Scientists at NTU Singapore, have developed an innovative solar-powered method to transform sewage sludge - a by-product of wastewater treatment - into green hydrogen for clean energy and single-cell protein for animal feed.
Published in Nature Water, the sludge-to-food-and-fuel method tackles two pressing global challenges: managing waste and generating sustainable resources.
Along with the growth of cities and industries comes an increase in sewage sludge, which is notoriously difficult to process and dispose of due to its complex structure, composition, and contaminants such as heavy metals and pathogens. However, common disposal methods - such as incineration or landfill - are time-consuming, energy-inefficient, and contribute to environmental pollution.
To tackle the problem of unwanted and difficult-to-treat sewage sludge, NTU researchers created a three-step solar-powered process that integrates mechanical, chemical, and biological techniques.
Proof-of-concept tests revealed that the NTU team’s process is more efficient than conventional techniques like anaerobic digestion, through which bacteria break down organic waste to produce biogas and nutrient-rich residue.
It recovers significantly more resources, completely removes heavy metal contaminants, has a smaller environmental footprint, and offers better economic feasibility.
