IIT-Gn Experts Found A Way To Use Sewage To Build Roads In India

In an effort to find the use of sewage sludge, the Indian Institute of Technology – Gandhinagar (or IIT-Gn for short) has found a way to treat it and helps it meets the demands to be used to build roads. Their method involves lime, or you may know it as calcium oxide.

Here is a brief explanation for those who do not know what sewage sludge is. It is the by-product of wastewater treatment, sometimes can be found in untreated sewage.

According to Manish Kumar, assistant professor and co-author, major in earth sciences at IIT-Gn, India is in the process of building an extensive network of roads and highways, lime can be a viable solution to substitute stabilizing sewage sludge and make them a construction material to be the sub-base layer.

He also shared that the quality of the final product met the Indian Road Congress’s 2012 guidelines.

The team behind this invention consists of four members and they tested the prospect of the idea by adding lime of different proportions to the sewage sludge. What they tested with was 2%, 4%, and 8% solution of lime. The mixture was then cured for a week, two weeks, or four weeks.

After the test, they found out that the mixture cured for 28 days yielded the best result. The solution they used contained 6% of lime. The total additional unconfined compressive strength the material has after being treated was increased to 1102 kPa. Untreated sewage sludge’s unconfined compressive strength is just 207 kPa.

The team further analyze the mixture and found out that lime can also prevent the leaching of material to the environment. If the lime content is increased, the level of iron, copper, and chromium leachates.

Tests also reveal that lime-treated sewage sludge’s plasticity and swelling are increased by 28% and 54% respectively.

Before this invention, sewage sludge is usually used to make bricks or fertilizer.

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