Around the world, there is a transition towards the ‘circular economy’ that focuses on the 3Rs of reducing material consumption, reusing materials, and recovering materials from waste. In the context of urban water resources management, a variety of cities and their respective water utilities are implementing circular economy concepts that promote the reduction of water consumption, reuse of water, and recovery of materials from wastewater.

2. EXPRESS WATERJune, 201852
COLUMN
DevelopingtheUrbanCircularWaterEconomy
Our traditional economy,
which is based on the ‘take-
make - consume - dispose’
model assumes that resources
are abundant, available, and
cheap to dispose of. However,
this model faces significant
challenges from a variety of
mega-trends. The world’s pop-
ulation will be 50% larger in
2050 compared to 2000 while
the world’s economy will have
nearly tripled by then.
Meanwhile, by mid-century,
66% of the world’s population
will be living in urban areas,
up from 54% in 2014. Annual
global material extraction will
reach 183 billion tonnes in
2050, more than twice the
amount in 2015. Regarding cli-
mate change, extreme weath-
er events will damage infra-
structure and harm human
health, potentially reducing
global GDP per annum by 3%.
Finally, by 2050, global
demand for water will out-
strip supply by 55% under a
business-as-usual scenario,
while water quality will be
severely threatened too:
already, 80% of the world’s
wastewater and over 95% in
some least developed coun-
tries is released to the envi-
ronment without treatment,
resulting in polluted rivers,
lakes, and coastal waters.
The Urban CircularWater
Economy
Around the world, there is
a transition towards the ‘cir-
cular economy’ that focuses
on the 3Rs of reducing materi-
al consumption, reusing mate-
rials, and recovering materi-
als from waste. In the context
of urban water resources
management, a variety of
cities and their respective
water utilities are implement-
ing circular economy concepts
that promote the reduction of
water consumption, reuse of
water, and recovery of materi-
als from wastewater.
ReducingWater Consump-
tion
Water utilities are using a
variety of demand manage-
ment tools to reduce water
consumption including pric-
ing of water, reducing leak-
ages in the systems, metering
all customers, using subsidies
and rebates to encourage the
installation of water-efficient
technologies and appliances in
homes and businesses, and
awareness initiatives that
educate the public on the need
to use water wisely. The over-
all aim of demand manage-
ment is to modify the atti-
tudes and behavior of cus-
tomers towards water during
both normal and atypical
times.
ScottishWater’sWater
Savings Calculator
Scottish Water provides
customers with an online
‘Water Savings Calculator’ to
determine their actual water
usage. At the start, customers
get to personalize the ques-
tions to suit their homes, so if
they do not own a car the cus-
tomer will not be asked how
often they clean it. Once com-
pleted - it takes around 5 mins
- the user is provided with
their own personalized water,
energy and spend profile, a
few free water-saving prod-
ucts that are easy to install,
along with a series of tips on
what can be done to save
water. For example, fixing a
dripping tap can save as much
as 48 liters of water a day, or
17,500 liters of water a year
and shaving 1 minute off your
shower could save £15 in ener-
gy bills and a further £15 in
water bills per year or £120
saved a year for an average 4-
person household.
Reuse ofWater
Water reuse involves col-
lecting, treating, and reusing
wastewater (recycling). It can
also involve the reuse of grey-
water or rainwater in houses
or buildings. Recycled water
can be used for non-potable
uses e.g. industrial, agricultur-
al etc. If treated appropriately,
recycled water can be blended
with surface or groundwater
to increase supplies. This
reduces the economic and
environmental costs related to
establishing new water sup-
plies.
PureWater San Diego
To enhance San Diego’s
resilience to drought, climate
change, and natural disasters,
the city has launched Pure
Water San Diego which is a
phased, multi-year pro-
gramme to provide one-third
of the city’s water supply
locally by 2035. The pro-
gramme will use proven tech-
nology to clean recycled water
to produce safe, high-quality
drinking water and provide a
reliable, sustainable water
supply. Currently, only 8 per-
cent of wastewater is recycled
with the rest being treated
and discharged into the ocean.
The Pure Water Program will
transform the city’s water sys-
tem into a complete cycle in
which wastewater will be
treated to recycled water
standards at an existing water
reclamation plant, before
being sent to a Pure Water
Facility. The purified water
will then be sent to an existing
reservoir and blended with
imported and local water sup-
plies. After which, the mixed
water will be treated at an
existing drinking water treat-
ment plant, before distribu-
tion to customers.
Recovery of Materials from
Wastewater
Traditionally, waste-
water is seen as a burden
that needs treating and dis-
posing of. However, waste-
water is a source of valuable
resources including energy
and nutrients. The positive
impact of recovering
resources from wastewater
is additional revenue
streams for utilities and
mitigation of emissions.
BerlinerWasserbetriebe
Recovering Resources
fromWastewater
Berliner Wasserbetriebe’s
Schönerlinde sewage treat-
ment plant is turning sewage
sludge into sewage gas to gen-
erate power and heat.
Additionally, the utility has
constructed three wind tur-
bines, with a capacity of 2 MW
each, as well as two micro gas
turbines to complement the
plant’s CHP unit. Overall,
around 84% of the energy
required by the plant is pro-
duced internally, saving up to
13,000 tons of carbon emis-
sions per year. Berliner
Wasserbetriebe has also
developed a patented process
for recovering phosphorous
from its sewage treatment
plants. The recovered phos-
phorous is sold under the
brand name ‘Berliner Pflanze’
(Berlin Plant) to horticulture
and agriculture producers in
the surrounding areas of the
city. Several years ago,
Berliner Pflanze won the
GreenTec Award for environ-
mentally-friendly recycling
products.
Overall, cities and their
respective water utilities can
implement the urban circular
water economy by using
demand management strate-
gies to reduce water con-
sumption, for instance,
enabling customers to calcu-
late their water savings poten-
tials, reusing wastewater to
supplement local supplies,
and by doing so reducing
dependency on imported
water, and recovering valu-
able resources from waste-
water to produce new prod-
ucts.
Robert Brears is the author
of Urban Water Security,
Founder of Mitidaption, and
Our Future Water."
@Mitidaption
URBAN WATER
By Robert C. Brears