Smart cities need smart foundations. After a decade of trial and error, municipal leaders are realizing that it’s not just about installing digital interfaces in traditional infrastructure or streamlining city operations. Real smart-city strategies start with people, not technology. It is about using technology and data purposefully to make better decisions and deliver a better quality of life.

Currently, we only have a glimpse of what technology could eventually do in the urban environment. In today’s post, Albert Mateu, Zigurat’s professor for Master’s in Smart City Manager, discusses two aspects of smart infrastructures: urban waste collection and water supply.

Urban Waste Collection: In need of Modernization

When it comes to waste collection, much hasn’t changed in the last 200 years: citizens still deposit the waste on the streets or near their homes and specialized transport comes to recollect it.

According to Albert Mateu, the cities have to readapt the urban infrastructures according to their evolution. It is within these improvements where a solution to the waste collection appears. If practically all other city services (water, gas, electricity, telecommunications, heating, sanitation, etc.) rely on pipes, why can’t’ we use them also for waste?

Mateu imagines a system where the citizens deposit the bags inside hatches or boxes which, in turn, are connected to a long network of underground pipes. Several kilometers away, a building with a “giant vacuum cleaner” sucks the bags. Containers and collection trucks disappear.

Over the past few years, we have witnessed how various innovations have been reshaping the technology. Systems with more capacity, lower cost, higher performance and efficiency, lower electricity consumption, easier installation etc. have appeared. Today we can find more than 1,000 systems in operation worldwide.

The so-called “Automated vacuum collection 2.0” is a true “Smart Infrastructure” that is being strongly promoted in cities committed to sustainability, climate change, urban resilience and the services provided. But above all, this shift could be significant for the citizen, who, after all, is the true protagonist of a city.

Desalination: A New Generation Solution for Obtaining Freshwater

It is foreseen that soon the large metropolises will face severe and serious water supply problems, mainly due to an increase in demand and greater scarcity of natural resources (water deficit balance).

We are all more or less familiar with the solution of reusing wastewater and urban runoff, which means using (properly treated) freshwater again and again, for that purpose. And of course, water reuse can meet many needs of a city, such as urban cleaning or urban runoff, surface water replenishment and aquifer recharge, business and industrial water demand, and cover certain non-potable residential needs (indirect reuse).

This technique consists of extracting the mineral components of saline water to produce fresh water suitable for various uses, obtaining salt as a by-product, with reverse osmosis being the most commonly used technology at present.

However, due to its high energy consumption (an average of 3 kWh / m3) and the associated infrastructure and maintenance costs, desalination is considerably more expensive than obtaining fresh water from rivers or groundwater.

Other factors that should be taken into account when talking about desalination are adverse environmental impacts and how to minimize them. For example, the use of renewable energies to feed desalination plants makes it possible to minimize greenhouse gas emissions and concentrate saltwater catchments far from biologically productive areas in order to avoid the trapping and dragging of marine organisms.

Albert Mateu concludes that desalination plays a crucial role in the “portfolio of water supply options”. However, it should be considered as one of the options among many. Above all, cities have to understand that a simple increase in water production (by any method and at any cost) is not conceivable without a powerful action in reducing consumption and increasing wastewater reuse.

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