Masters thesis — Sister Nivedita University, 2025. Full text: https://archive.org/details/sgng.20660-water-quality-and-fecal-coliform-dyanamics-in-aquacul-ture-bheri-
One of the world's oldest large-scale circular-economy food systems — a city farming fish in its own treated wastewater — and the measured trend is improving water quality, not declining.
The East Kolkata Wetlands' "bheris" — shallow fish ponds fed by treated urban wastewater — are a century-old, Ramsar-recognized circular system that converts municipal sewage into protein; a six-month multi-site assessment found a notable improvement in the Water Quality Index across several sites and a significant reduction in faecal coliform counts, indicating growing suitability for sustainable aquaculture.
Why it matters
One of the world's oldest large-scale circular-economy food systems — a city farming fish in its own treated wastewater — and the measured trend is improving water quality, not declining.
Use when: The most durable circular economies aren't new tech — Kolkata has been turning sewage into protein for a century; measure the system before assuming it's failing.
