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Dołączył: 21 Lut 2011
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 Wysłany: Nie 11:07, 24 Kwi 2011 Temat postu: babyliss lockenstab pvy uwm jaup oec |
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Composite SBR system the phenomenon of simultaneous nitrification and denitrification and nitrogen removal
Abstract: According to traditional theory of nitrogen, nitrification and denitrification can not at the same time. However, in recent years has been reported abroad, a phenomenon of simultaneous nitrification and denitrification,[link widoczny dla zalogowanych], especially under aerobic conditions, denitrification does exist in a variety of biological treatment systems, such as rotating biological contactors [1], SBR [2],[link widoczny dla zalogowanych], oxidation ditch, CAST and crafts. SBR compound system in this paper, simultaneous nitrification and denitrification and nitrogen removal were studied. Key words: composite SBR SBR nitrification and denitrification effects Phenomena of Simultaneous Nitrification and Deitrification and Denitrification Effect on a Combined Biofilm & Sequencing Batch Reactor System <LABEL class=lb onclick=done to research the mechanism and effect of a combined biofilm & sequencing batch reactor (SBR) system on the organic substance and nitrogen removal. The result shows that simultaneous nitrification and denitrification (SND) took place in an aeration state. Under the condition of dissolved oxygen value (DO) = 3-5mg / L, the removal of total nitrogen reached 80% and that of CODCr reached 95% in the meantime. Key words: wastewater treatment; nitrification; denitrification; nitrogen removal Introduction removal according to the traditional theory can not simultaneously nitrification and denitrification. However, in recent years has been reported abroad, a phenomenon of simultaneous nitrification and denitrification, especially under aerobic conditions, denitrification does exist in a variety of biological treatment systems, such as rotating biological contactors [1], SBR [2], oxidation ditch, CAST and crafts. SBR compound system in this paper, simultaneous nitrification and denitrification and nitrogen removal were studied. 1 Test Materials and methods 1.1 test device used in the experiment the reactor was 20cm × 30cm × 40cm plexiglass tank, the effective volume of 18L. Reactor placed YDT flexible three-dimensional packing, fixed up and down the biofilm attached to the filler surface. Contact with the composite system of both the characteristics of oxidation and SBR arts. Water by the time program controller, anaerobic, <LABEL class=lb onclick=section start, closing time. Mixture of the S Ⅴ, S Ⅵ, MLSS and MLVSS operating parameters such as periodic sampling to determine and maintain MLS in the 4-6mg / L, SV in 20%, and according to the parameters of the reactor to determine the operating conditions in a timely manner to be adjusted. Determination of DO and PH were measured from the line. 1.2 test water simulated this experiment with water as the water: CODCr400-500mg / L, NH3-N25-35mg / L, TN in the 40mg / L or so. Add the following nutrients: glucose, 169mg / L, peptone 169mg / L, sodium 63mg / L, anhydrous calcium chloride 23mg / L, potassium dihydrogen phosphate 23mg / L, magnesium sulfate 94mg / L, sodium bicarbonate 65mg / L, ammonium chloride 75mg / L, trace elements (iron sulfate,[link widoczny dla zalogowanych], manganese sulfate, copper sulfate, chloride drilling) 0.2mg / L. Simulated water distribution, water quality, stable and easy to control process for operating the reactor and sludge characteristics of morphology and microbiological characteristics of the study. During the test run, according to the different test requirements, adjust the water distribution components, change the part of the influent concentration and the ratio of components, but the TN and NH3-N levels remain basically unchanged. 1.3 sludge acclimation, operational parameters linked to film and take Amber Hill (municipal sewage) treatment plant sludge oxidation ditch return, the supernatant was discarded after sedimentation to settlement of the sludge as bacteria training. Taken during the operation mode are: water 0.5h, <LABEL class=lb onclick=This stage is mainly to train activated sludge. About two weeks later, there is a thin filler floc and a lot of free bacteria, but the combination of relatively loose, then normal water, and adjust the running state. CODCr removal rate at 90%, NH3-N removal rate of 80% of the end of acclimation, put into normal operation. Operating parameters of HRT 8h, SV in 20%, MLSS is about 4900mg / L, sludge retention time is 15d, carbon and nitrogen ratio of 13.2. 2 test results and discussion issued in the normal steady state operating conditions, the test run results in Table 1. Table 1, run under steady state conditions, the results Analysis Project CODCr / (mg.L-1) BOD5 / (mg.L-1) NH3-N / (mg.L-1) TKN / (mg.L-1) TN / (mg.L-1) water 49431032.341.642.8 water 25220.924.68.1 removal /% 959397.28981 2.1 dissolved oxygen concentration of dissolved oxygen is the most important one of the parameters, which directly affects the degree of nitrification and denitrification system. First, the concentration of dissolved oxygen shall meet the combined carbon oxidation and nitrification of organic matter needs; Secondly, they should not be too high concentration of dissolved oxygen, anaerobic micro-environment to ensure the formation of oxygen, while the system over-consumption of organic matter Bu Zhiyu affecting denitrification carbon source. The dissolved oxygen control in the appropriate range, the nitrification rate and denitrification rate closer, the better nitrogen removal. Water quality and activated sludge as the situation is different from the control of dissolved oxygen is also different. In addition, different processing structures, the occurrence of simultaneous nitrification and denitrification also vary the scope of the need to determine in practice. In this experiment, the biofilm mass transfer resistance is high, dissolved oxygen control in the 3-5mg / L, the nitrogen is best shown in Figure 1, the phenomenon of simultaneous nitrification and denitrification are the most obvious,[link widoczny dla zalogowanych], and When DO is greater than 5mm / L or less than 3mm / L, the denitrification and denitrification rate decreased significantly. 2.2 alkalinity of by theoretical calculation, when nitrification per g nitrogen oxide each consumes alkalinity 7.14g (in CaCO3). And denitrification, the reduction 1gNO3 - N will be recycled 3.57g alkalinity. Simultaneous nitrification and denitrification, the denitrification reaction will keep some of the alkalinity consumed in nitrification added alkalinity. General wastewater on nitrification, the alkalinity is often not adequate, if not to add alkalinity, and it will dramatically reduce the pH, the degree of nitrification of ammonia nitrogen. By simultaneous nitrification and denitrification is an ideal choice. Shown in Figure 2, the measured and simulated values of the difference between alkalinity, indicating the existence of the phenomenon of simultaneous nitrification and denitrification. 2.3 N ratio of carbon and nitrogen ratio can affect the wastewater nitrogen removal system. This study used three different carbon and nitrogen ratio. 13.2,8.4,4.6 respectively, under three different conditions were investigated CODCr, NH3-N, and TN removal and nitrogen removal process. From <LABEL class=lb onclick= CODCr removal from the impact of carbon and nitrogen ratio, as shown in Figure 3. The biofilm has a strong biosorption function, so the initial response to rapid adsorption of organic matter and convert most of the carbon source. to nitrogen ratio of 13.2,[link widoczny dla zalogowanych], for example, (as measured during the reaction of NO2 - N concentration was very low, it is ignored.) Can be seen from Figure 4, In the work cycle, nitrification compared to the ammonia completely converted to nitrate nitrogen, ammonia nitrogen concentration decreased, while total nitrogen concentrations decreased. This shows that: the reaction only occurred in the course of nitrification and denitrification occurred, the simultaneous nitrification and denitrification. we can see from Figure 5, the higher the influent carbon and nitrogen ratio, the lower the effluent total nitrogen, the removal rate correspondingly higher. Therefore, the phenomenon of simultaneous nitrification and denitrification N ratio increased with the water which has become increasingly obvious.
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