Canada is fortunate to have 25 percent of the world’s fresh water, however
our easy access has lead to wasteful habits. It is estimated that the average
person uses 340 liters per day while at work and at home. Compare that to many
small Guatemalan villages where two liters per day per family would be a luxury.
Our continued expectation for unlimited supply is not sustainable.
Because of our large demand for water, the old logic on delivery and disposal
no longer applies. The challenges include over-use of chemicals, energy used for
pumping, infrastructure lifecycle cost, waste treatment failures and sewage
sludge disposal. Municipalities have been reaching out to industry for solutions
for years, with little result until recently.
Hope for change is linked to LEED – Leadership in Energy Environmental
Design, which is educating all parties on how to decrease water use, how to
reuse and how to treat the waste. Points are awarded for following those
recommendations and buildings are rated for their success.
Homes can be entirely independent from the sewer and water infrastructure.
Many commercial buildings have decreased their water consumption by 50 percent
and more. The following is an overview of how the construction industry is
adapting materials, technology and installations to meet these new targets for
all types of construction.
Water Reuse
This is all about using the water that falls on a property for the occupants.
The intent is to stop directing rainfalls to ditches and the street, where it
becomes someone else’s problem instead of the owner’s asset. By capturing that
water, storing it and using it for household purposes, you can decrease the use
of municipal or well water.
Water consumption is relatively easy to estimate based on the number of
persons in your household and their habits. There are statistics on annual
rainfall for every location and, with a little math, the size of a cistern is
determined and you can begin to harvest rainwater. Harvesting from asphalt roofs
is not recommended because of the bituminous base content. Metal and green roofs
are ideal.
Most Natural Life readers are aware of these methods and many are already
using them. What is interesting is how a relatively conservative North American
building industry is enthusiastically adopting these unconventional methods. It
is now seen as a logical and practical solution, one that has been relied on for
decades in many other countries.
The harvested water is first used for laundry and showers, while municipal
water is encouraged for lavatories and kitchen sinks where it is more likely to
be ingested. Treatment equipment is available so it could be used there, but
regulatory bodies are not yet ready to relax laws where there might be health
risks.
Then, the so-called “grey water” from laundry and showers can be collected
for use in toilets and irrigation.
The reduction of potable water and “black water” sewage to and from the
municipality can easily be reduced by 50 to 75 percent. Commercially, LEED
awards a point for treating 100 percent of black water on site. Conventional
septic systems do not qualify because of their poor maintenance record.
Irrigation Systems
Native plants and grasses are naturally adapted to local conditions, thereby
eliminating the need for the application of water and chemicals. The days of
well watered, evenly cut lawns, (referred to as “turf grass”) will soon be
history. Instead, varieties of plants, mulch and grasses that require no cutting
and little or no water will be growing in its place.
Both commercially and residentially, LEED standards encourage less than 50
percent usage of potable municipal water for landscaping. This does not mean
that the result will be fields of weeds, because the goal is well-kept
properties. So new technologies have been developed that will help bring
landscaping back to an art form. Natural landscape specialists are knowledgeable
on the precise number of drops each plant requires and the preferred timeframe.
The rate at which the soil loses moisture under specific plants is also well
documented. Programming the requirements by using computer-controlled irrigation
technology results in meeting the landscape’s watering needs with minimum
amounts.
Indoor Water Reduction
New models of conventional fixtures decrease water usage by 20 to 30 percent.
Commercially, the automatic eye creates the best saving as does the waterless
urinal. Composting toilets are now considered a plumbing fixture. It was a
surprise to me to learn that they are being used in multifamily units with
success.
For those with a lifelong appreciation for water, these measures are old
news, yet for many this is a new discovery that makes perfect sense. LEED first
introduced this to commercial builders in 2004 and most of the easy changes like
replacing fixtures are complete.
Owners have noticed the difference in water bills and now are hungry for more
savings. For this reason, many projects on the drawing boards across the country
are showcasing green roofs, water harvesting and storm water management. In
March 2009, residential builders in Canada will have LEED for Homes to follow.
In the foreseeable future, new subdivisions will have a 50 percent reduction in
water demand and sewage waste.
In my next column, we will look at how energy can be saved in a big way.
Hugh Perry provides assistance in the preliminary stages of
design for sustainable buildings by preparing hand sketches, cost comparisons
and answers to the many questions regarding recycled materials, water use,
healthy environment, energy and durability. Email him at
hughper@gmail.com
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