FY2022

Contact Tim Wilkey Department PUBLIC WORKS

V3151

Project #

Project Name Digester Complex Rehabilitation

Type One Phase

Useful Life 20 years

GRANTEE NONE

PLAN None

Category Wastewater Treatment

MATCH % NONE

TIF DISTRICT None

Priority Critical (1)

Description The future project has two parts: 1) Provide process/related structures and equipment removing phosphorous before digestion. 2) Replace multiple heat exchangers (HEX) with internal corrosion and Struvite deposition, renovate five (5) digester covers, install seven (7) wall thimbles (access ports) in digester wall for inspection and cleaning, replace internal/external(buried) piping clogging with Struvite, replace (HEX) and recirculation pumps as required. An engineering study in 2020 will evaluate current and developing technologies for application to the waste stream characteristics and make project recommendations. Justification With biological nutrient removal as part of last ICWWTP project, captured phosphorous (P) accumulates in digesters causing Struvite formation. Removing P before digestion reduces Struvite formation and reduces maintenance costs. Also, the digester complex was constructed in 1989/2002 and has 5 covers in various stages of wear, with one leaking struvite infused liquid between tank and brick facade causing facade to face imminent future collapse. The 11 (HEX) are 15+ year old and multiple valves/pipes show struvite deposition to be replaced. Total Project Cost: $7,990,500 Status Active

Expenditures

Total

2021

2022

2023

2024

2025

PLANNING/DESIGN CONSTRUCTION

120,000

90,000

210,000

7,060,000

7,060,000

INSPECTION

4,000

4,000

ADMINISTRATION CONTINGENCY

4,000

4,000

712,500

712,500

120,000

7,870,500

7,990,500

Total

Funding Sources REVENUE BONDS

Total

2021

2022

2023

2024

2025

7,990,500

7,990,500

7,990,500

7,990,500

Total

Budget Impact/Other This project will reduce operating and maintenance cost through the rehabilitation of older equipment. The annual savings is less than $10,000 per year.

This serves as a declaration of official intent under Treasury Regulation 1.150-2 that it is reasonably expected that capital expenditures will be made in respect of the above-described project, such expenditures to be advanced from the Wastewater fund, and the City reasonably expects to reimburse all or a portion of the expenditures with the proceeds of bonds, notes or other indebtedness to be issued or incurred by the City in the future.

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