Utility officials have approved a proposal to replace two centrifuges at the Columbus City Utilities (CCU) wastewater treatment plant.
The project will allow the utility to keep up with city growth and stay flexible with biosolids operations, according to utilities officials.
The board consented to a guaranteed maximum proposal with Bowen Engineering for $2,015,746 to replace and upsize two biosolids centrifuges at the plant, located at 3465 S. Jonesville Road.
The utilities board during their meeting on April 17 approved a proposal with Bowen for $1,080,998, which was for the requisite equipment for the centrifuge replacement project. CCU Associate Director of Engineering Ashley Getz said the equipment had a longer-lead time, which was why it was approved first, adding that the proposal approved this week is to complete the installation of the equipment.
Centrifuges are used in wastewater treatment plants to separate solids from liquids in sludge, a process known as dewatering.
CCU’s most recent master plan explains that biosolids at the plant are dewatered using a centrifuge process that includes three dewatering centrifuge systems, with two centrifuges rated at 110 gallons per minute (GPM) each and one centrifuge rated for 250 GPM. Bowen will work to replace the two smaller capacity centrifuges with a pair rated at 250 GPM.
“The replacement of both of the existing smaller, centrifuges is recommended by 2042 to handle the maximum month sludge production and meet the utility’s desire to maintain dewatering operations to 6 hours per day, 5 days per week and provide full standby capacity,” according to the CCU master plan.
With the two smaller capacity centrifuges, CCU employees currently spend 8 hours a day on site for dewatering during the work week. The upgraded centrifuges will allow staff to spend less time on site.
The project is covered by a guaranteed savings contract Bowen has with CCU, and was made possible through sewer rate increases approved in the fall of 2024.
Sewer rates were increased over three phases, beginning with a 5.4% increase this year, a 9% increase in 2026 and a 5% increase in 2027.
Other sewer projects CCU is embarking on over the next three years that have moved forward in recent months include one to put a solar array on the plant and another to improve treatment of biosolids.
The CCU board and city council last year also approved water rate increases of 18% in 2026 and 15% in 2027. The water rate increases still need approval by the Indiana Utility Regulatory Commission (IURC) to be finalized. CCU Director Roger Kelso said Thursday that they expect that may happen in October.
The reason for the increases are planned capital projects over the next few years to critical utilities infrastructure that had been deferred in years past, according to CCU officials.
