BITS Pilani invents SAAnA reactor to transform waste management, bolster biogas

Researchers at the Hyderabad campus of BITS Pilani have developed an innovative solution that promises to transform organic waste management and biofuel production. The team has designed and patented the Sandwich Aerobic-Anaerobic-Aerobic (SAAnA) Reactor, a system that significantly reduces processing time, boosts biogas yield, and generates high-quality biofertilizer.

Developed at the BITS Environmental Science and Technology (BEST) Lab by Professor Sankar Ganesh Palani and researcher Atun Roy Choudhury, the SAAnA reactor addresses the inefficiencies of traditional waste-to-energy systems. Conventional methods often take up to 60 days and produce by-products of limited value. In contrast, the SAAnA reactor completes treatment in just 23 days—cutting processing time by 60%—while offering superior outputs.

The reactor operates in three precisely structured phases: five days of aerobic pre-treatment, 13 days of anaerobic digestion, and five days of aerobic post-treatment. This sandwich configuration ensures faster breakdown of waste, enhanced gas production, and improved nutrient recovery. On average, the system can produce up to 0.8 m³ of biogas per kilogram of volatile solids, making it highly efficient.

Designed to handle a wide range of organic wastes—such as fecal sludge, municipal solid waste, landfill leachate, and slaughterhouse residues—the SAAnA system allows multiple waste streams to be processed either individually or together. This integrated approach makes it scalable and adaptable for municipal and industrial applications.

The technology has been awarded an Indian patent under the Government of India’s Kapila Scheme, recognizing its potential for impactful innovation. Researchers describe the reactor as a sustainable and economically viable solution that reduces reliance on landfills, supports a circular economy, and converts waste into valuable resources.

With its versatility and efficiency, the BITS Pilani team believes that SAAnA reactor could play a pivotal role in shaping cleaner, greener, and more sustainable cities of the future.