无机絮凝剂对污泥屈服应力的影响研究

Effect of Inorganic Flocculant on Yield Stress for Sludge

污泥的流动行为对脱水、泵送、农业利用、土地填埋和焚烧具有重要影响。本文采用无机絮凝剂聚合氯化铝和氯化铁对污泥进行预处理,研究污泥絮凝剂对污泥流动行为的影响机理。同时采用三种不同方法分别计算污泥的静态屈服应力和动态屈服应力,以确定最佳的屈服应力确定方法。研究表明,污泥属于典型的非牛顿流体,具有触变特性。无机絮凝剂的添加提高了污泥絮体的强度,导致屈服应力和弹性模量显著增加,固相特性增强。对于具有触变性的污泥,根据剪切速率升高和下降的流动曲线分别计算得到的动态屈服应力相差较大,而由应变扫描实验得到的静态屈服应力值与动态屈服应力接近。

Rheology behavior has significant effect on dewatering,pumping,agricultural utilization,landfill and incineration. Inorganic flocculant including polyaluminium chloride and ferric chloride were employed to treat sludge for revealing its effect mechanism on rheological behavior. Three different measurements were introduced to determine the static and dynamic yield stress of various sludge samples. Results showed inorganic flocculant could improve floc strength,lead to higher yield stress and elastic modulus,indicat the significant solid behavior. For the sludge with thixotropy characteristics,there were significant differences between the dynamic yield stresses which were obtained from rheogram of increased shear rate and decreased,respectively. And the static yield stress obtained from strain sweep was similar with the dynamic.