Experiment Research On Inhibition Effect Of Synchronous Precipitation For Biological Phosphorus Removal

In recent years,the growing problem of lake eutrophication forced many countries andregions make strict emissions standards of nitrogen and phosphorus. However, biologicalsynchronous denitrification and phosphorus process is difficult to coordinate, which makes thebiological phosphorus removal out of effluent requirement, many sewage plant usedsynchronization sink chromatography to assist phosphorus removal. Meanwhile, the inhibitiondegree and mechanism of synchronous sink to biological phosphorus removal is not clear. On thebasis of SBR system-denitrification priority and paying attention to phosphorus removal, takingsewage runoff as testing water,this paper made experiments on synchronous sink assitingphosphorus removal.Biological phosphorus removal test under the SBR biodenitrification system shows that theappropriate operating conditions for SBR is instantaneous feed water-anaerobic for lhour-aeration for4hours-oxygen-starvation for1.5hours-precipitation for1hour-drainage rowmud. Under this conditions, SBR system is good on the removal efficiency of COD, TN, NH₃-N.When the concentration of influent COD, TN, NH₃-N is300⁴20mg/L,65⁷5mg/L,28³5mg/Lrespectively, the concentration of effluent COD,TN, NH₃-N is lower than50mg/L,20mg/L,5mg/L respectively, the removal rate is respectively above90%,70%,85%. But the effect of TPremoval is poor; when the influent TP concentration is6.2⁷.6mg/L, the concentration ofeffluent TP is between2.4mg/L and3.7mg/L, the removal rate is between40%and55%. Theeffluent TP concentration cannot meet the first grade A standards of Urban Sewage DisposalPlant Contamination Integrated Discharge Standard （GB18918-2002）.The test of synchronous sink auxiliary phosphorus removal showed that, in the threecommon chemical phosphorus removal elixir chloride-ferric chloride, ferrous sulfate, aluminium,the best phosphorus effect is ferrous sulfate, the best dosing quantity of ferrous sulfate for Fe/TPis1.5. In the early period of additive ferrous sulfate operation, in accordance with the proportionof the Fe/TP=1.5, the synchronous sink had certain stimulative effect on biological phosphorusremoval and chemical phosphorus re-dissolved in comparatively small amount, at this time thechemical phosphorus removal and biological phosphorus removal of the system presented asynergy, and in the middle-later operation, synchronous sink has certain inhibition on biologicalphosphorus removal, but chemical phosphorus re-dissolved in comparatively small amount. canmake the effluent TP concentration stable under0.5mg/L for long-term, which meets the firstgrade A standards; While in accordance with the proportion of Fe/TP=2, synchronous sink hasslight inhibition on biological phosphorus removal, and chemical phosphorus again re-dissolvedin large quantities in the early period. And in the middle-later operation, synchronous sink haslarger inhibition on biological phosphorus removal and chemical phosphorus again re-dissolvedin large quantities, and at this time of the system phosphorus effect reduced significantly, theeffluent TP concentration cannot satisfy level-1A emissions standards after the long run.