| Shortcut nitrification is the process which control final product of ammoniaoxidation stayed at nitrite. Nitrogen removal process, based on the shortcut nitrification,is the shortcut biological nitrogen renmoval process(i.e. shortcut nitrification-denitrification or shortcut nitrification-anammox) which is a promising technology inwastewater treatment as its short reaction time, high efficiency and low energy using.Nowadays, the macroscopic performance analysis of the biological nitrogen removalsystem is still the dominant area. The microelectrode was the common tools because ofits small size and high sensitivity during the study of biological wastewater treatmentprocess and it is possible for microelectrode to detect the environment and Spatialdistribution characteristics of nitrogen inside the sludge floc without damaging it,which has been a practical technology for microscope analysis. In this paper, on thebasis of macroscopic analysis of SBR shortcut nitrification system and the Rotatingbiological anaerobic ammonium oxidation system, the characteristic of sludge innerthe floc is studied with pH、NO3-、NO2-and NH4+microelectrode. The results providepowerful reference basis of further understanding the reaction mechanism in microenvironment as well as optimizing system operation conditions. The conclusionsachieved from this paper are listed:(1) The results of SBR shortcut nitrification system monitoring and analyzingindicated that the AOB was becoming the dominate bacteria with the system operationand both the ammonia removal efficiency and the nitrite accumulation rate increasedgradually. the ammonia oxidation efficiency dropped from83.35%to91.87%sharplyand the ammonia concentration in effluent decrease from40.27mg/L to19.47mg/L. the nitrite accumulation rate is up from81.61%to90.74%, the concentration of nitritein effluent is from131.51mg/L to175.42mg/L. Meanwhile, the nitrate effluentconcentration decreased, which means the SBR operated stably during the monitoring.(2) The results of microelectrode of the initial stage(5thday) and later stage(56thday) of the shortcut nitrification system indicated that the longer the system run, thecloser the nitrosification zone and the sludge floc surface were. The distancedecreasing from800μm（initial stage）to600μm（later stage）. Meanwhile, the amountof ammonia degration of the sludge in later stage was larger as well as the amount ofgeneration of nitrite, so did the ammnia degration rate and the nitrite generation rate,which was0.216μmol/(cm~2·h) and0.163μmol/(cm~2·h), respectively. The transfer rateof ammonia improved from69.7%to85.1%. And during the later stage, the utilizationrate of nitrite and the generation rate of nitrate was lower, which means that, as thesystem operated stably, the characteristics of shortcut nitrification was more obvious.(3) By analyzing the Rotating biological anaerobic ammonium oxidation system,the results revealed that the system is of high nitrogen removal efficiency. The averageremoval rate of ammonia and nitrite was91.18%and96.65%, respectively. Theremoval rate of total nitrogen was86.03%and the average total nitrogen load was0.41Kg/(m3·d). The pH increased from7.92to8.14.(4) The test of anammox granule under different pH with microelectron showedthat both the ammonia degration rate and nitrite degration rate decrease after increasing.When pH was7, the degration rates of ammonia and nitrite are0.037μmol/(cm~2·h) and0.039μmol/(cm~2·h), respectively. And when the pH was8, the reaction rate of ammoniaincreased to0.042μmol/(cm~2·h) and the nitrite degration rate increases to0.045μmol/(cm~2·h). Furthermore, improving pH to9, the reaction rate of ammonia andnitrite drop sharply, only0.020μmol/(cm~2·h) and0.024μmol/(cm~2·h), respectively. It isclearly that the anammox process performed faster and more characterized at pH8.(5) when pH is8, The test results of effects of temperature on characteristics innergranular sludge with microelectrode showed that though the ammonia and nitrite wasconsuming completely as the temperature was improving. The degration rate ofammonia and nitrite is0.048μmol/(cm~2·h) and0.050μmol/(cm~2·h), respectively. Whilethe reaction rate is both0.055μmol/(cm~2·h) at33℃. And The highest rate was observed when it was40℃and the rate of ammonia consumption and nitrite consumption was0.083μmol/(cm~2·h) and0.071μmol/(cm~2·h), respectively. It is obvious that theanammox performed perfectly when pH was8and the temperature was40℃。... |
PDF Full Text Request