Аннотация:The possible application of vermiculite, zeolite, expanded clay, and various clays to establish a biogeochemical barrier in ammonium- and nitrate-contaminated groundwater using an anammox bacterial community predominated by "Candidatus Jettenia ecosi" was studied. Anammox bacteria were shown to form active bioflms on most of the studied materials for per-meable and impermeable barriers, which provide for high rates of ammonium nitrogen consumption. Bioflm formation was afected by the morphology and mineral composition of the tested materials and by their ability to deposit ammonium ions, thus decreasing the nitrogen load. The highest areas of anammox bacterial bioflms were observed on kaolin clays, zeolite, and expanded clay. These results may be used to predict the course of the anammox process in aquifers based on the data on the mineral analysis of the country rocks and for the selection of the optimal materials for a permeable biogeochemical barrier.