| Refractory organic wastewater has the characteristics of low biodegradability,complex composition and high toxicity,which makes the direct application of biological methods in this type of wastewater difficult.In order to realize the effective treatment of this kind of wastewater,it is necessary to adopt efficient and environmentally friendly treatment technology to improve the biodegradability of difficult-to-degrade organic wastewater,provide favorable conditions for subsequent biological treatment,not only achieve the treatment effect,but also reduce the treatment cost and achieve the wastewater standard Emission or recycling.This topic studies the improvement of biodegradability of refractory organic wastewater by pretreatment of Fe/C microelectrolysis,Fenton method and Fe/C microelectrolysis-Fenton combined process,making the pretreated wastewater suitable for biological treatment.The analysis of the experimental results yielded the following conclusions:(1)The optimized experimental conditions of the Fe/C microelectrolysis response surface are initial pH=4.13,iron-carbon dosage 35.19 g/100 mL,time 118.5 min,effluent B/C is 0.398,COD removal rate is 23.49%.Pretreatment of COD in refractory organic wastewater by Fe/C microelectrolysis will model the degradation kinetics as Ct=1316.45e-0.00256t.The influence of three factors on the B/C of the effluent is dosage of Fe/C>initial pH>time,in which the interaction between Fe/C dosage and micro-electrolysis time has a significant effect on B/C.(2)The optimized experimental conditions of the Fenton oxidation process are:pH 3.02,m(H2O2):m(FeSO4·7H2O)ratio is 19.62,dosage of H2O2 is 61.2 mL/L,reaction time 121.03 min;at this time,the effluent B/C is 0.351,COD removal rate is 66.26%;Pretreatment of COD in refractory organic wastewater by Fenton oxidation will model the degradation kinetics as Ct=1296.317/(1+0.07343*t)^ 0.5;The amount of H2O2 has a significant effect on the effluent biochemical B/C,and the interaction between the factors has a significant effect on the effluent B/C.(3)The optimized experimental conditions of pretreatment microelectrolysis of Fe/C microelectrolysis-Fenton combined process are shown in conclusion(1);the optimized experimental conditions of Fenton oxidation process after microelectrolysis are:initial pH 3.089,dosage of H2O2 is 18.65 mL/L,reaction time 62.736 min.The effluent B/C is 0.524,COD removal rate is 82.95%.Fe/C micro-electrolysis-Fenton combined process for pretreatment of refractory organic wastewater,The model of COD degradation kinetics as Ct=e7.15747-0.01718*e0.02553t.The influence of the square terms of each factor is Fenton initial pH>time>dosage of H2O2.the interaction between each factor has no significant effect on the effluent B/C.(4)The Fe/C microelectrolysis-Fenton combined pretreatment process combines the advantages of Fe/C microelectrolysis and Fenton oxidation method,which is very considerable to improve the biodegradability of refractory organic wastewater.The wastewater B/C was increased from 0.262 to 0.524,and the COD removal rate reached 82.95%.The combined process reduces the sensitivity of Fenton oxidation to operating conditions,greatly reduces the water quality requirements of the Fe/C microelectrolysis-Fenton combined process to treat wastewater,and helps the development and application of the iron-carbon microelectrolysis-Fenton combined process in the water treatment industry. |
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