Bioremediation Of Organic Pollutant In Water Body

Water is a life line for mankind. It is one of necessary components of all organisms and the basest condition of surviving and reproducing of human being and other lives. Besides, it is also an important resource for industry and agriculture, the most active and important factor of environment, that compose the basic of ecosystem recycling.The activities of human life and their production have changed the physical, chemical or biological properties of natural water, which directly result in water pollution and fresh water shortage. In the near future, polluted water will become a important freshwater resource. After effectively purification by bioremediation technology, it will become a most important regenerated resource.1. This thesis studies the law of reaeration. Dissolved oxygen in water body not only lies on the transfer ratio of interface between water and air, but also is related to the oxygen diffusion in water body. For the reaeration process without turbulent, dissolved oxygen content in water body lies on the interface transfer process between water and air, having nothing to do with the depth of water because the diffusion coefficient in water is greater or equal to interface transfer coefficient between water and air. The result indicates that the surface transfer coefficient Kl of water body without turbulent equals 0.0291. However, the reaeration ratio has a close relationship with the depth of water for turbulent water body. The surface reaeration of turbulent water is related to turbulent kinetic energy, but the more important factor is the surface disturbing kinetic energy (that is surface turbulent state). The action of whirling fluid impels gases nearby to be involved in / attracted into water body, which accelerates the contact of oxygen and water body. The greater the turbulentkinetic energy (the higher the agitated speed) is, the higher the reaeration ratio is. In addition, the dispersion and distribution of oxygen in water body is put forward by the concept of content of oxygen transmission. The relation of reaeration coefficent k2 and the water depth H is showed as follows: k2=133.0×l01/3-0.01872 by fittingcalculation.2. The degradation of organics under the condition of turbulent or non-turbulent was studied. The relationship between reaeration and organics degradation process in water body has been expressed by COD. The mathematical relationship between dissolved oxygen in water body and COD is established. It was discovered that decomposition speed relates with the concentration of organics and dissolved oxygen, and the decomposition reaction is defined a second reaction, that is. The degradation ratio constant of glucose in non-turbulentand turbulent water body are respectively 0.029 and 0.736. It showes that the faster the agitation speed is ,the higher the strength of water body disturbing ,the greater the turbulent kinetic energy and the shorter the degradation time of organics is. At the same time, the reaeration speed of water body becomes faster with increasing of agitation speed. When agitating in high speed ,surface whirling of water body dissolves oxygen in air rapidly, which complements dissolved oxygen in time so that dissolved oxygen in water body almost remains steady. The degradation reaction is a first order reaction .Therefore the actual result is very close to the model calculation.The decomposition component was analyzed preliminarily by HPLC for the first time, in order to study the degradation of glucose under the condition of turbulent reaeration. No any new compounds was detected expect the peak of glucose.This indicates that glucose may be oxidized into carbon dioxide and water.3. First research about the influence of water reaeration treated by neutral salt and organic compounds is done. In a conclusion, neutral salt (KCl) hardly effect the reaeration, the reaeration ratio of which is almost the same as salt-free state. However, the water reaeration ratio is low down quite a bit when added glucose. When water body contains nitrogen such as urea, reaeration is affected slightly. That is all because the urea comsumes less oxygen when decomposed, while a molecule glucose would use up six molecule oxygen. This conclusion has very important significancein the treatment of salt-contained industrial effluent.4. The bioremediation for polluted water of Chengdu Yingma river section was studied firstly using chitin chelate complex bacterium(CCCB) that chitin is made from insect shell. It is tested the key factors of biomodification include the giving amount , method of adding, initial culture time and hydraulic stay time of period dynamic trials and so on. During initial cultivation, CCCB added is 40-50 ml/m3 for eight days. When dynamic operation, CCCB adds 2-4ml/m3, hydraulic stay time is about 19 hours. After initial culture and dynamic trial with engineering-scale course, water quality reachs the 4-5 grade standard of state surface water, and the releasing percent of CODCr is 84.12-91.22, the BOD5 is 86.2-95.5. The relationship between COD and BOD5 of Yingma river water was studied for the first time. It established the model of the relationship between COD and BOD5 and the espression is [BOD5] = 0A279[CODCr] + 0.064 . The concept of statistic was first quoted to and derived the biological degradation of various organics in river water. The dynamic parameter of degradation was expressed and calculated by CODcr and finally obtained the dynamic relationship of organics degradation:6. Based on the theory of dispersion , the pervasion equation of turbulence and advection has been derived from dispersion of turbulent flow, and the dispersion equations is solved by the method of volume module. Flow field of Yinma river has been studied for the first time. The distribution of flow field has been simulated by computation, and the distribution of the consistency of COD and DO along the river has been measured and computed .The result shows that the circular sprinkle technology applied in the test can meet the requirement of reaeration of water body completely. The circular water flow ejects to the water surface, which broke the clam situation of the water, accelerated the mass transfer process and recycled the microorganism in water body. The drift of bacterium with the water flow is reducedand the time of hydraulic stagnation is also improved, the circulation of bacterium in the water is achieved.7. The disposing of effluent of leather making by inorganic flocculant and co-operation of inorganic and organic flocculant and its mechanism was discussed, Inorganic polysilicate ferrous(PFSi, poly ferrous silicate) can effectively decrease COD of effluent by 76%. When PAC(poly aluminum chlorinate) and PFSi(weight ratio is 1:1-2:1), the ideal flocculant effect can be achieved. Particles of flocculate are bulkier, subside ratio is faster, COD of water treated is greatly decreased. The percent of COD released is more over than 80%. If adding organic floculant PADAMA(poly-dimethyl-diallyl-ammonium chloride) after effluent is disposed with flocculant (PAC+PFSi), the effect of disposition is enchased greatly and the releasing percent reaches 88. Flocculant co-operating is quite effective to effluent from every procedure as well in leathermaking wet process, especially to effluent from unhairing and bating procedures that the effluent contains amount of degraded protein. It also establishes a scientific fundemental for recycling or re-using partly of effluent of leather making, as well as saving water for tannery.8. In the article, it is carried out theoretically a deep study that the oxidation ditch technology applied extensively in the final biochemical treatment of waste water from tannery. On the basis of analyzing the hydraulic calculation of oxidation ditch, the increase of water head resulted from rotating bush for reaeration and the loss of water head of circular flow in the oxidation ditch have been discussed. The calculation for project example shows that the resistance arising from the bend of watercourse is the main reason for the loss of water head, the resistance from vertical baffleboard being second place, while the resistance coefficient of whirlpool just accounts for 1.2%.9. Reaeration rule of oxidation ditch is studied for the first time and the relation between the turbulent kinetic energy of oxidation ditch on cross section and the coefficient of transfer at the water surface is also analyzed. The equation of KL=10.02k1/2+0116 is developed by fitting the result of calculation. It is pointed outthat the organics degradation in oxidation ditch belonging to a second order reaction and the concentration equation of COD and DO during the process of organics degradation. It calculated the flow field of oxidation ditch by solving with finite volume-unit dispersion. The flow condition of water body in oxidation ditch in different seat is indicated distinctly. This result will be helpful to further consummating oxidation ditch technology and engineering design and operational administration of the project.The research method and results achieved in the article will provide scientific foundation for the bioremediation of wastewater and play an important role in the field of improvement process control of bioremediation of wastewater.