Green buildings and water efficiency

Alan Millin
freelance scientist, engineer, environmentalist and thinker
email:

Green building; the phrase has become something of a buzzword across the globe. The United States Environmental Protection Agency (EPA) defines green building as "..the practice of creating structures and using processes that are environmentally responsible and resource-efficient throughout a building's life-cycle from siting to design, construction, operation, maintenance, renovation and deconstruction. This practice expands and complements the classical building design concerns of economy, utility, durability, and comfort. Green building is also known as a sustainable or high performance building."

It’s true, green building is often referred to as sustainable building but, in reality, simply building a “green” building is no guarantee of that building being sustainable. It is here that many green building rating systems fall short. Green building is an important step on the road to sustainability but it is just a step. To certify a new building under one of the many green building rating systems, such as the US Leadership in Energy and Environmental Design (LEED®) system, and then walk away from it is to possibly condemn that building to a lifetime of low quality operation and maintenance that renders the building unsustainable. It is the operational phase a building’s lifecycle that will determine the success of the facility in terms of sustainability.

Renewable internal freshwater (m³ per capita) / Annual freshwater withdrawal (% of internal resources) Little Green Data Book Figure 1: Arab towns: Per capita renewable freshwater reserves vs. annual freshwater withdrawal rate (The World Bank, 2014)

Many different green building rating systems, regulations or guidelines have been implemented or proposed. In the UAE for instance, LEED is used but Abu Dhabi also has its own Estidama rating system. Dubai has issued its own green building regulations while Dubai World had also previously issued its own regulations. A conference speaker unveiled a copy of Ras Al Khaimah’s “Green Building Regulatory Guidelines” in October 2008. Qatar developed its Global Sustainability Assessment System (GSAS) after reviewing more than 140 rating systems while Egypt has its Green Pyramids rating systems and Lebanon its ARZ system.

One common element of major concern within Arab towns is that of water. Figure 1 shows the relationship of available water to the annual withdrawal rate[1].

Figure 1 clearly shows that some countries are dependent on water from sources other than internal, such as desalination.

What water we do have has to be effectively managed. In Qatar for example, although internal freshwater reserves are clearly limited, Doha’s buildings and roads have suffered from rising groundwater, attributed to uncontrolled irrigation, distribution system leakage, sewage system leakage and leakage from the tanker distribution system, with the problem aggravated by rainfall[2].Rising ground water is not an isolated problem occurring only in Doha. In the UAE, Al Ain is also experiencing rising groundwater which may cause damage to buildings[3]; In Saudi Arabia Jeddah is faced with the same issue[4].

While the underlying reasons for rising groundwater may be varied, it is clear that we need to manage water consumption and wastewater handling. Over 50% of the countries shown in Figure 1 are consuming more

water than they have in freshwater reserves.

Green building systems provide us with strategies to optimize our water consumption. These strategies include the installation of low-flow fittings and fixtures. LEED for example provides us with baseline flow rates for taps and toilet fittings which we can then strive to improve on. We can educate people on water conservation in their own homes so that each person makes a contribution to national water management.

Figure 2: Irrigation leakage

Washing machines are now smart enough to decide how much water to use, along with how much detergent should be used and the minimum temperature that the wash should be performed at. Indeed laundry equipment is available now that claims to use up to 75% less water than conventional machines and minimizes the use of chemical detergents by using polymer beads[5].

Figure 3: Excessive irrigation

One of the mantras of the green building community, used in relation to waste management, is Reduce, Reuse, Recycle. Efficient water fittings and fixtures allow us to apply a similar philosophy to wastewater management. Our goal should be first to reduce our wastewater generation and to do that we need to minimize our consumption by becoming more efficient with our water usage. Of course efficient water fittings alone will not minimize water consumption; we also need to consider our own water-consuming habits. Once we have reduced our water consumption to a minimum we can then consider ways to reuse water that has already satisfied our initial needs.

There are several factors inhibiting the growth of water reuse within the Arab region, including social acceptance and technical limitations [6]. The reuse of water does however offer considerable benefits. Processing on-site generated grey water, typically water that has been used but which has not come into contact with human waste and which accounts for up to 70% of domestic wastewater, has been shown to yield annual savings per family in excess of $300[6]. On-site grey water processing also allows the building occupants to be completely sure of the origin of their grey water supply. Wastewater that does make its way to municipality treatment plants can also be reused. Treated wastewater is useful for irrigation and also for cooling plant heat rejection.

Green building rating systems provide us with proven strategies to improve our management of water. A 2009 survey found that LEED projects have saved an aggregate 4.54 trillion liters of water[7]. LEED targets both indoor and outdoor water usage and also requires the installation of permanent water meters to monitor potable water consumption in the building and the grounds. Meters allow building owners and operators to quickly identify leaks and areas of high consumption. Project teams should resist the urge to “value engineer” meters out of projects. Strategies for improved water conservation are available now; we just need the will to implement them.

References:

  • The World Bank, The Little Green Data Book - 2014. 2014 ed. 2014, Washington D.C.: The World Bank. 248.
  • Hashim, D.M.A., Water, Agriculture and Environment in Arid Lands. 2009, Doha: Friends of Environment Centre. 375.
  • Ahmad, A. Rising water threatens Al Ain building foundations. 2012 [cited 2014 07 November 2014].
  • Arab News. http://www.arabnews.com/node/369577. 2011 [cited 2014 07 November].
  • Xeros, http://www.xeroscleaning.com/xeros-benefits. 2014: Xeros.
  • UNDP, Water Governance in the Arab Region. 2013: New York.
  • USGBC, LEED Reference Guide for Building Design and Construction V4. 2013: U.S. Green Building Council
  • .
< Prev Article Next Article >
Website Design by Traffic