Solar-powered process produces hydrogen from sewage sludge

According to UN-Habitat, over 100 million tonnes of sewage sludge are generated globally each year. Common disposal methods - including incineration or landfill - are time-consuming, energy-inefficient, and contribute to environmental pollution.

To tackle this problem, NTU researchers created a three-step solar-powered process that integrates mechanical, chemical, and biological techniques.

Proof-of-concept tests showed that the NTU team’s process is more efficient than conventional techniques like anaerobic digestion. It is said to recover ‘significantly more’ resources, removes heavy metal contaminants, has a smaller environmental footprint, and offers better economic feasibility.

In a statement, research lead Associate Professor Li Hong from NTU’s School of Mechanical and Aerospace Engineering (MAE) and the Energy Research Institute @ NTU (ERI@N) said, “Our method transforms waste into valuable resources, reducing environmental damage while creating renewable energy and sustainable food. This exemplifies the circular economy and contributes to a greener future.”

Three-step process

The process begins by mechanically breaking down the sewage sludge. A chemical treatment separates heavy metals from organic materials, including proteins and carbohydrates.