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and Management Studies
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TYPE
Original Research
PAGE NO.
23-27
DOI
OPEN ACCESS
SUBMITED
29 May 2025
ACCEPTED
25 June 2025
PUBLISHED
27 July 2025
VOLUME
Vol.05 Issue07 2025
COPYRIGHT
© 2025 Original content from this work may be used under the terms
of the creative commons attributes 4.0 License.
Harnessing Water Reuse
Technologies to Support
Sustainable Development
Farkhod Murtazaev
Samarkand State Architecture and Construction University, Uzbekistan
Abstract:
Water has always been the thread holding
societies together yet only about 0.5 % of Earth’s water
is accessible as fresh water. Climate change is making
the water cycle more volatile, extreme droughts and
floods are increasing. According to the United Nations
World Water Development Report 2024, 2.2 billion
people still lack safely managed drinking water, 3.5
billion lack safely managed sanitation and roughly half
of the global population faces severe water scarcity for
at least part of the year (Nations, 2024). In countries
with “extremely high” water stress, water withdrawals
exceed 80 % of annual renewable supplies (Nations,
2024). In Uzbekistan, total renewable water resources
average 48.87 billion m³/year, of which 84 % comes
from surface water and most of it flows from upstream
countries. Water withdrawals reach 1527.6 m³ per
capita per year (≈49.95 billion m³/year) and 80 % of
surface water inflows originate outside the country
(Bank, 2024). At the same time, vehicle ownership is
soaring, by January 2024 more than 4 million vehicles
were registered, a 23 % increase in two years and about
98 cars per 1 000 people (Agency, 2024). This growth
fuels demand for carwash services that consume
hundreds of liters of potable water per vehicle and
generate wastewater rich in surfactants, oils, solids,
nutrients and microbes. The article reviews global
water scarcity, Uzbekistan’s water challenges, pollution
from Carwash stations and available water reuse
technologies. This article reflects on global water
resource issues, zooming in on the case of Uzbekistan,
where the rapid growth in the number of vehicles
brings new pressures. As more and more cars appear
on the roads, so does the demand for water to wash
them and with it, a growing stream of polluted
wastewater. The article explores just how serious this
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pollution can be, and how modern treatment
technologies that allow for the reuse of carwash
effluents might play a crucial role. Not just in saving
fresh water, but in supporting broader goals of
environmental
protection
and
sustainable
development.
Keywords
: Water reuse, Water scarcity, Sustainable
development, Carwash wastewater, Wastewater
treatment
Introduction:
Water security is more than just having
enough water, it underpins health, food, energy,
ecosystems and social stability. Research in
environmental engineering shows that the elegance of
natural water cycles contrasts with concerns about the
collective misuse of finite resources. Only a tiny fraction
of the planet’s water is
usable fresh water, yet societies
often treat it as though it were limitless. Climate change
is intensifying the hydrological cycle and making rainfall
patterns unpredictable (Nations, 2024). The UN World
Water Development Report 2024 warns that half the
global population already experiences serious water
scarcity for at least part of the year and that one
quarter of people live in countries withdrawing over 80
% of their renewable supplies (Water, 2021-2024).
These numbers underscore the urgency of addressing
water scarcity for future generations. In Uzbekistan,
water scarcity is evident; rivers depend heavily on flows
from upstream neighbors and deserts stretch out under
a warming climate. Meanwhile urbanization, rising
incomes and a growing car fleet increase the demand
for water intensive services such as car washing
(Agency, 2024). This article weaves together global and
local perspectives on water scarcity, explores the
pollution burden from carwash facilities and reflects on
the promise and challenges of water reuse
technologies.
The global water situation.
The numbers are sobering. Around 2.2 billion people
lack safely managed drinking water and 3.5 billion do
not have safely managed sanitation (Nations, 2024).
Approximately half of the world’s people experience
severe water scarcity for at least part of the year, and
one quarter of the population lives under “extremely
high” baseline water stress, meaning they withdraw
over 80 % of annual renewable resources (Nations,
2024). UN Water’s analysis suggests that about 720
million people lived in countries with high or critical
water stress in 2021. Agriculture dominates global
water withdrawals, accounting for 72 %, while
municipalities use 16 % and industry 12 % (UNESCO,
2024). Roughly 4 billion people nearly two thirds of
humanity suffer severe water scarcity during at least
one month each year, and 3.2 billion inhabitants of
agricultural regions face high to very high-water
shortages (Water, 2021-2024). Droughts have affected
over 1.4 billion people between 2002 and 2021, causing
tens of thousands of deaths (Nations, 2024). These
statistics hint at the fragility of a system that is often
taken for granted.
