What is Recirculatory Aquaculture System (RAS)? How it Works?

The Smart Green Aquaculture Farm and Research Institute and the Recirculatory Aquaculture System (RAS) Facility were recently inaugurated in Hyderabad, Telangana.
The facility is India’s first commercial-scale tropical RAS-based aquaculture farm for rainbow trout.
It enables year-round tropical cultivation of rainbow trout and offers hands-on training in automation, biosecurity, and modern aquaculture systems.

About Recirculatory Aquaculture System (RAS)

RAS is a land-based, closed-loop technology that filters and reuses water for fish farming in a controlled environment.
Water Management: Advanced mechanical and biological filtration maintains optimal water quality while recycling about 90–99% of system water.
Key Components: The system includes biofilters, mechanical filters, oxygenators, and UV/ozone units to control waste, toxins, and pathogens.
Key Benefit: It enables high-density fish farming with minimal water use while reducing disease and biosecurity risks.
Government Support: The Pradhan Mantri Matsya Sampada Yojana (PMMSY) provides financial assistance for establishing RAS units.

Waste Creation: Fish in the tanks produce waste (ammonia) and consume oxygen.
Mechanical Filtration: The water leaves the tank and passes through a filter (often a drum filter) to remove solid waste (feces and uneaten food).
Biological Filtration: The water enters a biofilter containing beneficial bacteria. These bacteria convert toxic Ammonia (excreted by fish) into Nitrite and then into Nitrate (which is much less harmful).