1. Change Order Request Contract S02013C01 SSWRF RAS System Improvements Restore ED’s Original Delegated Authority Approve Changes in TPC Commission Agenda Item #6

2. Change Order Request Contract S02013D01 Engineering Services - SSWRF RAS System Improvements Restore ED’s Original Delegated Authority Commission Agenda Item #7

3. Biological Treatment Process
Key part of water reclamation process
Process creates sludge returned from secondary clarifiers back to aeration basins
Return Activated Sludge (RAS)
Returned through use of RAS pumping and piping system

4. RAS pumps in Aeration Buildings
Secondary clarifiers
Aeration Basins
RAS pumps in Aeration Buildings

5. RAS
Pump

6. RAS Piping System Sets of pipes and valves that convey RAS:
From secondary clarifiers to RAS pumps (suction pipes)
From pumps, to 28 aeration basins via discharge piping/valves (header and branch piping)
Aeration system divided into 4 batteries
To perform work on RAS piping, take out at least one battery
Valves used to isolate batteries

7. Battery 1 Battery 2 Battery 3 Battery 4 X X X X X X X X X X X X X X X

8. Branch piping to aeration basin
RAS Piping System
Branch piping to aeration basin
Discharge header

9. RAS Piping System RAS Pump Discharge Header Suction Header

10. RAS Piping System >30 years old
History of leaking, resulting in service interruptions, capacity reductions
District developed project S02013
Aeration Galleries RAS Header Piping Rehabilitation
In 2016, contracted with Arcadis (S02013D01) to perform engineering work

11. RAS Piping System
Arcadis design to replace pipeline segments already identified as needing replaced based on leak history and limited external inspection
Full internal inspection requires significant construction work to expose inside of pipe
¼ to ½ plant capacity reduction
Certain valves also to be replaced
Old, not fully functional

12. Arcadis Design Replacements under Contract S02013D01
Battery 1
Battery 2
Battery 3
Battery 4
Arcadis Design Replacements under Contract S02013D01 X X X X X X X X X X X X X X X X

13. Contract S02013C01
Arcadis developed bid/contract document (Contract S02013C01)
Bid document publicly bid, awarded this construction contract to Ahern in 2017
In addition to pipeline replacement, work included 2 new RAS pumps and other associated work
Pipeline replacement work requires either ¼ or ½ plant capacity reduction

14. Construct pipeline replacements Under Ahern Contract S02013C01
Battery 1
Battery 2
Battery 3
Battery 4
Construct pipeline replacements Under Ahern Contract S02013C01 X X X X X X X X X X X X X X X X

15. Construction/Inspection Results To Date
Replaced pipe segments and completed internal pipe inspections on batteries 1, 3, and 4
Discovered cement liner inside headers eroded away - resulted in internal pipeline corrosion
Reassembled those segments not originally scheduled for replacement
Pipe joints from original construction are unique type, difficult to reassemble, prone to leaking after reassembly

16. Replacements Complete on Batteries 1,3 and 4
Battery 1
Battery 2
Battery 3
Battery 4
Replacements Complete on Batteries 1,3 and 4 X X X X X X X X X X X X X X X X
Work Remaining Under Ahern Contract S02013C01

19. Battery 2 Work Remaining
Pipeline segment replacement and internal inspection on battery 2 has yet to start
Based on inspection of pipe segments in batteries 1,3, and 4, anticipate additional pipeline segments in battery 2 will also have liner erosion and pipeline corrosion (anticipate same pattern)
Pipe joints are same: prone to leakage after reassembly

20. Replacements Complete on Batteries 1,3 and 4
Battery 1
Battery 2
Battery 3
Battery 4
Replacements Complete on Batteries 1,3 and 4 X X X X X X X X X X X X X X X X
Work Remaining Under Ahern Contract S02013C01

21. Battery 2 Recommended Additional Work
Originally contracted work will require a ¼ plant shutdown
Significant capacity impacts for ~month
To avoid another ¼ plant shutdown in future:
recommend performing replacement of additional deteriorated pipeline segments at same time we have ¼ plant shutdown for original contracted work

22. Actions and Requests: Arcadis Contract Commission Item 7
Staff authorized engineering services for replacement of additional pipeline segments and valves in battery 2 using ED authority for change orders
Actual construction work under Ahern contract
Request $153,166 for engineering services for replacement of additional pipeline segments in batteries 1,3, and 4
Actual construction to be publicly bid

23. Arcadis Design Authorized under ED Authority
Battery 1
Battery 2
Battery 3
Battery 4
Arcadis Design Authorized under ED Authority
Additional Deteriorated Pipeline Segments X X X X X X X X X X X X X X X X

24. Arcadis Design Under Commission Request
Battery 1
Battery 2
Battery 3
Battery 4
Arcadis Design Under Commission Request
Additional Deteriorated Pipeline Segments X X X X X X X X X X X X X X X X

25. Actions and Requests: Ahern Contract Commission Item 6
Design by Arcadis under ED authority
Request $800,000 to perform following replacement on battery 2
RAS discharge and suction piping
2 RAS discharge header piping butterfly valves replaced with knife gate valves
4 RAS pump suction and discharge knife gate valves
Authorization of this work will avoid future plant capacity reduction

26. J. F. Ahern Work Under Requested Change Order
Battery 1
Battery 2
Battery 3
Battery 4
J. F. Ahern Work Under Requested Change Order
Replace additional deteriorated pipeline segments X X X X X X X X X X X X X X X X

27. Proposed Replacement Under Future Bid and Construction Contract
Battery 1
Battery 2
Battery 3
Battery 4
Proposed Replacement Under Future Bid and Construction Contract
Additional Deteriorated Pipeline Segments X X X X X X X X X X X X X X X X

28. Restore ED Authority: Ahern Contract S02013C01
ED Authority is $182,500
$70,362 of authority utilized, leaving balance of $112,138
Request to restore ED authority in case additional contract change orders are needed during beyond remaining authority

29. Restore ED Authority: Arcadis Contract S02013D01
ED Authority is $50,000
$48,863 authority utilized, leaving balance of $1,137
Request to restore ED authority in case additional contract change orders are needed during beyond remaining authority

30. Request to Increase Total Project Cost
Increase TPC by ~$1M due to change orders already incurred plus requested additional work

31. QUESTIONS?
No need in this case to re-state the request.