Design Year Dry Weather Average Flow Wet Weather Flow Components Peak Wet Weather Design Flow

10. Design Service Areas Design Service Area reflects purpose of sewer being considered Collecting Sewer Small diameter (usually 8-in) sewer that conveys flow from a small geographic unit – usually a few city blocks.

11. Design Service Areas Design Service Area reflects purpose of sewer being considered Collecting Sewer Serviceability rather than flow capacity is basis of design.

12. Design Service Areas Design Service Area reflects purpose of sewer being considered Trunk Sewer Conveys flow from a number of collecting sewers.

13. Design Service Areas Design Service Area reflects purpose of sewer being considered Trunk Sewer Usually 10-in to 18-in and sized on basis of flow capacity.

14. Design Service Areas Design Service Area reflects purpose of sewer being considered Intercepting Sewer Large diameter (usually >18-in) sewer that conveys flow from trunk and collecting sewers to downstream larger interceptor, pumping station or treatment facility.

15. Design Service Areas Some service areas require pumping Lift Station A lift station pumps wastewater to a higher elevation so that it may subsequently flow by gravity.

16. Design Service Areas Some service areas require pumping Pumping Station A pumping station pumps wastewater to a downstream pump station, interceptor or treatment system.

17. Design Service Areas Service area increases along length of individual sewer 8-in

18. Design Service Areas 12-in 8-in Service area increases along length of individual sewer

19. Design Service Areas 12-in 8-in 18-in Service area increases along length of individual sewer

20. Design Service Areas 12-in 8-in 18-in 21-in Service area increases along length of individual sewer

21. Design Service Areas 12-in 8-in 18-in 21-in 24-in Service area increases along length of individual sewer

22. Design Service Areas Service area normally increases along length of individual sewer From WI NR 110.13

23. Design Service Areas Service area normally increases along length of individual sewer From WI NR 110.13 Nominal Capacity CFSm 3 /s 0.700.020 1.090.031 1.570.044 2.450.069 3.530.100 4.810.136 6.280.178 Manning’s n = 0.013

24. Design Service Areas Service area normally increases along length of individual sewer Use slope adequate to maintain velocity greater than 2.0 ft/s (0.61 m/s)

25. Design Year Design year based on service life of sewerage components Pumping Stations Structures ~ 40 yr Equipment ~20 yr Collecting, Trunk & Intercepting Sewers 50 – 75 yr

26. Design Year Design year based on service life of sewerage components Pumping Stations Structures ~ 40 yr Equipment ~20 yr Today might choose 2035 for PS but base Structure on 2055 Collecting, Trunk & Intercepting Sewers 50 – 75 yr Today might choose 2090

27. Flow = Sales + Infiltration + Inflow Dry and Wet Weather Flows Sales: Wastewater discharged from customers Infiltration: Leakage to sewer system from saturated soils Inflow: surface flow into sewer system through defects

28. Infiltration – leaks to sewer from saturated soil Dry and Wet Weather Flows

29. Inflow – surface water intrusion through sewer defects Dry and Wet Weather Flows From Leaking Storm Sewer

30. Inflow – surface water intrusion through sewer defects From MH Cover From MH Joints Illegal Connections Dry and Wet Weather Flows

31. Sewer must include I/I capacity Dry and Wet Weather Flows

32. Sewer must include I/I capacity Dry and Wet Weather Flows

33. Sewer must include I/I capacity Dry and Wet Weather Flows http://www.yout ube.com/watch? v=bDvfTzjNjZI

34. Dry and Wet Weather Flows Dry and Wet Weather Flows based on data analysis Q (Peak Hourly) July JanDec Rain Events

35. Dry and Wet Weather Flows Dry and Wet Weather Flows based on data analysis Q (Peak Hourly) July JanDec Dry Weather

36. Dry and Wet Weather Flows Dry and Wet Weather Flows based on data analysis Q (Peak Hourly) July JanDec Wet Weather Wet Weather Peak with I/I

37. Dry and Wet Weather Flows Dry and Wet Weather Flows based on data analysis Example 1 – A new pumping station is to be designed to serve an established residential area that has projected growth. What design peak flow should be used for pumping equipment? Current Pop15,027Dry Peak Q9,780 m 3 /d 2035 Design Pop22,100Wet Avg Q6,240 m 3 /d Sales Data362,000 m 3 /qtrWet Peak Q (no storm)11,200 m 3 /d Dry Q4,820 m 3 /dWet Peak Q (storm)15,200 m 3 /d

