Water Treatment Plant Filters, Lime and Other Miscellaneous Improvements

Water Treatment Plant Filters, Lime and Other Miscellaneous Improvements

Project Manager

Water Resources / Candy Staring, P.E.

SUA Project No. 16WG08

What We're Doing

The City of Stillwater and the Stillwater Utilities Authority will be upgrading and improving the various processes at the Water Treatment Plant (WTP). Nearly every treatment process will be improved or modified to provide a higher quality, more stable water for our customers. The processes included in the project are: clarification, softening, recarbonation, filtration, disinfection and chemical feed systems. One of the larger chemical feed systems is Lime which is used to soften hard water. The existing lime feed system was installed in the 1980s and has long been showing signs of poor operation and recurring breakdowns. Due to the deterioration of the system and lack of ability to get replacement parts, the softening process must be replaced. In addition to the softening process improvements, replacement filters will be provided, various chemical feed systems will be upgraded to current standards, a new WTP generator will be installed and many other improvements will be made.

The work will be conducted in multiple phases in order to prioritize the efforts while keeping the WTP in operation.


Lime Softening - The Kaw Lake water flowing into the WTP has an average hardness that classifies it as moderate to hard water. A lime softening process is used to remove this hardness and reduce the potential for scaling inside the City's water lines and also inside our customer's plumbing. Customers may notice the benefits of a softer water because it reduces the amount of soap needed for washing laundry and bathing, leaves dishes shinier and cleaner and preserves the life of coffee makers, water heaters and other appliances that use water.

New Filters - The current filters are arranged in a configuration that prevents adequate cleaning. The new filters planned for the WTP will provide deeper beds for superior filtration, improved backwashing and better cleaning of the filter media for an overall higher quality of treated water. 

New Generator - A new generator for providing back up power during an electrical outage will provide an increase to the reliability of the WTP.

Chlorine System Replacement - Similar to Lime, the chlorine system is aging and deteriorating. WTP staff currently rely on outdated instruments for measurement and control. The chlorine system replacement will include a new chlorine scrubber, cylinder regulators, chlorine feeders and fine-tuned measurements and controls.

Miscellaneous - Additional improvements are being made to various chemical feed systems and processes. 

How We're Paying For It

Funds for the construction of the project and associated services will come from the City's Water Capital Fund. 



February 7, 2017: Black and Veatch has been hired to provide conceptual design services.

September 6, 2017: The project continues to be in the design phase. In July, SUA approved multiple additions to the scope due to discoveries of various safety issues and equipment deficiencies. Evaluation of the filters has been added in order to optimize filtration and improve overall functionality. Many chemical systems are being considered for rehabilitation due to their age, poor condition and frequent malfunctions.

March 12, 2018: After evaluating most of the process and chemical feed systems at the WTP, a priority has been assigned to each individual component. The Project Team is initializing design for the chlorine system upgrade which is the highest priority. Additionally, a Facilities Plan will be prepared to develop a conceptual and phasing plan for the remaining work with includes filters, lime, carbon dioxide, ammonia and many other improvements.

September 4, 2018: The chlorine design package is about 35 percent complete. Due to a funding grant available for generators, the generator design package has been accelerated and is at about 35 percent complete, as well. These separate efforts will comprise the first two construction packages. Once Black and Veatch completes a year of water quality testing, design work will proceed for the new filters. The results of the testing will also help the design team decide how best to modify the treatment scheme at the WTP in order to provide the highest water quality possible in the distribution system.

Actions Authorized by Stillwater Utilities Authority (SUA)

  • 1.9.17  | SUA-17-01 |  Professional Services Agreement

  • 7.17.17  | SUA-17-22 |  Amendment to Professional Services Agreement

  • 9.10.18  | SUA-18-34 |  Request for Additional Expenditures and to Execute      Contract Amendments to the Professional Services Agreement



(Posted Feb. 7, 2017):


Site plan of the WTP and locations of where work will take place.

Aerial site plan of Water Treatment plant with call outs for Filters, Solids Contact Unit and Lime Feed Stystem

(Posted February 7, 2017):

Existing equipment of the lime feed system located in the Lime Silo.

Photo of existing equipment inside lime silo