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Sewer Lateral Renewal Programs. Sewer laterals have been called the
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1. SEWER LATERAL RENEWAL PROGRAMSPrivate Property Inflow and Infiltration Henry R. (Kelly) Derr, Hazen and Sawyer
Richard (Dick) Eubank, Baltimore County
For the:
Chesapeake Water Environment Association
Collection Systems Committee Luncheon Seminar
May 4, 2007
2. Sewer Lateral Renewal Programs Sewer laterals have been called the “Final Frontier” of sewerage system renewal
Laterals have been given less attention in the past due to:
Lack of consistently effective and affordable inspection and renewal methods for small diameter lines
Complex issues of ownership and maintenance responsibilities
Sheer number of laterals
The situation is changing!
3. Recent Studies of Laterals US Census Bureau
National Census - 2001
WERF Studies
Survey of Public Works Agencies – 2004
Methods for Cost-Effective Rehabilitation of Private Lateral Sewers – 2006
Miami-Dade Water and Sewer District
Comprehensive Lateral Investigation Program - 2007
4. Number of Sewer Laterals Over 76 million sewer laterals in U.S.
(U.S. Census Bureau 2001)
Estimated 3.8 billion feet of lateral piping
Municipal survey responses for number of laterals:
Per mile of mainline: 30-300; on average 75-85.
Total per agency: 2,000-1,000,000
(WERF 2004 survey of public works agencies)
5. Sewer Laterals Are Often in Poor Condition Range of defects:
From minor (cracks allowing infiltration) to severe requiring immediate attention (collapsed pipes)
Main causes of defects:
Soil movements, ground settlement over time
Corrosion or encrustration
Tree root intrusion into pipe
Improper lateral construction practices (“break-ins”)
Improper excavation of other utilities (open cut, HDD installations)
Lack of maintenance
6. Typical Defects in Sewer Laterals Cracks and voids in pipe walls
Connections with mainline:
“Break-in” (“hammer tap”) and/or protruding laterals
Defective pipe joints:
Misaligned or open joints, cracked or displaced bells
Obstructions:
Tree roots, debris, encrustation
Collapsed pipes
7. Typical Results of Defective Laterals – I/I Inflow and infiltration enters the system :
Along the length of the lateral
Open joints
Cracked pipe
At the cleanout cap
At the ‘hammer tap’ connection
8. WERF 2004 Survey Estimated I/I from Laterals
45% of participating agencies had estimated how much laterals contribute to total I/I
Estimates are in the range of 7-80%, with an average of 40%
9. WERF 2004 SURVEY Materials Used for Sewer Laterals: Interestingly, a survey conducted in 1981 by OWASA of NC Utilities found that all used either CI or VCP with only a small percentage of ABS or PVC.Interestingly, a survey conducted in 1981 by OWASA of NC Utilities found that all used either CI or VCP with only a small percentage of ABS or PVC.
10. WERF 2004 SURVEY Definition of “private” sewer lateral varies
11. WERF 2004 SURVEY 58.4% of private laterals are at front of house, 31% at back
80% of utilities require cleanouts but only 29% are at the ROW / property line
75% of utilities record lateral locations but only 59% actively field locate
Only 38% of utilities have quantified lateral I/I separately
54% of utilities have allowed some type of drain connection in the past
21% still allow garage and basement drains to be connected
54% of utilities use some form of defect coding but less than 10% use PACP
12. WERF 2004 SURVEY Legal Issues
Entering private property - private property right issues:
Fourth amendment “right-to-privacy” considerations/administrative search warrants
The emergency exception
29% require signed permit from homeowner
11% have municipal code allowing entry
39% do not enter private property`
13. WERF 2004 SURVEY Liability Issues
Damages or injuries
25% will reimburse for damages
7% have disclaimer on right of entry permit
7% hire third party
77% reported no legal cases
Spending public funds on private properties
Enforcement measures for homeowners
14. WERF 2004 SURVEY Financing Issues:
41% of participating agencies may use public funds on private sewer laterals
15. WERF 2004 SURVEY Sources of Funds:
Public sector funding:
User fees – 34% (water supply, wastewater collection/ treatment)
