HomeMy WebLinkAboutWater_Filtration_Plant_Clearwell_Replacement_ProjectMarch 2022 Clearwells Alternatives Estimated 20-Year Net Present Value (NPV) Cost Comparison
At-Grade Circular Prestressed Concrete Tanks At-Grade Rectangular Cast in Place Concrete Tanks Extend Existing Clearwells Service Life
Estimated Service Life, years 60 - 100 Estimated Service Life, years 60 - 100 Estimated Service Life, years 20 – 40*
Tanks Tanks Clearwells
Construction Cost $5,398,600 Construction Cost $9,548,300 Repairs Cost $2,600,000 - $3,800,000
Annual O&M Costs $11,000 Annual O&M Costs $31,200 Annual O&M Costs $63,500
20-Year NPV $5,588,600 20-Year NPV 10,088,300 20-Year NPV $3,678,800 - $4,878,800
High Lift Pump Station High Lift Pump Station High Lift Pump Station
Construction Cost $4,746,100 Construction Cost $4,746,100 Construction Cost $4,746,100
Annual O&M Costs $148,700 Annual O&M Costs $148,700 Annual O&M Costs $148,700
20-Year NPV $7,277,100 20-Year NPV $7,277,100 20-Year NPV $7,277,100
Intermediate Pump Station Intermediate Pump Station UV Treatment Barrier
Construction Cost $2,554,600 Construction Cost $2,554,600 Construction Cost $3,900,000
Annual O&M Costs $41,100 Annual O&M Costs $34,200 Annual O&M Costs $63,000
20-Year NPV $3,254,600 20-Year NPV $3,144,600 20-Year NPV $4,980,000
20-Year NPV Storage and
Pumping
$16,110,300 20-Year NPV Storage and
Pumping
$20,459,400 20-Year NPV Storage, Pumping,
UV
$15,885.900 - $17,085,900
*
Cost Estimates Notes:
1. Prestressed concrete tanks annual operations and maintenance (O&M) costs include exterior power washing, recoating, and tuck pointing facia brick /
stone at year 20 with tank interior inspections every 5 years.
2. Cast in place concrete tanks annual O&M cost include interior crack repairs, exterior power washing, recoating, and tuck pointing facia brick/stone at
year 20 with interior tank inspections every 5 years.
3. Annual O&M costs associated with the clearwells’ extended service include concrete crack repair every 10 years; exterior power washing, recoating, and
tuck pointing facia brick/stone at year 20 with interior tank inspections every 2 years.
4. A range of estimated costs for extending the clearwells service life are present because of the following u ncertainties:
a. Current physical condition of clearwells
b. Type repairs that are feasible to implement
c. Type and extent of repairs WDNR will approve
d. Criteria WDNR will use to determine when tanks can be repaired versus must be replaced
5. High Lift Pump Station annual O&M costs include operations and maintenance labor, materials, and electricity.
6. Intermediate Pump Station annual O&M costs include operations and maintenance labor, materials, and electricity.
7. UV Treatment Barrier annual O&M costs include operations and maintenance labor, materials, electricity for UV reactors, and supplemental electricity for
High Lift Pumping to compensate for UV system headloss.