WaterHubs: Infrastructure for Urban Slums

By Saurabh Saraf 14 July, 2015

WaterHubs CEO Saraf on how WaterHubs is a holistic & fiscally viable water & sanitation solution for urban slums

With a urban slum population of 523mn & still growing, the need for basic infrastructure in Asia's cities is rising
Cities need to be circular; using 3% of land they produce: 50% of waste, 80% of GDP & use 75% of resources
WaterHubs provides a circular & fiscally viable solution (generates revenue from recycling) for up to 50,000 people

WaterHubs is a modular water & sanitation infrastructure solution for urban slums 1. Around 862 million people live in urban slums in developing countries2 with little access to basic services. By 2050 around 66% of the world’s population is expected to live in urban areas3 with developing countries witnessing massive urbanisation. Conventional infrastructure isn’t capable of dealing with today’s demands leading to the formation of slums. Therefore, for the long-term sustainability of cities we require an innovative solution. WaterHubs is an answer to some of these challenges.

Urbanisation in the developing world

In a century, a major part of the globe has moved to urban areas. From 10% to 55%, the increase has been drastic and is expected to continue. This is especially true for cities in the developing world, which will host the major part of this influx. It’s expected that 9% of the world’s population, by 2030, will be living in 41 megacities 4.

People living in urban areas has increased from 10% to 55% in a century

Developing regions will witness a surge in urbanisation in the coming decades

Interestingly enough there lies a correlation between the extent of urbanisation and the human development index 5 (HDI). Further more, highly urbanised & high-income countries also rank high on HDI, followed by middle-income and low-income countries. Needless to say, urbanisation has opened doors for a large number of people to opportunities for economic growth. What’s important is to make sure that the consequent infrastructure developments that aid growth be principled by tenets of sustainability. A sustainable or rather circular approach becomes all the more pertinent for our cities given that they produce 50% of global waste, 80% of global GDP, 60-80% of GHG emissions and consume 75% of  natural resources but occupy just 3% of global land surface 6.

A sustainable or rather circular approach is pertinent for our cities given that they:

  • produce 50% of global waste, 80% of global GDP, 60-80% of GHG emissions;
  • consume 75% of  natural resources; but
  • occupy just 3% of global land surface.

Human development index vs urbanisation are positively correlated


Lack of appropriate infrastructure in developing world forces people to slums

Emergence of slums in Asia, the “economic centre”

~523 mn people live in urban slums in Asia
61% of the entire urban slum population in developing countries

In developing countries, due to the major influx of populace into urban centres and lack of appropriate infrastructure, a large proportion of people are forced to live in slums.
Major Proportion of Urban Slum Populations (million) Lies in the Economic Center of Gravity i.e. AsiaRoughly 523 million live in urban slums in Asia, which is 61% of the entire urban slum population in developing countries7.
As much as the economic centre is moving towards Asia 8, so is the need for basic infrastructure provisions for the cities becoming increasingly important.

Sanitary provisions… or rather lack of it
Slums may have little or no access to basic provisions of sanitation and clean drinking water. The Millennium Development Goal (MDG), set by the UN, resolved to halve by 2015 the population without sustainable access to safe drinking water and basic sanitation and, by 2020 to significantly improve the lives of at least 100 million slum dwellers.

Some 2.5 bn people still do not have access to toilets

However, some 2.5 billion people still do not have access to toilets 9. Absence of sanitation facilities (or poorly managed facilities) leads to mass defecation, which has a toll on health and the environment.

WaterHubs: A resource ATM for urban slums

Days of centralised and controlled planning are far gone now, the world is dynamic and changing quickly. This means we need to evolve the way we plan and develop cities.

WaterHubs is a circular economy

By closing the metabolic loops of material flows within a system a lot can be done in terms of resource savings and efficiency. What’s needed is an integrated approach for tackling the water-waste-energy nexus with systemic solutions.
Closing the urban metabolic loops for realizing systemic efficiency and resource savings
Schematic WaterHubs Modular Blocks
In line with this, WaterHubs incorporates such tenets and is therefore an example of a circular economy in action. Developed at Biopolus (Hungary), WaterHubs is a modular water & sanitation infrastructure solution for urban slums. It integrates modular blocks of sanitation, water treatment & supply, organic waste processing, energy & nutrient recovery. The solution is co-created with the community and provides functions like:

  • Community services (toilets, shower etc…);
  • Biological sewage treatment & water recycling/reuse;
  • Waste processing and electricity access; and
  • Agricultural production.
How is WaterHubs any different from other infrastructure solutions?
With WaterHubs developing nations could design sustainable cities without needing to rely on conventional methods for infrastructure development. WaterHubs can also be used in existing slums thus ‘un-slumming’ them.  Technologies in WaterHubs are state of the art climate technologies and can serve 5,000 to 50,000 people. Although a decentralized solution, distributed networks can be formed to cover a population up to 1 million.
Our vision is to catalyze implementation of such facilities and reach 100 million people in the next 20-25 years. The short term goal for the next 5 years is to build facilities in different regions and cultures to reach a minimum of 100,000 people.

