Sewage treatment Plant at Narayan Swaroop Hospital is well constructed, aligned and smooth so that the water is treated and reused for cleaning, gardening. etc. Sewage Treatment Plant is the process of removing contaminants from waste water, containing mainly sewage. Physical, chemical and biological processes are used to remove contaminants and produce treated waste water (treated effluent) that is safe enough for release into the environment. A by-product of sewage treatment is a semi-solid waste or slurry called sewage sludge. The sludge has to undergo further treatment before being suitable for disposal or application to land.