Water management has become extremely challenging due to worst impacts of the climate change on the hydrological cycle due to unpredictable precipitation patterns. The harsh reality in some parts of the world today is that the daily showers and flushing of the toilets with the potable water has become unaffordable. Many cities in the world are facing the ‘Day zero’ when millions of settlers are without adequate water both for households and industries.
This scarcity is driven by ill-management of water resources by multiple parties, vulnerability to climate change, and the fast pace of economic and population growth. The single-biggest user of water worldwide is agriculture, followed by energy production, industry, and in last place household use. The climate crisis has multiple impacts, including from increasing heat and rising sea levels tied to global melting of the cryosphere. The draining of the aquifers and related saltwater intrusion from the oceans are already depleting freshwater resources at an increasing rate. While freshwater can be sourced via desalination, that path is expensive and energy intensive, effectively countering much of the good it might offer.
It is for this reason efficient treatment and reuse of wastewater is the current best hope to mitigate this global crisis. Agriculture-based economies which are exporting “virtual waters” must increase the share of wastewater to meet their internal needs. This is even more imperative for the world’s most populated countries, India, and China, as they work to stay the water scarcity crisis within their own lands. Besides that these countries will benefit from just water resource alone, building into the process an energy recovery capability helps achieve sustainability in the water reclamation process.
This paper presents how wastewater can be channelized into green energy resource such as biogas, microbial fuel cells, and biodiesel; and how it is transformed into various bio products, nutrients, food, and potable water in order to combat severe impacts of droughts. Furthermore, even while it has become the norm to measure carbon footprints to minimize global heating aspects of production and consumption, we propose instituting the new concept of calculating the “water footprint” for each of our future actions. This footprint includes consideration of what are referred to as green, blue and grey water, as they related to intake from precipitation, the surface or groundwater, and polluted water at the point-source as well as runoff. Understanding of the water footprint is not only relevant for government bodies, policy makers and industry, but also for us as individuals within our communities. Doing so could help transform our total available supply of water for all uses. It could also shift our thinking of water as something we consume to something which is genuinely renewable.