Bio-augmentation to rapid realize partial nitrification of real sewage

The feasibility of bio-augmentation processes in promoting start-up of partial nitrification of sewage was investigated in this study. Initially, partial nitrification was well-established in an anoxic/oxic reactor treating high-strength ammonia wastewater. Then the influent was replaced by real sewage instantly or gradually. In both cases, nitrite pathway could be maintained for 5-7 d. However, it was eventually destroyed due to the inevitable over-aeration. In another strategy, sewage was treated in the adsorption/biodegradation reactor. The nitrite pathway was obviously promoted by addition of the previous activated sludge from high ammonia wastewater treatment. Nitrite accumulation efficiency of sewage was quickly increased from 26% to 86% and maintained at a high level for 2 months. Moreover, the effluent has a favorable ratio of NH4+/NO2- for feeding anammox process. The experimental results indicated that appropriate bio-augmentation strategies could significantly improve the build-up partial nitrification of sewage in the pretreatment of anammox. (C) 2012 Elsevier Ltd. All rights reserved.