Bheri wastewater aquaculture treatment in
Carolina Márquez Luna
Kolkata, India.
2025
The catchment area of the East Kolkata Wetlands (EKW) is located in eastern Kolkata, bordered by the city, rivers, and agricultural land. It collects rainwater and surface runoff from surrounding urban and rural areas, recharging the wetlands and supporting their rich biodiversity. Acting as a natural drainage system, the wetlands help manage floodwaters and reduce urban flooding. However, the proximity to urban areas introduces challenges such as pollution and habitat loss that can impact the health of the wetlands.
It primarily relies on rainwater and surface runoff from surrounding urban and agricultural areas, which replenishes the wetlands and maintains water levels. Acting as a natural filtration system, the wetlands use aquatic plants and sediments to filter out pollutants, improving water quality and supporting biodiversity. The system promotes nutrient cycling, with organic matter from agricultural runoff enriching the water, benefiting both aquatic plants and fish populations.
Managed through a series of canals, sluices, and gates, the wetlands regulate water levels and effectively manage excess water, especially during monsoon seasons. Additionally, they supply irrigation water to surrounding agricultural fields, fostering a symbiotic relationship between the wetland ecosystem and local farming practices.
Circular Stories
Rainwater, surface runoff and sewage waste from surrounding areas fill the wetlands, where the water undergoes natural filtration through aquatic plants and sediments that help remove pollutants and improve quality. Nutrient-rich water from agricultural runoff enriches the ecosystem, promoting the growth of aquatic plants that absorb excess nutrients, thus preventing eutrophication. Fish farming within the wetlands contributes to this circularity by allowing fish to thrive in a nutrient-rich environment, which helps control algae and other microorganisms, maintaining ecosystem balance.
The wetlands also provide irrigation water for surrounding agricultural fields, particularly paddy fields, linking wetland health directly with agricultural productivity. Additionally, the wetlands act as a natural wastewater treatment system, reducing contaminants as water passes through before being released back into rivers or used for irrigation. The cleaned water is specifically utilized for paddy cultivation, while the remaining water flows into the Kulti River, supporting the broader hydrological network. Local communities play a crucial role in managing the wetlands sustainably, ensuring that the ecosystem remains balanced and fostering a circular relationship where people benefit from the wetland’s resources while preserving its health.
