Water Treatment Plant Expansion
Project
(Last Updated: September 17, 2008)
PROJECT BACKGROUND
The Ames Water Treatment Plant (WTP) is a conventional lime-softening facility. Source water for the plant comes from 22 alluvial wells located in four well fields. The plant has a rated capacity of 12 million gallons per day (mgd). The utility has annual revenues of approximately $6.7 million.
The Ames water utility was formed in 1891. The existing water treatment plant was constructed in 1927 as a 2 mgd iron removal facility. In 1931, lime softening was added, and the plant capacity was increased to 3 mgd. Treatment capacity was doubled with a plant expansion in 1962. In 1971, the capacity was again increased, this time to 9 mgd with the addition of four new filters. In 1988, the plant was expanded yet again, going to the current 12 mgd with the construction of a new settling basin and rehabilitation of the existing filters. The WTP currently maintains three ground storage reservoirs (7.75 mg), three elevated storage tanks (4 mg), and a booster pump station. In addition, the WTP controls a booster pump station and an elevated tank for a local industry.
A number of treatment units at the WTP are showing signs of deterioration. Many have undergone structural rehabilitations in the past 30 years, and major repairs or outright replacements are necessary in order to maintain the WTP’s existing capacity. The plant has limited redundancy for several treatment units; as a result, the replacement of some components while keeping the plant operational may be problematic.
During the summer of 2007, a new single-day peak demand record was set at 10.22 mgd, and a new peak three-day average was set at 9.81 mgd. The peak three-day average is 82 percent of the plant’s 12 mgd rated capacity. Using the rate of growth of the peak three-day average over the past five years and extrapolating forward, it is conceivable that the plant capacity could be reached as soon as 2012.
As a result of the growing summer peaks, the utility initiated a sustained water conservation program in 2007. The focus of the first year’s efforts was to simply raise public awareness about the way water is being used and to promote conservation by appealing to the community’s social consciousness. The City its water rate structure from a flat rate to a seasonal inclined-block structure. Options for mandatory conservation, such as alternate-day watering, will also be presented to the Ames City Council for consideration.
While conservation has numerous benefits and will continue to be
a priority for the Ames water utility, the trends of summer peak
usage suggest that planning for additional capacity needs to begin
immediately. Due to the age and condition of the existing facility,
a comprehensive assessment of the existing infrastructure is also
necessary. The Infrastructure and Capacity Needs Assessment is
the initial concept development phase for an anticipated Water
Treatment Plant rehabilitation, replacement, and/or expansion. This
first phase will determine the overall direction for the future of
the Water Treatment Plant. Subsequent phases will implement the
conclusions reached in this Needs Assessment phase.
CURRENT STATUS
On August 12, 2008, the Ames City Council awarded a professional services agreement to FOX Engineering, Inc. of Ames, Iowa. FOX has been tasked with completing an infrastructure and capacity needs assessment. FOX Engineering has partnered with HDR Engineering of Omaha, NE and Barr Engineering of Minneapolis, MN to complete their task. Their work will include the following.
A comprehensive evaluation of the existing treatment plant, including hydraulic and capacity confirmations, structural evaluations, code compliance status (electrical, mechanical, ADA, etc.), determining the remaining useful life of individual treatment components, and the ability to meet future Safe Drinking Water Act Regulations.
Reviewing the future demand projections for drinking water prepared by city staff.
Developing a list of potential treatment techniques that could be used in either a modernization/expansion of the existing treatment plant or the construction of a new facility.
After completing the evaluation of the existing
facility, determining the capacity that will be necessary to meet future demands,
and identifying appropriate treatment techniques for any new or
upgraded components, city staff will work with the team from FOX /
HDR / Barr to
determine whether the most appropriate, cost-effective alternative
is to remain at the existing site or to move to a new site and
construct a new treatment facility.
CUSTOMER INPUT
An open house will be held to present the project to the public. The open house will take place on September 30 in the Farwell T. Brown Auditorium of the Ames Public Library, located at 515 Douglas Avenue. The open house will run from 4 pm until 8:30 pm. While anyone who is interested in learning about the project is welcome to come anytime during the open house, targeted customers will be invited at the following times.
4:00 - Members of the Ames business and industry
5:30 - Neighbors of the Water Treatment Plant
7:00 - General public
A short, fifteen minute presentation will be given at the start of each session, followed by an opportunity for customers to review the background of the project one-on-one with staff from the Water and Pollution Control Department. Customers are encouraged to attend the open house and share their thoughts and suggestions on how the project might impact them and what priorities they would offer as the assessment process unfolds.
When the assessment phase wraps up, a second informational public meeting is planned. After a recommendation is formed on whether to modernize and expand the existing facility or to construct a new facility, a third open house is planned. As always, when the final recommendation is presented to the Ames City Council, the public will have an opportunity to share their thoughts with the Council.