Assessment of Anammox Bacteria in the Enrichment Culture on Sand and Granular Activated Carbon

Abstract

Anammox bacteria are specific group of autotrophic bacteria that are capable of oxidizing ammonium with nitrite to produce nitrogen gas. This group of bacteria has low biomass yield and therefore, attached growth and granular sludge systems are often exposed to these bacteria for the removal of biological nitrogen from wastewater. This study investigated the deposition of anammox bacteria in the enrichment culture to the surfaces of silica sand and granular activated carbon (GAC). The interactions between the bacterial cells and these media could be described by the Derjaguin-Landau-Verwey- Overbeek (DLVO) theory. The DLVO theory predicted that the deposition of anammox cells onto the surfaces of both media was possible under the current experimental conditions. The comparison of net interaction energies between anammox cells and both media surfaces indicated that the deposition onto the surface of the GAC was more favorable. The predictions by the DLVO theory were in agreement with the physical observations of samples taken from the actual batch experiments using a scanning electron microscope.