Appendix S Pump Station Evaluation

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Appendix S

Pump Station Evaluation

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Technical Memorandum

Date:

October 12, 2001

To: Orange

County

Utilities

Re:

Task 6.4 Raw Wastewater Pump Stations

1.0 Summary

In accordance with Task 6.4 of the Orange County Master Plan Update, PBS&J/CH2M Joint Venture (JV) staff supplemented Orange County Utility’s (OCU’s) TAG pump station inventory with information on privately operated pump stations. Per OCU’s request, staff interviews and pump station visits were not completed by the Joint Venture. OCU staff indicated that pump station conditions and rehabilitation needs are well known by OCU staff. The scope of this task, therefore, consisted of updating OCU’s existing pump station inventory with data for approximately 400 private pump stations not included within the existing inventory and developing estimates to be included within OCU’s Capital

Improvements Plan (CIP) for pump station rehabilitation and new construction. Private pump station data were acquired by mailing private pump station owners a questionnaire regarding the pump station equipment and maintenance company

information. Data regarding pump type, motor size, pump curve data, and other available information were then added to OCU’s existing pump station inventory.

Criteria for replacement and major improvements of the pump stations maintained by OCU were determined by OCU staff based on historical rehabilitation/replacement needs. Based on the historical needs, rehabilitation and replacement costs for OCU’s existing pump stations were projected over a 20 year period. In addition to the upkeep of current pump stations, new pump station construction, rehabilitation, and replacement costs were also included in the 20 year planning period.

2.0 Pump Station Inventory

OCU developed a pump station inventory as part of the Eastern Transmission System analysis. The TAG inventory identified a total of approximately 700 active or inactive pump stations owned by OCU. The TAG inventory indicates that OCU owns 557 duplex, 33 triplex, and 5 quadraplex pump stations, along with 17 pump stations with unknown pump

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APPENDIX S: PUMP STATION EVALUATION

counts and 80 inactive pump stations. Per Orange County’s Wastewater Division, the County actually operates and maintains:

• 505 duplex; • 33 triplex; and • 5 quadraplex

active pump stations. OCU has not identified the specific pump stations within the TAG inventory that should be removed.

As part of this project, data for approximately 400 private pump stations were gathered by sending an information sheet to the pump station owners. The data compiled were then added to the TAG inventory to supplement the OCU pump stations already included. In addition to those pump stations owned by OCU, approximately:

• 4 simplex; • 371 duplex; and • 1 triplex

active, and 21 inactive, pump stations are privately owned and operated within Orange County.

For each of these 1089 pump stations included within the updated TAG inventory, data regarding pump capacities, run times, pump curves, and major equipment are included, based on availability. The inventory in its entirety is attached as a separate file to the e-mail transmitting this TM.

3.0 Rehabilitation, Replacement, and Construction Costs

As previously stated, OCU staff familiar with historical lift station rehabilitation, replacement, and construction needs identified typical criteria to be used by the JV for planning and cost estimating purposes. The following assumptions for developing a rehabilitation and replacement program were identified:

• An average of 15 new duplex pump stations are constructed each year

• An average of 1 new master (triplex) pump station is constructed every other year • Comprehensive pump station rehabilitation is required every 20 years

• Intermediate pump replacements are required every 10 years (and are included as part of the comprehensive pump station rehabilitations)

OCU’s master pump stations are large, high capacity pump stations with flows of at least 1000 gallons per minute. In general, master pump stations typically are triplex or

quadraplex pump stations. As a result of their larger size, fewer master pump stations are constructed each year.

Pump replacement generally consists of replacing the pump, elbow, check valve, and control panel replacement. A comprehensive pump station rehabilitation consists of repairing all mechanical, structural, instrumentation, electrical, generators, HVAC, and noise and odor control components. A detailed listing of the items that may be addressed during each type of rehabilitation is provided in Table 1.

