A Study On The Simulation Measure Of Throwing Microorganisms To Waihuan River In Tianjin

At present the pollution of water envrionment in china is very rigorous, especial- lly the river basin is polluted widely, and this station has presented a development trend. The Waihuan River of Tianjin had been appeared a serious dirty phenomenon from 2005, and the river had been polluted severely. Science and Technology Commission of Tianjin has set up a research programs "additive microorganisms to improve the water quality technical study"(the item number is 043115111-5). The issue is in the early stage of the scheme, aimed at small and model test study to identify the best parameters for bacteria, make the CODCr's removal ratio over 30% ,that of TN was more than 25%.In view of the model errors in the simulation test ,firstly it carry on model calibration test to decrease the objective error. Through static experiments we get a conclusion of eight bacteria mixed addition, by which we identify the best dosage of mixed bacteria under different CODCr. Using MICROPAN AQUA, we determine that continual addition is the best way of additive microorganisms in simulation test.On the basis mixed addition test is played , the result show the CODCr's highest removal ratio reach 20% and that of NH3-N does not exceed 15%.Therefore, mixed addition is not feasible. Then according to the characteristics of photosynthetic bacteria and yeast, it take the small-scale test that throw only that two kinds of bacteria CODCr and NH3-N removal ratio reached 41.9% and 72.8%, the result can meet the engineering requirements. In order to verify the results of small-scale test, it do only photosynthetic bacteria and yeast's model test, define some important parameters for additive bacteria:the removal of NH3-N relative begin to decline after 13 days from the first additive microorganisms, then the test can start to the second, so the second additive microorganisms time is 13 days, the dosage is 1/3 of the first dosage. the best time to stay is eight days. Namely, from that point on which additive bacteria, the water flow after eight days, CODCr and NH3-N degradation can reach the engineering requirements.Finally, since the trial process repeated appeared blank comparison group CODCr and NH3-N degradation bacteria better than the group additive bacteria, it is a reoxygenation pilot studies. Results shows that the highest removal ratio of CODCr can reach 20% ,The maximum removal of NH3-N can achieve 13% and it prove that it is not up to the requirements of the project only through Reoxygenation.