Water Utilities Supply Chain
Challenges and Case Studies:

C02 AND THE DES MOINES WATER WORKS

The Des Moines Water Works (DMWW) provides
drinking watertoapproximately 600,000 customers
in the Des Moines metropolitan area, it operates
three water treatment plants: f lour Drive Treatment
Plant, L D. McMullen Treatment Plant at Maffitt
Reservoir and Saylorville Water Treatment Plant.
DMWW also operates Des Moines Water Works Park
and Maffitt Reservoir Park. The treatment plants
at Fleur Drive and L. D. McMullen both useC02as
part of the water treatment process.

Seasonal changes in demand affect treatment
requirements therefore extending or limiting the
duration that the CO, storage amount will last. To
ensure a sufficient supply, an automated inventory
system orders CO, when storage drops to a point so
that the system can receive a full 40,000 lb. tanker
load of product. DMWW has also established itself
as a priority customer with their supplier. These
practices have worked for decades, and there has
always been a sufficient supply of CO, on-site. But
this all changed with the COVID-19 pandemic.

CO, is largely produced as a byproduct of other

processes, including the manufacture of ethanol,
oil and natural gas refining, and ammonia and
hydrogen production. The largest source of CO,
(35%) comes from ethanol. DMWW is supplied CO.
that is captured from this process.

In the spring of 2020, reductions in economic
activities due to COVID-19 significantly lowered
the demand for gasoline and hence for ethanol
(see sharp decrease in graphic below). Lack of
drivers on the road and the lowered demand for
ethanol led many ethanol manufacturers to reduce
their production levels or, in some cases, to shut
their plants. When this happened, C02 shortages
quickly followed.

To compound matters, there are many competing
uses for C02; its application in drinking water
treatment makes up less than 4% of global use. The
largest user of CO,, in the Des Moines metropolitan
area is the food industry. The competing uses for
CO, made finding product more difficult. The
effects of the shortage were soon felt by DMWW's
supplier, resulting in a 24-hour notice that CO,
would no longer be available to the Water Works.

/	\

Weekly U.S. Refiner and Blender Net Input of Fuel Ethanol

Thousand Barrels per Day
1,250

1.0°0

500	'

250

iSii	2014	2016	2018	2020	2022

— Weekly U.S. Refiner and Blender Net Input of Fuel Ethanol

Source: U.S. Energy Information Administration

V	J

COVID-19 and Unintended
Consequences

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Response and Mitigation

DMWW worried about its ability to continue treating water. If water could not be treated, they would not
be able to provide safe drinking water for basic sanitation or to protect public health during the COVID-19
pandemic. This would have not only negatively impacted its residential customers but also other lifeline
services such as hospitals and care facilities. Since these consequences were not acceptable to DMWW, staff
immediately began looking for ways to locate and procure additional C02.

"How could you not help the
city of Des Moines?" said Seth
Harder, General Manager of Husker
Ag, which oversees Lincolnway.
"Drinking water is very essential."

While hopeful that the local C02 shortage
would be resolved, DMWW Water Production
Department was ready with several "Plan B"
actions to be able to continue to produce
water, which included the following:

•	Adjusting pH to reduce C02 use

•	Implementing water use restrictions

•	Reducing lime softening

•	Switching to citric or phosphoric acid

•	Issuing a boil water notice or boil water
advisory and maintaining sanitary water
and fire protection

DMWW contacted chemical suppliers, the Iowa
Water and Wastewater Agency Response Network
(IOWARN), the Iowa Department of Natural
Resources, the Iowa Association of Water Agencies
(IAWA), the neighboring utilities, and the Iowa
Department of Homeland Security and Emergency Management (HSEMD). The plan was to communicate
the urgent need for CO, to the Water Work's entire public and private partner network to reestablish the
CO, supply. HSEMD kept the Governor's office updated which supported high level communication with
various companies and organizations in an attempt to find a resolution.

The local CO, suppliers understood the criticality of the situation but were unable to make commitments
to new customers. DMWW took it a step further and reached out to the ethanol manufacturer, Lincolnway
Energy, that provides CO, to their supplier. Ultimately, persistence was key as DMWW was able to convince
their supplier's ethanol manufacturer in the Midwest to reopen its plant and start production to ensure
CO, would be available again.

Lessons Learned

DMWW was fortunate - communication with the CO, manufacturer that serves their supplier proved
successful. While the utility came close to running out of C02, DMWW did not have to modify either water
treatment or water usage. However, this experience did produce other lessons learned:

Establish relationships. Start with your local
emergency management agency (EMA) - EMAs
can provide points of contact you may need
during an emergency. Also, get involved with
your state WARN. This will help you to know
what other utilities in your state have and what
they may be able to lend during emergencies.

Know your full supply chain to include
manufacturers

Leverage interdependencies. For example,
the food industry is just as reliant on safe
drinking water as it is on C02. Agreements can
be reached to share limited supplies of CO, if
industry realizes that a lack of clean water could
be just as impactful as a lack of C02.

Be flexible. Suppliers may not be able to make
on-time deliveries because of the lack of drivers.
By extending the times to receive chemical

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deliveries, utilities have a much better chance
of having chemicals in sufficient supplies. For
example, DMWW no longer has set treatment
chemical delivery hours.

• Drive it yourself. DMWW has considered what
would happen if the treatment chemical were

available, but there were no truck drivers
to make the delivery. The Water Works asked
HSEMD if they would be able to assist by asking
the state Department of Transportation for
temporary emergency waivers if DMWW needed
to use drivers that did not have the exact type
of CDL required to haul chemicals.

As COVID-19 proved, treatment chemical shortages can be unforeseen and occur with little notice. While
no utility can predict supply chain disruptions, all utilities can and should take steps to better plan for and
respond to future challenges. These include communicating and working with suppliers and manufacturers,
leveraging relationships with interdependent sectors, and coordinating with state primacy agencies on
treatment alternatives in advance of any shortages.

Additional Resources

You can find more information on using supply
chain management best practices and preparing
for supply chain challenges at https://www.epa.
gov/waterutilitvresponse/water-and-wastewater
sector-suoolv-chain-resHience.

Office of Water (4608T)

EPA 817-F22-002

July 2022

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