| Hypersaline wastewater, characterized as salinity of higher than1%, is difficult to bedirectly treated by conventional biological treatment technologies because of the seriousprohibition of inorganic salts for the growth of microorganisms. Currently, the effectivedisposal of organic wastewater with high salinity has become a hot and difficult point. Thewastewater from producing ethyl chloride, characterized as high salinity, COD, phosphorusand sulfur, was selected as our studied target for the purpose of seeking for reasonable andeffective treatment technology. Based on a vast number of investigations of the correspondingtreatment technologies for hypersaline and ethyl chloride wastewater, it was found that theprocedures of flash evaporation （one of the core technologies in hypersaline wastewatertreatment） were tedious, high energy and costs consumable. An intensive treatmenttechnology by the combination of rectification-fenton oxidation-precipitation pretreatmentprocesses with salt-tolerant microorganisms was proposed in this study.The purpose of using rectification, Fenton oxidation, and precipitation processes was toreduce the load of wastewater treatment, desulphurize and remove phosphorus from originalwastewater. Under the optimized conditions, the COD, sulfur ion, and total phosphorus inwastewater decreased from228.00g·L-1to56.60g L-1,88.94g·L-1to12.26g·L-1, and10.37g·L-1to0.98g·L-1, respectively. The optimized parameters included the rectification time of20min, the pH of3.10, the ratio of hydrogen peroxide and ferrous ion of4:1in Fentonreaction,5ml·L-1of hydrogen peroxide, and14.50g L-1of lime in precipitation reaction.One salt-tolerant microganism was selected for domestication to investigate thecombined rectification, Fenton oxidation, and precipitation with microorganism degradationtechniques. Environmental factors influencing the growth of microorganisms wereinvestigated to improve the salt tolerance of bacteria and provide appropriate methods for theextensive bacterial culture. The results showed that this bacterium belongs to aerobic bacteria,so it can be used for the aerobic degradation test. The demosticated bacteria can grownormally in culture medium with5%salinity under the optimized conditions.The apporiate dosage of microorganisms, degradation time and recycling times wereevaluated to explore the optimized treatment parameters. The demosticated bacteria exhibitedgood degradation efficiency to degrade the COD of wastewater （with a salinity of3.8%-4.2%）from>20000mg·L-1to close to10000mg·L-1.The degradation process of wastewater by microorganism can be seen as the microbestake the biodegradable material as source of nutrients, proceeding grow propagation via theirown enzymatic reaction in the wastewater. The physiological and biochemical characteristicsand type of bacterium were investigated and identified to obtain the relevant information of bacterial enzymatic reaction. This also provided background support for further improving thedegradation ability and activity of bacteria. This research can provide a technical support forthe following study and industrial practice. |
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