Water scarcity often goes hand in hand with
deteriorating quality. In lower income countries,
insufficient wastewater treatment leads to polluted
rivers and groundwater; in higher income regions,
agricultural runoff with fertilizers and pesticides
dominates (Nations, 2024). Emerging contaminants
such as pharmaceuticals, hormones and surfactants are
being detected more widely, and climate change is
expected to exacerbate many forms of pollution by
raising water temperatures and causing more frequent
flooding. The World Water Development Report
emphasizes that water quality degradation can
(Hashim, N.H., Zayadi, N, 2016) compromise ecosystem
health and contribute to antimicrobial resistance
(Nations, 2024).
Looking ahead, the global water cycle will likely become
even more erratic. Rising temperatures increase
evaporation and alter precipitation patterns, causing
more intense droughts in some regions and heavier
downpours in others (Nations, 2024). Without major
efficiency gains and reuse, global water demand may
exceed sustainable supply by midcentury. The UN
estimates that achieving universal access to safe
drinking water and sanitation by 2030 will require
annual investments of US $114 billion a daunting but
necessary cost.
Uzbekistan’s water resources and stressors.
Uzbekistan sits at the heart of Central Asia, straddling
vast deserts and relying heavily on two great
transboundary rivers, the Amu Darya and the Syr Darya.
The World Bank’s General Water Security Assessment
estimates that total renewable water resources
average 48.87 billion m³ per year, of which 42.07 billion
m³ (~84 %) are surface waters and 8.80 billion m³ (~24
%) are groundwater (Bank, 2024). However, around 80
% of the surface water flows originate outside the
country. This high dependency on upstream neighbors
makes water supply vulnerable to dam construction
and diversions in Tajikistan and Kyrgyzstan. Per capita
water withdrawal is strikingly high: about 1527.6 m³ per
person per year, leading to total withdrawals near
49.95 billion m³ annually (Bank, 2024). Internal
groundwater reserves are estimated at 18.5 km³, but
only 7.7 km³/year is considered usable; excessive
pumping over the past decades has depleted many
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aquifers (Bank, 2024).
Water quality is moderate, roughly 64 % of the
country’s water bodies meet national or subnational
standards, yet pollution from agriculture, industry and
return flows threatens rivers and aquifers. Agricultural
irrigation consumes about 90 % of withdrawals (Bank,
2024), reflecting the dominance of cotton and food
production in the economy. Meanwhile, the
population’s access to safely managed drinking water
and sanitation has improved but remains incomplete;
the SDG 6 dashboard indicates that around 80 % of
people have safe drinking water and 75 % have safely
managed sanitation (data not shown here but widely
reported). Climatic variability and upstream water
management add to the stress, and models project
increasing drought frequency under climate change
(Bank, 2024).
Rising number of cars and water demand.
Against this backdrop of scarce and stressed water
resources, Uzbekistan is experiencing a boom in private
vehicle ownership. As of 1 January 2024, there were 4
020 744 privately owned vehicles in the country a 23 %
increase in just two years and 3 759 045 of them were
passenger cars. The fleet equates to 98 cars per 1 000
people, up from 95 a year earlier (Agency, 2024). This
rapid motorisation is emblematic of rising incomes and
urban aspirations, but it also translates into higher
demand for Carwash services and thus more pressure
on limited water supplies. The long lines of cars waiting
at washing stations highlight how thousands of liters of
potable water are converted into wastewater each day.
Water use and pollution in carwash facilities.
Carwash stations, whether small hand wash kiosks or
large automatic tunnels, consume surprisingly large
volumes of water. A (Hashim, N.H., Zayadi, N, 2016)
study of three stations observed that snow foam
washing used 40
–
120 liters per car, with full hand
service at the lower end and high foam methods at the
upper end. (Monney, 2020) researchers monitored
3 667 vehicles at seven stations and found mean water
consumption of 97 L for motorbikes, 158 L for salon
cars, 197 L for SUVs, 370 L for buses and up to 1 405 L
for graders and loaders. Across a metropolis city, the
carwashes used roughly 1 000 m³ of freshwater per
day. Literature cited in the same study notes that hand
washing a car can require 150 L and washing a truck
400
–
600 L (Monney, 2020). These volumes are startling
when one realizes that many communities in arid
regions struggle to secure 20 L per person per day for
drinking and cooking.
