Natural Wetland in India Filters 198 Million Gallons of Waste Every Day Without Chemicals

By Amanda Froelich, The Mind Unleashed
What if it was possible to filter human waste in a sanitary and eco-friendly way? We have news for you — it is. In the East Kolkata Wetlands (EKW) in India, 198 million gallons of human waste is treated every day through a process called bioremediation. Not only do the wetlands keep Kolkata sewage-free, they support a fertile aquatic garden and protect the low-lying city from flooding.As The Better India reports, the EKW is the world’s only fully functional organic sewage management system. What was once was a patchwork of low-lying salt marshes and slow-running rivers is now a vast network of man-made wetlands which are bordered by green embankments.

The “kidneys of Kolkata” are maintained by farmers and fisherman. Each day, the wetlands receive nearly 750 million liters of the city’s waste each day. With the help of sunshine, oxygen, and microbial action, the sewage is organically treated.

How it works

Urban waste is routed through a maze of small inlets, each managed by a fishery cooperative. The cooperatives are in charge of the inflow of the wastewater. After the sewage settles, only the clear top layers of water flow into the shallow wetland.

A parabolic fish gate is in place to separate the wetland water from the wastewater. Its purpose is to prevent fish from swimming into the oxygen-deprived urban waste water. There, they would die.

It takes less than 20 days for nature to do its work. Organic waste, located in the inlets, settles down where it partly decomposes in the warm shallow water. Then, through a series of biological steps, the waste is converted into fish food. Soil bacteria, macro-algae, plant bacteria, and plants themselves all contribute the decomposition of the waste. The ecological processes are accelerated when sunlight penetrates the settled water.

After the process of bioremediation, the purified, nutrient-rich water is channeled into ponds, called bheries, where algae and fish thrive. Some of the water is also used to grow paddy and vegetables on the banks of the wetlands.

In addition to keeping Kolkata sewage-free and providing fertilizer to grow crops, the wetlands act as a natural flood control system. When floods threaten Kolkata, gravitational forces take the discharge eastward of the city, into the wetlands. In a way, the EKW serves as a natural spill basin. This function is essential during the monsoon season when the entire Gangetic delta is at-risk of flooding.

Despite their usefulness, the wetlands are at risk. A voracious appetite for real estate is threatening the fish ponds, where buyers seek to build. To raise awareness about this conundrum and the enormous value of the wetland’s environmental services, former city sanitation engineer Dhrubajyoti Ghosh has dedicated himself to campaigning for the unique ecosystem. Over the past couple of decades, he has developed technology options from the traditional practice of wastewater aquaculture. So far, four other towns have adopted the wastewater designs.

To this day, Ghosh works to preserve the EKW. He says,

“I am still learning how this delicate ecosystem works, how to further refine it, and why some places are better suited than others. I am happy to give any advice or help absolutely free, this is the best system of its kind in the world and could be helping millions of people. If I have failed in one thing it is this; not enough people know about it or are benefiting from it.”

What are your thoughts? Please comment below and share this news!

h/t The Better India



  1. It is amazing that people such as Mr. Ghosh of India has and will continue to give freely of his time in order to teach others how to use nature to filter human waste rather than using man made chemicals, which always end up destroying our world and doing more damage to our ecosystem than causing anything of value to be fixed.

    For example, using Monsanto chemicals / pesticides to grow better crops and kill destroyer insects or plant disease, has all but decimated our honey bees which are so essential to our world and the crops that we continually grow.

    Now we are growing GMO crops which were intended to feed cattle, not humans. If other countries, even the USA, began to use the system of filtering our own human waste, breaking it down so that each state had their own system like India has, we might even be able to create energy from it instead of using disasters such as Chernobyl and what happened in Japan which is still busy destroying our sea life.

    There are many such humans with exceptional minds like Mr. Ghosh of India and if they were all put together to begin engineering systems that help the world rather than destroying it, we might be looking at a long living fertile planet rather than a dying rotating orb which someday will no longer be fit for human life. But it takes people who love earth, and other humans and not big money hungry corporations that can only see dollar signs while engineering their killing chemicals.

    It was nice also to find out about this open hearted rebel Wes Annac because I enjoy reading about victorious human awareness and things that are truly fixing our planet rather than making it a ticking time bomb. Thanks Wes for your work; it’s great stuff.


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