Water management in commercial buildings—thinking differently
Throughout the world, there is increased pressure to track and conserve water in nonresidential buildings. This article reviews the current water management options, such as using greywater and rainwater, and looks at less traditional management options, such as wastewater and condensate reuse.
As the world's population continues to grow and our cities and suburbs expand, with more buildings to accommodate the growth, we are facing a major challenge to manage and protect our valuable water resources. This is becoming especially critical under the added pressure of climate change.
The conventional and common approach to water management involves supplying potable water and disposing of wastewater and stormwater. The latter may be disposed of onsite. It is becoming increasingly apparent that this conventional, centralized approach must change in response to urbanization trends and climate predictions. As the availability of clean freshwater resources is diminished,
it is becoming clear that wastewater and stormwater should be viewed as alternative and valuable sources of water, and not just inconveniences needing to be dealt with. Consequently, rainwater collection and reuse and the reuse of highly treated wastewater effluent are attracting increased attention. They are most-commonly provided for nonpotable end uses; potable reuse is also gaining traction.
Many communities have begun to implement simple and relatively inexpensive water-reuse projects, such as irrigating golf courses and parks, and the benefits of these are seen almost immediately. Benefits from widespread adoption include improved reliability and drought resistance of the water supply, utility savings in infrastructure maintenance and deferred capital expenses, and the immediate rewards of green and lush outdoor recreation spaces.
There are also environmental advantages to consider. The use of reclaimed water ensures the transfer of nutrients to beneficial uses rather than discharging them into receiving waterways. Contamination of bays and lakes with nutrient-rich stormwater and wastewater increases the risk of eutrophication (excessively high nutrient concentrations), the consequences of which include low dissolved oxygen concentrations, algal blooms, and declining shellfish populations and periodic fish kills.