Effects of salinity on the nitrification of activated sludge before and after acclimation
- Received Date: 18/07/2007
- Accepted Date: 27/06/2006
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Key words:
- salinity /
- acclimation /
- inhibition /
- nitrification /
- specific nitrification rate
Abstract: The effects of salinity on the nitrification of activated sludge without acclimation and with acclimation were studied respectively on the basis of batch experiments. In this study, it was found that nitrobacteria were more sensitive to salinity than nitrosomonas. For the activated sludge without acclimation, nitrosomonas were hardly inhibited and nitrobacteria were inhibited at saline content of 5 g/L. While they were both severely inhibited at 10 g/L and completely inhibited at 30 g/L. For the sludge acclimated in saline wastewater, the specific nitrification rate was lower and NO-2-N accumulates greatly in the initial phase of acclimation because of few halo-tolerant bacteria and the sensitivity of nitrobacteria to salinity. However, nitrosomonas increased and the specific nitrification rate increased as the acclimation time became longer, the nitrobacteria also increased to enough number to oxidize NO-2-N to NO-3-N rapidly. The nitrobacteria flora after acclimation could still be active at saline content of 30 g/L.
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