Effects of pH and temperature on coupling nitritation and anammox in biofilters treating dairy wastewater

► Furnace slag and marble chips raised pH to enhance nitritation-anammox in biofilters. ► Ammonium oxidizing and anammox bacteria accounted for 69-74% of bacterial population. ► Ammonium removal rate was significantly higher at pH 8.1 than pH 7.6. ► Free ammonia concentration should be controlled to avoid inhibition to anammox. ► Temperature effects were superior to pH effects on simultaneous nitritation-anammox.