Gas Mixing in Anaerobic Sludge Digestion

The continuous anaerobic gas mixing system is suitable for use in sealed digester tanks whether cylindrical, cylindrical spherical, or egg shaped. Its design optimizes the sludge digestion process and produces a more homogenous mix than other systems. The two categories of confined and unconfined gas injection systems are discussed. Wabag’s sequential gas mixing system, which is categorized under unconfined gas mixing system has shown some unique advantages over other mixing systems has been explained in details in this chapter. The items associated with gas mixing system such as gas lances, lance head, and lance bottom diffuser are also explained. The advantages and disadvantages of various types of gas mixing systems are presented. Along with the lance system efficiency, the important design parameters and a comparison on operating data of various gas recirculation systems have been discussed in detail.