Everywhere you go, people are
talking about water. Globally, it is estimated that 1.1 billion people live
withoutclean drinking water. In the U.S., every state is faced with
challenging water issues, from shortages to pollution. In Wisconsin, we are
organizing efforts to make our state a hub for water technology and innovation.
In the midst of this, the City of
Waukesha is facing enforcement action related to high levels of radium in their
drinking water. They are currently
operating three treatment systems that remove radium from water and blend that
water with the rest of the system to achieve compliance.
A solution to achieve compliance was
to purchase Lake Michigan water. In December of 2017 the Waukesha Common
Council unanimously approved a 40-year plan to purchase water from the City of
Milwaukee. Lake Michigan water has much lower levels of radium than Waukesha
water. This solution has become one of the most talked about topics in
Waukesha, Wisconsin and the Great Lakes Community.
This article evaluates
the impact the new water source will have on commercial and industrial users.
Our purpose is not to take a position on the issue but to help users understand
the potential impacts this change will have on their business.
Methodology
The water characteristics of
Waukesha’s existing water supply and Lake Michigan water are quite different. These
differences require varied treatment programs for commercial and industrial
users. The two most common water systems managed by these users are boiler and cooling
tower systems. To demonstrate the impacts that switching to Lake Michigan water
will have, we have evaluated the treatment programs for these types of
systems.
Each commercial/industrial user
has a unique water system that requires its own water treatment program. In
order to simplify the analysis, we evaluated the most common types of systems. The
conclusions that we have reached are specific to these systems. However, the conclusions should help users
with similar systems understand the impacts of changing to Lake Michigan as a
water source.
Cooling Tower Systems
Cooling towers are used by
commercial and industrial facilities for a variety of purposes, from comfort to
controlling industrial processes. Water treatment programs for cooling systems
are designed to prevent scaling, corrosion and biological growth which reduces the energy
efficiency of these systems. Waukesha’s existing water supply has a high level
of hardness requiring many users to soften their water prior to its use in a
cooling tower. Cooling water systems that use Lake Michigan water can be
operated without softeners because the water has a relatively low level of
hardness. For the purpose of this article we will compare these two types of
systems.
The single largest difference
between the treatment requirements in a cooling system using Waukesha water vs.
Lake Michigan water is that a water softener is not necessary. This has several
impacts on water use, salt use and overall cost.
Impacts on Water Usage
The amount of water used in the
cooling tower will increase when the change is made to Lake Michigan water. This
is because the tower will run at fewer cycles of concentration on Lake Water. In
layman’s terms this means that the water cannot be recycled in the tower as
many times when Lake Michigan water is used. This will require an additional 1.45 million
gallons of water use in the cooling tower for an average sized facility. However,
since water softening will no longer be required, there is water savings
related to regenerating the softeners. The volume of water used to regenerate the softener in this system over
the course of a year is approximately 2 million gallons. Therefore, the net change in water usage when changing from the existing
water supply to Lake Michigan water is more than 500,000 gallons per year.
Impacts
on Salt Usage & Chloride Discharge
Water softeners use considerable
amounts of salt in their operation. For this example system, the annual salt
usage would be 89,510 pounds per year. The salt purchase obviously has a fixed
cost; however, there are also operational costs associated with softeners such
as maintenance, repair and loading salt into the softener (consider that 89,510
pounds of salt is equal to 1,119, eighty pound bags of salt).
There is also an environmental
impact related to the salt usage. During regeneration the chloride associated
with salt in a water softener is discharged to the sewer. In this example, the
89,510 pounds of salt equates to 53,706 pounds per year of chloride discharged
to the sewer system. Chloride levels have been increasing in surface water
since the early 1960’s and regulatory agencies have been enacting chloride
regulations throughout the country. The use of Lake Michigan water would likely
reduce the need for water softeners in the City of Waukesha; as a result,
chloride discharged by the wastewater utility would decrease.
Impacts on Water Treatment Costs
The table below shows the changes
in water treatment costs expected in an average sized cooling system when the
change is made to Lake Michigan water. Overall, a commercial/industrial user
should expect to see a reduction in their water treatment costs. The majority of
that savings is the result of the elimination of the water softening system.
Water Supply Impact: Waukesha Vs. Lake Michigan
The construction for the pipeline
to supply Waukesha with Lake Michigan water is slated to begin in 2019 or 2020
with the completion at the end of 2022. Lake Michigan water will begin flowing
into Waukesha in 2023.
If your facility will be impacted
by the change to Lake Michigan water and you have questions, please reach out
to Watertech at 414-425-3339.
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STAFF CONTRIBUTORS |
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Joseph
Russell, President, Watertech of America, Inc.
Joe is the President and owner of Watertech of America, Inc., a Wisconsin
based industrial and commercial water and wastewater treatment company. Watertech provides water
treatment chemicals, equipment and automated water management systems to help
customers reduce, reuse and recyle water inside their facilities.
He holds has a bachelors of science degree in Mechanical Engineering from The
University of Wisconsin-Milwaukee. He
currently serves on the Professional Advisory Board for UW- Milwaukee’s
School of Freshwater Science.
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Jon Tiegs, Vice President, Watertech of America, Inc.
Jon has 19 year of experience providing solutions to industrial water and wastewater customers. He is passionate about the water industry and enjoys combining his experience in the industry with today’s technologies to develop innovative solutions for Watertech’s clients.
He has a Bachelor's of Business Administration for the University of Wisconsin Whitewater.
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