A team of engineering students has devised a method to convert hospital personal protective equipment (PPE) waste, which typically swells up landfills, into bricks that are stronger and do not use any cement. Not only do these poly bricks have a three-time higher compressive strength as compared to the common red bricks, they are much lighter and can be produced in a far shorter time.
Since the curing time to reach ISO standards is less than 24 hours, the bricks are ready faster and cheaper than red or concrete hollow bricks and meet the water absorption specifications. Showcasing a working model for creating poly bricks, the team of civil engineering students from Sona College of Technology, Salem, emerged winners from among 25 teams that participated in the All India Council for Technical Education (AICTE) Smart India Hackathon held at Jaipur, bagging a Rs 1,00,000 prize.
How the process begins
The poly brick making process starts by sterilising PPE kits with ultraviolet (UV) rays, subjecting it to heat at 160-degree centigrade, adding sand aggregates and casting the polypropylene mass into bricks. N Karuppasamy, assistant professor of civil engineering, Sona College of Technology, who mentored the team said that a patent application has been filed for this technology.
The poly bricks are eco-friendly as they do not use any cement or water in the process and cause minimal in-process emissions as the PPE plastic waste is subjected to less than 200 degrees centigrade. The added edge of poly brick production is the total elimination of cement typically used in manufacture of hollow concrete bricks. No cement use eliminates carbon emissions generated during cement production.
The WHO, in a February 2022 report, brought out the added burden that PPE kits used during the Covid-19 pandemic was putting on the environment, due to their single-use nature. The medical waste, including PPE kits, surgical masks among others, made of polypropylene plastic puts a tremendous strain on waste management systems.
When the five-member team set out to look for the most innovative method to waste generated by discarded PPE kits in hospitals, their lead mentor R Malathy, dean (R&D) and professor of civil engineering, added an additional dimension of “creating wealth from this hazardous waste.”
The team from the civil engineering department of Sona College — Aravind Kumar from final year, Kamalesh J B and Dharani Raj U, both from third year, and Adhavan P and Harshini EK, both from second year -— found this solution while participating in a nationwide competition to find ‘an effective method for tackling improper disposal of Covid PPE’.
Not a cakewalk
Repurposing PPE kits into poly bricks was tough as it involved understanding the chemical and physical properties of polymers and discovering the proportion of materials that would result in the best binding properties. Two of the five teammates were focused on testing at multiple stages so that the final product met tough building material standards, said Harshini.
“We began with desk research on material properties at different temperatures even before conceiving a product option. Once we zeroed in on the poly bricks, developing a prototype with the right strength, adhesion and the right end-cost was the next challenge,” said Kamlesh. “We deployed SketchUp software for product visualisation to arrive at the right formula for mixing polypropylene and aggregates. Replicating industrial machinery at the Hackathon laboratory setting to get the final product that beat the stress tests was rewarding,” he told FE.
Ready for tech transfer
Chocko Valliappa, vice-chairman, Sona Group of Education Institutions, said, “Working in a group the students came up with a solution through innovative and quick thinking. The technology is now available to hospital chains and other organisations interested in technology transfer to help tackle PPE waste and also reduce poisonous emissions.”
These eco-friendly bricks can be used as regular bricks for walls as also as paver blocks instead of red bricks – in the process reducing plastic waste as well as pollution caused during cement production. While cement use is ubiquitous in construction, manufacture of poly bricks and paver blocks from PPE waste with absolutely zero water or cement promotes a reduction in water wastage, harmful emissions, as well as contamination of water by microplastics.
The civil engineering department has also patented a technology to use plastic waste in brick production that replaces almost 70% of sand with plastic.
ECO-FRIENDLY SOLUTION
Production cost of poly bricks is lower than that of red or concrete hollow bricks.
Can be used to build walls or paver blocks
The student team has applied for a patent on the production process