Research On Characteristics Of Baffled Homogenize Pool

The quality and quantity of the urban domestic sewage fluctuate with work and rest law, and which of industrial waste water will inevitably fluctuate with the production. The fluctuation will lead to the treatment facilities can not be run under the best conditions, affecting the water quality at the outlet. As an important facility for adjusting the water quantity and quality, the performance of the adjustive pool will directly affects the stability of the water quality and quantity in the follow-up treatments. The design principle of present adjustive pool is mainly based on statistical or mass balance models. These models, however, Put less emphasis on the effect of the pool's structure on water quality homogenize, and it also can not accurately describe the homogenize efficiency of the different type adjustive pool, respectively.Many different structures of homogenize pool were designed in order to improve homogenize effection, but homogenize principles and its corresponding mathematical model for particular structure haven't be established. In this paper, three types of baffled homogenize pools with different internal structures are designed to establish the mathematical model which contains the structures parameters of the homogenize pool. The mathematical model is verified and corrected through experiments, the tracer diffusion and the dead zone of the homogenize pool are emphases considered, and the homogenize effect is compared through the analysis of variance. The results are applied to the transformation of a coking plant. Several conclusions can be drawn as follows:1) The time of flow duration along the different corridors and decomposition of the impact load reached the exit are different in the homogenize pool. Based on the three baffled homogenize pools with different internal structures, new mathematical models of import export concentration with the impact load changes were established, respectively. This models contain geometry parameters which reflects the structural features of different flow.2) There are some differences in results from calculation based on mass balance models and the experiments carried out in the reciprocating baffled homogenize pool, perforated in opposite side baffled homogenize pool and perforated in same side baffled homogenize pool. The deviation are 44%, 33.8% and 26.9%, respectively, when using four-stages influent water and the using four-stages influent water are 16%, 11.2% and 10.9%, respectively. These large differences indicate that the homogenize effect of the pool related to the internal structure, the mass balance model can not generally being applied to all kinds of homogenize pool.3) Correcting the diffusion and dead zones to the new mathematical model, in the three different baffled homogenize pools, when using single-stage influent water, the deviation between calculation and test results decreased from 36%, 27.2% and 30.9% to 14.8 %, 14% and 8.7%, respectively; when using fours-stages influent water , the deviation are decreased from 21.4%, 15.2% and 12.1% to 8.7%, 4.2% and 4%, respectively. The deviation decline sharply after revised, which indicate the deviation mainly results from the dead zone.4) Compared with the test results in three different baffled homogenize pools, the deviation in the revised new model is 0.34, 0.41 and 0.32 times of the calculated deviation of the mass balance model when using single-stage influent water, and the deviation decreased to 0.54, 0.38 and 0.37 times when using four-stages influent water. Thus, the revised new mathematical model can reflect accurately homogenize law of the baffled homogenize pools.5) The fluctuation of influent concentration show a zigzag trend. When influent concentration variance is 1021.1, In the reciprocating baffled homogenize pool, perforated in opposite side baffled homogenize pool and perforated in same side baffled homogenize pool, their effluent concentration variance were 197.2, 90.9 and 41.9 respectively, when using single-stage influent water; and that were 46.39, 38.57 and 36.93 respectively, when using four-stages influent water. their effluent concentration variance. Therefore, homogenize effection with using four-stages influent water better than the single-stage influent water when the structural parameters of the pool didn't change. With adding a perforated wall, the homogenize effection can be improved under the same ways of influent water, Under the experimental conditions, using four-stages influent water in perforated baffled pool, homogenize effection is best.6) The transformation of multi-stages influent water and vertical uniform distribution with water for reciprocating baffled adjustive pool in a coking plant were carried out. The results show that the outflowed COD concentration fluctuation is not significantly when the value of the inflowed COD concentration fluctuation is less than 150mg/L and the outflowed COD concentration fluctuation obviously and the fluctuation declines slightly when the inflowed COD concentration fluctuation is more than 400mg/L before the transformation. After the transformation, the inflowed COD concentration fluctuation is about 500mg/L, the outflowed COD declines to about 200mg/L, the peak numbers reduced from 6 into 1, homogenize effection improved significantly.