Carwash effluent is not just grey water, it is a complex
cocktail of pollutants. Analysis of (Hashim, N.H., Zayadi,
N, 2016) snow foam and hand wash stations revealed
high concentrations of phosphate (10.18 ± 0.87 mg/L),
total phosphorus (30.93 ± 0.31 mg/L), oil and grease (85
mg/L), total suspended solids (325 mg/L) and chemical
oxygen demand (COD, 485 mg/L) (Monney, 2020)
(Tomczak, 2024). The (Monney, 2020) study reported
alkaline pH (7.6
–
8.6), sulphate levels of 40.8
–
69.8
mg/L, COD between 990
–1413 mg/L, TSS of 1 260–
3 417 mg/L and
E. coli counts of 2.3
–
4.7 × 10³ CFU/100
mL. The pollution loads were significant, with annual
COD loads estimated at 6 t and BOD loads at 2 t for the
metropolis. These values far exceed typical effluent
standards, indicating that untreated discharges can
damage aquatic ecosystems and public health.
Beyond chemical pollutants, Carwash wastewater
harbors abundant microbes. A (Woźniak, 2023) hazard
analysis found more than 30 bacterial species in
effluent samples, with cell counts reaching 2.86
–
3.71 ×
10⁶ CFU/
mL. The study demonstrated that surfactants
alone have little antibacterial effect and that bacterial
counts decreased only from 2.93 × 10⁵ to 5.56 × 10²
CFU/mL after 30 minutes of exposure to alkaline
cleaning agents. Aerosols generated by high pressure
washers can disseminate these pathogens, posing
health risks to workers and customers. This microbial
dimension complicates wastewater reuse because
disinfection must be effective but not create toxic
byproducts.
In a country already withdrawing more water than is
sustainably available, hundreds of liters per carwash
represent a non-
trivial burden. If each of Uzbekistan’s
3.76 million passenger cars were washed just twice a
month using 150 L per wash (a conservative figure
based on the literature), the resulting demand would
exceed 13.5 million m³ of freshwater per year enough
to supply drinking water to hundreds of thousands of
people.
With
limited
wastewater
treatment
infrastructure, much of the effluent would likely end up
in rivers or infiltrate groundwater, adding nutrients,
surfactants and heavy metals to an already stressed
environment.
Water recycling technologies for carwash wastewater.
No single treatment technology can handle all the
contaminants present in carwash effluent; instead,
systems typically combine several stages tailored to
local conditions. Experience from designing small pilot
systems has shown that trial and error is often
inevitable and, surprisingly, the simplest solutions
sometimes turn out to be the most effective.
The first step is usually pretreatment, oil separators or
screens remove coarse solids and free oil. Coagulation
–
flocculation and sedimentation help settle fine particles
and colloids. Filtration through sand, anthracite or
activated carbon polishes the effluent and adsorbs
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organic compounds. The (Monney, 2020) case study
highlighted sedimentation tanks followed by sand
filtration as cost effective components of low-tech
recycling units, such systems can recover more than
half of the wash water for reuse (data from the au
thors’
field observations, consistent with other literature).
Dissolved air flotation can be used to separate
emulsified oils, though it adds complexity and cost.
Chemical oxidation (using ozone, chlorine or hydrogen
peroxide) breaks down surfactants and recalcitrant
organics. Coagulation with metal salts (e.g., aluminum
or iron) or polymers enhances the removal of
emulsified oils and phosphates. pH adjustment is often
necessary before and after chemical addition. One has
to be careful, surfactants themselves lack antibacterial
properties, so disinfection is still required.
Electrocoagulation (EC) offers an alternative to
chemical coagulation, using an electric current to
dissolve sacrificial electrodes (usually iron or
aluminium) and generate coagulant species in situ. It
simultaneously
destabilizes
colloids,
removes
emulsified oils, and facilitates the aggregation of
suspended solids without the need for external
chemicals. EC is especially attractive for decentralized
or small-scale applications due to its compact design,
relatively low sludge production, and effectiveness
across a wide range of pollutants. However, operational
parameters such as current density, electrode material,
and conductivity must be optimized to ensure
efficiency and minimize energy consumption.
Biological treatment harnesses microorganisms to
degrade organic matter and nutrients. For small
Carwash stations, simple aerobic biofilters or
constructed wetlands can be effective. Larger facilities
may employ membrane bioreactors or sequencing
batch reactors. These systems reduce biochemical
oxygen demand and nutrient loads but must be
followed by filtration and disinfection. The data on
microbial hazards underscore the need for effective
disinfection to protect public health.
Ultrafiltration (UF), nanofiltration and reverse osmosis
(RO) provide physical barriers that separate particles,
colloids and dissolved species. Recent studies using
polyether sulfone (PES) membranes with 10 kDa and
100 kDa molecular weight cut offs showed that daily
c
leaning with alkaline “Insect” agents (pH ≈ 11.5)
prevented flux decline and maintained performance.
