| In recent years, it is serious increasingly that the nitrogen, phosphorus compound causes the phenomenon of water pollution and water eutrophication. Therefore, the treatment of the wastewater not only needs to remove COD, but also still needs to take off nitrogen and phosphorus from the sewage. This requires a wastewater treatment system to possess many kinds of treatment functions.The experiment of nitrogen and phosphorus removal in single stage aerobic sequencing batch reactor systems will be introduced in this paper.In this systems,nitrogen could be removed at low pH value efficiently.The performance of nitrogen removal with a single stage aerobic SBR system was investigated in different pH conditions(pH=8±0.2 and pH=6.5±0.2)by simulated municipal wastewater. The operation run mode was determined to be: influent→aeration(4h)→settling(4h)→effluent. This results showed that the removal of ammonium nitrogen was averaged over 80% when the ammonia nitrogen concentration in influent were 25~40 mg·L-1 in two SBR. A fraction of ammonium nitrogen was removed via simultaneous nitrification and denitrification at pH value of 8±0.2; while, little nitrite and nitrate were observed in effluent, The formation rate of NO2--N was almost zero, and the maximal concentration of NO3--N was only 1.6 mg·L-1 at pH value of 6.5±0.2; but the TIN removal amount was 25.75 mg·L-1, and the sludge production was 22.2 mg·L-1,which was less than the TIN removal amount. It proves that nitrogen removal was not realized by traditional nitrification/denitri- fication approach. It is achieved by the discharge of rich-nitrogen sludge.In our previous research of single stage aerobic SBR systems with glucose as a sole carbon source,wastewater enter the aeration phase directly, without anaerobic phase, which was conventionally considered as a key phase for phosphorus removal, but a predominant phosphorus result still can be achieved,and unconspicuous increase of PHAs were observed.To investigate the phenomena on biological phosphorus removal which appeared in this experiment, parallel experiments were conducted with both glucose and acetate as a carbon source in single stage aerobic SBR systems.To investigate the energy storages supplied for excess phosphate uptake in a sequencing batch reactor (SBR) with single-stage oxic process, glucose(R1) and acetate(R2) were fed to two SBRs as the sole carbon source, respectively. The operation run mode was determined to be: influent→aeration(4h)→settling(8h) →effluent.The phosphours removal rate of R1 which was about 6 mgP.gSS-1 was higher than R2 which was about 3.4~4 mgP.gSS-1. R1 reactor showed much lower transformations of PHAs which were conventionally considered as the key intracellular storages of enhanced biological phosphorus removal,the concentration was about 1.2mg.g-1. Instead, they showed a much higher transformation of glycogen. But there were higher transformation of PHAs and glycogen which were the primary enery source in R2, and the concentration of glycogen was still higher than reaction before until the end of reaction.It is suggest that glycogen synthesized at the first 30min was the primary enery source in aerobic stage, and ATP provided for poly-P in idle stage; but the primary enery source in aerobic stage were both glycogen and PHAs in R2, the rest of glycogen and poly-p could still provided for idle stage.
|
PDF Full Text Request