1. Southwest Section AWWA 2018 – Baton Rouge, LA
How to Make the Most of Your CIP: Using a Risk Based Approach for Prioritizing Water Treatment Plant Renewal
Chad M. Simmons, P.E., BCEE – Freese and Nichols
Brett Buff, P.E. – North Texas Municipal Water District
Southwest Section AWWA 2018 – Baton Rouge, LA

2. location
Wylie WTP 2

3. NTMWD Service area
NTMWD serves >1.6M people across 90 communities with 6 WTPs
Wylie WTP single site with 4 WTPs
Plant 1 constructed in 1950’s and Plant 4 in early 2000’s 3

4. Wylie water treatment system
Raw Water 3
Plant 3
Current capacity = MGD
Future capacity = 840 MGD
Plant 4
Plant ’s (70 MGD); rapid mix, clariflocculators, filters, chem feed, ozone
Plant 2 – 1980’s (280 MGD), 8 trains, rapid mix, flocculation/sed basins, filters
Plant 3 – 1990’s, (280 MGD), 8 trains, rapid mix, flocculation/sed basins, filters
Plant 4 – early 2000’s, (140 MGD), 4 trains, rapid mix, flocculation/sed basins, filters
Chem Feed: ammonia, caustic, chlorine, chlorine dioxide, ferric sulfate, fluoride, lime, ozone, polymer
Plant 2
Plant 1 4

5. Use a Risk Based Approach to: Determine what to fix and when
Purpose
Use a Risk Based Approach to:
Determine what to fix and when
Develop a prioritized list of capital projects
Integrate improvements in the existing CIP
Preserve required capacity

6. Refine Asset Management approach
drivers
Aging infrastructure
Refine Asset Management approach
Desire to incorporate system renewal into CIP
Business approach using Risk Management in infrastructure renewal

7. Methodology
Asset inventory
Develop scoring system
Perform site visits at Plants I, II, III, IV
Apply condition and criticality score
Prioritize improvements
Prepare cost estimates
Combine improvements into prioritized projects
Incorporate into CIP

8. Facilities evaluated
Plants I-IV, Raw Water Pump Stations and piping from Lake Lavon to High Service Pump Stations
Raw Water Pump Station and Conveyance Piping
Rapid Mix, Flocculation, Sedimentation, Filters
Disinfection Facilities, Clear Wells
High Service Pump Stations
Yard Piping (>24” and select smaller process lines)
Chemical Feed and Storage
Backwash Reclamation
Sludge Handling
Electrical and Instrumentation
Flow Meters

9. Risk = ƒ (Condition x Criticality)
Risk based assessment
Risk = ƒ (Condition x Criticality)
What is the Likelihood of Asset Failure?
What is the Consequence of Asset Failure?
Asset age
Asset material
Performance of asset
Maintenance history
Water quality/System impact
Capacity affected
Redundancy
Outage duration

10. Condition Scoring (Vertical Assets)
DESCRIPTION
New, perfect condition 25
Good condition, no improvements recommended to maintain function 50
Fair condition, improvements recommended to improve performance or efficiency 75
Poor condition, improvements recommended to maintain reliability
100
Imminent failure, rehabilitation or replacement required
New Bulk
Storage Tanks 25
Paint
Stripping 50
Small Cracks,
Spalling 75
Aging
Infrastructure
100
Inoperable, No Replacement Parts

11. Criticality Scoring (Vertical Assets)
Capacity Affected (20%)
Redundancy (20%)
≤ 35 MGD Lost (<5%) = 10
Full Backup = 20
MGD Lost (7-9%) = 30
Partial Backup = 50
MGD Lost (9-18%)= 50
MGD Lost (18-36%) = 70
≥ 280 MGD Lost (>36%)= 100
Shared, Not Redundant = 80
Dependent = 100
Water Quality/System Impact (40%)
Outage Duration (20%)
Mild Impact = 20
≤ 2 Days = 10
Operational Hindrance = 50
Days = 40
Major Impact = 80
Days = 70
Mandatory = 100
≥ 30 Days = 100
Redundancy recognizes role of parallel and spare units or equipment
Water quality recognizes imperatives vs benefits. Fluoride not necessary to treatment or water quality whereas filters are the most important barrier in the treatment process and are mandatory

