Rational approach for design of cascade aerator

The term aeration in Water Treatment practices is applied to that process in which water is brought into intimate contact with air. In the present day practice, aeration finds wide application to improve the physical and chemical characteristics of water for its domestic, commercial and industrial use. Cascade aerators are the most widely used aerators in the water treatment practices. Many varieties of cascade aerators are in use. Pilot plant studies are often desirable in connection with an engineering analysis of the applicability of aeration process to water treatment problems. Results of few pilot plant runs, using relatively simple equipment, may if properly analyzed, provide useful aerator design criteria. The literature on design practice of aerator reveals that systematic studies to rationalize the design of this unit have not been made. At present the design of cascade aerator is carried out purely on empirical basis. The design of cascade aerator is usually carried out on the basis of 0.015 to 0.045 sq.m of plan area per cum/ hour of flow . It does not speak of any oxygen transfer requirements of water treatment plant. The paper presents the rational approach for cascade aerator design based on oxygen addition on the basis of actual plant studies conducted at three different water works having 100 MLD, 30MLD & 20 MLD capacity. The present paper highlights the data and the results obtained during the study conducted at Wena water works, Nagpur of 30 MLD capacity.