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TO: Mayor Thomas J. Weisner
FROM: David E. Schumacher, P.E; Superintendent of Water Production
DATE: February 19, 2015
SUBJECT:
A resolution authorizing the conditional purchase of a PAX model PWM600 water mixing unit for the Water Production Division.
PURPOSE:
To obtain City Council approval for the potential purchase of the PAX Water Technologies, Inc. PWM600 water mixing unit from Utility Service Company, Inc. (USCI) Perry, GA. The purchase is contingent upon completion of a successful trial and testing period.
BACKGROUND:
The subject purchase is contingent upon completion of a successful trial and testing period of the PAX model PWM600 water mixing unit (see attached data sheet) at the City of Aurora's Southeast Standpipe. The standpipe is a 5 million gallon finished water storage vessel located at 1718 Normantown Road. The standpipe was constructed and placed in service in 1988 to provide water distribution storage and pressure to the far southeast area of Aurora.
A standpipe is defined as a ground-level water storage tank for which the height is greater than the diameter. The overflow height of the Southeast Standpipe is 134 feet. By nature, water movement and mixing within this type of tank is less than ideal; essentially water movement inside the tank is similar to that of liquid moving up and down in a straw. Because of poor mixing within the standpipe, the water temperature does not remain uniform within the entire water column. This is referred to as stratification, or in other words, the water temperature greatly varies throughout the 134 feet of water with warmer temperatures occurring at the top and colder temperatures at the bottom where fresh, new water enters the tank. Stratification within the water column can result in water quality degradation which is most evident in the loss of total chlorine residual as shown by data collected from the chlorine residual analyzer currently located at the standpipe. The combination of inadequate mixing and rising water temperatures throughout the summer can have significant impacts on water quality. The PWM600 mixer is designed to mix and move water continuously throughout the entire water column, providing uniform temperatures and stable chlorine residual throughout the storage vessel.
DISCUSSION:
The Water Production Division (WPD) conducted a similar trial during 2013 - 2014 at the Barnes Road Standpipe with a successful outcome. As with that trial, the WPD will once again work with USCI and PAX to have the mixer installed inside of the standpipe and monitor performance. PAX and USCI are providing the mixer and the initial trial installation at no cost to the city. The trial will commence upon approval of this resolution request and continue until October 2015. Should the trial prove successful, the WPD would then request a purchase order and complete the acquisition with USCI. Should the trial prove unsuccessful, the equipment will be removed at no cost to the City of Aurora.
The PWM600 mixer is uniquely designed and is the only known product currently available that utilizes an exposed impeller to generate significant water movement within a storage vessel of the standpipe's size with a 3 hp motor. The attached letter provided by PAX outlines the sole-source status regarding this specific product. Therefore, this purchase would be in accordance with the City of Aurora Code of Ordinances, Section 2-335 (a) (3); the product or service desired is provided by only one (1) source.
Funding for this purchase was approved by a 2015 Decision Package with funds available in the Water Production Division budget account 510-4058-511-38-01.
IMPACT STATEMENT:
None.
RECOMMENDATIONS:
That a resolution authorizing the potential purchase of the PAX model PWM600 water mixing unit in the amount of $47,064.00 upon completion of a successful trial and testing period be approved by the Mayor and City Council. It is further recommended that this matter be forwarded to the Buildings, Grounds, and Infrastructure Committee for their review and recommendation.
cc: Alderman Peters, Chairman
Alderman Garza
Alderman Bugg
Alderman Saville, Alternate
CITY OF AURORA, ILLINOIS
RESOLUTION NO. _________
DATE OF PASSAGE ________________
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A Resolution Authorizing the Conditional Purchase of a PAX Model PWM600 Water Mixing Unit for the Water Production Division.
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WHEREAS, the City of Aurora has a population of more than 25,000 persons and is, therefore, a home rule unit under subsection (a) of Section 6 of Article VII of the Illinois Constitution of 1970; and
WHEREAS, subject to said Section, a home rule unit may exercise any power and perform any function pertaining to its government and affairs for the protection of the public health, safety, morals, and welfare; and
WHEREAS, the Water Production Division seeks to conduct a trial and testing period of a PAX model PWM600 mixing unit in the Southeast Standpipe to determine whether the unit's performance is acceptable to justify its purchase; and
WHEREAS, upon completion of the trial, the Water Production Division will either purchase the unit from Utility Service Company, Inc. or have the unit removed at no cost to the City of Aurora, contingent upon the outcome of the trial; and
WHEREAS, budgetary authority is granted and funds are available in the 2015 City Budget in Account No. 510-4058-511-38-01; and
WHEREAS, in accordance with the City of Aurora Code of Ordinances, Section 2-335 (a) (3), the product or service desired is provided by only one (1) source;
NOW, THEREFORE, BE IT RESOLVED by the City Council of the City of Aurora, Illinois, as follows: that its Purchasing Director be and is hereby authorized to issue purchase orders for the purchase of the PAX model PWM600 mixing unit from Utility Service Company, Inc. in the amount of $47,064.00 contingent upon a successful trial by the Water Production Division and Utility Service Company, Inc.