38. Dry and Wet Weather Flows Dry and Wet Weather Flows based on data analysis Average Daily Sales = 362,000 m 3 (qtr) qtr(91.25 d)(15,027 cap) = 0.264 m 3 /cap/d

39. Dry and Wet Weather Flows Dry and Wet Weather Flows based on data analysis Wet Weather Infiltration: Infiltration = Q WetAvg – (Sales/Pop)(Pop) = 6,240 m 3 /d – (0.264 m 3 /cap/d)(15,027 cap) = 2,270 m 3 /d Sales: 0.264 m 3 /cap/d

40. Dry and Wet Weather Flows Dry and Wet Weather Flows based on data analysis Wet Weather Inflow: Inflow = Q PeakStorm – Q PeakNoStorm = 15,200 m 3 /d – 11,200 m 3 /d = 4,000 m 3 /d Sales: 0.264 m 3 /cap/d Infiltration = 2,270 m 3 /d

41. Dry and Wet Weather Flows Dry and Wet Weather Flows based on data analysis Peaking Factor on Sales: PF = (Q WetPeak – Infiltration) = 11,200 – 2,270 = 2.25 (Sales/cap)(cap) 0.264(15,027) Sales: 0.264 m 3 /cap/d Infiltration = 2,270 m 3 /d Inflow = 4,000 m 3 /d

42. Dry and Wet Weather Flows Dry and Wet Weather Flows based on data analysis Design Peak Wet Weather Flow: Q PeakDes = (Sales/cap)(cap)(PF) + Infiltration + Inflow Q PeakDes = 0.264(22,100)(2.25) + 2,270 + 4,000 m 3 /d = 19,400 m 3 /d = 0.225 m 3 /s Sales: 0.264 m 3 /cap/d Infiltration = 2,270 m 3 /d Inflow = 4,000 m 3 /d PF = 2.25

43. Dry and Wet Weather Flows Dry and Wet Weather Flows based on unit loadings Example 2 – A currently unsewered area is to be connected to a Publicly-Owned Treatment Works (POTW). What size sewer is needed? Residential lots205Full Service RestaurantSeating for 50 Cap/residence2.20Trucking Co.24 Employees County Park175 visitors/dGas Station2 Toilets Cocktail LoungeSeating for 42Realty Office6 Employees; 18 Visitors Design for 25% future growth.

44. Dry and Wet Weather Flows Dry and Wet Weather Flows based on unit loadings Average Flow Calculation: CategoryFactorUnitsUnit FlowFlow (gpd) ResidentialCapita4517533,825 County ParkVisitors175152,625 Cocktail LoungeSeats4220840 Full Service RestaurantSeats50603,000 Trucking CompanyEmployees2420480 Gas StationToilets2400800 Realty OfficeEmployees620120 Realty Office VisitorsVisitors18590 Total41,780 use42,000

45. 45 Harmon’s Relationship 1 often used to estimate Hourly Flow Peak Factor for Dry Weather Conditions 1 Use actual data if available. Dry and Wet Weather Flows

46. Dry and Wet Weather Flows based on unit loadings Equivalent Cap = 42,000 gal(cap) = 560 cap d(75 gal)

47. Dry and Wet Weather Flows Dry and Wet Weather Flows based on unit loadings  560 Equiv Cap PF = 1 += 1 + [14/(4 + 0.56 1/2 )] = 4.0

48. Dry and Wet Weather Flows Dry and Wet Weather Flows based on unit loadings Peak Dry Weather Flow = 42,000(4.0) gpd = 168,000 gpd Add 50 gal/cap/d for I/I Allowance = 560(50) gpd = 28,000 gpd Total = (168,000 + 28,000)(1.25) gpd = 245,000 gpd = 0.38 cfs For Future

49. Dry and Wet Weather Flows Dry and Wet Weather Flows based on unit loadings For 2 ft/s design velocity: A = Q/V = 0.38 ft 3 (s) = 0.19 ft 2  0.49 ft s(2.0 ft) (use 8-in)

50. Learning goals for today are to improve understanding of: Sewer system Design Service Areas Sewer system Design Year Dry Weather and Wet Weather Flows Design Year Population for Service Area Per-capita Dry Weather Average Flow Design Year Dry Weather Average Flow Wet Weather Flow Components Peak Wet Weather Design Flow