Comparison of oxygen transfer efficiency using new types of baffle blocks

Abstract

Oxygen is needed for the natural ecological balance and organisms in water. Dissolved Oxygen (DO) in water can be increased naturally in different ways. In particular, some hydraulic structures are designed so re-oxygenation of water occurs spontaneously in a short distance and time. Baffled chutes are designed to dissipate the energy of flow in irrigation systems, wastewater systems, and stormwater systems. Staggered baffle blocks placed in a chute channel not only dissipate the energy of the water but also allow free oxygen transition between the water-air surface with the hydraulic jumps. While the water flows over the blocks, between the blocks, and around the blocks, entrained air bubbles pass into the water. The entrained air bubbles in the flow start to dissolve within the chute. Thus, the oxygen concentration in water increases by itself. In this study, the amount of DO was determined for baffle blocks with 6 different geometric shapes, different flow discharges and angle variations (10°≤α≤56°). These tests demonstrated that the oxygen efficiency of the new baffle blocks proposed in this study is very effective. Type-1 block provided more oxygen efficiency for steep chutes, while Type-6 block provided more efficiency for low slope chutes.