Human Waste Could Make Concrete Stronger: Indian Researchers Find Innovative Solution

Human waste could soon find an unexpected use in construction. Researchers from Manipal University Jaipur, led by civil engineer Raghuvesh Tiwari, have found that biochar made from human fecal sludge can partially replace cement in concrete.

The researchers collected fecal-sludge biochar from a treatment plant in Warangal, India. The waste was dried and heated at 350–450°C in a low-oxygen environment, then ground into a fine powder.

The team replaced 5%, 10% and 15% of cement with the biochar and tested the concrete. The 5% mixture performed best overall. After 91 days, it showed about a 20% increase in compressive strength and a 36% increase in flexural strength.

Researchers say the silica-rich biochar can improve the chemical bonding within concrete, while its fine particles help fill tiny gaps and create a denser structure.

The findings suggest that human waste could be converted into a useful construction material, potentially reducing cement consumption and helping address environmental pollution.