School of Civil Engineering, SASTRA University, Thanjavur , India
Center for Advanced Research in Environment, School of Civil Engineering, SASTRA University, Thanjavur 613401 India
Center for Advanced Research in Environment, School of Civil Engineering, SASTRA University, Thanjavur India
In this paper, the effect of step geometry with five different tread values from 0.40 m to 0.60 m with an increment of 0.05 m and three different types of water namely potable, non-potable and recycled water on aeration efficiency of stepped cascade aeration was studied. Detailed experimental investigations were carried out for different hydraulic loading rates of 0.005 m2/s to 0.035 m2/s. All the experiments were conducted for nappe flow condition. Results revealed that overall aeration efficiency at standard conditions (E20) approaches maximum for t/h = 4, number of steps = 12, hydraulic loading rate = 0.02 to 0.025 m2/s for potable and non-potable water. In the case of recycled water maximum efficiency was achieved for t/h = 3.67. Results also revealed that stepped cascade aeration was found to be a very suitable option for enhancing DO content in treatment of waste water before discharging it to water bodies to save aquatic life.