Comparison of oxygen transfer efficiency using new types of baffle blocks

Abstract

Oxygen is needed in water to maintain the natural ecological balance and the health of organisms. The amount of dissolved oxygen (DO) in water can be increased naturally in different ways. In particular, some hydraulic structures are designed so reoxygenation of water occurs spontaneously over a short distance and in a short 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 by means of hydraulic jumps. While water flows over, between and around the blocks, air bubbles are entrained into the water. The entrained air bubbles in the flow start to dissolve within the chute and the DO concentration in the water thus increases. In this study, the amount of DO was determined for baffle blocks with six different geometric shapes, different flow discharges and angle variations (10° ≤ α ≤ 56°). The oxygen transfer efficiency of the new baffle blocks designed in this study was found to be very effective. Different block types were found to have greater oxygen transfer efficiency for chutes with different slopes.