Water Water Water: Site visit at BEL Sewage Treatment Plant

On our third day at Biome, we visited the sewage treatment plant of BEL township, which treats sewage coming from staff quarters and canteen. The 1.15 MLD plant works on extended aeration technique to treat the raw sewage. The flowchart of the treatment plant is as follows:

Sewage flow in plant

When the plant was initially established, the water was treated only using stabilization ponds. With time, oxidation ponds were made to use water for horticulture. In today’s date, the technology used to treat the sewage is activated sludge process. The previously dug oxidation ponds are now being used as a reservoir for storm water, which is used for irrigation in dry months. The main issue faced in the working was sludge bulking in the clarifier and high pH of water outlet.

The last step of treatment is through wetlands from which the water goes to a clear water tank and further to the CETP for tertiary treatment. Using wetlands is an economically as well as environmentally sustainable method of treatment to reduce excess nutrients and organic matter. Being engineering students, learning about the wetlands gave us a perspective towards sustainable solutions, which went beyond the regular technologies of sewage treatment. Wetlands are also a source of biodiversity and supports the food chain. In much larger areas, wetlands attract various flora and fauna making the area ecologically rich. It also helps in recharge of ground water aquifers and stabilization of shore lines.