sparger

A sparger is a device used to introduce gas into a liquid, creating bubbles and enabling gas–liquid contact. Spargers are employed in a range of industrial processes to promote mass transfer, including aeration in wastewater treatment, oxygen supply in fermentation and cell culture, chemical reactors, and gas stripping or scrubbing operations.

There are several sparger types. Porous spargers use sintered metal, ceramic, or polymer materials with tiny pores to release numerous fine bubbles. Capillary or needle spargers deliver gas through small tubes or orifices to produce uniform, small bubbles. Jet spargers introduce gas at high velocity through a nozzle, yielding a broad bubble distribution and enhanced mixing. Membrane spargers rely on gas-permeable membranes to release gas as microbubbles and can reduce shear in sensitive systems. Diffusers are a broader category often used in aeration tanks and aquaria.

Applications and design considerations. In bioreactors and wastewater aeration tanks, spargers supply oxygen and promote gas transfer while balancing shear, foaming, and energy use. The choice of sparger depends on the required oxygen transfer rate, gas pressure, liquid properties, and whether foaming, fouling, or corrosion is a concern. In stirred tanks, spargers are typically located at the vessel base or around the impellers to ensure even gas distribution.

Maintenance and performance. Porous spargers are prone to clogging and require periodic cleaning. Material selection focuses on chemical compatibility and corrosion resistance. Optimal sparger design aims to maximize the volumetric mass transfer coefficient k_La while minimizing energy consumption and foam formation.