【作者】 邓晓；

【导师】 杨麒； 李小明；

【作者基本信息】 湖南大学 ， 环境工程， 2014， 硕士

【摘要】 随着人们生活水平的提高、城市化进程的加剧，污水处理行业快速发展。污泥产量日益增多。为了便于后续处理处置，降低污泥含水率，提高污泥脱水性能是很有必要的。本文研究了生物表面活性剂鼠李糖脂对污泥脱水及沉降性能的影响。并将鼠李糖脂对污泥脱水性能的影响与同为阴离子型的化学表面活性剂十二烷基硫酸钠（sodium dodecyl sulfate，SDS）进行了比较。此外，还研究了生物表面活性剂分别与阴离子化学表面活性剂SDS和阳离子化学表面活性剂溴化十六烷基三甲铵（cetyltrimethyl ammonium bromide，CTAB）复配对污泥脱水性能的。通过测定污泥CST （Capillary Suction Time，毛细吸水时间）、泥饼含水率等表征污泥脱水性能，同时测定Zeta电位、上清液EPS含量、浊度等分析了表面活性剂强化污泥脱水性能的机理。实验首先考察了鼠李糖脂不同投加量对污泥的脱水性能的影响。结果表明相对于原污泥，随着鼠李糖脂投加量的增大，越来越多的EPS (ExtracellularPolymeric Substances，胞外聚合物)从污泥表面脱落并溶入污泥液相中。低投加量的鼠李糖脂就能显著的降低污泥的表面张力。Zeta电位会随着鼠李糖脂投加量的增加而增大。鼠李糖脂的投加对污泥的脱水速率不能起到促进作用，但能使污泥脱水后的泥饼含水率更低。但并不是鼠李糖脂投加量越大，得到的泥饼含水率越低。鼠李糖脂最佳投加量为0.10g/gDS (本文中投加量以表面活性剂与干污泥重量比定义，单位g/gDS (Dry Sludge))。随后实验将鼠李糖脂与SDS对污泥脱水性能的影响做了比较。相比于鼠李糖脂，SDS在相同投加量时，CST值上升更高，脱水速率恶化得更严重。SDS相比于原污泥也能使污泥泥饼含水率降低，但相比较起来鼠李糖脂在更低的投加浓度达到了更好的脱水效果。当鼠李糖脂与SDS复配时，相比于单独添加各组分，复配使得污泥脱水速率恶化，但在鼠李糖脂与SDS复配比为3:1时，CST值与单独添加鼠李糖脂的相差不大。表面活性剂的投加都会使污泥泥饼含水率降低。相对于单独投加鼠李糖脂，鼠李糖脂与SDS复配在比例为3:1、2:1时，显著降低污泥离心后泥饼含水率。但当SDS占的比例超过一定比例范围时，泥饼含水率会逐渐变大。鼠李糖脂与阳离子化学表面活性剂CTAB复配比例为1:1、1:2、1:3时，相比于两者单独投加，无论是脱水速率（CST值）还是脱水程度（污泥脱水后泥饼含水率）都得到了很大的改善。并且随着复配体系中CTAB所占比例的增加，效果越明显。更多还原

【Abstract】 With the accelerating of the urbanization, as the by-product of the sewagetreatment, large amounts of municipal sewage sludge has been produced. In order tofacilitate the accompanying treatment and disposal of sludge, it is necessary todecrease the water content of sludge and improve the dewaterability.In this study, effect of biosurfactant rhamnolipid on dewaterability of activatedsludge has been investigated. And effects of rhamnolipid and the anionic chemicalsurfactant sodium dodecyl sulfate (SDS) on dewaterability of activated sludge havebeen compared. Besides, effect of biosurfactant co-conditioned with ordinarychemical surfactants, including SDS and cetyltrimethyl ammonium bromide (CTAB),on sludge dewaterability have also discussed. In this investigation, Capillary SuctionTime (CST) and the water content of dewatered sludge cakes were measured tocharacterize the sludge dewaterability, while Zeta potential, the ExtracellularPolymeric Substances (EPS) content in supernatant and turbidity were determined toanalyze the mechanism of the experimental phenomena.Firstly, effect of biosurfactant rhamnolipid on dewaterability of activated sludgewas investigated. The results show that more and more EPS was solubilized from thesurface of sludge flocs and dissolved into aqueous phase. The surface tension of thesludge could decreased significantly at low dosage. And Zeta potential increased withadding rhamnolipid. The dosage of rhamnolipid couldn’t improve the dewatering rateof activated sludge, while could decrease the water content of dewatered sludge cakes,The optimum dosage of rhamnolipid was0.10g/gDS (Dry Sludge). Then theexperiment compared effect of rhamnolipid with SDS on dewaterability of activatedsludge. Compared with rhamnolipid, SDS would deteriorate the dewatering rate moresignificantly, in terms of more increase of CST. Compared with the raw sludge,adding SDS could reduce the water content of dewatered sludge cakes too. Butcompared with activated sludge conditioned with rhamnolipid, rhamnolipid drew drierdewatered sludge cakes at the same concentration.Compared with adding any surfactant alone, the dewatering rate of the sludgepretreated with the combination of rhamnolipid and SDS deteriorated. When theproportion of the combination system was3:1, CST didn’t increase greatly comparedwith rhamnolipid alone. Compared with rhamnolipid alone, the water content of centrifuged sludge decreased significantly when the the combination rate ofrhamnolipid and SDS were3:1and2:1, and increased with the percentage of SDS incombination system rising. Compared with rhamnolipid or CTAB alone, thecombination of rhamnolipid and CTAB within proportions of1:2or1:3,could notonly decrease the water content of dewatered sludge cakes, but also improve thedewatering rate of activated sludge. And with the proportion of CTAB increasing, thedewaterability improved more obviously.更多还原