The Research On Pulping Effluent Treated With Iron-Carbon Micro-Electrolysis Process Strengthened By H₂O₂

The emissions of the pulping effluent is large, toxic for organism and unbiodegradable, containing a variety of organic contaminants and having a long cycle of environmental pollution. This paper takes the pulping effluent as research object, which uses iron-carbon micro-electrolysis process strengthened by H2O2to study the removal efficiency of AOX and CODCr and optimize its process conditions. Meanwhile, this paper characterizes AOX before and after degradation and investigates various water treatment methods and the treatment effect of the combination technology. This paper concludes as followings:(1) The parameter values and operation effects of the optimized process of iron-carbon micro-electrolysis process strengthened by H2O2are as follows:the dosage of H2O2is112.5mmol/L, Fe/C is1.5:1, pH is3.0, the reaction time was70mins, the ratio of effluent volume and iron filings mass is6:1, and the removal rates of wastewater AOX and CODCr after treating are71.5%and80.4%respectively.(2) The maximum deviation of the predicted and experimental values of the model equation calculation is±2.8%by using RSM to optimize the main factors, using a central composite design to analyze RSM and establishing a quadratic model. Validation studies show that the removal rate of AOX is (72.8±0.5)%under the conditions of pH:2.5, the reaction time:70mins, the dosage of H2O2:140.625mmol/L and Fe/C:1.0.(3) Use the GC-MS combined technique to test and analyze the AOX components. The analysis shows that AOX components are mainly aromatic compounds with benzene rings. After the treatment of the iron-carbon micro-electrolysis strengthened by H2O2, the change of AOX components’type is small but the relative content significantly reduces. To a certain extent, the macromolecules are degraded to small molecules.(4) Use exponential function fitting AOX concentration in wastewater along with the changing process of the reaction time. The apparent reaction order of AOX degradation reaction is1.78by half-life method. AOX degradation kinetic equation can be expressed as dCA/dt=-kACA178.(5) In the five methods of the experiment, the iron-carbon micro-electrolysis treatment strengthened by H2O2works best. Investigate the effects of three kinds treatment of combined process:coagulation-aerobic-iron-carbon micro-electrolysis process strengthened by H2O2, coagulation-aerobic Fenton and iron-carbon micro-electrolysis process strengthened by H2O2aerobic-coagulation. The final effluent CODCr<200mg/L, AOX<12mg/L, which is up to the existing National discharge standards. From the point of cost saving, coagulation-aerobic-iron-carbon micro-electrolysis process strengthened by H2O2is better.