Local funds – 13% (property taxes, special assessments on the property)
Federal and state funds – 10% (general obligation bonds)
16. WERF 2004 SURVEY Sources of Funds:
Financial assistance to homeowners:
As partial or full funding, or as a loan to the homeowners – provided by 32% of utilities
Various payment options possible
Partial payments – 4%
Hardship cases – 11%
Loans – 16%
Payment plans – 7%
Insurance – 2%
17. WERF 2004 SURVEY Who pays:
For maintenance:
66% require homeowner to arrange for maintenance and 59% require homeowner to pay for maintenance
For inspection:
55% require homeowner to arrange for and pay for inspection
For renewal:
57% require homeowner to arrange for and pay for lateral repairs or rehabilitation
18. WERF 2004 SURVEY Enforcement:
29% do nothing
11% place a lien against property
29% apply fines
14% discontinue water service
17% do combination of methods
Discontinuing water service is most effective approach followed by fines and liens
19. WERF 2004 SURVEY CASE STUDIES
Tacoma, Washington
Prince William County, Virginia
Sarasota, Florida
Lafayette, Louisiana
20. Tacoma, WA: July 2003
Relined 69 upper laterals using CIPP (Perma-Lateral™)
Cost $1,025/lateral (includes cleaning, pre & post CCTV)
Peak RDI/I reduction 18-39% (depends on size of storm)
Paid by the city
Access to private property with signed release agreement
21. Prince William Service Authority, Virginia Mar/Apr 2004
Relined 20 entire laterals (?85’) (LMK T-Liner®)
Cost $5,921/lateral (includes cleaning, pre & post CCTV)
Effectiveness not quantified yet (but visible)
Paid by the agency
Access agreement to enter the private property
22. Sarasota, Florida May 2001-May 2002
Replaced 297 upper laterals by
pipe bursting (Tric Trenchless™)
Cost $2,450/lateral (with COs)
Reduction in pumped volumes in LS’s on extreme wet days:
178,000 gal (33%) in LS-1
63,500 gal (73%) in LS-5
Paid by the agency
Access agreement to enter the private property
23. Lafayette, Louisiana April 2003
Sealed 26 entire laterals, plus 5 mainlines and 7 manholes
by flood grouting (Sanipor®)
Cost $580/lateral (approx)
Fluid exfiltration test to assess effectiveness: immediately and 21 months after
Paid by the agency
Access agreement to enter the private property
24. H&S Recent Experience Research Programs:
WERF Studies
Methods for Cost-Effective Rehabilitation of Private Lateral Sewers – 2006
Miami-Dade Water and Sewer District
Comprehensive Lateral Investigation Program
Field Experience:
National experience replacing or renewing over 50,000 laterals
25. MDWASD Lateral Programs Extensive I/I Removal Program Since 1994
Completed in 2002
Corrected over 32,000 defects
Removed about 130 MGD of ADF from WWTP
RDI/I Continued to be excessive
Determined to be from above the GWT – Laterals!
Initiated Lateral Program
Initial Lateral Pilot Program
Comprehensive Lateral Investigation Program CLIP – Funded in 2002 as part of Consent Decree In 1994 measured 325 MGD ADF to WWTP of which 40 to 50% was I/I. By 2002 removed about 130 MGD of ADF or almost 80% of ADF I/I.In 1994 measured 325 MGD ADF to WWTP of which 40 to 50% was I/I. By 2002 removed about 130 MGD of ADF or almost 80% of ADF I/I.
26. MDWASD CLIP Comprehensive Lateral Investigation Program (CLIP)
Investigated:
Lateral ownership and management practices
Lateral renewal financial arrangements
Legal and regulatory issues
Renewal methods and materials
Literature survey and questionnaire
Review of renewal methods and costs
27. MDWASD CLIP National Survey
Questionnaires sent to over 50 utilities
In depth interviews with 12 utilities
Interviews with contractors
Pilot Program
Selected 52 basins for Pilot Program
Main line sewers repaired in pilot basins
Public Outreach Program to gain access to private laterals
Proceeding with 5 Step Peak Flow Master Plan
MDWASD has 976 PS’s of which 500 contributed excess RDII of over 250 MGD. The 52 basins were selected for optimal size (15000 feet), terminal location, constant speed pumps and discharge to gravity system.MDWASD has 976 PS’s of which 500 contributed excess RDII of over 250 MGD. The 52 basins were selected for optimal size (15000 feet), terminal location, constant speed pumps and discharge to gravity system.
