How can we make money from human waste?

As an undergraduate student in Kampala, my head was full of thoughts about how I was going to make a living after my studies. Back then Rich Dad Poor Dad was still a best-seller, and I thought to myself: I can become a billionaire if I sell a billion of something to a billion people. Needless to say, it would have to be something that anyone can afford, like toothpaste or chewing gum.

So, I wondered, what does every human need? It dawned on me: everyone needs water, food, and energy, every day. The next question was how I could make valuable goods from all the three as a civil engineer.

A fascination with sanitation

Over the course of my studies, I became interested in the intimate connections between water, food, and energy. I learnt about the water and nutrient cycles, and how we can recover resources from waste and use them to fertilize crops and generate energy.

The world’s population is rapidly growing, and much of this growth is happening in low- and middle-income countries. Most people now live in cities, and this proportion is likely to increase with time. These cities are going to be thirsty, hungry, and energy demanding, and we will need to become much more efficient in the ways we manage our resources if we are to meet their demands.

Looking at the supply side, each of us generates about 1.5 litres of excreta daily – all together, a huge amount of waste. We can, of course, flush it down the drain and into our rivers, lakes, and oceans; or we can turn our pee and poo into valuable resources, like power and protein.

Such resource recovery cuts the costs we all have to bare from emissions of pathogens and pollutants. For instance, consider Lake Victoria – a mammoth source of fresh water not only for Kampala, where I come from, but for several other cities in Kenya and Tanzania. Releasing waste into Lake Victoria not only drives the treatment costs of drinking water up, but it also amplifies risks to public health arising from water-borne diseases. Additionally, the abundance of organic matter in excreta chokes life in water, affecting fish stocks and other aquatic animals.

A resource recovery approach to sanitation and waste management brings water, food, energy, and health systems together. And extracting value from waste can be a lucrative business. For one thing, the raw materials are cheap, and a steady, abundant supply is guaranteed as long as humans exist.

Wasted opportunities

In 2014, while working on my master’s thesis, I met Kim Andersson and Arno Rosemarin, who have devoted their careers to sustainable sanitation and resource recovery (in SEI’s EcoSanRes programme and SEI Initiative on Sustainable Sanitation, among others). It was around this time that the concept of “sh*t flow diagrams” (SFDs) gained prominence in the sanitation discourse.

SFDs show the status of excreta management in a city, representing the flows of excreta from where they are generated all the way to their final destination. The green arrows in a sh*t-flow diagram are the safely managed excreta flows; the red arrows represent the flows of excreta that end up in the city environment, poorly treated, or not treated at all.

SFDs are designed to warn of potential pollution. But Kim and Arno saw in these red and green arrows missed opportunities, since excreta contain nutrients, organic matter, water, and energy that are rarely recovered, even in the most advanced treatment systems. That is how the idea for the REVAMP (resource value mapping) tool was born.

REVAMP – unlocking the sanitation transformation?

Essentially, REVAMP uses the information about a city’s excreta flows (adding food waste, animal manure, and other organic waste) to estimate the potential monetary (and other) value the city could get from them. The tool is created to assist cities in development of common vision for resource recovery initiatives, based on the city’s real needs.

REVAMP is now in beta version, but over the next three to four years we want to turn it to a more robust and comprehensive tool. We want to co-develop the tool together with the people who will be using it in the future, like those working in municipal authorities, managers of urban waste systems, energy and water planners, and food and agricultural planners.

As a decision-support tool, REVAMP will show what options are available for resource recovery from waste and what they could be worth based on local market prices for similar products. After that, it is up to decision-makers in a city to decide what resource recovery option to choose.

We hope REVAMP will bring different stakeholders to the table and help them reach holistic solutions for water and resource ownership and management in their cities. In this way, REVAMP could help break the silo thinking that so often obstructs information exchange and collaboration between those working with energy, water, agriculture, sanitation, and waste management.

The REVAMP team is setting up projects in Naivasha, Kenya and Chia, Colombia, and we have received interest from stakeholders in Durban, South Africa and Stockholm, Sweden. We hope to better understand what resource-recovery options are most attractive to local decision-makers and businesses. Equally important, we will learn about social acceptance, and about the institutional and regulatory environment needed to make the options work.

While my dreams of becoming a billionaire may have faded along the way, the idea of helping billions of people meet their everyday needs has stayed with me. And who knows, maybe one day every city in the world will be using REVAMP to understand how to make value from waste, while keeping people and the environment safe and sound.