The $2.2 million bond the city of Highland used to pay for recent updates to its wastewater system will be paid off this year. However, engineers say that investment needs to be quintupled in order to fix other outstanding issues with the sanitary mains and update the treatment plant to accommodate the city’s future growth.
The engineering firm Crawford, Murphy & Tilly (CMT), which has been consulting the city on its sanitary sewer system for the last five years, recently completed a study of the entire system and estimates an extra $11 million in capital is what it will take for complete rehabilitation.
“Everybody wants clean water,” said Highland City Manager Mark Latham. “This report discusses near-term and long-range improvements to meet the wastewater needs of the community during the next 20 years and beyond.”
Between 2014 and 2015, CMT worked with the city to rehabilitate the smaller, vitrified clay pipe (VCP) sewers that were considered to be in “poor to fair” condition. These sewers — some of which are a century old — are what bring wastewater from residences and businesses to larger trunk sewers.
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Since the completion of the project, CMT representative Scott Knight said the city has seen an improvement in the system, and VCP sanitary sewers will continue to be updated, based on priority.
However, according to Knight, inspections done in 2016 showed that 50 percent of the city’s trunk sewers also needed to be rehabilitated. The plan for the trunk lines call for the same method used on the smaller sewers — cured-in-place pipe lining (CIPP).
CIPP process curing a new plastic pipe inside existing mains, creating a pipe within a pipe. Using the CIPP method means excavation of the old mains can be avoided, thus cutting costs significantly. Knight said that this process increases pipe life by 50 or more years.
CMT also found that 46 out of the 56 city manholes need to be restored. Many of these manholes are made of brick, and according to Knight, some of the brick is decaying. The old structures let in excess water, which could further damage the sewers, cause back-ups and possibly create sinkholes.
To remedy this problem, CMT is proposing to fix the manholes by replacing the hole lid/cover and using a chemical seal to uphold the manhole structure.
The second part involves the water reclamation plant. The current plant was built about 40 years ago. Latham said water reclamation plants need to be updated every 20 to 25 years, so an update is long overdue.
The restoration would address almost every structure located in the plant, according to Knight. Aging equipment would need to be replaced, too.
City officials are also working to acquire an additional four and a half acres of land next to the plant, which is located off of Iberg Road.
“This will also bring ability to expand,” Latham said. “As Highland grows, there will be more wastewater.”
This year, the bond used to pay for previous wastewater improvements will be retired, Latham said. If approved for the program, the city will take out a loan through the Illinois State Revolving Fund (SRF). The loan is expected to be paid off at a 1.85 percent interest rate over the next 20 years. If the city adjusts the payments of the loan for inflation cost it will not increase rates, making the project affordable.
“We’re doing an investment to the system,” Latham said. “The good news is it does not require a rate increase to complete it.”
The City Council is expected to vote on a final plan sometime this spring. If the city is approved for the SRF loan, construction is estimated to begin in 2018 and is anticipated to take about 18 months. City officials are hopeful that the project will be finished by 2020.