Immobilization of Anammox biomass in sodium alginate

Abstract

Anaerobic ammonium oxidation (anammox) is a process of ammonium and nitrite conversion into nitrogen gas. Nowadays, anammox is applied into many wastewater treatment plants worldwide. However, anammox bacteria are characterized by a slow growth rate, which may cause problems in maintaining the biomass in the system. The promising technique which can help to maintain the biomass in the reactor and effectively prevent loss of anammox bacteria from a system is immobilization. Selection and optimization of the appropriate immobilization technique for investigated biomass is crucial for conducting an effective process. One of the ways for bacteria immobilization is gel entrapment. The main goal of the study was to test sodium alginate as an immobilization medium for anammox biomass. In the present study procedure of immobilization in sodium alginate was optimised, then the mechanical and chemical properties of the obtained pellets were investigated. Series of batch experiments revealed that immobilized anammox biomass was able to remove ammonia and nitrite nitrogen effectively. The calculated specific anammox activity (SAA) for immobilized anammox biomass was 0.18 g N·gVSS-1·d-1, while for non-immobilized biomass was 0.36 g N·gVSS-1·d.