Fenton氧化对制浆造纸废水分子量及可生化性变化的影响

以制浆造纸废水的初沉池出水为研究对象,对不同剂量的Fenton氧化试剂处理制浆造纸厂初沉废水的效果进行了研究,初沉废水中的分子量大于10 000的有机污染物含量占到83%,废水可生化性较差;在Fe2+与H2O2的摩尔比为1∶5,废水pH为3.5的条件下,H2O2(30%)投加量小于3.25 mL/L时,Fenton试剂的氧化效率更高;H2O2(30%)投加量为6.50 mL/L时,废水中污染物的去除率更高,其中废水COD的去除率为79.5%,AOX的去除率为75.3%,色度去除率为97.5%,同时处理后废水中分子量在500~3 000之间的有机物含量占到82.98%,废水的BOD5/COD值提高到0.56。Fenton氧化作为前置技术处理制浆造纸废水,可以降低废水中的有机物分子量,减少废水的生物毒性,增加废水生物降解性,有助于后续生物处理的正常运行。

Effect of Fenton oxidation on biodegradability and molecular weight changes of wastewater

The oxidation viability of primary clarifier effluent of pulp and paper making wastewater with different dosage of Fenton reagent was studied in this work. The organic pollutants with molecular weight greater than 10 000 were accounted for 83% in the primary clarifier effluent and their biodegradability was worse. Under the conditions of pH of 3.5, the Fe²⁺:H₂O₂ mole ratio of 1:5,the H₂O₂(30%) dose of lower than 3.25 mL/L,the Fenton reagent showed higher oxidation efficiency. When the dose of H₂O₂(30%) increased to 6.50 mL/L, over 79.5% of COD abatement, 75.3% of AOX (absorbable organic halogen) reduction, 97.5% of chroma decrease achieved and the pollutants of low molecular weight at the range of 500~3 000 were accounted for 82.98% of the total in the effluent, while the ratio of BOD₅/COD increased to 0.56. As a pre-oxidation process for the treatment of pulp and paper making wastewater, Fenton oxidation can decrease the molecular weight of organic matters in pulp and paper wastewater and the toxicity of wastewater, and then consequently results the increments of the wastewater biodegradability and stable operation of subsequent bio-process.