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3.1 New Pump Station Construction

OCU does not typically pay for the construction of duplex pump stations. Approximately 15 new duplex pump stations are constructed each year by developers, and ownership is then conveyed to OCU. As a result, routine operation, maintenance, and rehabilitation become OCU’s responsibility. Construction costs provide an indication of average rehabilitation costs, though, so historical cost estimates for the construction of duplex pump stations were evaluated. Approximately one triplex pump station is constructed by the County every other year.

Historical construction cost data was reviewed as part of the cost factor development

completed in accordance with Task 11 of the Master Plan Update. As part of that task, it was determined that the average pump station construction cost is approximately equal to:

PS construction cost = 3959.5 * (capacity of pump station in gpm)0.6322 Based on the TAG inventory, the average pump sizes for the existing 541 duplex pump stations and 33 triplex pump stations are 361 gpm and 1941 gpm, respectively. The average duplex pump station construction cost is, therefore, approximately $255,000, and the average triplex pump station construction cost is approximately $950,000.

3.2 Existing Pump Station Rehabilitation

Rehabilitation of existing pump stations consists of replacing pumps every 10 years and completing a comprehensive pump station rehabilitation (which includes pump

replacement) every 20 years.

Duplex pump station pump replacement costs were determined by reviewing pump data within the TAG inventory. Several size categories were developed, and for each category, the average pump horsepower, flow, and head conditions were determined based on OCU’s current pump inventory. Cost quotations were then obtained from vendors for pumps within each size category, and an overall weighted average cost was calculated and utilized to determine average pump replacement costs. Table 2 summarizes the data utilized in the development of the duplex pump station pump replacement costs.

Master pump station pump replacement cost estimates were obtained from the Orange County 14 Pump Stations – Summary of Findings report prepared by CDM. The report summarized pump replacement costs associated with major pump station rehabilitation. The pump replacement costs from the report were isolated and utilized to determine the average pump replacement costs for the intermediate master pump station pump replacements (Table 3).

Comprehensive pump station rehabilitation cost data were also gathered in order to

estimate annual rehabilitation costs over the 20 year planning period. Per OCU staff, duplex pump station rehabilitation costs are approximately 80% to 90% of construction costs. An average of $220,000 (which is approximately 85% of the estimated $255,000 construction cost) was, therefore, utilized as the average duplex pump station comprehensive

rehabilitation cost. Estimated master pump station rehabilitation costs were based on data provided in the Orange County 14 Pump Stations – Summary of Findings report prepared by CDM. The rehabilitation costs presented within the report provide estimates for

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presented within the report were based on completing the comprehensive rehabilitation improvements identified in Table 1, as necessary.

The costs presented within the referenced report are summarized in Table 4. As indicated within the table, the number of pumps varies between 2 and 4. Average pump station rehabilitation costs were calculated based on the number of pumps within the pump station. These costs are presented in Table 5. The data indicate that the total pump station

rehabilitation costs average approximately $540,000 for a triplex pump station and $760,000 for a quadraplex pump station. These rehabilitation costs were, therefore, utilized to

develop the 20 year planning rehabilitation cost estimates.

3.3 CIP

Costs

A matrix (Table 6) was developed to illustrate the pump station needs and develop the planning cost estimates. The rehabilitation and construction criteria discussed at the beginning of this section were used to develop the data included within the matrix. The annual costs for the programmed rehabilitation, replacement, and construction projections developed from the matrix are summarized in Table 7. The cost basis includes the

rehabilitation, replacement, and construction costs discussed previously.

The costs presented in Table 7 are all in year 2000 dollars, as no cost escalation factor was assumed. The cost matrix does allow inflation and interest rates to be entered, however, so the inflated costs can be easily calculated in the future with the rates determined later in the master planning process. Total expenditures for the 20 year planning period are projected to be approximately $134 million, in year 2000 dollars.

4.0 Conclusions

According to the County staff, 543 pump stations are currently maintained by OCU. Private pump station data gathered as part of this study indicates that 397 pump stations are

privately owned and maintained within Orange County. Of the 397 privately owned pump stations, 21 of these are currently not active.

