HomeMy WebLinkAboutA001 - Council Action Form dated November 12, 2024ITEM #:35
DATE:11-12-24
DEPT:W&PC
SUBJECT:WATER TREATMENT PLANT LIME POND UNDERDRAIN
IMPROVEMENTS
COUNCIL ACTION FORM
BACKGROUND:
The Water Treatment Plant is a lime softening plant. Lime residuals from the water softening process
are piped to large ponds, where it is stored and dewatered. The material is removed annually and
recycled by applying it to farm fields as an agricultural liming agent. The cost of the annual removal is
based on the weight of the lime removed, including any remaining water. For FY 2024/25, the cost for
lime removal is budgeted at $392,140.
In 1997, a project was undertaken at the three oldest ponds to improve the dewatering and thus reduce
the cost of disposal. Over time, the effectiveness of these improvements has been negatively impacted
due to the combination of repeated excavation of lime from the cells and sediment that is plugging the
drains. The drains are no longer operating as intended, resulting in increased operating costs to haul
away excess water.
In 2021, the original underdrains in one cell were reconstructed as a trial to see if the dewatering could
be improved. The trial was successful, and now the underdrains in the other two cells are proposed to
be replaced. This project will consist of installing two new underdrain systems down the mid-line
of Cells 1 and 3.
On September 24, 2024, City Council approved preliminary plans and specifications for the Water
Treatment Plant Lime Pond Underdrain Improvements. Bid documents were sent to twelve contractors.
The bid was also advertised on the Current Bid Opportunities section of the Purchasing webpage and a
Legal Notice was published on the websites of a contractor plan room service with statewide
circulation. On October 23, 2024, four bids were received as shown in the table below.
BIDDER BID AMOUNT
Con-Struct Inc.
Ames, IA $200,669
Keller Excavating
Boone, IA $214,000
WRH, Inc.
Amana, IA $316,500
JB Holland Construction Inc.
Decorah, IA $371,700
Staff has reviewed the bids and determined the apparent low bid from Con-Struct Inc, of Ames, IA, is
acceptable.
The total estimated construction project cost is $222,000. The work was designed in-house, so there are
no engineering fees. This project was included in the 2024/25 Lime Lagoon Improvements CIP Project
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in the amount of $283,000, which also includes $61,000 to replace the existing decant pump.
ALTERNATIVES:
1. Approve final plans and specifications and award a contract to Con-Struct Inc., of Ames, IA for
the Water Treatment Plant Lime Pond Underdrain Improvements in the amount of $200,669.
2. Reject the bids and delay the project.
CITY MANAGER'S RECOMMENDED ACTION:
The lime pond underdrains are critical to the lime sludge dewatering process. Replacing the damaged
underdrain and adding additional underdrains will improve the overall dewatering of the lime sludge.
These drainage improvements are anticipated to result in cost savings associated with annual removal
and hauling costs. Therefore, it is the recommendation of the City Manager that the City Council adopt
Alternative No. 1, as described above.
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