JOHNSON COUNTY GOVERNMENT
STATE OF KANSAS
NEWS RELEASE
For immediate release: July 14, 2011
Contact: John O’Neil, general manager at Johnson County Wastewater, at (913) 715-8570
OLATHE, KS (Johnson County Square) — Johnson County is going to a great depth to carry millions of gallons of treated wastewater from the Mill Creek Wastewater Treatment Plant in Shawnee to empty into the Kansas River.
On Thursday, July 14, the Johnson County Board of Commissioners authorized construction of an underground effluent pipe between the treatment plant at 20001 West 47th Street, just south of the river, to a discharge point on the river located just downstream of the raw water intake site of Water District No. 1. The intake is just east of I-435. The treatment plant is about 1.3 miles west of I-435.
The total authorization for the Mill Creek Regional Wastewater Treatment Plant Effluent Capacity Improvements was increased by $37,830,000 to $41.6 million by the Board.
In a related action, the Board approved a contract, totaling $31,979,450, with S.J. Louis Construction of Texas to construct the effluent tunnel. The Texas firm submitted the lowest bid among six bidders. The other bids ranged from $32 to almost $39.9 million.
The project will span approximately 9,800 feet, almost two miles, with a concrete pipe with a 96-inch-diameter. The tunnel will be buried deep –approximately 100 to 110 feet - and require boring under portions of Mill Creek, I-435, Wilder Road, Holliday Drive, and railroad tracks.
Treated plant effluent will flow by gravity through the tunnel to the river. Plant effluent currently is pumped to the same discharge location, but the pumping station does not have the capacity to pump extreme wet weather flows. The pumping station will be taken out of service after completion of the project, which includes construction of new plant piping to convey treated wastewater from the plant’s final stage lagoon to the tunnel.
The tunnel will eliminate the risk of untreated sewage flows into nearby Mill Creek and the Kansas River in time of heavy rains since it is underground, so groundwater can’t seep in and treated wastewater can’t seep out.
“What the tunnel does do is reduce our carbon footprint and operating costs since we will not need electricity to pump the effluent as we do now,” John O’Neil, general manager for Johnson County Wastewater, said. He estimated the project, once completed, will save more than $200,000 annually in moving ultimate future flows.
Construction of the tunnel is expected to begin by late summer with completion by late 2013.
It is the second tunnel project for Johnson County Wastewater in two years. In 2009, the Board of County Commissioners authorized a 3,300-linear-foot tunneling project under the Overland Park Arboretum near Antioch Road and 179th Street. The tunnel, with 60-inch piping and depths of up to 74 feet, preserved hundreds of trees and parkland at the arboretum that would have been removed if open-cut trenching had been used in the project.
The tunnel, costing $5.9 million, was completed in mid-April 2010.
The project was part of construction of Blue River 26 gravity sewers, costing $18 million and totaling more than 37,000 linear feet, that will open up an area of approximately 25 square miles for development in southern Johnson County.