The Research Of Sludge Concentration Variation Of Oxidation Ditch T

The oxidation ditch T has been applied widely in the wastewater treatment engineering, since introduced into China in the 80'of 20th.Owe to the much advantages, such as simple process treat ability continuously, no more final sedimentation tank and correspondingly the less accessorial buildings and tanks with management could be fouled. It is adaptive to control the quality index of influent and effluent by adopting the SBR process, the acreage needed is smaller; and the effect of nitrogen removal is obvious,For the sake of further application of the oxidation ditch T in the engineering of wastewater treatment; some home scholars carried out the research on the problem of the oxidation ditch T design and calculation. Some domestic units operating oxidation ditch T also have made the measurement about the actual running status, and pointed out the great difference between the original design calculation and actual circumstance in the sludge concentration distribution of oxidation ditch T. The value of valid sludge needs to be limited again.Standpoints on the sludge concentration distribution and operation model have been put forward in some research articles, and some scholars suggested to discharge the excess sludge in the side ditch but not the side ditch.In order to design Luofang WWTP in Shenzhen, the most large-scale one among the city WWTP with adopting the oxidation ditch T, the author referred to large data on the process introduction, design and calculation, the measurement of operation parameter. Based on the current research on this process, the author pointed out that it is necessary to work over the distribution condition of the sludge concentration, which is the foundational problem of the process, especially the effect of sludge concentration distribution on the condition of various running model,For the sake of instructing the design for the Luofang WWTP in Shenzhen and also the other projects, This research is focused on the distribution of sludge concentration in the ditch, with setting up the mathematic model of oxidation ditch T by math's analyse. The computer programm is written on the basis of the model by author with dynamic simulating on oxidation ditch T in this researchThe author has made sure the quantity of valid active sludge in the ditch, and effectfactors of is also ascertained on the equality of oxidation and aerobic sludge. Through researching the various operation models, the sludge concentration distribution is made sure in this research, and then the author also pointed out the advantageous factors of operating with triple ditch. Such as moving the discharge place of excess sludge from the middle to side ditch.The main conclusion as followed:Through the study main conclusion of the thesis follows as that:1. As a whole the sludge concentration in three-ditch type oxidation ditch changes with exponential curve, which could be denoted by a general equation: S = Ae ' + Bte ' + C , coefficients among the equation could be identified by comparative coefficient means proposed in the thesis.2. Some new operation scenarios would be adopted to reduce risk of anoxic digestion of sludge settled under current operation mode.3. The ratio of sludge concentration in middle ditch and side ditches is not fixed, which is relative with operation mode. If only compartmentalization of operation duration changes, the ratio of sludge concentration in middle ditch and side ditches would change too, and its variety scope is between 2.35 and 2.91.4. The equipments utilization rate of three-ditch type oxidation ditch is between 50% and 53%, which is related with running mode.5. The valid activated sludge in three-ditch type oxidation ditch is about 43%~44%, generally 44% would be adopted.6. Aerobic activated sludge in whole valid activated sludge occupies 2/3, and anaerobic activated sludge 1/3.7. It's necessary to set discharge tube of excess sludge in the side ditch.