By Sunil Negi
New Delhi: As India grapples with water scarcity and polluted rivers, a Japanese wastewater treatment system called Jhokasou is drawing attention as a possible solution for decentralized sewage management.
Jhokasou, also written as Johkasou, means “tank for purification” in Japanese. It is a compact, on-site treatment system that has been used widely across Japan for decades. Instead of relying on large centralized sewage plants and extensive sewer networks, Jhokasou units treat wastewater directly at the source in homes, apartments, schools and small communities. The system separates solids, biologically treats the water, and disinfects it so that it can be safely reused for gardening, flushing and other non-potable purposes. Treated water from Jhokasou units meets strict Japanese standards with BOD levels below 10 mg per liter.
The technology is relevant for India because it is compact, energy efficient and does not require a full sewer network to function. This makes it suitable for rural areas, housing societies and peri-urban locations where laying big pipelines is difficult and expensive. Japan currently has more than 8.6 million small Jhokasou units in operation, mostly in areas outside major city sewer systems.
Japanese company Daiki Axis has been promoting the technology in India through its CSR initiative called the DIAL Project – Daiki Axis India Action and Innovation for the Environment. At the national finals of DIAL 2025-26 held recently in New Delhi, student teams presented projects on using Jhokasou for decentralized recycling of wastewater from rural to urban India. The company says the goal is to help students develop practical action plans that can contribute to a cleaner and more sustainable India in line with Viksit Bharat @ 2047.
With a large share of India’s sewage still untreated and many rivers polluted, experts say decentralized options like Jhokasou could help bridge the gap by enabling local treatment and reuse of water. Daiki Axis India has announced plans to expand the initiative through funding, mentoring and study tours to Japan, and aims to take the technology from research to wider public implementation.
