The theme of this year’s World Toilet Day is to ‘leave no one behind’ and fulfil Sustainable Development Goal 6 to ensure sanitation for all by 2030. It’s a goal that will only be achieved if there is greater recognition of how faecal sludge management can be used to deliver inclusive sanitation more quickly and more sustainably, writes senior process engineer Joel Westberg.
When plans for a centralised wastewater network in a sub-Saharan African city proved to be unworkable, I helped develop a more sustainable solution using faecal sludge management (FSM).
One day I took my client to visit the site of the new FSM facility and I explained how the system would provide sanitation for 60,000 people, just like the conventional sewerage they had originally wanted, but for 70% less capital investment.
The client was astonished and wondered why they had not considered FSM in the first place.
In my experience of working as an engineer in the developing world, FSM is often dismissed as an option on sanitation infrastructure projects, even before a feasibility study is commissioned.
I believe this is because of a common and widespread misconception of what sanitation means.
Say ‘sanitation’ to people and most will think of sewers, pipelines and wastewater treatment plants.
But there are other ways to achieve equitable access to sanitation, notably FSM.
Sustainable solution
FSM is disregarded as the cheap and least preferred option when on closer analysis it will be the most effective, sustainable and economic solution.
What’s more, FSM systems can be just as innovative and sophisticated as conventional wastewater infrastructure and offer many advantages.
Technical challenges and varying topography can make it difficult to connect all parts of a city to a centralised wastewater system. The decentralised nature of FSM-based systems makes them more practical in informal, high-density or peri-urban areas of cities in developing countries.
Research shows they are significantly more affordable to build and maintain, offering 10 to 15 times lower capital costs and 80% whole-life cost savings compared to sewer networks.
This is why it is widely accepted Sustainable Development Goal 6 (SDG6), to achieve access to adequate and equitable sanitation and hygiene for all and end open defecation by 2030, will never be reached without FSM-based systems.
It is also important to remember that SDG6 calls for universal and equitable access through ‘safely managed sanitation’, and that definition is applicable to FSM as much as centralised sewer systems.
Sanitation coverage
When cities in the developing world receive funds to invest in improving access to sanitation for their citizens, it is easy to understand why the big and expensive showcase infrastructure projects are put on the table first.
They don’t know if they will ever receive such investment again and they want equality. They want what cities in the developed world have – sewers, modern wastewater treatment plants and the latest technology.
But in many cases FSM will deliver the same level of sanitation coverage and the same desired outcomes for less cost and in less time.
This is where consultant engineers have a crucial role, working to eliminate the bias in the industry towards centralised sewer systems and raising awareness among donors and stakeholders of the alternatives to sewers.
All too often when the terms of reference are defined for a project to extend sanitation coverage in a city, it has been decided almost by default, rather than by discussion and analysis, that a centralised sewer system is the right option.