Domestication And Screening Of Salt-tolerant Bacteria And Its Application In The Propylene Oxide Production Wastewater

Propylene Oxide is very important materials of organic compound, its main productionmethod is chlorohydrin method. Waste water containing large amounts of organic chlorides,it’s belongs to high salinity and hard to biodegradation. The emissions and harm toenvironment of the wastewater cannot be ignored. Research on the treatment of the POproduction wastewater that produced by chlorohydrin method.Study the wastewater treatment by the degrade the method of micro-biologicaldegradation. According to the characteristics of high salt wastewater of chlorohydrin methodproduction PO, select the Yuncheng salt lake as the fist bacterial source of domestication andcultivate in research; meanwhile consideration of soil microbe is rich, select the soilcontaminated by PO production wastewater as the second bacterial source of domesticationand cultivate. By the method of gradually increase the proportion of PO productionwastewater in the culture medium, preliminary domestication and screening the salt-tolerantbacteria that has better tolerability for PO production wastewater. Meanwhile, through oncemore domestication and screening the salt-tolerant bacteria that has best biodegradability ofspecificity and efficiency. Study the degradation effect of the superior salt-tolerant bacteriaunder different conditions which include the time of culture bacteria, the initial pH of thewaste water, the degradation time, the degradation temperature by method of single factor andorthogonal experiments, and then determine the best condition of wastewater treatment.Besides these, budget cost and discussed the mechanism of superior salt-tolerant bacteria fortreatment wastewater. Through various analysis methods to study and analysis on the aboveexperimental results, obtain the following main results:⑴By using the method of increase proportion of wastewater repeatedly and gradually todomesticate and isolate a superior salt-tolerant bacteria called YH-2that have the obviousdegradation effect on PO production wastewater. ⑵Use the superior salt-tolerant bacteria to treatment PO production wastewater(bacterialculture medium of1mL treatment the wastewater of50mL), research the effect of differentfactors on treatment the wastewater. The magnitude of the effect of different main factors is:initial pH of the waste water﹥the degradation time﹥the time of culture bacteria﹥thedegradation temperature; The optimum degradation conditions is: the time of culture bacteriais3d, initial pH of the waste water is10, the degradation time is5d, the degradationtemperature is32℃. On this condition, the degradation rate of CODcr of waste water is70.9%.⑶Preliminary appraisal YH-2belongs to the genus bacillus by observation bacterialcolony, gram staining, contact enzyme experiment. The bacteria can secrete large amounts ofmucus form the slime layer of bacteria in training process, in addition, it can produce catalase.⑷The mechanism of degradation of salt-tolerant bacteria YH-2in the process ofdegradation of PO production wastewater: Use of mucous layer to adsorption organics orinorganics matter in the wastewater, and then produce polymerization. Through microbialflocculation to degradation of wastewater; The catalase that produced in the salt-tolerantbacteria YH-2cell using hydrogen peroxide to make the ether, aldehyde, ketone and alcoholin the substrate oxygenolysis into micro-molecular organics or completely oxidizes to CO2and H2O; The salt-tolerant bacteria YH-2through biological dechlorination degrade theorganic chloride in the wastewater into small molecule organic matter, and biodegradablefuther or effective use of, or completely degraded to CO2and H2O.⑸In the process of degradation of waste water, without add any nutrient elements, so theoperation is simple. the cost of superior salt-tolerant bacteria to treatment PO productionwastewater is8.938yuan per ton, the degradation cost was reduced by20%～30%than theaverage method, it has obvious cost advantages; YH-2not only have certain resistance tosalt,and have the good effect of dechlorination on the organic chloride in wastewater. So inthe study, the salt-tolerant bacteria have obvious advantage no matter in cost,salttolerance,effect on degradation the wastewater.