WaterHubs can serve 5,ooo – 50,000 people with state of the art climate technologies
It doesn’t rely on conventional planning

WaterHubs can expand in the form of decentralised and distributed blocks




There are three main differentiator of are WaterHubs:

  1. Holistic: Instead of a narrow focus on solving one problem, we look at it with other problems &/or demands. Instead of installing a toilet where there is none, we install an entire infrastructure that not only offers sanitation services but also treats the waste and extracts value from it (energy, nutrients etc…).
  2. Utility infrastructure: The community is able to treat the WaterHubs facility as a utility. Having a provision for community service is an essential component of our design. WaterHubs wouldn’t be a zone of filth or toilets but rather an aesthetic and pleasant space that can be used for daily activities & chores.
  3. Fiscal viability: Instead of being a cost centre for the city, WaterHubs will be a revenue generator. By extracting value from supposed waste WaterHubs will pay for itself.

Core Technology of Wastewater Treatment in WaterHubs

WaterHubs provides basic sanitation needs whilst recycling water & waste thereby also generating revenue

Overall we see great potential in WaterHubs as a solution for basic water & sanitation services for slums. At the same time there is tremendous opportunity to save and recycle resources including water and waste.
WaterHubs can be a model of integration and symbiosis between nature, technology and even society that we can show the world!

  1. www.waterhubs.org
  2. https://sustainabledevelopment.un.org/content/documents/745habitat.pdf
  3. https://esa.un.org/unpd/wup/
  4. https://www.economist.com/blogs/graphicdetail/2015/02/daily-chart-1
  5. https://hdr.undp.org/en/content/human-development-index-hdi
  6. https://www.unep.org/pdf/GI-REC_4pager.pdf
  7. https://sustainabledevelopment.un.org/content/documents/745habitat.pdf
  8. https://www.mckinsey.com/insights/urbanization/urban_world_cities_and_the_rise_of_the_consuming_class
  9. https://www.un.org/millenniumgoals/pdf/Goal_7_fs.pdf

Further Reading

  • 2014 State of Environment Report Review – China’s overall environmental quality in 2014 was “average”, but with polluters tampering with monitoring, can we even believe this data? We take a closer look at the mixed news
  • Rural Drinking Water Solutions – 783 million people in rural areas still lack safe drinking water due to diseases coursing through waterways. Ling Li on why a traditional water distribution system is not necessarily the best answer & shares cheaper alternatives
  • Wastewater to Energy in Urumqi – In Urumqi, China water & energy demand has increased due to rapid growth. Veolia’s Nina Cambadelis on how they upgraded a wastewater treatment plant in Urumqi to produce biogas from the digestion of sewage sludge
  • China’s Economy: Linear to Circular – China is the 3rd country globally to enact polices to move towards a circular economy. See how & why China needs to make this transition; which industries are affected, what is the role of industrial parks?

Urban water challenges & solutions

  • Urban Water-Energy Strategies – With rising urbanisation and the need for more water & power in Chinese cities, water & sustainability expert, Robert Brears shares some price & non-price management tools to better manage urban demands
  • Can Cities Meet Increasing Water Demands – Nitin Dani and Georgina Glanfield from Green Initiatives Shanghai share their thoughts on how Chinese cities can ensure water security. Can the public play a role?
  • Consumers Willing To Pay More for Water – Lu Shuping, President of Xylem China, shares the findings of a survey of six Tier 1 & Tier 2 cities in China which show that consumers understand the seriousness of water issues & are willing to pay more for safe drinking water China Water

Drinking water in China

Chinas Long March To Drinking Water 2015 Reprot - EnglishChinas Long March To Safe Drinking Water 2015 - CH

  • Water Source: Who Is Responsible? – Data shows water source quality improving but some experts question how accurate this can be without a specific standard? Moreover, pollutants, ineffective treatment & unclear ministry responsibilities pose threats. CWR’s Hongqiao Liu expands
Saurabh Saraf
Author: Saurabh Saraf
Saurabh is the CEO of WaterHubs. He has an entrepreneurial background with experience in the environment and energy sector, management consulting and policy research. He has founded cleantech ventures and has assisted other start-ups in the cleantech and social space. He was involved as a consultant on projects commissioned by the Swedish Energy Agency on alternative venture capital investing approaches in the cleantech domain and the role of public venture capital in this area. Since 2014 he is leading WaterHubs, a modular water & sanitary infrastructure solution for urban slums. The solution aims to bundle technologies into a system that thus integrates resource management and enhances biological production. This social business in being developed at the Biopolus Institute, Hungary.
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