The rapid growth patterns of megacities in developing countries are unpredictable. Sanitation infrastructure, on the other hand, is pretty rigid. It’s usually reactionary as well – housing sprouts up, and sanitation is dealt with later, often when donor funding comes through for big, centralized infrastructure.
But could sanitation infrastructure be designed to grow along with the settlement patterns of fast-developing urban areas rather than come later? A team of German researchers led by engineer Peter Cornel is doing just that with local partners in Hanoi, Vietnam – the video below highlights one of their pilot projects:
Video credit: Future Now
Part of the inspiration came from an unlikely source: street food. People in Hanoi tend to cook food and then eat on the street, which also happens to be very near where sewage tends to overflow from saturated septic tanks. As the population is also overflowing, more waste (both food and sewage) is ending up on the streets and in waterbodies, not just causing health hazards but also sacrificing the recreational value of urban waterways.
The project Cornel’s team is piloting is a “semi-central processing system”: first, wastewater is recycled in households, then food waste and sewage are integrated for processing. Value is created from waste by generating electricity, heat and fertilizer. Of most interest is that the system is semi-decentralized. The plants that process waste are small in size and modular, so they can be located near residential buildings that produce the waste - more plants would be installed in response to population growth. The electricity and heat produced then go back to the buildings where the waste came from in the first place – closing the loop.