The use of the anaerobic baffled reactor (ABR) for wastewater treatment: a review

A review concerning the development, applicability and possible future application of the anaerobic baffled reactor for wastewater treatment is presented. The reactor design has been developed since the early 1980s and has several advantages over well established systems such as the upflow anaerobic sludge blanket and the anaerobic filter. These include: better resilience to hydraulic and organic shock loadings, longer biomass retention times, lower sludge yields, and the ability to partially separate between the various phases of anaerobic catabolism. The latter causes a shift in bacterial populations allowing increased protection against toxic materials and higher resistance to changes in environmental parameters such as pH and temperature. The physical structure of the anaerobic baffled reactor enables important modifications to be made such as the insertion of an aerobic polishing stage, resulting in a reactor which is capable of treating difficult wastewaters which currently require several units, ultimately significantly reducing capital costs.