Page 55 - Green Builder Sept-Oct 2019 Issue

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Tips, Technology and Common Sense
Solutions for a Thirsty World enough water for their needs, companies offering
rainwater harvesting services will likely want to explore
the efficacy and profitability of different systems.
Many experimental rainwater harvesting (RWH)
systems and studies provide valuable insight, such
as “Urban rainwater harvesting systems: Research,
implementation and future perspectives,”written by
a team of academics from the U.S., United Kingdom,
Australia, South Africa, Israel, Italy, Brazil, Japan and
South Korea, and published in 2017.
A major finding was that the selection of technologies
used and the implementation of RWH systems are often
influenced by local laws and regulations and economic
constraints. Another was that design protocols tend to
focus on water conservation, ignoring other potential
benefits of rainwater harvesting. They found that
while RWH systems in urban areas show a wide range
of applications, many potential benefits tend to be
controversial.
Conventional rainwater harvesting systems and
innovative “new systems” are discussed, including
modular systems, collapsible tanks, and high-level, low-
energy systems, as well as more complex systems that
incorporate infiltration systems, bio-retention cells, and
even rain gardens. RWH systems with dual storage CREDIT: WORLD HEALTH ORGANIZATION
facilities are also considered.
It’s a no-brainer that when it comes to quality,
harvested rainwater relies on the materials used for RWH
systems and is affected by runoff surfaces. Acid rain can Waste not, want less. Rainwater harvesting and recycling are considered key ways to meet
be an issue in areas where there is a lot of vehicular the world’s ever-growing water demands in the next several decades.
traffic, industry and high-density housing or office development. gutters, and both galvanized iron and copper piping. The microbial
Even agricultural bush-burning can be a problem, though this is quality of the water is another factor that must be taken into account,
normally restricted to rural areas and/or developing nations. and depending on the end-use of the water, it may be necessary to
Contaminants also come from roofs and gutters, particularly incorporate filters and pumps in RWH systems.
when metal is part of the structure including zinc and aluminum
H O-NO
2
In some parts of the world, the concept of rainwater harvesting takes
on new importance when it comes to a basic function: flushing a
toilet. The feeling tends to be one where drinking water is considered
too valuable to be flushed down the drain. That philosophy is
explored in a new European study.
“An Analysis of the Effectiveness of Two Rainwater Harvesting
Systems Located in Central Eastern Europe,” published in January
2019, examines two systems established for toilet flushing needs in
Kosice, Slovakia and Rzeszów, Poland, where drinking water is in
short supply, and where rainwater harvesting systems are rarely
COURTESY OF INNOVATIVE WATER SOLUTIONS there are no formal regulations or guidelines that encourage the use
used because they are considered unprofitable. As such, the fact that

of RWH systems is considered a disadvantage.
Student dormitories in major urban areas were used for the study,
and in both cases, there was a high and constant demand for water.

the Nemcova dormitory in Kosice, and 90 cubic meters in the Ikar
dormitory in Rzeszów—and water was discharged to both via a
Thinking bigger. It’s free, it’s natural and it’s abundant—yet rainwater harvesting Similar-sized underground tanks were used—100 cubic meters in
is only now starting to become a viable, logical option for thirsty nations. pipe system. The Kosice roof was sloping while the other was flat.

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