Novel autotrophic nitrogen removal system using gel entrapment technology

► A pilot-scale nitritation-anammox plant using gel entrapment technology was operated. ► Nitrifying bacteria were immobilized in gel cubes, resulting stable nitritation rate. ► Anammox bacteria were entrapped in gel cubes, resulting high denitrification rate. ► The overall nitrogen removal efficiency of combined both process was 84.4%. ► Stable nitrogen removal was attained even at high influent SS concentration.