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.

► Partial nitrification of sewage was promoted by the bio-augmentation process.
► Nitrite pathway was maintained by controlling DO and NLR after bio-augmentation.
► The effluent of sewage treatment was suitable to feed anammox process.
► Integration of bio-augmentation and anammox was favorable to treat real sewage.