Study On Performance Of Steady Course In The System Of Denitrifying Phosphorus Removal

According to mechanism of biological phosphorus removal, phosphorus is assimilated superfluously in A/O or A/A. In A/O, Phosphorus bacteria takes the oxygenous molecule for the electronic accepter, in A/A, (NO₃)^--N is took for the electronic accepter. Owing to short transfer link and low redox of (NO₃)^--N, ATP that (NO₃)^--N produces is two third times for that oxygenous molecule does. From the angle of biological phosporus removal, absorbency of phosphorus in anoxic condition is lower than in aerobic condition. However, Nitrogen removal and phosporus removal are syncretized in the anoxic process of phosporus removal, and from the angle of that energy which is consumed, phosporus removal in anoxic condition is a metabolic mode that can retrench energy sources. Large numbers of date indicated that it can reduce 75 percent of oxygenous wastage in anoxic condition compared with in aerobic condition ,and it can cut over 50 percent of discharged rich phosphorus sludge. So far, There are two different test result about activity of sludge and steady function in the system of denitrifying phosphorus removal, as follows: l)It can run stably and chronically in A/A. 2)Along with run time increasing , biomass will decrease gradually in the system of A/A . Therefor, in this dissertation, author will study the main influencing factors that influence the ability of phosphorus removal and long and steady run in the system of denitrifying phosphorus removal.In the material course of study, author went along a few phases of research through single factor test in the system of denitrifying phosphorus removal (It is studied mainly basing on some factors about concentration of (NO₃)^--N, anaerobic time, anoxic time, aerobic time, SRT and COD, etc.) and orthogonal test in the system of denitrifying phosphorus removal (according to four factors and four levels of the Orthogonal test).According to the above study results, it indicated that: â‘ The key to make the system of denitrifying phosphorus removal oprerate steadily is increasing the latter aerobic time. It was also found in the test that the latter aeration for 0.5h would ensure not only steady operation, but also good effect of phosphorus removal in the system of A/AO-SBR.â‘¡ In the system of A/A-SBR or the system of A/AO-SBR, they all could be found the phenomena of denitrifying phosphorus removal in the earlier stage of test, However, along with the run time increasing in the system of A/A-SBR, the effect of phosphorusremoval would weaken, Ys will also decrease gradually to zero or even minus, the ability of phosphorus removal camedown finally. In the system of A/AO-SBR, the anoxic course would gain favorable effect when it was controlled in feasible condition, and it could run chronically and stably.(3) When anaerobic time is 2h, anoxic time is 3.5h, concentration of NO_<sup>--N is 30mg/L in the initial stage of anoxic course, the system of A/A could gain favorable effect of phosphorus removal.â‘£ SRT is also a pivotal factor that affected the long and steady run of the system of A/AO-SBR. It was found through the test , when the system run according to anaerobic time for 2h,anoxic time for 3.5h, aerobic time for 0.5h, concentration of NO_<sup>-N is 30mg/L, SRT was 25d, it could gain better effect of phosphorus removal.(5) Through Orthogonal test, it indicated that the optimal condtion of the long and steady run for the system of denitrifying phosphorus removal is anaerobic time for 2h,anoxic time for 3.5h, aerobic time for 0.5h, concentration of NO_<sup>--N is 30mg/L, SRT was 25d, when concentration of COD was250mg/L, concentration of (PO₄)^3--P was 4.3-5.8mg/L, concentration of NH3-N was 20-25mg/L in inflow.(6) Through the ability of the system of traditional biological phosphorus removal comparing with the ability of the system of denitrifying phosphorus removal, it was found that the system of denitrifying phosphorus removal have the ability of phosphorus removal ,but it was lower than the system of traditional biological phosphorus removal. General factors that affected the ability of phosphorus removal were SRI, sludge productivity , content of phosphorus in surplus sludge, etc.(7) Through searching the kinetic mode of the system of denitrifying phosphorus removal, the followings were deduced: a) the kinetic mode of (PO₄)^3--P that was released in anaerobic course was P_t=P₀—3.15XTt² +10.1Xt, b) the kinetic mode of (PO₄)^3--P that was absorbed in anoxic course was P_t'=Po+7.6X+2.2t²â€” 14t.This dissertation belongs to the task that was staked by China Natural Science Fund and Cadreman of Chongqing University. The researchs can offer some academic evidence for study about technics denitrifying phosphorus removal. So ,the researchs are important both in application and theory.