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TO: Mayor Richard C. Irvin
FROM: Alex Alexandrou, Chief Management Officer
Ken Schroth, Director of Public Works/City Engineer
Robert Leible, Superintendent of Water Production
DATE: November 30, 2023
SUBJECT:
Amendment of the City's existing lease agreement with Holcim-Mamr, Inc. (Holcim), formerly known as LaFarge Aggregates Illinois, Inc. to extend certain lease internal deadlines as well as acknowledge price increases from the previous lease.
PURPOSE:
To afford the City additional time to secure regulatory approvals required for it to undertake a more cost-effective means of storing lime residual material produced in the City's water treatment process.
BACKGROUND:
All residents of the City of Aurora are provided with potable water from the city-owned and operated Water Treatment Plant (WTP). A key, primary treatment process utilized at the WTP is lime softening. This process removes and collects the solid particles that are present in the raw water sources (the Fox River and groundwater), as well as chemically softening the water to remove dissolved minerals and metals, which provides customers more aesthetically pleasing drinking water. As the solid particles and precipitates are removed by the clarification process, these treatment by-products are concentrated and removed for ultimate disposal.
Since the WTP's construction in 1992, the lime residual material has been disposed by landfilling at great annual expense to the City. In 2012, through an Illinois Environmental Protection Agency (IEPA) permit, the Water Production Division (WPD) began a program to dispose of the lime residual material via land application on agricultural fields. Land application allows a beneficial reuse of the waste product and reduces the cost of ultimate disposal by approximately 25%. As this process is still expensive, starting in 2006, a more efficient method of ultimate disposal was investigated regarding placing the lime residual in repurposed portions of ...
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