Start-Up Characteristics of Biological Aerated Filter with Composite Steel Slag Media for Nitrogen and Phosphorus Removal

Abstract

The treatment performance and biofilm development of the start-up stage in an up-flow Biological Aerated Filter (BAF) with composite steel slag media is investigated, while the operating conditions is HRT 2h, temperature 23-27°C, DO 3-5mg/L. The results showed that the composite steel slag media BAF could be secussfuly operated in a short time, while the phosphorus could be removed 90% in 8 days as well as the ammonia nitrogen and COD could be removed 80% in 25 days after the beginning of reactor start-up. At the same time, the biofilm on the carrier could be observed and a lot of protozoa population, such as Rotifera, Vorticellidae and Parameciidae, could be characteristiced with optical microscope in the BAF system. It is conclued that the operation of the composite steel slag media BAF for nitrogen and phosphorus removal could be carried out quickly and conveniently, and provided a unique advantage for the future application.