28. Lateral Management MDWASD CLIP Survey Results
Ownership
Majority owned from main to property line
Cleanout at property line
Several cases – customer owned entire lateral to main
New construction
All utilities responsible for tap on main
Most utilities responsible for lateral to property line
One utility responsible for entire lateral to building
29. Lateral Management MDWASD CLIP Survey Results
Renewal financing policy options (private side)
No action None
Voluntary participation by customer 7%
Customer funded 11%
Utility funded 11%
Shared Funding
Grants or low interest loans 44%
Lateral Insurance programs 20%
Fixed price contracts 7%
A total of 28 utilities provided information on financingA total of 28 utilities provided information on financing
30. Lateral Management MDWASD CLIP Survey Results
Legal issues
Enforceable ordinance 25%
Customer application for lateral renewal 50%
Customer indemnification of utility 25%
Certifies right of utility access
Report on lateral condition included in sale of 3% building
No clear action 10%
31. Lateral Management MDWASD CLIP Survey Results
Inspection Methods
CCTV inspection
As part of sewer main inspection
After lateral problem identified
Smoke testing
Dye testing (potty test)
Air testing
FELL – 41
Focused Electrode Leak Locator
32. Lateral Management MDWASD CLIP Survey Results
Renewal Methods
Open cut replacement
Cured in place lining
Full lining
Segmental lining
Full lining with ‘Tophat’
Full lining with ‘T-Liner’
Pipe Bursting
Grouting
33. MDWASD CLIP RESULTS Public Outreach Program
9,202 Letters sent
Responses – 6,543 (71%)
‘Yes’ Responses – 6,291 (96% of responders)
Lateral Inspection Program
Public Side – 4,341 passed
Private Side – 3,768 passed
Total of 1,376 repairs identified
To date, 1,222 repairs completed
MDWASD has 976 PS’s of which 500 contributed excess RDII of over 250 MGD. The 52 basins were selected for optimal size (15000 feet), terminal location, constant speed pumps and discharge to gravity system.MDWASD has 976 PS’s of which 500 contributed excess RDII of over 250 MGD. The 52 basins were selected for optimal size (15000 feet), terminal location, constant speed pumps and discharge to gravity system.
34. MDWASD CLIP RESULTS Costs
Mainline inspection/repair $4,171,214
Lateral inspection $4,241,327
Lateral repairs $4,518,235
Admin costs $ 493,118
Total Program Costs $13,423,894
Unit Costs
Mainline inspection/repair $8.68/L.F.
Lateral inspection $550/Lateral
Lateral repair $801/Lateral
MDWASD has 976 PS’s of which 500 contributed excess RDII of over 250 MGD. The 52 basins were selected for optimal size (15000 feet), terminal location, constant speed pumps and discharge to gravity system.MDWASD has 976 PS’s of which 500 contributed excess RDII of over 250 MGD. The 52 basins were selected for optimal size (15000 feet), terminal location, constant speed pumps and discharge to gravity system.
35. MDWASD CLIP RESULTS Cost Effective Analysis
Estimated cost to pump and treat
$6 per Gallon per day = $8,645/GPM
Mainline inspection/repair
0.024 GPM/LF = $362/GPM removed
23 times more cost-effective than pump and treat
Lateral inspection/repair
$2,308/GPM removed
About 3.7 times more cost effective than pump and treat
Total Program - $1,011/GPM removed
Flow reduction based on pre and post flow monitoring. For peak hourly flow.
Flow reduction based on pre and post flow monitoring. For peak hourly flow.
36. MDWASD CLIP RECOMMENDATIONS Public Outreach Program was successful
Public readily gave permission for entry
Lateral renewal program was cost effective
Proposed to expand program to all 500 critical basins with excessive RDII Flow reduction based on pre and post flow monitoring. For peak hourly flow.
Flow reduction based on pre and post flow monitoring. For peak hourly flow.
37. Baltimore County Cleanout Repair Program
Broken or missing cleanout caps identified as problem
“Standard Approach” would be:
Identify problem lateral (Smoke test)
Memo to plumbing inspection with copy to homeowner
Inspector visits site and citing homeowner
Return inspection
Log to database with hard copy to homeowner
Flow reduction based on pre and post flow monitoring. For peak hourly flow.
Flow reduction based on pre and post flow monitoring. For peak hourly flow.
38. Baltimore County Cleanout Repair Program
Problems with “Standard Approach” are:
Time consuming and labor intensive
Can ‘fall through the cracks’
Costly at about $74 in costs to utility for each homeowner with defective lateral
Results in poor customer relations
Improved Approach
Following smoke test, go directly to homeowners and request entry permission
Repair using County resources
Flow reduction based on pre and post flow monitoring. For peak hourly flow.
Flow reduction based on pre and post flow monitoring. For peak hourly flow.
39. Baltimore County Cleanout Repair Program Results
Reduced number and volume of SSO’s
Flooded basements reduced by 50%
According to insurance department
Previously cleaning 30 to 35 basements, now only 8 to 14 per event
Better customer relations
Fewer insurance claims
Only one homeowner refused entry
Relented when told of $300 cost of being cited for leaking cleanout
Flow reduction based on pre and post flow monitoring. For peak hourly flow.
Flow reduction based on pre and post flow monitoring. For peak hourly flow.
40. SEWER LATERAL RENEWAL PROGRAMSPrivate Property Inflow and Infiltration Henry R. (Kelly) Derr, Hazen and Sawyer
Richard Eubank, Baltimore County
For the:
Chesapeake Water Environment Association
Collection Systems Committee Luncheon Seminar
May 4, 2007