Based on historical data, rehabilitation and replacement costs for the pump stations

maintained by OCU are estimated to total approximately $159 million dollars over the next 20 years. This equates to an average expenditure of $8 million per year in year 2000 dollars. The cost estimate includes the costs for comprehensive rehabilitation of each pump station once every 20 years and pump replacement 10 years before/after the comprehensive

rehabilitation. In addition, construction of new duplex and triplex pump stations is included at a rate determined by OCU based on historical construction requirements. Based on the construction criteria provided, it is estimated that OCU will operate approximately 805 duplex, 43 triplex, and 5 quadraplex pump stations 20 years from now.

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TABLE 1

Pump Station Rehabilitation Components Description

Intermediate (Every 10 Years)

Comprehensive (Every 20 Years) Civil and Mechanical Improvements

Sump pump replacement √ √

Installation of energy dissipaters at wet wells √

Slide gate installation √

Line stop installation √

Installation of in-line valves at bypass piping √

Removal of existing pumps, shafts, and motors √ √

Installation of new pumps and accessories √ √

Discharge line replacement √ √

Check valve replacement √ √

Gate valve replacement √

Plug valve replacement √ √

Installation of concrete vaults and lids √

Rehabilitation of gravity lines √

Manhole rehabilitation √

Installation of electric cranes in drywells √

Grit chamber removal √

Removal of chlorine yard piping √

Comminutor removal √

Gate removal √

Structural Improvements

Repair of interior wet well walls and pump pedestals √ √

Blast cleaning of influent channels, wet wells, screenings rooms, √

Replacement of brittle or weakened rebar √

Restoration of concrete to original design thickness √

Application of new coating on all interior surfaces √

Dampproofing inside walls of drywells √

Replacement of wetwell doors √

Repainting of existing materials for protection √ √

Stair handrail replacement √

New roof √

Asbestos testing and removal/disposal not included √

Electrical and Instrumentation System Improvements

New odor control system wire and conduit √

New lighting √

New generator, generator transfer switch, and generator control √ New above-ground double-wall fuel tank or generator enclosure √

Generator controls √

New conduit and wire √

Control panel replacement √ √

New high-efficiency squirrel cage induction type pump motors √ VFDs for pumps with solid-state soft start bypass starters √ Replacement of motor control center (including conduit, wire, √

New service entrance rated main breakers √

Flow meter replacement √

Install hydrostatic level transducers or ultrasonic level sensors √

Replace existing alarm dialers √

Install SCADA termination cabinets √

HVAC, Noise, and Odor Control Improvements

Replacement of HVAC drywell ventilation systems √

Construction of drywell separation walls to improve HVAC √

Completion of VFD related air conditioning work √ √

Installation of noise proof generator enclosures √

Installation of biofilter odor control systems √

Replacement of biofilter media √ √

Plumbing, Emergency Generator Fuel Tanks, and Fuel Piping Improvements

Installation of backflow prevention devices on water connections √

Replacement of water closet and lavatory fixtures √

Replacement of sanitary piping √

New above ground fuel tanks √

New above ground contained piping meeting current state √

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TABLE 2

Average Duplex Pump Replacement Cost

Pump Size # of PS Average Average Flow TDH Cost1 Cost * # of PS

(hp) Horsepower (gpm) (ft) ($) ($) 0 - 5.0 186 5 195 38 3,500 651,000 5.1 - 10.0 155 9 234 63 4,700 728,500 10.2 - 20.0 122 19 492 75 8,100 988,200 20.1 - 40.2 51 29 632 102 15,500 790,500 40.3 - 60.0 21 49 899 104 15,500 325,500 60.1 - 90.0 5 82 1586 99 27,500 137,500 > 90.0 1 148 3500 98 54,100 54,100 Total 5412 3,675,300

Overall Weighted Average 14.2 361 $6,794

1_{Costs are based on vendor quotes}

2 _{Total does not match TAG inventory duplex pump station total because pump sizes were not listed for every pump station}

