If time travel were possible, and an engineer from the 1860s could travel in time to 2019, he (the first female engineer had not graduated yet) would not recognize much of the technology we have today. Personal computers, cell phones, cars, planes, and antibiotics would probably be unfathomable to him. But he would definitely recognize our current piped water and sanitation (WSS) infrastructure, as it looks and operates almost exactly the same as it did 150 years ago. Certainly, there have been significant improvements in the sector, especially in water and wastewater treatment, but the principles on which the piped WSS technology is based have not seen any fundamental changes since the 1860s, when it was (re)introduced on a large scale.
When looking at the urban WSS sector specifically, the contrast with the energy sector is stark, as both sectors share some similar characteristics. Yet, when taking a look at the number of patents filed and the volume of global investments in the energy and water sector, the water industry is lagging far behind.
Vested interests, pricing and subsidy policies, and regulation also play a role. These explanations directly relate to the characteristics of the current technology. WSS infrastructure is very capital-intensive and long-lived, which gives rise to locked-in effects, while the monopolistic nature of the service makes innovation less necessary. In addition, the individual elements of WSS systems have very different lifespans. Whereas piped networks can last for up to 70 to 100 years, the pumps needed to transport the water or wastewater have much shorter lifespans, and so do treatment plants. This variety in lifespans ensures that the WSS system remains functional with relatively small upgrades. At the same time, the fragmentation in the sector may hinder not only the generation, but also the diffusion of new technologies in a sector where regulation tends to be more backward than forward looking.
Many technologies that already exist can provide alternatives to the current centralized, conventional piped WSS systems. They include, amongst others, rainwater harvesting, distributed stormwater management, water reclamation and recycling, source separation technologies that use dual distribution systems to provide different water qualities for different uses, and a much more prominent role of nature-based solutions to deal with wastewater. There are also increasingly more options to personalize water supply and wastewater systems by installing at-home water treatment systems (such as UV microbiological systems, personalized membrane technology, whole-house filters for chlorine, taste, odor and particulates, recycling of water and treating wastewater within buildings) and separation of wastewater, that in combination with rainwater harvesting may provide more alternatives to consumers that allow them to have more decision-making power.
Some countries are embarking on policies to move to a circular economy. Moving from a linear water system to a (short) close-looped circular configuration has already resulted in very significant reductions in potable water consumption and wastewater discharges where these technologies have been applied. Green infrastructure, such as green roofs, rain gardens, and other measures to manage stormwater in such a way that it can replace low-value use of potable water, are another set of technologies. And finally, technologies such as 3D printing, driverless cars (that can provide water as a backup in fully personalized water systems on a demand basis) and improvements in the management of water consumption (through better data on actual, in real-time monitoring of use) can all result in changes in the demand for potable water, enabling a shift away from large centralized systems where appropriate to more decentralized and personalized solutions.
To move to a future with a wider range of technologies in use, more insight is needed in the actual trade-offs when adopting alternative technologies. Often the full cost of conventional systems is not taken into account, while sunk cost fallacies tend to stifle innovation. The adoption of alternative technologies will depend on context – more likely in places that have not yet embarked on the conventional technology: places that need to change their conventional systems as they are in need of replacement and countries that want to move from a linear to a circular economy. It will also require looking into a wide range of incentives that prevent the adoption of different technologies, which goes way beyond the traditional scope of WSS regulation and will require the realignment and/or creation of incentives in and outside the sector to allow for innovation to take place.