Development of Self‐Propelled Aerators

Low rate biological treatment processes such as aerated lagoons, oxidation ditches, etc. offer several advantages over high rate processes, especially at small communities and industrial plants. However, in order to satisfy mixing requirements in low rate treatment processes a substantial amount of energy must be provided. The energy consumption can be significantly reduced by the use of mobile, and, in particular, self‐propelled aerators. Self‐propelled aerators differ from stationary aerators in two major respects. First, their movement upon the water surface in treatment installations or natural water bodies causes the involvement of considerably larger volumes of water in the mixing process and second, they provide more uniform suspension of microorganisms in the water being aerated. At the same time, the driving force causing the aerators to move upon the water surface is induced by the aeration device itself. This eliminates the need for special propelling devices and thus permits a simple design of the aeration device. In this study, parameters for self‐propelled mechanical and jet aerators are analyzed and several possible applications are discussed. The major parameters for self‐propelled aerators are the linear velocity of movement upon the water surface, the period of rotation, the service area, and the oxygenation capacity. Possible applications of self‐propelled jet aerators are illustrated by means of examples.