12. condition Scoring (yard piping)
CONDITION PARAMETERS & WEIGHTING SYSTEM
Age (50%)
Pipe Repairs (25%)
Based on # Repairs in Last 10 Years
< 1959 = 100
1960 – 1969 = 90
> 6 Repairs = 100
1970 – 1979 = 70
4 – 5 Repairs = 60
= 50
2 – 3 Repairs = 30
= 30
No Repairs = 0
= 10
2010 – 2015 = 0
Valve Repairs (25%)

13. criticality Scoring (yard piping)
CRITICALITY PARAMETERS & WEIGHTING SYSTEM
Capacity Affected (70%)
Outage Duration (30%)
Based on Percent of Total Capacity (770 MGD) Lost
Based on Discussions with Field Crew and Response Time
<35 MGD = 10
< 2 Days = 10
36-69 MGD Capacity Lost = 30
3 – 15 Days = 40
MGD Capacity Lost = 50
Capacity Lost = 70
>280 MGD Capacity Lost = 100
Days = 70
≥ 30 Days = 100

14. Scoring Sheet

15. Low Risk Medium Risk High Risk
Facility risk matrix
(0-25)
(26-50)
(51-75)
(76-85)
(86-100)
(0-30)
Low Risk
(31-50)
Medium Risk
(51-70)
High Risk
(71-100)

16. Plant 1 – Facility risk matrix

17. Plant 2 – Facility risk matrix

18. YARD PIPING

19. Cip development CIP Scheduling Considerations Existing CIP projects
Combined Facilities into Prioritized Projects
Prioritized Facilities Based on Risk Scores
Developed OPCCs by Facility
Integrated Projects into CIP Schedule
CIP Scheduling Considerations
Existing CIP projects
Constructability
Water production capacity
Projected water demands
Capacity required to be off-line during construction
100 MGD of excess capacity from October through June
35 MGD of excess capacity from July through September

20. Combined Facilities into Prioritized Projects
Cip development
Combined Facilities into Prioritized Projects
Developed 34 CIP Projects to be implemented through 2028 totaling $229M

21. Project implementation schedule
Plant 1
Plant 2
Plant 3
Plant 4
Plant Other
Rolled up capacity and costs

22. Project implementation schedule

23. 2018 Wylie WTP Complex Filter System Replacements (NTMWD 441)
Chlorine Improvements
HSPS 3-1
(NTMWD 480)
70 MGD Plant Expansion
(NTMWD 387)
HSPS 2-1 Electrical Imp.
(NTD 414/603)
Plant 1 Rapid Mix and Sedimentation Improvements
(NTD 375)
Plant Wide Electrical Repairs
(NTMWD 368/FNI 11 & 13)
Filter Underdrain Imp. & BAF Conversion
(NTD 434)

24. 2019 Wylie WTP Complex Chlorine Improvements Expand HSPS 3-1
(NTMWD 604)
CW 3-1
(NTMWD 397)
Filter Underdrain Imp. & BAF Conversion
(NTD 434)
70 MGD Plant Expansion
(NTMWD 387)
HSPS 2-1 Electrical Imp.
(NTD 603)
Rockwall CW & HSPS Rehabilitation
(NTMWD 608/FNI 15)
Plant 2 Water
(FNI 4)
Plant 1 Rapid Mix and Sedimentation Improvements
(NTD 375)
Plant 2 Filter Repairs; Backwash and Clearwells
(NTD 610 & 618/FNI 2)

25. Used Risked Based Approach to prioritize renewal of assets
summary
Used Risked Based Approach to prioritize renewal of assets
Inventoried assets and conducted site visits
Applied condition and criticality score
Prioritized improvements
Developed cost estimates
Combined improvements into prioritized projects
Incorporated projects within NTMWD’s existing CIP
Continually revaluate implementation schedule insuring sufficient capacity

26. Questions?