Experimental Study Of The Pulse Electric Flocculation Pretreatment On The Treatment Of Spironolactone Wastewater

Pharmaceutical wastewater with a wide range of pollutants, high value of COD, poor biodegradability, toxicity, and high salt content, heavy odor and deep color and other characteristics, using conventional treatment technology can not achieve the desired treatment effect, therefore, studying using varieties of biological, physical and chemical methods, developing new pretreatment technology, are the key to resolve such wastewater pollution problems while improving the processing efficiency and reducing processing costs. As a new wastewater treatment technology, electro coagulation has high efficiency, fast, easy operation, less pollution, without adding chemical reagents and many other advantages, has been used in a variety of wastewater treatment. This passage takes the spironolactone pharmaceutical wastewater as an example, studied the treatment effect of pulse electro coagulation to refractory pharmaceutical wastewater and influencing factors in pretreatment processes, compared the pros and cons of electro coagulation technology, traditional chemical coagulation and Fenton’s reagent method in treatment effect, and discussed the reaction mechanism.The main experimental results and conclusions as follows:(1) Through the Analysis of the production process and synthesis steps of spironolactone, we find that the main pollutants in wastewater conclude vegetable oil, sulfites (SOC12water decomposition into hydrogen chloride and sulfur dioxide), dimethylformamide (DMF), acetone and tetrahydrofuran. Calculated the theoretical COD value is17224.56mg/L, determined on experimental value is18160.24mg/L, the main COD contributors from:dimethylformamide (DMF), acetone and tetrahydrofuran, these three types of pollutants account for92.84%of the total COD.(2) Form the reaction by single factor electro coagulation,we find that the best electrode material in electric flocculation experiments is the mixed Fe-A1electrode, as the analysis of variance COD degradation efficiency in the mixed Fe-Al electrode with a separate iron electrode and the aluminum electrode processing shows a significant difference. compared COD removal efficiency in the processing time for electro coagulation experience between35minutes and15-65minutes also shows significant differences, but between45-65minutes COD removal efficiency doesn’t show significant difference with each time period.the minimum processing time of spironolactone wastewater should be longer than35min, and more than45min the COD removal rate changes little.(3) Electro coagulation reactor has a good decolonization for wastewater,the best decolonization can reach93.75%in the single factor experiment, the effluent color in less than100. The pH has little effect on the treatment of electro coagulation to spironolactone wastewater, as electro coagulation reactor can adapt to pH quickly,pH within5-10in water, it can be stabilized between7-9when out of water.(4) Electro coagulation reaction of the four elements and three levels of orthogonal test analysis shows that:the main influencing factors to the level of the electrode materials is: coagulation time> pH value> plate spacing; the optimal experimental conditions of PH is8, the flocculation time is45min, the plate spacing is lcm and with Fe-A1electrode material, the highest removal efficiency of the COD can reach59.53%; by the analysis of variance shows:pH value, electrode spacing and electrode material does not have a significant impact on the COD removal efficiency, but flocculation time has a significant effect on COD removal rate.(5) Get by pulsed electro coagulation process and other pre-process research:COD removal efficiency of chemical flocculants to spironolactone wastewater is PAC>Fecl3>Al2(SO4)3, and its maximum processing efficiency is only15%; COD removal efficiency of Fenton’s reagent to spironolactone wastewater is H2O2dosage> iron dosage> reaction time> impact of pH, all less than the electro coagulation reactor59.53%.(6) By electro coagulation orthogonal experimental data to establish the regression model shows that: the experimental Y (removal rate)=-47.831+11.784pH+3.696time+(-3.100) pitch+(-0.818) pH*pH+(-0.048)time*time+(-0.157) pitch*pitch, the goodness of fit is0.984, indicated that this model can explain98%of the variance, with high goodness of fit, so the better choice of model is non-linear regression.