ENVIRONMENT AND ENERGY
35
In dual distribution systems, the partially treated
wastewater is delivered to customers through a
parallel network of distribution pipes separate from the
community’s potable water distribution system.
The reclaimed water distribution system becomes a third
water utility, in addition to wastewater and potable water.
Reclaimed water systems are operated, maintained and
managed in a way that is similar to the potable water
system (US EPA, 2012).
Direct use of treated municipal wastewater has been
practised for some time, for example in St. Petersburg,
Florida, where reclaimed water is provided for several
residential properties, commercial developments and
industrial parks, as well as a resource recovery power plant,
a baseball stadium and some schools (US EPA, 2004).
Supplying nutritionally adequate and safe food to city
dwellers poses a substantial challenge. Peri-urban
agriculture offers one solution but requires adequate
water. Municipal wastewater is often (usually informally)
used without treatment, resulting in serious health risks
for both farmers and those who consume the food. Social
customs and diets dictate how risky this practice is. An
example of direct wastewater reuse is the sewage fed
ponds in Kolkata, India (Box 3).
Managing urban runoff
Climate change adaptation seeks to lower the flood risks
associated with extreme rain events, but if developed
in synergy with urban development, it can also address
some of the problems associated with urban wastewater
management.
Cities are increasingly concerned with the effects of climate
change, which include higher risks of flooding and raised
temperatures, combined with increasing demands for safe
drinking water supplies (State of Green, 2015).
Rainwater in the form of surface runoff can contribute to cities’
water balance and be collected to create attractive recreational
areas. A good example comes from Denmark (Box 4), which
shows how it is possible to use rainwater as a resource to
create more resilient and liveable cities. PA
In the next edition, Plumbing Africa will look at the
extent and nature of industrial wastewater production. It
will highlight the opportunities from the use and recycling
of wastewater and the recovery of energy and useful
by-products when addressing natural resource challenges
in the context of sustainable industrial development.
October 2018 Volume 24 I Number 8