Technical BRIEF
Water on Wheels (WOW) Mobile Emergency Water
Treatment System Cart
An affordable and easy-to-operate water decontamination system
Following a natural disaster, communities need access to
clean water not only for drinking but also for cooking,
cleaning, and medical triage. If the water system is
contaminated, water treatment will be needed. Similarly,
mitigation and recovery following a man-made incident or
an accident could require water treatment.
Not all the water being treated needs to be drinking
water quality. In some longer-term recovery efforts,
contaminated stormwater or wash water from building
decontamination activities only need to be treated to
levels safe for disposal to the wastewater treatment
plants or back to the environment. Mobile treatment of
the highly contaminated water can significantly reduce
the volume of water to be transported, and reduce the
liability and cost of transporting and disposing of a
hazardous waste.
Most emergency water treatment systems are large and
expensive tractor-trailer mounted systems. They can be
complicated to operate and maintain (high pressures and
concentrated wastes) given their use of reverse osmosis
water treatment technology. An emergency water
treatment system could be designed and built so the
sequence of treatments can be configured on-site to treat
a broad spectrum of contaminants without using
unnecessary and costly unit processes, and without
producing large amounts of contaminated waste. The
broad spectrum of potential contaminants includes
chemical, biological and radionuclide contaminants.
Rather than a treatment system, bottled water is typically
the first responder's choice when responding to an
incident. However, long-term dependence on bottled
water creates a large solid waste disposal problem and,
often times, large vehicles transporting bottled water are
unable to get to affected locations because of road debris
and damage. In large or extended recoveries, bottled
water use for bathing, sanitation, and other non-potable
purposes is impractical. However, bottled water could be
used in conjunction with an inexpensive and versatile
mobile emergency water treatment system providing
water for non-potable water applications such as toilet
Based on these considerations, through a cooperative
research agreement, a list of capabilities needed for a
mobile emergency water system (listed below) was
developed. The research and testing that produced the
final system (Figure 1) is described here.
Treatment Train
	Up to 10 gallons per minute
	Pre-filtration to reduce turbidity and improve
	Two media filtration/adsorption tanks for
targeted chemical or radiological contaminant
removal (e.g. Granular Activated Carbon or Ion
	UV LED for additional microbial inactivation
	On-site chlorine gas and bleach generation for
	Ability to add or subract treatment processes in
the field
U.S. Environmental Protection Agency
EPA/600/S-20/110 Updated April 2020
Figure 1.Final version of the water on wheels (WOW)
mobile emergency water treatment system cart at the USEPA
Water Security Test Bed (Idaho)

	Ability to re-circulate treated water to increase
Power Supplies
	Dual Fuel Generator (propane, gasoline)
	12v DC deep cell marine battery w/solar panel
	Weighs less than 500 pounds
	Fits in back of pick-up truck
	2-person transport
Research Approach
Cooperative Research and Development
Utilizing a Cooperative Research and Development
Agreement (CRADA) with the non-profit humanitarian
relief organization WaterStep, a prototype mobile
emergency water treatment system was first fabricated
and evaluated at the U.S. Environmental Protection
Agency (USEPA) Test & Evaluation Facility located in
Cincinnati, Ohio. The mobile emergency water treatment
system was then challenged at the USEPA Water Security
Test Bed, located near Idaho Falls, Idaho, replicating a
field scale emergency response. Components of the
mobile system were then deployed to Puerto Rico in
response to Hurricane Maria. The mobile emergency
water treatment system was modified and expanded
based upon the field results and challenged once again at
the Water Security Test Bed.
Prototype Evaluation
Pilot testing at the Test & Evaluation Facility confirmed
the ability of multiple water treatment process to be
quickly configured to treat sufficient quantities of
contaminated water. Initial full-scale testing at the Water
Security Test Bed demonstrated greater than 7 log
reduction of Bacillus globigii, an anthrax surrogate,
recirculating in batch mode. Field deployment also
demonstrated that the mobile framework was capable of
being easily transported via pick-up truck and rolled into
position by two people.
Hurricane Maria Deployment
Shortly thereafter, Hurricane Maria made landfall in
Puerto Rico on Wednesday, September 20, 2017. Within
just three weeks, WaterStep's team was on the ground
training emergency workers and distributing kits with
components of the 2nd generation WOW Cart. In addition
to providing drinking water, in parallel, an added feature
to the kits were 1 litre containers that produced a 1%
solution of liquid bleach, to be used for general cleaning
and for support of medical triage by medical personnel.
Over 100 kits were deployed and hundreds of people
trained in the proper use of the equipment. Though some
kits are still being used there, many are now positioned
and poised to be used during the next disaster.
Final Evaluation
Learning from both the field challenge and Hurricane
Maria experience, the final version of the WOW Cart was
challenged at the Test & Evaluation Facility with
secondary wastewater and subsequently tested again at
the Water Security Test Bed against lagoon water
contaminated with diesel fuel and Escherichia coli. The
WOW Cart successfully removed 4 to 6 logs of E. coli and
total coliforms, respectively, to non-detection levels from
the contaminated lagoon simultaneously with diesel fuel
components. Diesel fuel components were removed to
below detection levels, which made the water safe to
drink. Results did reveal that extremely dirty water
(turbidity >120 NTU) could foul the chemical water
treatment process prematurely and prevent adequate
supplies of treated water from being available.
Future Research Activities
This research is driven by requirements under the federal
Safe Drinking Water Act and Clean Water Act. It also
responds to part of the National Response Framework
developed by the Federal Emergency Management
Agency (FEMA). The USEPA will continue to partner with
drinking water and storm water utilities, disaster relief
organizations, FEMA and other state and federal agencies
as well as private companies to protect public health and
he environment. Technology development and
ntegration will continue including:
Additional pre-filtration technologies to treat
extremely contaminated water
Evaluation/integration of innovative future
treatment technologies
Real-time and remote operating and reporting
Applications to medical triage in the field and
at forward operating bases
Case study field evaluations
Technical Contacts
	Jim Goodrich. Eoodrich.iames(a)epa.Eov
	John Hall, hall.iohn(a)epa.Eov
Communications Contact
	Lahne Mattas-Curry, mattas-currv(a)epa.Eov
U.S. Environmental Protection Agency

Additional Information
Goodrich JA, Hall JS, Hogg M, Daniels KT,
Meiners GC, Witt SM. 2019. Design,
Testing, and Deployment of a Mobile
Emergency Water Treatment System, Final
Report. Cincinnati, OH: U.S. Environmental
Protection Agency. EPA/600/R-19/0781
June 2019. public record re
Disclaimer: The U.S. Environmental
Protection Agency (EPA) through its Office
of Research and Development funded and
managed the research described herein
under Cooperative Research and
Development Agreement # 865-15 with
WaterStep and contract EP-C-12-014 with
Aptim. It has been subjected to the
Agency's review and has been approved for
publication. Note that approval does not
signify that the contents necessarily reflect
the views of the Agency. Any mention of
trade names, products, or services does not
imply an endorsement by the U.S.
Government or EPA. The EPA does not
endorse any commercial products, services,
or enterprises.
U.S. Environmental Protection Agency