The growth of urban settlements is subject to a range of factors influenced by demographic, economic, political, environmental, cultural, and social factors. Weather variability, or climate change, has recently risen up this list. These two factors: climate change and urban population growth, are dramatically affecting urban water management. On one hand, growing populations increase urban water demand and on the other, climate change has increased water variability (volume, distribution, timing and quality).
Parallel to these factors, urban water management has a few problems of its own. Global water infrastructure, whether for water supply, storm or waste water management; is old and was built for the demand of cities 30 to 100 years ago. It is ill-equipped to handle the current challenges of today, including population growth and climate change. The water sector is conservative, focused on public health, reliable service, and compliance with regulations, with good reason. However, traditional centralized, networked systems of drinking water supply, storm water drainage, and wastewater disposal are not sufficient. In reality, water is demanded, and storm and waste water are generated in decentralized, disorganized locations.
Citizen concern is growing as they experience first-hand that growing populations and climate change have effects on their water. Water security, flooding, healthy water bodies, affordability of services, etc. are all trending stories in the news these days.
How will cities adapt? Reframe. Develop new responses.
Instead of sourcing water from sources farther away or deeper underground, what if we asked how to reduce our need? How do we reuse what we have, or recycle what we’ve used? Water management philosophy in cities has to evolve to include other solutions beyond new traditional infrastructure that very expensive to build and maintain and takes time to construct.
Changing the paradigm from traditional technocratic solutions to those that are more agile, adaptable, and affordable is the key for the future. Although the water sector is conservative by nature, it needs innovation to challenge the status quo and that can overcome the constraints of existing infrastructure, governance, and prior decisions. It’s easy to put blame on governments, which are working hard and dealing at high volume to supply the demand of constituents. Citizens also must change their habits and tastes in order to make change work.
Below, I review two water innovations that reduce, reuse, and recycle urban water resources. By no means are these innovations an exhaustive list, rather they are innovations that may influence and impact urban water supply management.
Reproducing Urban Supply
Water for human consumptive uses, like drinking, cooking, bathing etc. are the major concerns for urban areas. Globally, about 2.5 percent of the water in the world is freshwater, and only 32 percent of that is accessible. Although there is enough water in the world for everyone, the distribution of the resource is the one of most concern. Moreover, growing cities get thirsty fast, requiring exponentially more water for their people and their needs. How to quench the growing thirst without getting more water? The innovations below range from small to large scale solutions that create more water.
Water from the Sun
Water is all around us, even though we cannot see it. On sticky summer days we can feel it in the form of humidity or early mornings we can see it as fog. Science has long searched for ways to harvest atmospheric moisture but each solution had problems. Dehumidifiers consume lots of power, wick nets do not collect enough water, and both perform optimally in humid environments. The main question: how to develop a water harvesting solution that consumes low amounts of energy, produces enough volume of drinkable water, and that works in an arid environment.
The answer was found by combining material science, the understanding of dew point, and solar power into the creation of a solar water collector. Two similar approaches were developed in 2017 but the principles are the same: air is allowed to flow through the device, special nano-materials are used to collect the water molecules in that air, a temperature change is created to allow for condensation. The water is then collected. The energy and the aridity problem are solved at the same time through the use of solar power. The products that are in development can generate about 3 liters of water per day, and that level of water production is scalable. The science fiction of pulling water out of thin, dry air is fast becoming fact.
Water from our Waste
The second innovation in reproducing water supply may not be as appetizing as the previous: water from waste. If you are like me and enjoy watching survivor reality shows, we have seen the star drink “water” from animal dung or even consume their own urine. Although it turns our stomach, we accept it as a form of survival. But can we accept something similar for our daily water intake? Reclaimed waste water is not a new concept in the field of engineering, but it is something that is hard to swallow conceptually.
Countries like Namibia, one of the driest on earth, have been doing this for decades. Before the mid-1900’s, the capital city of Windhoek sourced local springs for drinking water supply. When these springs dried up, combined with years of drought, the most viable way to keep with demand was wastewater reuse.
The process is natural; bacteria aid in the processing of human waste, while at the same time draw out moisture, doing what nature would do normally, just faster. Of course, the water is treated before it is recirculated into the water supply system.
Bill Gates was recently recorded drinking a glass of “poop water” to demonstrate the product of the Omniprocessor, a project funded by the Gates Foundation. It is the evolution of wastewater reuse. The machine is fed sludge which is then boiled. The water vapor is the first byproduct that is turned into drinking water. The dried sludge is the second byproduct which is burned to fuel the machine as well as produce excess energy to feed a power grid. The burned ash is a third byproduct that can be disposed of without any harmful issue. The machine is a closed system that is more modular than a wastewater facility, and affordable enough for developing countries.
Each of these solutions also provides added value. The solar water collector and Omniprocesser both generate their own power, which lower the impacts on the environment. Solar water can be scaled up to provide more water in arid areas without additional infrastructure. Water from waste embraces the 1980’s concept of Reduce, Reuse, and Recycle for human waste, and also mitigates the impact of wastewater treatment.
Urban water management strategies have been conservative for the last century, focusing on capital-intensive infrastructure solutions for water supply. In the years to come, urban water systems will need to integrate existing infrastructure with innovations in providing hybrid solutions that are agile, adaptable, and affordable. Although change rarely happens unless there is some catastrophic event, the confluence of population growth and climate change have managed to force cities and their respective water authorities to change the paradigm. Solar water collectors and water from waste are two such innovations that are agile, adaptive, and affordable for the developed and developing world to supplement the growing demand for water. However, we should always be mindful of how much we use versus how much we need.
Image: Stockholm (Pixabay)
Source: Meeting of the Minds
This article is culled from daily press coverage from around the world. It is posted on the Urban Gateway by way of keeping all users informed about matters of interest. The opinion expressed in this article is that of the author and in no way reflects the opinion of UN-Habitat.