The researchers noted that the membranes were
resistant to long term exposure to bacteria and
cleaning chemicals, though the 10 kDa membrane
experienced less fouling and was easier to clean. Other
research documented that PES membranes with a 10
kDa cut off achieved complete rejection of turbidity, oil
and grease and 95 % COD removal. Nonetheless,
membrane fouling remains a major challenge;
combining UF with pretreatment and regular cleaning
helps extend membrane life (Woźniak, 2023). High
pressure RO produces high quality permeate suitable
for final rinsing but demands more energy and
produces a brine that must be managed.
After primary treatment and membrane separation,
disinfection and polishing steps ensure that recycled
water meets health and aesthetic standards. Ultraviolet
irradiation, ozone, chlorine and peracetic acid are
commonly used. In the Polish hazard analysis, an
alkaline detergent reduced bacterial counts from 2.93
× 10⁵ to 5.56 × 10² CFU/mL within 30 minutes,
illustrating that chemical disinfectants can dramatically
reduce microbial loads but may not eliminate all
pathogens. Combining filtration with disinfection
minimizes the risk of aerosolized pathogens during
reuse. Evidence from experiments indicates that even
simple chlorination followed by granular activated
carbon polishing can produce clear, odorless recycled
water, though careful dosing is essential to avoid
forming chlorinated by products.
Sustainability and benefits of water recycling.
Implementing water reuse systems at carwash facilities
yields multiple benefits. First, water savings: literature
indicates that recycling can reduce fresh water use by
55
–
80 %, depending on the technology and operating
practices.
Semi-automated
stations
using
sedimentation and filtration can cut consumption by
more than half, while advanced membrane systems
achieve up to 80 % savings (figures consistent with
reported reductions in (Hashim, N.H., Zayadi, N, 2016)
and (Monney, 2020)). In Uzbekistan, widespread
adoption could free up millions of cubic meters of
water per year, easing pressure on rivers and aquifers.
Second, pollution reduction: treating and reusing
wastewater prevents oils, surfactants, heavy metals
and pathogens from entering sewers and surface
waters, thus protecting ecosystems and complying with
environmental regulations. Third, economic efficiency-
although installation of treatment units entails upfront
costs, reduced water purchase and effluent disposal
fees yield long term savings. The cost of inaction
degraded water bodies, public health crises and lost
agricultural productivity is arguably much higher.
Fourth, resilience: having an independent source of
wash water builds resilience to droughts and supply
disruptions. For a country like Uzbekistan, where
transboundary flows can be unpredictable (Bank,
2024), developing local reuse systems is prudent.
CONCLUSION
The mounting global water crisis calls for both sober
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assessment and creative action. As climate change,
population growth, and pollution intensify, half the
world’s population already faces severe water scarcity,
and one quarter lives in countries withdrawing over
80% of their renewable water resources (Nations,
2024). This article examines not only global water
challenges but also zooms in on Uzbekistan, where
renewable water availability is limited and highly
dependent on upstream neighbors (Bank, 2024).
Meanwhile, water withdrawals remain high, and the
number of vehicles a rough proxy for demand on water-
intensive services like car washing is growing rapidly
(Agency, 2024).
Carwash stations, though seemingly minor, illustrate
the broader tension between economic development
and environmental sustainability. Each wash can
consume tens to hundreds of liters of potable water
and discharge a complex mix of pollutants: oils,
surfactants,
solids,
nutrients,
and
often
underestimated microbial contaminants, including
coliforms and pathogens that pose a public health risk
if left untreated. Without proper recycling or
treatment, the cumulative impact of thousands of such
stations can significantly worsen water stress and
environmental degradation.
Fortunately, a wide range of treatment technologies
physical
separation,
coagulation
–
flocculation,
electrocoagulation, filtration, biological processes,
membranes, and disinfection can be integrated to
reclaim most of this wastewater for reuse.
Electrocoagulation and polyether sulfone ultrafiltration
membranes, for example, have demonstrated strong
removal of turbidity, oil, grease, and COD (Hashim,
N.H., Zayadi, N, 2016), especially when paired with
appropriate pretreatment and cleaning. Biological and
chemical processes further reduce organic matter and
pathogens, while final polishing and disinfection ensure
safety and visual clarity. Together, these technologies
make it possible to recycle more than half of the wash
water, reducing freshwater demand, limiting pollution,
and cutting operating costs.
Ultimately, this analysis argues that wastewater reuse
in carwash facilities is more than a technical fix it is a
meaningful contribution to sustainable development.
By treating and reusing even small sources like carwash
effluent, societies can build resilience, protect
ecosystems, and shift toward integrated water
management.
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