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How infrastructure can optimise the value of poo

19 November 2018

Functioning sanitation systems are vital for healthy cities – but not every city can afford to have complex underground sewage systems. On World Toilet Day, Jack Sim, founder of the UN-affiliated, explores some interesting alternatives.

How infrastructure can optimise the value of poo
Image credit: Shutterstock

Since the pioneering and life-saving work of Bazalgette in 19th century London, sanitation systems have been based around the assumption that the provision of a network of underground pipes to remove sewage from individual properties is essential for a functioning system. 

The problem with this as a solution is that the construction, operation and especially maintenance of underground sewer networks is prohibitively expensive for most cities in the global south.

Getting bogged down in trying to design and maintain cheaper underground sewer networks, or finding extra sources of finance, is not the answer.

Instead, what’s starting to work – and at increasing scale – is a different approach. It involves identifying all the functions that need to be performed, the existing components in each specific location, the needs and potential contributions of all stakeholders, and then re-combining those components to align the economic incentives of all stakeholders in culturally-appropriate ways.

From taboo to new renewable resource

Recognising the inherent value of human faeces as inputs for either fuel (via anaerobic digestion) or compost enables a different train of thinking, design, and infrastructure provision. 

Rather than relying on ‘high cost, high maintenance’ sewage pipes to remove a flow of combined human waste, separating out the faeces right from the start enables different forms of economic value to be created and exchanged.

This means that, potentially, users of toilets are inevitably producing a valuable resource on an ongoing basis.

Hence the economic cost of toilet and sanitation provision can be shared affordably through new business models involving a different grouping of stakeholders: toilet users, collectors of human faeces including those traditionally doing dangerous latrine-emptying work, energy-producing plants, compost producers, designers and providers of appropriate toilets with easy collection features, and transport providers.

Knock-on benefits

So why is this good news for the overall cost of urban infrastructure in the global south? 
Transforming sanitation is critical to good health and good social outcomes, and hence to good economic outcomes. 

Investing in infrastructure in areas where there’s no sanitation provision, and therefore high incidence of preventable serious disease and death, is a difficult case to argue, which increases the cost of finance. 

But since low cost and self-sustaining methods of providing sanitation now exist, human health in many urban areas of the global South can now be significantly and permanently improved. 

In turn, this makes achieving an ROI on other forms of infrastructure investment far more likely, reducing that cost. 

New opportunity: one third of the world’s population?

Given that 2.4 billion people – yes, one third of the world’s population – still lack access to decent sanitation, and 900 million have no access at all, the potential opportunity for transformation via new viable business models is extremely large. 

Given the enthusiastic support for the UN’s SDGs (Sustainable Development Goals) at the first Global Engineering Congress recently, it will be great to see the infrastructure sector step up to the opportunity.

Food for thought I hope, wherever we may be sitting this World Toilet Day.