Engineers at IIT-Kanpur have built an automated treatment system for industrial wastewater that combines locally sourced sand, solar photocatalysis on a zinc-oxide-coated galvanised sheet, and inline sensors, and have already demonstrated it at a textile plant in Jaipur. In a report published 21 August 2026, the institute said the technology is patented and is now being extended to food-wastewater streams and hydrogen production The Times of India.
Key takeaways
- IIT-Kanpur team led by Prof Shantanu Bhattacharya built a photocatalytic wastewater treatment train using sand, solar radiation and zinc oxide grown on galvanised plain sheet The Times of India.
- After 2–3 hours of solar photocatalysis, BOD fell from 156 mg/L to 10 mg/L and COD fell from 2,400 mg/L to 125 mg/L at the Jaipur demonstration site The Times of India.
- Sensors monitor pH, total dissolved solids (TDS) and colour at multiple treatment stages, and the system has been patented The Times of India.
- The same technology is now being applied to food-waste streams, and researchers are exploring use of the treated effluent for hydrogen production The Times of India.
- Coverage of Indian wastewater R&D also notes IIT-Guwahati's rotating-anode electrocoagulation reactor, which achieved up to 98.2% arsenate and 91.8% fluoride removal in published work The Shillong Times.
What happened
The Times of India reported on 21 August 2026 that researchers at IIT-Kanpur designed a treatment train aimed squarely at the kind of variable, high-COD effluent produced by textile and steel plants. The sequence starts in a coagulation-flocculation tank where pH is conditioned and suspended sludge is allowed to settle, then passes through a sand filter, then enters the photocatalysis tank where zinc oxide grown on a galvanised plain sheet is activated by sunlight for two to three hours The Times of India.
After that solar step, BOD came down from 156 mg/L to 10 mg/L and COD from 2,400 mg/L to 125 mg/L, with a final carbon filter polishing residual particles that the sand stage did not catch The Times of India. Research scholar Suraj Kumar said the system is automated: "This plant is currently installed in a textile industry in Jaipur. With this technology, the treated wastewater is being used for washing clothes and plantation" The Times of India.
Prof Bhattacharya told the paper that the team has since applied the same train to food-wastewater and is now looking at producing hydrogen from the treated stream, and the institute says the design has been patented The Times of India. A separate line of Indian R&D on low-cost water treatment — IIT-Guwahati's rotating-anode electrocoagulation reactor, published in Chemical Engineering Journal — was covered on 28 August 2026 and shows the broader push towards affordable, automated reactors in the country, with up to 98.2% arsenate and 91.8% fluoride removal in its initial demonstration The Shillong Times.
Specification read
Reading the reported figures in buyer units: the demonstration plant moved wastewater from 2,400 mg/L COD to 125 mg/L COD in a single 2–3 hour photocatalysis pass after a coag-floc and sand-filter pretreatment, with BOD cut from 156 mg/L to 10 mg/L over the same step The Times of India. The source does not state a flow rate in cubic metres per day, so plant throughput cannot be derived from the article; small industrial photocatalysis pilots of this class typically run from under 1 m³/day up to a few tens of m³/day (general industry range, not from the sources). The train the project bears on is the secondary-to-tertiary cut: it assumes a working coagulation-flocculation stage for pH and colour control, a sand filter for suspended solids, a solar-driven photocatalysis step as the main organic-removal unit, and a final carbon polish for residual colour and micropollutants — the same position DAF, MBR and other tertiary polishing units occupy in conventional lines.
For an operator, the recognition case is narrow: if your plant is a textile or steel effluent train running at moderate flows with influent BOD in the 100–200 mg/L range and COD in the 1,000–3,000 mg/L range, and you are under pressure to reduce freshwater draw by reusing process wash water, a solar-driven photocatalysis stage behind an existing coag-floc and sand filter is the piece of new equipment this work points to, and it is the kind of polishing step that sits in front of an Mbr Membrane Systems train or a Water Purification polishing skid. Plants also still need a robust upstream gas-phase and dust stage such as the Air Dust Treatment units we cover, because photocatalyst lifetime tracks influent cleanliness.
FAQ
What does the IIT-Kanpur system actually remove?
It cuts BOD from 156 mg/L to 10 mg/L and COD from 2,400 mg/L to 125 mg/L after 2–3 hours of solar photocatalysis, with pH, TDS and colour monitored by sensors at each stage The Times of India.
Is the system commercial and what does it cost?
The Times of India report says only that the design is patented and is installed at a textile plant in Jaipur, and that it uses locally available sand and solar radiation to keep operating cost down; the article does not publish a price, capex figure or lead time, so any number from a vendor quotation would fall outside what the source supports The Times of India.
How do I compare it to a DAF or clarifier upstream of my textile or food plant?
DAF and clarifier comparison pieces for similar duty points are in our guides for food and beverage duty in Waterloo and for mining/metals duty in Nome DAF vs Clarifier for Food & Bev Wastewater in Waterloo: 2026 Factory Guide and DAF vs Clarifier for Mining/Metals Wastewater in Nome, US: 2026 Factory Guide; primary clarification feed is what stabilises a downstream photocatalysis reactor like IIT-Kanpur's.
Is the technology limited to textile effluent?
Prof Bhattacharya told The Times of India that the team has used the same train on food-wastewater and is now exploring hydrogen production from the treated stream, so the photocatalysis + sand-filter combination is being positioned across more than one industry The Times of India.
