活性污泥固定化、改性及对生活污水的处理

通过正交设计,以COD去除率为考核指标对固定化载体聚乙烯醇(PVA)、海藻酸钠(SA)与活性污泥的配比进行参数优化;使用硫酸钠、硝酸钠、磷酸钠为交联剂对固定化颗粒进行二次交联改性,研究其污水处理效果,探究在不同温度和pH值条件下固定化活性污泥对生活污水的处理效果及其稳定性。结果表明,固定化活性污泥对生活污水中的COD、NH4+-N、TP处理效果优于普通活性污泥,且固定化活性污泥颗粒运行稳定,20 d仍有较好的污水处理效果;正交试验结果显示,固定化活性污泥的适宜固定化载体浓度及污泥配比为质量分数8%聚乙烯醇(PVA)、2%海藻酸钠(SA)、质量分数50%活性污泥(普通活性污泥与包埋剂质量比1∶1)。经过二次交联的固定化活性污泥提高了污水处理效果,硫酸钠作为二次交联剂效果最好,污水中COD、NH4+-N和TP的去除率达93.5%、92.3%、78.0%;经固定化后活性污泥对温度和pH值的适应范围变宽,在温度低于4℃高于40℃、pH≤5和pH≥9仍然有较好的处理效果,去除效果均比普通活性污泥提高10%以上。

Immobilization and modification of activated sludge and its domestic sewage treatment

This paper is engaged in a study of the effect of immobilized activated sludge on treating the domestic sewage and its running stability. By means of the orthogonal design,it has optimized the ratio of immobilized carriers,the polyvinyl alcohol(PVA) and the sodium alginate( SA),to the activated sludge with the COD removal rate being taken as the evaluation index.At the same time,the paper has also studied the sodium sulfate,sodium nitrate and sodium phosphate by using the secondary cross-linking modified immobilized sludge as the cross-linking agents according to the different temperatures and the p H conditions,its domestic sewage treatment effect. The results of the above experiments indicate that the immobilized activated sludge is endowed with better treatment effect of COD,NH4+-N and TP than the ordinary activated sludge,whereas the immobilized activated sludge particles can also bring about stable treatment effect. What is more,20 days later after the treatment,it could be expected for the removal efficiency ratio of COD,NH4+-N and TP in the domestic sewage treated to reach 76. 2%,76. 6%and 71. 3%,respectively. What’s more,the orthogonal testing results also prove that,when the ratio stays at a mass fraction of 8. 0% PVA and 2. 0% SA to 50% with the activated sludge( mass ratio of ordinary activated sludge to embedding agent 1:1),it can be expected to gain the best sphere forming effect,with high mechanical strength,nice elasticity with no tailing residue. Moreover,through the secondary cross-linking modification,it can be expected to improve the sewage treated effect of the immobilized activated sludge. And,particularly speaking,when the sodium sulfate is used as the secondary cross-linking agent,it can be expected for the sludge to gained the best removal rates of COD,NH4+-N and TP in treating the domestic sewage, say, up to the percentages of 93. 5%, 92. 3% and78. 0%,respectively. Besides,the immobilized activated sludge can also enjoy better adaptability to the different temperatures and p H values. For instance,when the temperature is lower than 4 °C and higher than 40 °C,the p H value can be equal or lower than 5 as well as equal or more than 9,still keeping nice treatment effect. And,in addition,the removal effect can still be expected to be over 10% higher than that of the ordinary activated sludge.