Comparison on factors affecting nitrification of different flow direction BAFs
- Received Date: 29/08/2008
- Accepted Date: 14/08/2008
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Key words:
- biological aerated filter /
- nitrification /
- flow direction /
- influencing factor /
- comparitive test
Abstract: The comparitive test of different flow direction single-stage ceramic BAFs was carried out when factors, e.g. temperature, hydraulic loading, air/water ratio, NH3-N load and organic load changed equally. The results show that the nitrification and stability of UBAF are superior than DBAF. The economical air/water ratios of UBAF and DBAF are 3∶1～6∶1 and 3∶1～5∶1 respectively if organic and NH3-N are removed in single BAF. The NH3-N removal rates in UBAF and DBAF are similar while the applied organic load is less than 11 kg/(m3·d) and the loading ratio of organic to NH3-N is less than 5. Under the condition of high inlet COD, the competitive ability of nitrifiers to heterotrophs in DBAF is not as good as UBAF’s. UBAF is suitable for the first filter of two-stage BAFs, while DBAF is more suitable for the second filter probably for enhancing the two-stage filters system stability,denitrification efficiency and effluent quality.
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