Many would not believe this but the world’s largest organic sewage management system is in the city of Calcutta (Kolkata), India. The megapolis that is Kolkata produces around 750 million liters of wastewater as well as sewage every day. However, core area of Kolkata doesn’t have one single sewage treatment plant. Where is the sewage going? This ecological juggernaut processes around 198 mn gallons of wastewater as well as sewage, which is produced every day. The innovative and eco-friendly plant relies on only nature and does not use any chemicals. The East Kolkata Wetlands (EKW) is the world’s only totally functional organic sewage management system.

Utilizing the aid of local farmers as well as fishers, the surrounding wetlands are also kept in good health so as to organically clean the sewage with the help of sunlight, oxygen, as well as beneficial microbes. The entire establishment is run on the process known as bio-remediation and is able to clean wastewater within a period of three weeks. The marshy and muddy wasteland also have unique, beautiful, and fragile ecosystems which are a haven for biodiversity. Besides, they provide many other benefits. The wetlands also have dry areas as well as seasonal wetlands.

Wastewater from the Kolkata city is put through small inlets. A local fishery cooperative later segregates the densely polluted water from the clearer surface water. A parabolic fish-gate is used to separate the wetland water from the wastewater. This helps the top layer of the water, which is generally clear, to flow in to large wetlands whereas the wastewater decomposes on its own. It also becomes fish food through various organic processes. The separated water is then later used to rear and raise fish in ponds, which are known as bheries or even to grow crops on the banks of such wetlands. The East Kolkata Wetlands are the fruits of the efforts of Dhrubajyoti Ghosh, who has, in the past, been honored with Global 500 Award by the United Nations for environmental achievement.

About Charukesi Rajakumar

Greenubuntu Evangelist and Author at Apart from being an environmentalist and passionate nature lover, Charukeshi Rajkumar has more than 35 years of software industry experience, with more than 20 years focused on Business and Functional Analysis, including team lead roles. She can be reached at