Add contingency of $3,000 to cover control panel and miscellaneous appurtanance costs

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TABLE 3

OCU Master Pump Station Pump Replacement Costs

Costs taken from the Orange County 14 Pump Stations - Summary of Findings report (CDM, May 2000)

Lift Station Number of Pumps Total Rehabilitation

Cost

Pump Cost Only Cost per Pump

3006 3 $555,600 $48,834 3038 3 $850,500 $107,334 3151 3 $490,200 -3177 3 $756,600 $78,834 3178 3 $850,000 $63,834 3190 3 $739,000 $63,834 3319 4 $1,004,300 -3321 3 $324,800 -3368 3 $255,500 -3377 2 $450,900 -3411 3 $346,100 -3419 3 $296,500 -3498 4 $516,500 -3499 3 $490,400 $63,834 Maximum $1,004,300 $107,334 $35,778 Minimum $255,500 $48,834 $16,278 Average $566,207 $71,084 $23,695

Therefore utilize: $25,000 average master pump station pump replacement cost (per pump) (Pump costs include 8 hours labor per pump and miscellaneous equipment cost of $250 per pump)

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TABLE 4

OCU Master Pump Station Rehabilitation Costs

Taken from Orange County 14 Pump Stations - Summary of Findings (CDM, May 2000)

Lift Station # of Pumps Civil/Mechanical Structural Instrumentation Electrical

HVAC, Noise, & Odor Control

Plumbing and

Generators Total Rehab Cost

3006 3 $288,700 $9,600 $25,000 $200,300 $32,000 $0 $555,600 3038 3 $417,700 $95,500 $27,500 $267,700 $37,000 $5,000 $850,400 3151 3 $121,800 $57,900 $36,900 $256,600 $15,000 $2,000 $490,200 3177 3 $393,200 $134,700 $31,900 $158,700 $37,000 $1,000 $756,500 3178 3 $329,200 $171,600 $36,100 $275,200 $37,000 $1,000 $850,100 3190 3 $311,900 $148,100 $27,000 $214,100 $37,000 $1,000 $739,100 3319 4 $236,500 $503,800 $45,800 $201,700 $14,500 $2,000 $1,004,300 3321 3 $105,200 $40,000 $21,900 $120,800 $15,000 $22,000 $324,900 3368 3 $114,400 $85,300 $25,900 $11,900 $15,000 $3,000 $255,500 3377 2 $75,300 $35,800 $46,900 $293,000 $0 $0 $451,000 3411 3 $68,900 $96,100 $31,900 $132,300 $15,000 $2,000 $346,200 3419 3 $74,000 $63,100 $27,000 $95,400 $15,000 $22,000 $296,500 3498 4 $234,900 $103,200 $44,900 $133,600 $0 $0 $516,600 3499 3 $224,600 $103,200 $36,900 $105,800 $20,000 $0 $490,500 Total $2,996,300 $1,647,900 $465,600 $2,467,100 $289,500 $61,000 $7,927,400

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TABLE 5

OCU Master Pump Station Rehabilitation Costs

Costs taken from the Orange County 14 Pump Stations - Summary of Findings report (CDM, May 2000)

Lift Station # of Pumps

Duplex PS Triplex PS Quadplex PS

3006 3 - $555,600 -3038 3 - $850,500 -3151 3 - $490,200 -3177 3 - $756,600 -3178 3 - $850,000 -3190 3 - $739,000 -3319 4 - - $1,004,300 3321 3 - $324,800 -3368 3 - $255,500 -3377 2 $450,900 - -3411 3 - $346,100 -3419 3 - $296,500 -3498 4 - - $516,500 3499 3 - $490,400 -Maximum $450,900 $850,500 $1,004,300 Minimum $450,900 $255,500 $516,500 Average $450,9001 $541,382 $760,400

1_{Duplex rehab cost not representative of a typical duplex pump station}

Therefore utilize: $540,000 triplex pump station rehabilitation cost $760,000 quadplex pump station rehabilitation cost

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