表面活性剂对污泥脱水性能的影响及其作用机理

Effect of surfactant on activated sludge dewaterability and its mechanism

研究了阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)和阴离子表面活性剂十二烷基硫酸钠(SDS)对活性污泥脱水和沉降性能的影响,及其改善活性污泥脱水效能的作用机理。结果表明,质量分数8%的CTAB可使污泥比阻(SRF)从8.5×1012m/kg降为7.5×1011m/kg,滤饼的含水率降至75%左右,污泥的沉降性能最好,上清液的浊度也较小。相比之下,SDS对污泥沉降、脱水性能的改善效果明显逊于CTAB。实验表明,表面活性剂主要是通过溶出胞外聚合物(EPS)破坏污泥结构释放内部结合水来加快污泥的沉降速度和提高其脱水性能。

The effects of a cationic surfactant（ CTAB） and an anionic surfactant（ SDS） on the dewaterability and settling performance of activated sludge were studied. The mechanism of the two surfactants in the activated sludge system was elucidated. The results indicated that the specific resistance to filtration（ SRF） decreased from 8. 5 × 1012 m / kg to 7. 5 × 1011 m / kg,and the water content in the remaining sludge cake after pumping filtration decreased from 99. 4% to 75% by adding 8% of CTAB,which resulted in optimal sludge settling and a lower supernatant turbidity of the activated sludge. In contrast,the settling performance and dewaterability by adding SDS were correspondingly worse. Further studies showed that the surfactant increased sludge dewaterability and improved the sedimentation rate as a result of stripping extracellular polymeric substances（ EPS） and damaging the internal structure of sludge,which released bound water.