Water Treatment/Conservation
Products with the water treatment/conservation feature either
increase the quality of water or reduce the amount of water
used on a site. Generally, this involves reducing the amount
of water that must be treated by municipal septic systems,
with the accompanying chemical and energy costs. This can
be accomplished in two ways: by physically restricting the
amount of water that can pass through a fixture (showerhead,
faucet, toilet) or by recycling water that has already entered
the site. For instance, graywater from cooking or handwashing
may be channeled to flush toilets; captured rainwater
may be used for irrigation.
Water Conservation issues address efficient use of water as well
as an overall reduction in the volume consumed. Water-saving
showerheads and toilets are now widely used in residences as
well as commercial buildings. Even in the Great Lakes region,
with its abundant freshwater, conservation becomes an issue
as municipal water treatment plants and septic systems are
strained by urban sprawl. With the exception of buildings
utilizing well-water and septic systems, all water that comes
into or leaves a building must be treated.
Vacuum-assisted or composting toilets use very little water and
therefore produce less waste. The advantages of composting
toilets are that no waste enters the already overburdened
waste stream, and the resulting compost can be used as
fertilizer. The potential to separate the wastewater stream
into “graywater” (dirty from washing or cooking but not
containing human or animal waste) and “blackwater” (sewagecontaining biological waste or factory effluent) can be incorporated
into plumbing and fixture design. Restrooms in Japan
commonly direct water from the sink drain to the toilet tank,
where it is used to flush toilets. The use of indigenous plants
that are drought-tolerant reduces the need for irrigation, as
important a consideration for the homeowner in Detroit as in
Phoenix.
Rainwater collected from roofs or paved parking lots can be
used for flushing toilets and landscape irrigation. The building
itself can be designed to act as a collector of rainwater, to be
stored in a cistern for later use. For health reasons, current
building codes prohibit the use of this gathered water for
human consumption, but it is possible that future water
purification devices will make on-site water safe to drink
—at a lower cost than current municipal water treatment.